Questions and Answers in Community Dentistry
Questions and Answers in Community Dentistry
Questions and Answers in Community Dentistry
Community Dentistry
Questions and Answers in
Community Dentistry
Mamatha GS BDS
Lecturer
Department of Preventive and Community Dentistry
Dr DY Patil Dental College and Hospital, Pimpri
Pune, India
RS Dolas
Dean
Professor
Department of Oral and Maxillofacial Surgery
Dr DY Patil Dental College and Hospital, Pimpri
Pune, India
Preface
There exist quite a many comprehensive books in the field of Preventive and
Community Dentistry, and more and more published year on year; what is
not easily accessible, is in fact a good compilation of the key topics to prepare
for taking Under Graduate exam in the subject of Preventive and Community
Dentistry.
With this very thought in mind, the journey to publish a good consolidation
of the key topics began. The objective was to progress and achieve success on
the following two axesFirst: Focus on the key topics, filtered and well aligned
with the University syllabus. Second: Provide answers to the filtered questions
with simplistic precision, making it easy to understand as well as grasp with
ease.
We hope that this compilation will provide you as a student, an easy access
to informative material useful for the examination. Accept our best wishes
and good luck for your examination and future.
Pradnya Kakodkar
Mamatha GS
Acknowledgments
We begin to look back at all the support members who helped us fulfill our
noble objective of writing this book in the interest of the students.
At the very beginning, we wish to offer our heartfelt thanks to Dr RS Dolas,
Dean, Dr DY Patil College and Hospital, Pimpri, Pune, India for his perennial
cooperation and support.
Dr Sahana Hegde Shetiya, Head of the Department, Preventive and
Community Dentistry who had been extremely supportive and has always
given her apt and timely feedback. This helped us immensely during our
endeavor. We also wish to offer thanks to all our fellow colleagues in the
department for lending us their helping hand all throughout
Special thanks to our dear friend Dr Aswini S (Community Dentist) who
was very helpful during the manuscript preparation.
Words fall short when it comes to acknowledging the unceasing support
and encouragement of our family members and friends. At every juncture
they were there nothing would have been probably possible without them.
Last but not the least, this book would not have been possible without the
support of Shri Jitendar P Vij (Chairman and Managing Director) of M/s Jaypee
Brothers Medical Publishers (P) Ltd. and Dr Shekhar Arora who helped us
build the collaboration. Also, the efforts of Mr Tarun Duneja (Director
Publishing), Mr KK Raman (Production Manager), Mr Pawan Kishor Tiwari
(Proof Reader), Mr Abhinay Kumar Nigam (DTP Operator) and the entire
dedicated team at the publishing house can simply not be fathomed.
A sincere thanks to all of them who have helped us achieve this milestone.
Contents
QUESTIONS
1. Define public health.
2. Discuss the changing concepts in public health.
3. Characteristics of public health method.
4. Principles/Guidelines followed in dental public health practice.
5. Characteristics of public health techniques.
6. Define dental public health.
7. Functions of public health dentist.
8. a. Procedural steps in dental public health.
b. Define community.
9. Tools of dental public health.
10. Similarities between public health dentist and private dentist.
11. Differences between public health dentist and private dentist.
ANSWER 1
Public health is defined as: The art and science of preventing disease,
prolonging life and promoting physical and mental efficiency,
through organized community efforts; for the sanitation of the environment,
the control of communicable infections, the education of the individual in
the personal hygiene, the organization of medical and nursing services
for the early diagnosis and preventive treatment of disease and the
development of the social machinery to ensure everyone a standard of living
adequate for the maintenance of health, so organizing these benefits so as to
enable every citizen to realize his birth right of health and longevity.
Winslow (1920).
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ANSWER 2
Changing Concepts in Public Health
1. Disease control phase (18801920): Mainly aimed to control mans physical
environment, e.g. water supply, sewage disposal, etc. Measures were not
aimed to control specific disease but improve the health of the people due
to disease and death.
2. Health promotional phase (19201960): It is realized that the public health
had neglected the citizen as an individual, to overcome this, one more
goal was added, along with disease control activities, i.e. health promotion
of individuals. As a beginning, personal health services such as Mother
child health services, School health services, and Industrial health services
were initiated. This program was further expanded, which included:
a. Provision of basic health services through Primary Health Centers and
sub-centers for rural and urban area.
b. Community development program to promote village development
through the active participation of whole community. However, this
failed due to inadequate resources.
3. Social engineering phase (19601980): Many of the acute illness problems
were solved but new health problems began to appear, as the preventive
medicine and practice of public health advanced. Chronic disease like
diabetes, cardiovascular disease, cancer, alcoholism, etc. began to emerge
in developed world. These could not be solved by isolation, immunization
and disinfections. A new factor risk factors as determinants of these
diseases came into existence. Social and behavioral aspects of disease and
health were given new priority.
4. Health for all phase (19812000 A.D): Most people in the developed
countries enjoy all the determinants of good health, in contrast only 10
20% in developing countries have access to health services. It was
concluded that the neglected 80% of the world population have an equal
claim to health care, protection from killer diseases of childhood and to
the primary health care for mothers and children. Against this background,
in 1981, the members of WHO pledged themselves to an ambitious target
to provide Health for all by the year 2000; i.e. attainment for all of a
level of health that will permit all people to lead a socially and
economically productive life. Here, services were moved from control of
communicable diseases to preventive, therapeutic, rehabilitative aspects
of chronic disease and behavioral disorders, organization of medical care,
safe drinking water, sanitation, nutrition, education, adequate income and
comprehensive health care.
Public Health and Dental Public Health / 3
ANSWER 3
Characteristics of Public Health Method
1. Group responsibility.
2. Team work.
3. Prevention. (It is a major objective because it is ethical, involves team work
and is cost effective).
4. Counteracting medical indigence.
5. Dealing with multifactorial problem (using the science of epidemiology
and biostatistical methods).
6. Deals with healthy or apparently healthy people as well as the sick.
7. Health education of the public.
8. Social sciences.
9. Logistics.
10. Insurance/payment.
ANSWER 4
(Same as answer 3).
ANSWER 5
Characteristics of Public Health Techniques
The important techniques are:
1. Use of health center,
2. Case finding and
3. Use of community health council.
1. Health center: These are community buildings to house health
administration and a number of out-patient or preventive services not easily
housed in a hospital. Usually each center is for 50,000 to 1,00,000 population.
Large cities will have many centers. A variant of this health unit in some
countries are school based dental clinics.
2. Case finding: It is also called Screening. The objective of this is to search
the diseases in the community in their early stage through simple tests.
4 / Questions and Answers in Community Dentistry
ANSWER 6
The Council on Dental Education of the American Dental Association has
defined dental public health as: The science and art of preventing and
controlling dental diseases and promoting dental health through organized
community efforts. It is that form of dental practice, which serves the
community as a patient rather than the individual. It is concerned with the
dental health education of the public, with applied dental research, and with
the administration of group dental care programs, as well as the prevention
and control of dental disease on a community basis.
ANSWER 7
Functions of Public Health Dentist
1. Conduct health education programs to create awareness among people.
2. Educating and motivating an individual or community to utilize rendered
dental services.
3. To organize dental camps and delivering dental services for the needy
like people in rural areas, orphanages, mentally/physically compromised
children, etc.
4. Conducting school dental health programs and providing preventive
dental care to the school children like topical fluoride applications, pit and
fissure sealants.
5. Conducting dental treatment camps and providing treatments like
extractions, oral prophylaxis, fluoride applications, simple restorations,
ART, etc. in schools or in community for general public.
6. Updating the knowledge of people regarding new dental preventive
methods and procedures.
7. Conducting surveys to collect baseline data, know the nature and extent
of the diseases in the community and plan programs accordingly, to
decrease the incidence of the diseases.
8. Conducting dental public health activities and field experiences for dental
students and dental nursing students.
Public Health and Dental Public Health / 5
ANSWER 8A
Procedural Steps in Dental Public Health
1. Survey: Surveys are methods for collection of data, analyzing and
evaluating them in order to determine the amount of disease problems in
a community and also to identify cases that have not been identified.
2. Analysis: It is necessary to arrange or organize the data collected from the
survey in such a way that meaningful figures are obtained. Analysis can
be done manually or using computers.
3. Program planning: After analyzing the problem, the next step is program
planning. The objective is to design the plan so that it is accepted by the
community and in which they are interested in, which is comprehensive
and cheaper. It has to be ensured that the community is well informed
about the program so that they participate in all the steps involved.
4. Program operation: Execution of the program once the plan has been
accepted. A public health team, which constitutes of professionals in
various disciplines, has to be employed for executing the program.
Example: Water fluoridation, which includes a team of dentists, engineers,
chemists, water works department, public health authorities.
5. Financing: Financing in public health program is usually through the
government or by the local or state authorities. Before planning a program,
public health personnel should identify the source of funds and also plan
for management of the same.
6. Program appraisal: Final step in any public health program where
effectiveness of the program is assessed. The baseline data prior to the
introduction of the program serves as an indicator against the effectiveness
of the program after the implementation. The criteria for evaluation are
appropriateness, adequacy, effectiveness and efficiency.
ANSWER 8B
A community is a definite group of people or population having common
organization, living in the same region or area following similar rules and
regulations under the same environment.
ANSWER 9
Tools of Dental Public Health
1. Epidemiology: Epi = upon, demos = people, logos = science.
Is defined as the study of the distribution and determinants of health
6 / Questions and Answers in Community Dentistry
related states and events in population and the application of the study to
the control of health problems. It aims to minimize or eradicate the disease
or health problem and its consequences and to minimize the chances of its
occurrence in future. It also helps to define the magnitude and occurrence
of disease in man, identify the etiologic factors and provide necessary data
for planning, implementation and evaluation of programs for preventing,
controlling and treating diseases.
2. Biostatistics: Is a branch of statistics concerned with mathematical facts
and data relating to the biological events. It involves compiling, analyzing,
tabulating and representing the data in the mathematical or graphical
manner. It gives the correlation or association between two attributes.
3. Social sciences: It includes sociology, cultural anthropology, social
psychology, economics and political science. Public health worker when
emphasizes on organized community effort, it is necessary to know the
group behaviors of individuals, their culture, customs and habits etc. Social
scientists are the persons, who play an important role in understanding
the group behavior and are necessary to match effort and effect.
4. Principles of administration: There are two main divisions in
administrative work: Organization and Management.
a. Organization: Which deals with the structure of an agency and the way
people are arranged into groups within it.
b. Management: Concerned with the handling of personnel and operations
in such a way that the work of the agency gets done.
5. Preventive dentistry: Prevention is better then cure, so prevent the disease
before it starts. Different levels of prevention are:
a. Primary prevention: Health promotion (Health education, lobby efforts
and research) and Specific protection is protecting the oral cavity from
disease before it occurs. (water fluoridation, plaque control,
immunization).
b. Secondary prevention: Disease is in its initial stages. Includes Early
diagnosis and prompt treatment (simple restorations, scaling).
c. Tertiary prevention: Disease is in advanced stage which includes
disability limitation (e.g. Root canal treatment, extractions and
rehabilitation, e.g. removable or fixed prosthesis, implants, maxillofacial
prosthesis).
Public Health and Dental Public Health / 7
ANSWER 10
Similarities Between Public Health Dentistry and Clinical Dentistry
ANSWER 11
Differences Between Private Dental Practice and Public Health Dentistry
QUESTIONS
1. Define health.
2. Explain the changing concepts of health.
3. Dimensions of health.
4. Spectrum of health.
5. Indicators of health.
6. Determinants of health.
7. Concepts of disease causation.
8. What is meant by tenet of epidemiology?
9. Explain the term Natural history of disease.
10. What is iceberg of disease?
11. Incubation time.
12. Epidemiological triad.
13. Risk factor.
14. Risk groups/Risk approach.
15. Mortality.
16. Morbidity.
17. Tooth mortality.
18. Spectrum of disease.
ANSWER 1
Health is a state of complete physical, mental and social well-being and not
merely an absence of disease or infirmity given by WHO in 1948.
ANSWER 2
Changing Concepts of Health
In a world of continuous changes new concepts are bound to emerge based
on new patterns of thought. Health has evolved over centuries as a concept
Health and Disease / 9
from an individual concern to a world wide social goal. The brief account of
the changing concepts of health is as follows.
1. Biomedical concept: This concept has its basis in the germ theory of diseases
which dominated medical thought at the turn of the 20th century. The
medical profession viewed the human body as a machine, disease as a
consequence of breakdown of the machine and one of the doctors task as
repair of the machine. Thus health in this narrow view was termed as
absence of disease. This concept minimized the role of environment, social,
physiological and cultural determinants of health. Developments in
medical and social sciences led to the conclusion that biomedical concept
of health was inadequate.
2. Ecological concept: The ecologists put forward an attractive hypothesis
which viewed health as a dynamic equilibrium between man and his
environment and disease as maladjustment of the human organism to
environment.
3. Psychosocial concept: Contemporary development in social sciences
revealed that health is not only a biomedical phenomenon but one which
is influenced by social, psychological, cultural, economic and political
factors of the people concerned. These factors must be taken into
consideration in defining and measuring health. Thus health is both a
biological and social phenomenon.
4. Holistic concept: It is a synthesis of all the above mentioned concepts. It
recognizes the strength of social, economic, political and environmental
influences on health. This implies a sound mind in a sound body in a sound
family in a sound environment. It implies that all sectors of society have a
effect on health.
ANSWER 3
Health is multidimensional. The various dimensions function individually in
its own nature and interact with one another and thus constitutes to health.
Dysfunction or disturbance in the equilibrium of the various factors will alter
the health. The different dimensions of health are:
Physical Dimension
It is probably the easiest to understand. It conceptualizes health biologically
as a state in which every cell and every organ is functioning at optimum
capacity and in perfect harmony with the rest of the body. The signs of physical
health in an individual are: A good complexion, clear skin, bright eyes, lustrous
10 / Questions and Answers in Community Dentistry
hair with a body well clothed with firm flesh not too fat, a sweet breath, good
appetite, sound sleep, regular activity of bowel and bladder, smooth and easy
coordinated bodily movements and all the organs and other bodily activities
are within the range of normality for the individuals age and sex.
Mental Dimension
The mental health has been defined as a state of balance between the individual
and the surrounding world, a state of harmony between oneself and others, a
co-existence between the realities of the self and that of the other people and
that of the environment. The mind and body were considered independent
entities but however researchers have discovered that psychological factors
can induce all kind of illness, not simple mental ones.
Social Dimension
Social well being implies harmony and integration within the individual,
between each individual and other members of society and between
individuals and the world in which they live. It includes the levels of social
skills one possesses, social functioning and the ability to see oneself as a
member of the larger society. Social health is routed in positive material
environment and positive human environment which is concerned with
the social network of the individual.
Spiritual Dimension
Spiritual health in this context refers to that part of the individual which reaches
out and strives for meaning and purpose in life. Proponents of holistic health
believe that time has come to give serious consideration to the spiritual
dimension and to the role this plays in health and disease. Spiritual health is
the intangible something that transcend physiology and psychology.
Emotional Dimension
Historically the mental and emotional dimensions have been seen as one
element or as two closely related elements. However as more research becomes
available, a definite difference is emerging. Mental health can be seen as
knowing or cognition while emotional health relates to feelings.
Vocational Dimension
It is a new dimension. It is part of human existence and plays a role in
promoting both physical and mental health. The importance of this dimension
Health and Disease / 11
Others
A few other dimensions have also been suggested such as: philosophical
dimension, cultural dimension, socio-economical dimension, environmental
dimension, educational dimension, nutritional dimension, curative dimension,
and preventive dimension.
ANSWER 4
Health and disease lie along a continuum and there is no single cut-off point.
The lowest point on the spectrum is death and the highest point is the positive
health (Fig. 2.1). The spectral concept of health emphasizes that the health of
an individual is not static, it is a dynamic phenomenon and a process of
continuous change within a range of optimum well being to various levels of
dysfunction, including the state of total dysfunction namely the death. What
is considered maximum health today may be considered minimum tomorrow.
It implies that health is a state not to be attained once and for all but ever to be
renewed.
ANSWER 5
Indicators of health are required not only to measure the health status of the
community but also to compare the health status of one country with that of
the another for assessment of healthcare needs, for allocation of scarce
resources and for monitoring and evaluation of health services, activities and
programs. Since health is multidimensional there are a number of indicators
which may be classified as:
12 / Questions and Answers in Community Dentistry
1. Mortality indicators.
2. Morbidity indicators.
3. Disability rates.
4. Nutritional status indicators.
5. Health care delivery indicators.
6. Utilization rates.
7. Indicators of social and mental health.
8. Environmental indicators.
9. Socio-economic indicators.
10. Health policy indicators.
11. Indicators of quality of life.
12. Other indicators (e.g. social indicators, basic needs indicators and health
for all indicators).
ANSWER 6
Health is multi-factorial. The factors which influence health lie both within
the individual and externally in the society in which he or she lives. These
factors interact and these interactions maybe health promoting or deleterious.
The most important determinants of health are heredity, environment, lifestyle,
socio-economic conditions, health and family services and other factors.
1. Heredity: The physical and mental traits of every human being are to some
extent determined by the nature of his/her genes at the moment of
conception. The genetic makeup is unique and it can not be altered after
conception. A number of diseases are known to be of genetic origin, e.g.
chromosomal anomalies, errors of metabolism, mental retardation, some
type of diabetes, etc. The state of health therefore depends partly on the
genetic constitution of man.
2. Environment: Environment is classified as internal and external. Internal
environment of man pertains to each and every component, part, tissue,
organ and their harmonious functioning within the system. The external
or Macro environment consists of those things to which the man is
exposed after conception (all that which is external to the individual human
host). These can be divided into physical, biological and psycho-social
components all of which can affect the health of man and his susceptibility
to illness. There is this other term, Micro environment which includes
individuals way of living and lifestyle, e.g. eating and other habits.
The environmental factors play a very important role in determining health
of the individual.
Health and Disease / 13
3. Lifestyle: Lifestyle means the way people live and this reflects the social
values, attitudes, activities, culture, behavioral patterns and personal habits.
Health requires the promotion of healthy lifestyles. Many current day
health problems like obesity, lung cancer, drug addiction, heart disease,
diabetes are associated with lifestyle changes.
4. Socioeconomic conditions: For years health has been a privilege and not a
right. Socioeconomic conditions have long been known to influence health.
a. The per capita GNP is the most widely accepted measure of general
economic performance. The economic status determines the purchasing
power, standard of living, quality of life, family size, health care and
the pattern of disease in the community. Ironically affluence may also
be a contributing cause of illness, e.g. coronary heart disease, diabetes
and obesity in upper socio economic groups.
b. Education: The second major factor influencing health status is
education. The world map of illiteracy closely coincides with the maps
of poverty, malnutrition, ill health and high child mortality rates.
Studies indicate that education to some extent compensates the effects
of poverty on health. Kerala in India is a striking example of highest
literacy rate and lowest infant mortality rate.
c. Occupation: The very state of being employed in productive work
promotes health. For many, loss of work may mean loss of income and
status. It can cause psychological and social damage.
d. Political system: Health is also related to countrys political system. The
resources allocation, manpower policy, choice of technology and the
degree to which health services are made available to different sects of
people are governed by the political system. If the health pattern of the
community has to be changed, the political as well as social and
economical actions are required.
5. Health and family welfare services: The term Health and family welfare
services cover a wide spectrum of personal and community services for
treatment of diseases, prevention of illness and promotion of health. The
purpose of health services is to improve the health status of the population.
E.g. immunization of children, safe drinking water, care of pregnant
women, etc are all part of health services which must reach the social
periphery, should be equally distributed, accessible at a cost which the
country and community can afford and socially acceptable. All these are
ingredients of what is now termed as primary health care.
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ANSWER 7
Concepts of Disease Causation
1. Germ theory of disease: This concept gained momentum during the 19th
and the early part of 20th century. The emphasis had shifted from empirical
causes (e.g. bad air) to micro organisms as the sole cause of disease. The
disease model was referred to as one to one relationship between causal
agent and disease.
Disease agent Man Disease
The realization that disease is rarely caused by a single agent alone
and multiple factors are responsible, leads the germ theory of disease to
be obsolete.
2. Epidemiological triad: This encompasses a broader concept of disease
causation. It includes factors like the agent, the host and the environment.
A new dimension of time factor is also included, which makes it an
epidemiological tetrad. This model has helped epidemiologists to focus
on different classes of factors, especially with regards to infectious disease.
3. Multifactorial causation: Pettenkofer of Munich was an early proponent
of the concept that disease is due to multiple factors. The modern days,
diseases like lung cancer, bronchitis, chronic heart diseases, mental illness
etc. could not be explained on the basis of the germ theory and that there
are often other factors like social, cultural, economical, genetic,
psychological, etc. which play a role in disease occurrence. This theory
de-emphasizes the concept of disease agent and stresses multiplicity of
interactions between host and environment. This multifactorial concept
offers multiple approaches for the prevention/control of disease.
4. Web of causation: This model of disease causation was suggested by
Macmohan and Pugh. This model is ideally suited in the study of chronic
diseases where the disease agent is often not known but is the outcome
of interaction of multiple factors. It considers all the predisposing factors
of any type and their complex inter relationship with each other. The web
Health and Disease / 15
ANSWER 8
The basic tenet of epidemiology refers to the study of the clusters of causes
and the combination of effects and how they relate to each other.
ANSWER 9
The term Natural history of disease is a key concept in epidemiology. It
signifies the way in which disease evolves over the time from the earlier stage
of its prepathogenesis phase to its termination as recovery and disability or
death. This can be studied under two phases.
1. Prepathogenesis phase: This refers to the period before the onset of disease
in man. The disease agent has not yet entered man but the factors which
favor its interaction with the human host are already existing in the
environment. This situation is frequently referred to as Man in the midst
of disease or Man exposed to the risk of disease.
16 / Questions and Answers in Community Dentistry
2. Pathogenesis phase: This phase begins with the entry of the disease agent
in the susceptible human host. The further events in the pathogenesis phase
include disease agent multiplication, physiological changes, progression
of disease through a period of incubation and later through early and late
pathogenesis. The final outcome of the disease may be recovery and
disability or death. The pathogenesis phase could be modified by
intervention measures such as immunization and chemotherapy.
ANSWER 10
ANSWER 11
Incubation Period
It is defined as the time interval between invasion by an infectious agent and
appearance of the first sign and symptom of the disease in question.
The incubation period varies for different infectious diseases and also from
one person to another with the same disease. In some, incubation period is
very short. The length of incubation period is characteristic of each disease.
Health and Disease / 17
ANSWER 12
Epidemiological Triad (Fig. 2.4)
This encompasses a broader concept of disease causation. It includes factors
like the agent, the host and the environment. These factors should interact
over a period of time for the disease to occur.
Agent
The disease agent is defined as a substance living or non-living, or a force,
tangible or intangible, the excessive presence or relative lack of which may
initiate or perpetuate a disease process.
Disease agents may be classified broadly into the following groups:
1 Biological agents: These are living agents of diseaseviruses, rickettsiae,
fungi, bacteria, protozoa and metazoa. The occurrence of the disease is
based on the infectivity, pathogenicity and virulence of the organism.
18 / Questions and Answers in Community Dentistry
Host
In epidemiological terminology, the human host is referred to as soil and the
disease agent as the seed. The host factors may be classified as:
1. Demographic characteristicse.g. age, sex, ethnicity, residence,
occupation, etc.
2. Biologicale.g. genetic, biochemical, immunological, physiological, etc.
3. Social and economic factors.
4. Lifestylee.g. nutrition, personality traits, habits, alcohol, exercise, etc.
The association of a particular disease with a specific set of host factors
frequently provide an insight into the cause of the disease.
Environment
The external or the macro-environment is defined as all that which is external
to the individual human host, living and non-living and with which he is in
constant interaction.
1. Physical environment: It is applied to non-living things and physical factors
(air, water, soil, housing, etc.)
2. Biological environment: It is the universe of the living things which
surrounds man, including man himself. The living things are the viruses
and other microbial agents, insects, rodents, animals and plants . These
are constantly working for the survival and in this process, some of them
Act as disease-producing agents, reservoirs of infection, intermediate hosts
and vectors of disease.
3. Psychosocial environment: It includes a complex of psychosocial factors
which are defined as those factors affecting personal health, health care
Health and Disease / 19
and commonly well being that stem from the psychosocial make up of
individuals and structure and functions of social groups. They include
cultural values, customs, beliefs, attitudes, morals, religion, education,
lifestyle, community life, healthcare services, social and political
organization.
A stable and a harmonious equilibrium between man and his
environment is needed to reduce mans vulnerability to disease and to
permit him to lead a more satisfying and a productive life.
ANSWER 13
Risk Factor
When the disease agent is not firmly identified, the etiology of a disease is
generally discussed in terms of risk factors. They are often suggestive, but not
a absolute proof of cause and effect relation. The risk factors may be truly
causative (e.g. smoking and lung cancer), they may be merely contributory to
the undesired outcome (e.g. lack of exercise is a risk factor for coronary heart
disease), they may have a additive or synergistic effect (e.g. alcohol exerts
synergistic effect with tobacco in the occurrence of oral cancer), or they may
be predictive in the statistical sense (e.g. illiteracy for perinatal mortality).
Some risk factors may be modified and thus can help in the process of
prevention, while some cannot be modified (e.g. age, sex, race, family, genetic
factors, etc.). Epidemiological methods are needed to identify risk factors and
estimate the degree of risk.
ANSWER 14
In risk approach strategy the care is first directed towards the identified
risk groups or target groups who need more care and attention, unlike the
20 / Questions and Answers in Community Dentistry
population strategy, where the resources are directed towards the whole
population. This kind of approach helps in saving the resources and also
attending those people who need urgent care. The guidelines for defining at
risk groups are:
1. Biological situation
Age groups: Infants, toddlers, geriatric population.
Sex: Females in the reproductive age.
Physiological state: Pregnancy, cholesterol levels, high blood pressure.
Genetic factors: Family history of genetic disorder.
Other health conditions: Disease, physical malfunctioning, unhealthy
behavior.
2. Physical situation
Unhealthy living conditions, locality (rural, urban slums), overcrowding.
Environmental conditions: Poor water supply, proximity to industries.
3. Socio-cultural and cultural situation
Social class: Lower socio-economic class
Customs: Harmful to health.
Lifestyles: Consuming high cholesterol diet, increased sugar consumption,
etc.
Habits: Those smoking, chewing tobacco, alcohol users, etc.
Lack of education and lack of access to healthcare.
ANSWER 15
Mortality (Death)
Mortality indicators represent the traditional measures of health status. They
are probably the most often used indirect indicators of health. The mortality
indicators are:
Crude death rate
Expectation of life
Infant mortality rate
Child mortality rate
Maternal mortality rate
Disease specific mortality rate
Proportional mortality rate.
ANSWER 16
Morbidity is defined as any departure, subjective or objective, from a state of
physiological well being. According to Dorland, it is the condition of being
diseased or morbid. The morbidity indicators are:
Health and Disease / 21
ANSWER 17
Tooth Mortality
It is the number of teeth lost divided by total number of the teeth present.
ANSWER 18
Spectrum of Disease (Fig. 2.5)
It is a graphical representation of variations in the manifestations of disease.
It is similar to the spectrum of light where the colors vary from one end to
the other, but difficult to determine where one color ends and the other be-
gins. At one end of the disease spectrum are subclinical infections which are
not ordinarily identified and at the other end are the fatal illnesses. In the
middle of the spectrum lie illnesses ranging in severity from mild to severe.
These different manifestations are simply reflections of individuals differ-
ent states of immunity and receptivity. In infectious diseases, the spectrum
of diseases, is also referred to as the gradient of infection.
3 General
Epidemiology
LONG QUESTIONS
1. Define epidemiology. Aims of epidemiology and uses of epidemiology.
What are the different types of epidemiological studies?
2. Describe the procedural steps in descriptive epidemiology.
3. Compare and contrast the retrospective and prospective studies.
4. Experimental epidemiology.
5. How do you design an epidemiological investigation? Write a note on
scientific method in epidemiology.
SHORT NOTES
6. Tools of measurements.
7. Incidence.
8. Prevalence.
9. Cross-sectional study.
10. Longitudinal study.
11. Bimodality.
12. Case control study.
13. Cohort study.
14. Bias.
15. Odds ratio. (Refer Ans 12)
16. Attributable risk. (Refer Ans 13)
17. Relative risk. (Refer Ans 13)
18. RCT (Randomized control trials).
19. Blinding.
20. Analytical studies.
21. Non-randomized control trials.
22. Epidemic.
General Epidemiology / 23
23. Pandemic.
24. Exotic.
25. Zoonosis.
26. Epizootic.
27. Endemic.
28. Surveillance.
29. Quarantine.
30. Cohort.
31. Principles of epidemiology.
32. Confounding factor.
33. Epidemiologist.
ANSWER 1
John M. Last (1988) defined epidemiology as the study of the distribution
and determinants of health related states or events in specified population
and the application of this study to the control of health problems.
Aims of Epidemiology
The International Epidemiological Association has listed three main aims of
epidemiology, which was put forward by Lowe and Kostrzewski in 1973 as
follows:
To describe the size and distribution of the disease problems in human
populations
To provide the data essential for planning, implementation and evaluation
of health services for the prevention, control and treatment of disease and/or
setting up priorities among those services
To identify etiological factors in the pathogenesis of disease.
Uses of Epidemiology
To study historically the rise and fall of disease in the population
To identify and quantify the health problems in a community
The epidemiological data is used for planning, developing and evaluation
of the health services
To evaluate the degree of individuals risk for the disease
Syndrome identification
To study the disease pattern in the community
To identify the cause and the risk factors of the disease.
24 / Questions and Answers in Community Dentistry
ANSWER 2
The procedures involved in descriptive study are as follows:
1. Defining the population to be studied.
2. Defining the disease under study.
3. Describing the disease.
4. Measurement of disease.
5. Comparing with known indices.
6. Formulation of etiological hypothesis.
Time Distribution
The epidemiologists have identified three kinds of time trends or fluctuations
in disease occurrence.
1. Short-term fluctuations.
2. Periodic fluctuations.
3. Long-term fluctuations.
1. Short-term fluctuations: The epidemic is the best known example for short
term fluctuation. The three major types of epidemics may be distinguished
as:
a. Common source epidemics
b. Propagated epidemics
c. Slow epidemic
a. Common source epidemics or point source epidemics:
i. Single exposure: These are known as point source epidemics. The
exposure of diseased agent is brief and essentially simultaneous;
the resultant cases all develop within one incubation period, e.g.
food poisoning.
ii. Continuous or multiple exposures: Some times the exposure from
same source may be prolonged, continuous repeated or intermittent-
not necessarily at the same time or place, e.g. contaminated well
water.
b. Propagated epidemics: It is most often of infectious origin and results
from arthropod vector/animal reservoir/person to person transmission
of an infectious agent, e.g. epidemics of hepatitis A and polio.
c. Slow epidemic: This is well known for non-communicable diseases which
are lifestyle related, e.g. diabetes, ischemic heart disease, obesity, etc.
These conditions take a long time to manifest and are slowly progressive
in nature.
2. Periodic fluctuations
a. Seasonal trend: It is well known for many communicable diseases. The
seasonal variations of disease occurrences may be related to
environmental condition, e.g. temperature, humidity, rainfall,
overcrowding, life cycle of vectors, etc. which directly or indirectly
favor disease transmission, e.g. measles is common in early spring,
upper respiratory diseases is common in winter, gastrointestinal
infection common in summer.
26 / Questions and Answers in Community Dentistry
b. Cyclic trend: Some diseases occur in cycles spread over short periods of
time which may be days, weeks, months, years, e.g. measles was found
to appear in cycles with major peaks every 23 years.
3. Long term or secular trends: The term secular trend implies changes in the
occurrence of disease (progressive increase or decrease) over a long period
or time, generally several years or decades, e.g. coronary heart disease,
lung cancer, diabetes are increasing in developed countries and TB, typhoid
and polio are decreasing in developed countries.
Place Distribution
It is the study of geographical distribution of cases in different population. By
studying this variation, the disease pattern has been found. The distribution
of diseases according to places can be classified as:
1. International variation
2. National variation
3. Rural/urban differences
4. Local variation.
1. International variation: Descriptive studies by place have shown that the
pattern of disease is not the same everywhere. For example we know cancer
exists all over the world, but the incidence of different types of cancer
varies with respect to the places. Cancer of the stomach is very common in
Japan but unusual in US. Cancers of the oral cavity and uterine cervix are
exceedingly common in India as compared to industrialized countries.
2. National variation: Variation in the prevalence and incidence of the disease
occurrence exists within countries or national boundaries. For the example
the distribution of endemic goiter, lathyrism, flourosis, guinea worm
disease, leprosy, malaria, nutritional deficiency diseases have all shown
variations in their distribution in India, with some parts of the country
more affected and others less affected or not affected at all.
3. Rural/urban variation: Rural/urban variations in disease distribution are
well known. Chronic bronchitis, accidents, lung cancer, cardio-vascular
diseases, mental illness and drug dependence are usually more frequent
in urban than in rural areas. On the other hand skin, zoonotic diseases and
soil-transmitted helminths may be more frequent in rural areas than in
urban areas.
4. Local distribution: Inner and outer city variations in disease frequency
are well known. These variations are best studied with the aid of spot
maps or shaded maps. These maps show at a glance areas of high or low
frequency, the boundaries and patterns of disease distribution. For example
General Epidemiology / 27
Person Distribution
In descriptive studies, the disease is further characterized by defining the
persons who develop the disease by age, sex, occupation, marital status, habits,
social class and other host factors. These factors do not necessarily represent
etiological factors, but they contribute a good deal to our understanding of
the natural history of disease.
1. Age: Age is strongly related to disease than any other single host factor.
Certain diseases are more frequent in certain age groups than in others,
e.g. measles in childhood, cancer in middle aged and atherosclerosis in
old age.
2. Sex: It is another host characteristic which is often studied in relation to
disease. It has been found that certain chronic diseases such as diabetes,
hyperthyroidism and obesity are strikingly more common in women than
men and diseases such as lung cancer and coronary heart diseases are less
frequent in women.
3. Ethnicity: Differences in disease occurrence have been noted between
population subgroups of different racial and ethnic origin. Differences
whether they are related to genetic or environmental factors have been a
stimulus to further studies.
4. Marital status: In countries where studies on mortality in relation to marital
status have been conducted, it was found that mortality rates were always
lower for married males and females than for the unmarried, of the same
age and sex.
5. Occupation: It may alter the habit pattern of employees, e.g. sleep, alcohol,
smoking, drug addiction, night shifts, etc. It is obvious that persons working
in particular occupations are exposed to particular types of risks. Workers
in coal mines are more likely to suffer from silicosis.
6. Social class: Individual in the upper social classes has a longer life
expectancy and better health and nutritional status than those in the lower
social classes. Certain diseases (e.g. coronary heart disease, hypertension
and diabetes) have shown a higher prevalence in upper classes than in
lower classes.
28 / Questions and Answers in Community Dentistry
Measurement of Disease
It is mandatory to have a clear picture of the amount of disease (disease
load) in the population. This information can be available in terms of
mortality, morbidity, disability and so on. When calculating morbidity it can
be expressed as prevalence and incidence rate.
Formulation of Hypothesis
By studying the distribution of disease and utilizing the techniques of
descriptive epidemiology, it is often possible to formulate hypothesis relating
to disease etiology. Hypothesis is a supposition, arrived at from observation
or reflection. It can be accepted or rejected, using the technique of analytical
epidemiology.
ANSWER 3
Differences Between Case Control and Cohort Studies
ANSWER 4
Experimental Epidemiology
Experimental or intervention studies are the ones which involve some action,
intervention or manipulation such as deliberate application or withdrawal of
the suspected cause or changing one variable in the causative chain in the
experimental group while making no change in control group and observing
and comparing the outcome of the experiment in both the groups.
Experimental studies have become major area of epidemiological studies. They
may be conducted in animals or human beings.
The Protocol
The protocol specifies the aims and objectives of the study, questions to be
answered, criteria for the selection of study and control group, size of the
sample, the procedures for allocation of subjects in to study and control groups,
treatment to be appliedwhen, where, how and to what kind of patients,
General Epidemiology / 31
Randomization
Randomization is a statistical procedure by which the participants are allocated
into groups usually called Study and control groups, to receive or not
receive an experimental preventive or therapeutic procedure, manoeuvre or
intervention. Randomization is an attempt to eliminate bias and allow for
comparability. It ensures that the investigator has no control over allocation
of participants to either study or control group, thus eliminating what is known
as Selection bias. In other words, by random allocation, every individual
gets an equal chance of being allocated into either group or any of the trial
groups. It is best done by using a table of random numbers.
Manipulation
Having formed the study and control group, the next step is to intervene or
manipulate the study (experimental) group by the deliberate application or
withdrawal or reduction of the suspected causal factor (e.g. this may be a
drug, vaccine, dietary component, habit, etc.) as laid down in the protocol.
32 / Questions and Answers in Community Dentistry
Follow-up
This implies examination of the experimental and control group subjects at
defined intervals of time, in a standard manner, with equal intensity, under
the same given circumstances, in the same time frame till final assessment of
outcome. The follow-up may be short or may require many years depending
upon the study undertaken.
Assessment
The final step is assessment of the outcome of the trial in terms of
1. Positive results: Benefits of the experimental measure such as reduced
incidence or severity of the disease, cost to the health service or other
appropriate outcome in the study and control groups
2. Negative results: Severity and frequency of side effects and complication,
if any, including death.
ANSWER 5
Steps in Designing an Epidemiological Trial /
Scientific Method in Epidemiology
1. Establishing the objectives.
2. Designing the investigation.
3. Selecting the sample.
4. Conducting the examination.
5. Analyzing the data.
6. Drawing the conclusion and publishing the results.
Descriptive study
Analytical study (case control/cohort study).
Experimental study (randomized/non-randomized).
ANSWER 6
Tools of Measurements
Rate
It measures the occurrence of some particular event in a population during a
given time period, e.g. crude rate, specific rate and standard rate.
Ratio
It expresses a relation in the size between two random quantities. Numerator
is not a component of the denominator.
Formula; A:B or A/B
E.g. the ratio of dentist to population in a state in India is 1:1000 or 1/1000,
which means for every 1000 people there is one dentist.
Proportion
It is a ratio, which indicates the relation in magnitude of a part of the whole.
Numerator is included in the denominator. It is usually expressed as
percentage.
The number of decayed teeth in children
e.g. 100
Total DMFT in children
ANSWER 7
Incidence
The number of new cases occurring in a defined population during a specified
period of time. It is given by the formula:
ANSWER 8
Prevalence
Refers to all current cases (old + new) existing at a given point in time, or over
a period of time in a given population. It is given by the formula:
Uses of Prevalence
1. Helps to estimate the magnitude of health/disease problems in the
community and identify high risk population
2. Useful for administrative and planning purposes.
ANSWER 9
Cross-sectional study is also known as prevalence study. It is based on a
single examination of a cross- section of population at one point in timethe
results of which can be projected on the whole population provided the
sampling has been done correctly. This studies are more useful for chronic
than short-lived diseases. Such a study tells us about the distribution of a
disease in a population rather than its etiology. It provides information about
disease prevalence; it provides very little information about the natural history
of disease or about the rate of occurrence of new cases.
ANSWER 10
Longitudinal study also called as incidence study. There is an increasing
emphasis on the value of longitudinal studies in which observations are
repeated in the same population over a prolonged period of time by means of
follow-up examinations. Cross-sectional studies have been likened to a
photograph and longitudinal studies to a cine film. Longitudinal studies are
useful:
36 / Questions and Answers in Community Dentistry
ANSWER 11
Sometimes there may be two separate peaks instead of one in the age incidence
curve of a disease. Such phenomenon is referred to as bimodality, e.g. as in
the case of Hodgkins disease, the curve is bimodal with an initial
peak between the ages 15 and 35 years, and a later peak starting at age 50.
Bimodality of age curve is also seen in tuberculosis, pneumonia, leukemia,
etc. The occurrence of two or more peaks in an age curve suggests that
different etiologic factors may be involved in the disease, as it occurs at different
ages.
ANSWER 12
Case Control Study (Flow chart 3.2)
These studies are often called retrospective studies or Trohoc studies, used to
test hypothesis. The case control studies have the following distinct features:
1. Both exposure and outcome of the disease have occurred before the start
of the study.
2. The study proceeds backwards from effect to cause.
3. It uses a control or comparison group to support or refute an influence.
3. Measurement of exposure
4. Analysis and interpretation.
Selection of Controls
a. Controls must be free from the disease under study, similar to the cases
except for the absence of disease. Controls should comprise of persons
who have not been exposed to the disease or some other factor whose
influence is been studied.
b. Sources of Controls
Hospital controls: Controls may be selected from the same hospital as
the cases, but with different illness other than the study disease.
Relatives: The controls may also be taken up from relatives (spouses
and siblings). Sibling controls are unsuitable where genetic condition
are under study.
Neighborhood controls: Controls may be people living in same locality
of cases, persons working in the same factory, children attending same
school.
General population: Population control can be obtained from defined
geographic areas, by taking a random sample of individuals free of the
study disease.
38 / Questions and Answers in Community Dentistry
Matching
The controls may differ from the cases in a number of ways such as age, sex,
occupation, social status etc. To ensure comparability between the cases and
the control a process what is called as matching is involved by which we
select controls in such a way that they are similar to cases with regards to
certain pertinent selection variables which is known to influence the outcome
of disease. While matching it should be borne in mind that the suspected
etiological factor or variable we wish to measure should not be matched,
because by matching, its etiological role is eliminated in that study.
Measurement of Exposure
Information about exposure should be obtained in precisely the same manner
for both cases and controls. This may be obtained by interviews, questionnaires
and past records of cases and controls (hospital records, employment records,
etc).
1. Exposure rates
a 125 125
Cases: = = 100 = 96.1%
( a + c ) ( 125 + 5 ) 130
b 347 347
Controls: = = 100 = 61.3%
( b + d ) ( 347 + 219 ) 566
Interpretation: The frequency rate of oral cancer was definitely more in
those chewing tobacco compared to the non-chewers.
2. Odds ratio (Cross product): It is the measure of the strength of the
association between the risk factor and outcome. It is calculated by taking
the cross product of the entries.
125 219
OD = ad/bc =
347 5
General Epidemiology / 39
OD = 15.7
Interpretation: The people chewing tobacco showed 15.7 times more risk
of developing oral cancer as compared to the non-tobacco chewers.
ANSWER 13
Cohort study Flow chart 3.3 also known as prospective study, longitudinal
study, incidence study, forward- looking study.
Follow-up
Regular follow-up is required which comprises of periodic medical
examination, reviewing hospital records, surveillance of death records, mailed
questionnaires, telephone calls, periodic home visits- preferably on an annual
basis.
Analysis
The data is analyzed in terms of:
1. Incidence rates of outcome among exposed and non-exposed
2. Estimation of risk.
Example
Sugar consumption Developed dental caries Not developed dental caries
Yes (5000) 250 (a) 4750 (b)
No (2000) 2 (c) 1998 (d)
c 2 2
Among those not consuming sugar = = = = 1 per 1000
c + d 2 + 1998 2000
2. Estimation of risk: This is done in terms of two indices.
a. Relative risk
b. Attributable risk
a. Relative risk: Relative risk is the ratio of incidence of the disease or death
among exposed and the incidence among non exposed .
Incidence of disease among exposed
RR =
Incidence of disease among non-exposed
As per above mentioned example
ANSWER 14
Bias is any systematic error in the determination of the association between
exposure and diseases.
ANSWER 18
ANSWER 19
In order to reduce the bias in the experimental trial a procedure is followed
what is known as blinding. Blinding can be done in three ways:
1. Single blind trial: The trial is so planned that the participant is not aware
whether he belongs to the study group or control group.
2. Double blind trial: The trial is so planned that neither the investigator nor
the participant is aware of the group allocation and the treatment received.
3. Triple blind trial: This goes one step further. The participant, the
investigator and the person analyzing the data are all blind . Ideally, of
course, triple blinding should be used; but the double blinding is the most
frequently used method when a blind trial is conducted.
ANSWER 20
Analytical studies are one of the major type of epidemiological studies. The
subject of interest in analytical studies is the individual within the population.
Although individuals are evaluated in analytical studies, the inference is not
to the individuals, but the total population from which they are selected. The
starting point for analytical studies is descriptive study findings suggesting
further investigations. Hypothesis developed by descriptive findings are tested
by analytical methods to find out, whether an association exits between two
categories of events. Analytical studies comprise of two distinct types of
observational studies.
1. Case control study
2. Cohort study
ANSWER 21
Non-randomized Trials / Non-experimented Trials
Although the experimental method is almost always to be preferred, it is not
always possible for ethical, administrative and other reasons to resort to a
randomized controlled trial in human beings and hence non-randomized trials
46 / Questions and Answers in Community Dentistry
ANSWER 22
Epidemic
The level of disease that is substantially above the usual for the population or
community.
ANSWER 23
Pandemic
An epidemic usually affecting a large proportion of the population occurring
over a wide geographic area such as a section of a nation, the entire nation, a
continent of the world.
ANSWER 24
Exotic
Diseases which are imported into a country in which they does not otherwise
occur.
ANSWER 25
Zoonosis
An infection or infectious disease transmissible under natural conditions from
vertebrate animals to man.
ANSWER 26
Epizootic
An outbreak (epidemic) of disease in an animal population often with the
implication that it may also affect human population.
General Epidemiology / 47
ANSWER 27
Endemic
It refers to the constant presence of a disease or infectious agent within a given
geographic area or population group without importation from outside.
ANSWER 28
Surveillance has been defined as the continuous scrutiny of the factors that
determine the occurrence and distribution of disease and other conditions of
ill health. It is essential for effective control and prevention and includes the
collection, analysis, interpretation and distribution of relevant data for action.
The ultimate objective of surveillance is prevention. Surveillance may
comprise:
1. Individual surveillance: This is surveillance of infected person until they
are no longer a significant risk to other individuals.
2. Local population surveillance, e.g. surveillance of malaria.
3. National population surveillance, e.g. surveillance of small pox after the
disease has been eradicated.
4. International surveillance, e.g. at international level WHO maintains
surveillance of important disease (Sars, influenza, malaria, etc).
ANSWER 29
Quarantine
The limitation of freedom of movement of such well persons or domestic
animals exposed to communicable diseases for a period of time longer than
the usual incubation period for the disease in such a manner as to prevent
effective contact with those not so exposed.
ANSWER 30
Cohort is defined as a group of people who share common characteristic or
experience within a defined time period (e.g. age, sex, occupation, etc).
ANSWER 31
Principles of Epidemiology
1. Exact observation.
(strict, vigorous, accurate, precise)
2. Correct interpretation.
(free from error)
48 / Questions and Answers in Community Dentistry
3. Rationale explanation.
(Intelligent, sensible, reasonable)
4. Scientific construction.
(by expert knowledge and technical skill).
ANSWER 32
Confounding factor is defined as one which is associated both with exposure
and disease, and is distributed unequally in study and control groups.
ANSWER 33
The epidemiologist goes into the community to find the persons who have
the disease or experience of the suspected causal factor. The epidemiologist is
essentially a planner who is familiar with the statistical and epidemiological
techniques, he has a good knowledge of bacteriology, immunology,
physiology, well grounded in the diagnosis of disease and particularly
relationship of various environmental factors that may influence health of
individuals. The epidemiologist considers the community as a unit rather then
the individual. He is confronted with relevant data derived from a particular
epidemiological study. He seeks to identify a particular source of infection,
mode of spread or an etiological factor in order to determine a future trend
and recommend specific control measures. The epidemiologist concentrates
more on the prevention and control of future disease then about the cure of
current disease.
Biostatistics / 49
4 Biostatistics
QUESTIONS
1. a. Define biostatistics and write a note on the uses of biostatistics.
b. Role of biostatistician. (Refer Ans 1a)
2. Define data and different types of data.
3. Sampling methods.
4. Stratified sample. (Refer 2 in Ans 3)
5. Cluster sampling. (Refer 4 in Ans 3)
6. Measures of central tendency.
7. Measures of dispersion.
8. Standard deviation. (Refer Ans 7)
9. Data presentation.
10. Histogram. (Refer Ans 9)
11. Normal distribution/Normal curve/Gaussian distribution.
12. Test of significance.
13. Chi-square test.
14. t test.
15. Correlation.
16. Regression.
17. Hypothesis.
ANSWER 1
Biostatistics
It is a method of collection, organizing, analyzing, tabulating and interpretation
of data related to living organisms and human beings.
50 / Questions and Answers in Community Dentistry
Uses of Biostatistics
To define normalcy (To define what is normal or healthy in a population
and to find the limits of normality).
To test whether the difference between two populations regarding a
particular attribute is real or a chance occurrence
To study the correlation or association between two or more attributes in
the same population
To evaluate the efficacy of an agent in the field
To assess the state of oral health in the community and to determine the
availability and utilization of dental care facilities
To determine the success or failure of specific oral health programs or to
evaluate the program action.
ANSWER 2
A collective recording of observation either numerical or otherwise is called
as data.
Data can be classified as:
1. Qualitative data.
2. Quantitative data.
Discrete
Continuous.
3. Primary data.
4. Secondary data.
Qualitative Data
Here the data is collected on the basis of qualities or attributes, e.g. sex,
malocclusion, character of the persons etc.
Quantitative Data
Here the data is collected through measurements.
Discrete data: Here the variable takes only whole value, e.g. DMFT
Continuous data: Here the variable is in the range, decimal or fraction,
e.g. height, age, arch length.
Primary Data
Here the data is obtained by the investigator himself. It is the first hand data.
The data may be obtained by direct personal interview, oral health examination
and questionnaire method, e.g. results obtained from a survey or an
epidemiological study.
Biostatistics / 51
Secondary Data
The data already recorded is utilized to serve the purpose of the objective of
the study, e.g. hospital records, results of the previously done survey.
ANSWER 3
Sampling
The word sample means a group of individuals who are actually available for
the investigation. It is not possible to include each member of the population
in the study as it is not feasible in terms of time, money and manpower. The
sample thus selected should be representative of the entire population such
that the inferences drawn from the sample are applied to the whole population
or universe. The different sampling methods are:
Probability sampling Non-probability sampling
1. Simple random 1. Accidental/incidental/ convenience
2. Stratified random 2. Judgment/purposive
3. Systematic random 3. Quota
4. Cluster 4. Sequential
5. Multiphase 5. Snowball
6. Multistage
Probability Sampling
Here every individual in the community has an equal chance of been selected.
It is a representative sample and the inferences drawn can be generalized to
the whole community.
1. Simple random sampling: Here the sample unit is selected in such a way
that every unit of the population has an equal chance of been selected. The
sampling units are the individuals from a community or group and the
sampling frame is the community or group from where the sample will be
drawn. The word random indicates haphazard which seems to be
misnomer in this sampling context, but instead here each unit in the
community has a equal chance. The sample can be drawn using a random
number table or the lottery method. Every individual is given a serial
number.
In the lottery method, numbered paper slips are used, they are shuffled
and a blind fold selection is done to pick up desired number of the sample.
The table of random number consists of numbers arranged in column
and rows. You can choose any page and start selecting the number in a
systematic manner, i.e. the row, column or diagonally till your desired
sample is reached.
52 / Questions and Answers in Community Dentistry
Non-Probability Sampling
Here, there may not be representation to the whole community. All the units
do not stand a fair chance of selection. When the inferences are generalized to
the whole community it may not be true.
1. Accidental/incidental/convenience: Here sample is selected by the
convenience of the situation for the examiner.
2. Purposive/judgment /deliberate sampling: The sample is selected by the
judgment of the person entrusted with the job. The knowledge and attitude
of the person will decide the effectiveness of the sample. It is easy to carry
out and does not require preparation of any sampling framework. The
limitation is that it may substantially under-represent the rates of the
population in the study.
3. Quota sampling: The sample drawn is in accordance with the ratio of the
existing quota. e.g: The ratio of boys: girls is 1:2, then the sample selected
should maintain the ratio (a sample of 250 boys and 500 girls).
54 / Questions and Answers in Community Dentistry
4. Sequential sampling: Here number of sequential lots are drawn one after
another from a universe depending on the results of earlier samples. So
this sample is based on quality control. If the first sample is clearly
acceptable, no new sample is needed to be drawn. If it is unacceptable the
lot is rejected, if the initial sample is doubtful the next sample may be
drawn.
5. Snowball sampling (Chain referral sampling): Here the sample is selected
by asking the people who meet the criteria for inclusion in the study to
suggest other people who would meet those criteria. This is a useful and a
easy way to identify hard to find individuals.
ANSWER 6
Measures of Central Tendency
When the data is collected, there should be a single estimate so that it
summarizes the observations, which also enables comparison of two or more
data series. This single estimate of a series of data that summarizes the data is
known as the parameter and one such parameter is the measure of central
tendency. The most commonly used measures of central tendency are:
1. Mean (mathematical estimate)
2. Median (positional estimate)
3. Mode (based on frequency)
For example 5, 7, 6, 4, 1, 3, 0, 5, 2, 3.
5 + 7 + 6 + 4 + 1 + 3 + 0 + 5 + 2 + 3 36
X= = = 3.6
10 10
When observation are many, the above method is tedious and hence
frequency distribution tables are formed.
Biostatistics / 55
X1 f 1 128
Mean = = = 1.72
f1 74
41 32.45
X1 f1 32.45
Mean = = = 0.79
f1 41
Arithmetic mean in the simplest measure, but this measure is highly
influenced by extreme values. Hence, in such cases, it is better to use median.
56 / Questions and Answers in Community Dentistry
Median
If is the middle value in a distribution such that one half of the units in the
distribution have a value smaller than or equal to the median and one half has
a value higher than or equal to the median.
Steps
1. First arrange the data in the order of magnitude.
2. If the number of observation is odd than (n+1)/2 will be a single value and
this center value will be the median.
3. If the observation is even, the mean of the middle values may be taken as
the median.
For example
If the series is even: 1, 4, 2, 7, 8, 4, 3, 8, 10, 12.
1, 2, 3, 4, 4, 7, 8, 8, 10, 12,
4+7 11
= = 5.5 ....... is the median
2 2
If the series is odd: 1, 2, 3, 4, 7, 8, 8, 10, 12.
The median here is 7.
Mode
The mode or the modal value is that value in a series of observation that occur
with the greatest frequency,
For example: 6, 6, 1, 13, 12, 5, 6, 5, 7, 8, 6, 7, 5.
Six would be the mode as it occurs more than any other number. When
the mode is ill defined and there are many modes for a series then it can be
calculated using the relation.
MODE = 3 median 2 mean.
ANSWER 7
Measures of Dispersion
Central tendency gives us a single value that represents the entire data, but
this does not adequately describe the data and it is necessary to know how
widely the observations are spread on either side of the average. The measures
of dispersion help us to study the spread of values about the central value. It
is mainly used to:
1. Determine the reliability of an average
2. Sum as a basis for control of variability
3. Compare two or more series in relation to their variability
4. Facilitate further statistical analysis.
Biostatistics / 57
d2
S=
(n 1)
( X1 X ) f1
2
ANSWER 9
Presentation of Data
The data can be presented in different types:
1. Tabulation
Simple table
Frequency distribution table
2. Charts and diagrams:
Bar diagram
Simple bar diagram
Multiple bar diagram
Component bar diagram
Proportional bar diagram
Histogram
Frequency polygon
Line chart/diagram
3. Pie diagram
4. Pictogram.
5. Cartograms or spot diagram.
6. Scatter diagram.
Table 4.1: Yearwise distribution of boys and girls in the dental school
2003 23 37
2004 35 35
2005 20 50
Steps involved:
1. See the largest and the smallest value in the data series.
2. Divide the group in small group or class interval of same size.
Biostatistics / 59
Bar Diagram
1. Simple bar diagram (Fig. 4.1): It is used to represent qualitative data. It
represents only one variable. It is represented in the form of the bars. The
width of the bars remains the same and only the length changes depending
on the frequency.
7. Line diagram (Fig. 4.7): This is used to represent quantitative data and to
compare between two or more variables. The line diagram is drawn by
first plotting the data on the graph sheet and then connecting all the dots
to form the line.
Fig. 4.7: Yearwise presentation of the number of dental and education camps
8. Pie diagram (Fig. 4.8): This is used to represent qualitative data and single
variable. The data is represented as the segments of a circle. To calculate
the angle of the segment, divide the observation by the total observations
and multiply by 360.
9. Cartogram/Spot map: These maps are used to show geographical
distribution of frequencies of a characteristic, e.g. John Snows spot map
which shows the distribution of the water source and the spread of cholera
epidemic.
Biostatistics / 63
ANSWER 11
The Normal Curve (Fig. 4.10)
It is also called as normal distribution/bell shaped curve/Gaussian
distribution.
64 / Questions and Answers in Community Dentistry
When the frequency is large and class interval is reduced, the frequency
polygon tends to lose its angulation giving rise to a smooth curve known as
frequency curve or normal curve.
ANSWER 12
Test of Significance
It is natural for sample estimates to vary from sample to sample. It is necessary
to find out whether the differences are true or by a chance. The tests of
Biostatistics / 65
ANSWER 13
2 Test)
Chi-square Test (
It is pronounced as Kye square test.
2 (O E ) 2
The 2 statistic is calculated as =
E
O = Observed frequency
E = Expected frequency
Row total Column total
Expected frequency =
Grand total
Degree of freedom = (r 1) x (c 1)
r = number of rows
c = number of column
66 / Questions and Answers in Community Dentistry
This test is used to check whether there exists any difference for the
qualitative data.
After calculation, the 2 value is compared with the table with respect to
the degree of freedom and if the p value is lesser than the calculated 2 value
then the null hypothesis is rejected.
2 [(O E ) 0.5]2
=
E
The test, tells the presence or absence of an association between two
2
ANSWER 14
t test (Students t Test)
WS Gossett gave the t distribution analysis. His pen name was student and
hence his work was called as Students t test.
There are two types of t test: Paired t test and unpaired t test
When each individual gives a pair of observations, to test for the difference
in the pair of values, paired t test is utilized.
When sample in 2 groups give individual values, to test for the difference
in between the groups, unpaired t test is used.
The test procedure for testing the significance of difference using paired
t test is as follows:
a. The null hypothesis is stated, as there is no difference in the pairs of
observations
b. The difference in each set of paired observation is obtained as d = X1 X2
c. Compute mean of the differences, d = d/n where, n is the number of
pairs
d. Calculate standard deviation of the difference and standard error of
difference SD/
e. The test statistic t is calculated from t = d/SD/
f. Find the degree of freedom. The degree of freedom is n 1, since mean of
difference of n pairs of observations are obtained.
g. Compare the calculated t value with the table value for (n 1) degree of
freedom to find the p value
Biostatistics / 67
ANSWER 15
Correlation
When dealing with measurements on two sets of variables in the same person,
one variable may be related to the other in some way, e.g. level of fluoride in
drinking water and community fluorosis. Change in value of one variable
result in a change in the value of the other variable. The relationship between
two such variables is correlation. The magnitude or degree of relationship
between two variables is called correlation coefficient and is denoted by r.
The correlation coefficient ranges from 1 r + 1.
The formula for computation of correlation coefficient of two variables is
given as
N XY (X Y )
r=
N X 2 (X )2 Y 2 (Y )2
ANSWER 16
Regression
Correlation coefficient only measures the degree of relationship between X
and Y variable but does not give an idea about the changes in which variable
results in the change of the other. This is done in regression. The variable
which causes the change is called the independent variable. The variable which
changes in same manner with a change in the independent variable is called
dependent variable. The change of the dependent variable with respect to a
change in the independent variable is called regression. This regression is
measured through regression coefficient, which gives the amount of increase
or decrease, in the dependent variable for an unit of change in the independent
68 / Questions and Answers in Community Dentistry
ANSWER 17
A hypothesis is a supposition, arrived at from observation or reflection.
To test statistical significance about the population parameters or true value
of universe, 2 hypothesis or presumptions are made
1. Null hypothesis (H0) = Hypothesis of no difference. It asserts that there is
no real difference in the samples and the particular matter under
consideration.
2. Alternative hypothesis (H1) = Stating that the sample result is different
(greater or lesser).
Epidemiology of Dental Caries / 69
5 Levels of Prevention
QUESTION
Write a note on levels of prevention.
ANSWER
In modern day, the concept of prevention has become broad-based. It has
become customary to define prevention in terms of four levels:
1. Primordial prevention
2. Primary prevention
3. Secondary prevention
4. Tertiary prevention.
Primordial Prevention
It is a new concept, receiving special attention in the prevention of chronic
disease. This is primary prevention in its purest sense, that is, prevention of
the emergence or development of risk factors in countries or population groups
in which they have not yet appeared. For example, many adult health problems
(e.g. obesity, hypertension) have their early origins in childhood, because this
is the time when lifestyles are formed (for example smoking, eating pattern,
physical exercise). In primordial prevention, efforts are directed towards
discouraging children from adopting harmful lifestyles. The main intervention
in primordial prevention is through individual and mass education.
Primary Prevention
Primary prevention can be defined as action taken prior to the onset of disease,
which removes the possibility that a disease will ever occur. It signifies
intervention in the prepathogenesis phase of a disease or health problem (e.g.
low birth weight) or other departure from health. It includes the concept of
70 / Questions and Answers in Community Dentistry
High-risk Strategy
It aims to bring preventive care in individuals at special risk. This requires
detection of individuals at high risk by the optimum use of clinical methods.
In summary primary prevention is a holistic approach. The mode of
intervention here is through health promotion and specific protection.
Secondary Prevention
Secondary prevention can be defined as action which halts the progress of a
disease at its incipient stage and prevents complications. The mode of
intervention is early diagnosis (e.g. screening tests, case finding programs)
and adequate treatment. By this an attempt is made to arrest the disease
process, restore health and prevent any irreversible pathological changes to
take place. Secondary prevention is largely a domain of clinical practice.
Though it will prevent the people in the community from acquiring the disease.
Secondary prevention is an imperfect tool in the control of transmission of
disease. It is often more expensive and less effective than primary prevention.
Tertiary Prevention
When the disease process has advanced beyond its early stages, it is still
possible to accomplish prevention by what might be called tertiary
prevention. It signifies intervention in the late pathogenesis phase. Tertiary
prevention can be defined as all measures available to reduce/limit
impairments and disabilities, minimize suffering caused by existing departures
from good health and to promote the patients adjustments to irremediable
condition. Tertiary prevention extends the concept of prevention into fields
of rehabilitation. The mode of intervention here is disability limitation and
rehabilitation.
Epidemiology of Dental Caries / 71
6 Epidemiology of
Dental Caries
QUESTIONS
1. Define dental caries. Discuss the epidemiology of dental caries.
2. Describe the role of host and agent factor in the epidemiology of dental
caries. (Refer Ans 1)
3. Agent factor in dental caries/micro-organisms in the causation of dental
caries. (Refer Ans 1)
4. Rainfall and dental caries.(Refer Ans 1, Environment factors)
5. Diet and dental caries. (Refer Ans 1, Non-climatological environment
factors)
6. Trace elements and dental caries.
7. Selenium and dental caries.
8. Nursing bottle caries.
9. Studies on sugar and dental caries.
10. Vipeholm study. (Refer Ans 9)
11. Hopewood house study. (Refer Ans 9)
12. Turku sugar study. (Refer Ans 9)
13. Stephans Curve.
ANSWER 1
Dental caries is defined as a chronic infectious disease which results from the
demineralization of the inorganic portion and destruction of the organic
portion of the tooth.
Host Factors
1. Age: Caries used to be considered as the disease of the childhood. The
older teenagers were found to have more DMFT compared to the younger
teenagers. (Caries immediately after teeth eruption were lower and then
after few years carious lesion were seen to develop). According to
Hollander and Dunning greatest intensity of caries process lies in 1525
years of age, decrease occurring in 2535 years and an increase seen after
60 years (root caries).
2. Sex: Females generally demonstrate higher DMFT scores than do the males.
This difference is small enough to be explained by the early eruption of
teeth in females (i.e. they are in contact with the environment for a longer
period of time). Few studies show higher caries status in males, while few
studies show no difference. The impact of this determinant has never been
well quantified.
3. Race and ethnicity: Contentions that certain race enjoy a high degree
of resistance to dental caries have been around for a long time now.
Epidemiology of Dental Caries / 73
They probably stemmed from the early observations that some races in
Africa and India enjoyed more freedom from caries compared to
Europeans. In the US, in 1970, the whites had greater DMFT compared to
the African Americans but around 198687 the situation reversed
completely.
4. Socioeconomic status (SES): Education, income and occupation govern
the SES of the individual which also reflect the attitude and values. Studies
have shown more disease prevalence in the lower SES. Lower SES groups
had more D and M component and higher SES had more of F component.
Overall the difference could be attributed to the difference in the access
and affordability for dental care in different SES groups.
5. Emotional disturbances: There is a widespread clinical impression that
emotional disturbance, particularly transitory anxiety status influence the
incidence of dental caries. Salivary changes have been shown to occur in
connection with changes in the mental health. Four major diagnostic groups
were considered for the study: Primary behavior disorders, psychopathic
personality, schizophrenia, and manic depressive psychosis and alcoholism
without psychosis. Statistical analysis demonstrated a higher dental caries
experience at all ages among the manic depressive group than in the
baseline hospital population. A correlation between mental stress and caries
has also been demonstrated in a study.
6. Familial heredity: There is a widespread clinical impression that dental
caries varies considerably from family to family and that inheritance of a
characteristic tooth structure either good or poor is common. There are a
few genetic studies and in such studies it is difficult to distinguish between
true inheritance through the chromosomes and the transmission of dietary
and other habits through family indoctrination. However in a study by
MANSBRIDGE , finds a greater resemblance in caries experience between
identical twins than between fraternal twins, while unrelated pairs of
children show less resemblance than either type of twins.
7. Tooth:
a. Composition
b. Morphologic characteristics
c. Position
a. Composition: Tooth is a calcified tissue, with its different parts made up
of differing concentration of inorganic, organic components and water.
Evidences indicate that alteration of tooth by disturbances in the
composition is of secondary importance in dental caries. The rate of
caries progression may be influenced but initiation is altered little.
74 / Questions and Answers in Community Dentistry
Miscellaneous: Peroxide
Enzymes: Carbohydrases, proteases, oxidases.
Other properties of saliva:
b. Flow rate: It is determined by the amount of saliva secreted for a period
of time. The flow rate is directly proportional to the dental caries.
Increased flow rate, greater oral clearance and flushing of the oral cavity,
thereby reduced risk of caries. Rampant caries is typically a result of
reduced flow rate.
c. pH of saliva: It is mainly determined by the bicarbonate concentration.
The pH increases with the flow rate. Studies have shown an inverse
relation of pH and dental caries.
d. Buffering capacity: It determines the ability of the saliva to neutralize
the acids. Studies have shown an inverse relation between buffering
capacity and dental caries.
e. Viscosity of saliva: It is due to the mucin content in the saliva. Few studies
have reported that a high caries incidence is associated with thick
mucinous saliva.
f. The antibacterial properties of saliva have been investigated by
numerous researchers to explain wide variation in caries incidence
among different people.
i. Lactoperoxidase: These enzymes participate in killing micro-
organisms by catalyzing the hydrogen peroxide mediated oxidation
of a variety of substances in the microbes. It has a high affinity for
the enamel surface and it forms an important defense mechanism,
limiting early microbial colonization of tooth surfaces.
ii. Lysozyme: It is a small, highly positive, enzyme that catalyzes the
degradation of the negatively charged peptidoglycan matrix of
microbial cell walls. There is strong evidence that it binds to
hydroxyapatite and maintains its activity after binding.
iii. Lactoferrin: It is an iron binding protein in the saliva and plays an
important role in host defense mechanism. It binds and limits the
amount of free iron, which is essential for the microbial growth.
iv. IgA: It is a predominant immunoglobulin in the saliva. Secretory
IgA is an effective agglutinin because each molecule possesses four
antigen binding sites. It inhibits adherence and thereby prevents
colonization of mucosal surfaces and teeth by organisms facilitating
their disposal by swallowing.
g. Other salivary components with protective function:
i. Proline rich protein-mucins and glycoproteins: Because of their high
proline content, these are rigid collagen like molecules designed to
76 / Questions and Answers in Community Dentistry
Agent Factor
The association of micro-organism to tooth decay goes back a long way to
about 5000 BC. According to the Sumerian text, tooth decay was caused by a
worm that drank the blood of the teeth and fed on the roots of the teeth. Also,
since the days of WD Miller, who proposed the Chemico-parasitic theory, dental
research has been directed towards the identification of microbial agent for
the disease. In 1915, Kligler became the first to associate lactobacilli as the
causative organism. Later, in working with germ-free rats, Orland et al., found
that they were unable to produce caries in the presence of a highly cariogenic
diet. In 1924, Streptococcus mutans was detected by Clark which was
considered the main etiological agent for dental caries. Studies report that,
the Streptococcus mutans is responsible for the initiation and lactobacilli for
the progression of the caries. The Actinomyces strains are linked with the
root caries. In the case of caries, it has long been recognized that carbohydrates
residues are essential for the organisms to produce caries.
Environment Factors
1. Climatological (Geographical trends): Study of variation in dental caries
with respect to the latitude and distance from the seacoast. Low caries
was observed near the equator. A perfect progression of caries prevalence
with variation in latitude has been reported.
2. Sunshine: A study by BR East, who compared dental caries among rural
children with the mean annual sunshine of the place where they lived,
reveals an inverse relation which is highly statistically significant. Also in
a study by Ockerse, a high correlation of 0.879 between sunshine and
dental caries in certain areas of South Africa has been documented.
3. Temperature: It varies almost entirely with the latitude. Temperature in
turn, acts to vary the calorie requirement and water intake of the individual.
The food pattern is affected by the temperature that is probably how caries
seem to vary with respect to the temperature.
Epidemiology of Dental Caries / 77
ANSWER 6
Trace Elements and Dental Caries
Trace element is essential for humans when it has a vital function and is
required to avoid a deficiency state. These elements do have an effect on the
prevalence of dental caries. Navia has suggested a classification of trace
elements into 5 groups depending on the caries promoting or inhibiting
property.
1. Caries promoting elements: Selenium, magnesium, cadmium, platinum,
lead, silicon.
2. Elements that are mildly cariostatic: Molybdenum, vanadium, strontium,
calcium, boron, lithium, gold.
Epidemiology of Dental Caries / 79
ANSWER 7
Selenium and Dental Caries
Persons who consume food that are rich in selenium have higher than usual
dental caries. In a survey of teeth of children reared in seleniferous area west
of the Cascade Mountains in Oregon, it was found that these children
experienced a higher incidence of caries than did the children reared in east
of the Cascades, where there is no selenium in the soil. The findings were
corroborated by the other study in Wyoming. It is speculated that the
incorporation of selenium during the tooth development changes the protein
components of the enamel and makes it more prone to caries.
ANSWER 8
Nursing Bottle Caries/Baby Bottle Decay/ Baby Bottle Tooth Syndrome.
This is particularly, a distressing caries syndrome related to dietary habit. It is
characterized by rampant caries in the primary anterior teeth of the infants,
typically 1 to 3 years old, where teeth are often decayed to the gingival level.
The condition is attributed to the practice of putting an infant to bed with a
bottle of sweetened drink (pacifier- juice, water or milk, sweetened with syrup
or honey), usually to ensure that the child goes to sleep quickly and remains
pacified should it wake during the night. When the child lies with the bottle
in the mouth, the tongue extends slightly outside and covers the lower anterior
teeth. As the child falls asleep sucking stops, such that the movement of the
jaw which normally stimulates the saliva no longer takes place. In short the
problem is compounded by low salivary flow rate during sleep. The beverage
spreads over the upper teeth and the lower posterior teeth and is constantly
bathed in sugary solution for hours at a time, often everyday soon leading to
rampant caries. There is evidence however that the condition is widespread
and usually prevalent in the lower SES groups or where infants have been
cared by persons with little education.
80 / Questions and Answers in Community Dentistry
ANSWER 9
Studies on Sugar and Dental Caries
Vipeholm Study (Gustafsson et al-1954)
It was a 5 year investigation of 436 adult inmates in a mental institution at
Vipeholm Hospital near Lund, Sweden. The main purpose of the study was
to investigate how the caries activity is influenced by:
1. By ingestion at meals refined sugar (non-sticky form)
2. By ingestion at meals of sugar (sticky form).
3. By ingestion between meals of sugar (sticky form)
The design of the study divided the inmates in 7 groups:
1. A control group.
2. A sucrose group (300 gms of sucrose given in solution, but reduced to
75 gms during the last 2 years).
3. A bread group (345 gms of sweet bread containing 50 gms of sugar daily).
4. A chocolate group (65 gms of milk chocolate daily between meals during
last 2 years).
5. A caramel group (22 caramels = 70 gms of sugar in 4 portions between
meals).
6. An 8 toffee group (8 sticky toffees = 60 gms of sugar daily for 3 years).
7. A 24 toffee group (24 sticky toffees = 120 gms of sugar for 18 months).
The main conclusions of the study were:
1. An increase in carbohydrate (mainly sugar) definitely increases the caries
activity.
2. The risk of sugar increasing caries is greater if the sugar is consumed
between meals.
3. The risk of sugar increasing caries is greater if the sugar is consumed in a
form that will be retained on the surfaces of the teeth.
4. The increase in caries activity varies widely between individuals.
5. Upon withdrawal of caries rich foods, the increased caries activity rapidly
disappears.
6. Caries lesions may continue to appear despite the avoidance of refined
sugar and maximum restrictions of natural sugars dietary carbohydrates.
7. A high concentration of sugar in solution and its prolonged retention on
tooth surfaces leads to increased caries activity.
8. The clearance time of sugar correlates closely with caries activity.
The study showed that the physical form is much more important in
cariogenicity than the total amount of sugar ingested.
all the children had lived from infancy at Hopewood House. All lived on a
strict institutional diet, that, with the exception of an occasional serving of
egg yolk, was entirely vegetable in nature and largely raw. The absence of
meat and a rigid restriction of refined carbohydrate were the two principal
features of the Hopewood House diet. The meals were supplemented by
vitamin concentrates and a occasional serving of nuts and a sweetening agent
such as honey. The fluoride content of water and food was insignificant and
no tea was consumed.
At the end of 10 year period, the 13 year old children had a mean DMFT
per child of 1.6.
Fifty three percentage of the children at the Hopewood House were caries
free whereas only 0.4% of the 13 year old state schoolchildren were caries
free.
The childrens oral hygiene was poor, calculus uncommon, but gingivitis
was prevalent in 75% of children. This work shows that, in institutionalized
children, at least, dental caries can be reduced by a Spartan diet, without the
beneficial effects of fluoride and in the presence of unfavorable oral hygiene.
Follow-up examination of the children who had left the school at the age
of 13 years, revealed a steep increase of dental caries and this concludes that
teeth do not acquire permanent resistance to dental caries.
Tristan-da-Cunha Study
It is a rocky island in the south Atlantic 1500 miles west-south-west of Cape
Town. The inhabitants approximately 200 were mostly of European origin
and had only occasional contact with the outside world. Because of a volcanic
eruption the islanders were evacuated to England between 1961 and 1963.
Prior to 1940 their diet was very low in sugar but since 1940 the island shore
had solid sugar and sugar containing foods. The dental health of the islanders
has been recorded many times before and after the sugar trading started. In
1937 the dental caries experience was very low but a steady deterioration in
the dental health since then, faster in children than the adults has been
observed. The study is valuable in that it shows an increase in caries experience
paralleling an increase in sugar consumption in the same population.
ANSWER 13
Stephan conducted a laboratory investigation with sugared rinses. He found
that the ingestion of sugar caused the immediate sharp drop in plaque pH
followed by a gradual return to a normal pH from salivary buffer action. This
data was plotted on a graph which was demonstrated in the form of a curve,
called as Stephans curve (Fig. 6.2). Of the various sugared rinses that is sucrose,
fructose, glucose and starch; sucrose showed the highest pH drop.
Fig. 6.2: Stephans curve: The group with the sucrose rinse showed a sharp and
immediate drop in plaque pH; the control group with a water rinse showed no change
Fluorides / 83
7 Prevention of
Dental Caries
QUESTIONS
1. Define preventive dentistry.
2. What are the different preventive measures for dental caries.
3. Discuss in detail the levels of prevention for dental caries.
4. Diet counseling. (Refer Ans 1)
5. Sugar substitutes.
6. Xylitol.
ANSWER 1
Preventive dentistry It is the procedure employed in practice of dentistry
and community dental health program which prevent occurrence of oral
disease and oral abnormalities.
ANSWER 2
Prevention of Dental Caries
The methods of caries control can be studied under the following 3 types:
Chemical measures
Nutritional measures
Mechanical measures.
Chemical Measures
A vast number of chemical substances have been proposed for the purpose of
controlling caries. The use of some of these has been based upon sound
experimental evidence the use of others has been purely empiric and without
any scientific foundation. These chemicals include:
Substances which alter the tooth surface or tooth structure: Fluoride,
bisbiguanides, silver nitrate, zinc chloride and potassium ferocyanide
84 / Questions and Answers in Community Dentistry
Nutritional Measures
This can be achieved by doing alteration in the diet of the individual which is
best described through Diet Counseling.
Diet refers to the food that we intake in-order to maintain our body. The
diet what the mother takes during pregnancy or falls short to take certain
foods show its effects on the foetus, while what the individual takes during
its life time also shows its effects on the body, which can be classified as pre-
eruptive and post-eruptive effects. The undesirable dietary effects on the body
can be nullified through diet alteration or modification which can be sought
through diet counseling.
Procedures in Counseling
The complete case-history should be recorded which includes the socio-
demographic variables, chief complaint, medical and dental history, history
of medication, habits and other relevant history about the case.
Diet diary is to be maintained by the patient in which he/she records all
that is consumed in the day. This diary is maintained for 1, 3, 5 or 7 day.
The diet diary is collected and analyzed for the four food groups and the
sugar consumption
After analyses, the dietary modification prescribed and the patient is on
follow-up
Prevention of Dental Caries / 85
Mechanical Measures
The control of dental caries by mechanical measures refers to procedures
specifically designed for and aimed at removal of plaque from tooth surfaces.
The different methods are:
Prophylaxis by the dentist
Toothbrushing
Mouth rinsing
Use of interdental aids
Incorporation of detergent food in the diet
Pit and fissure sealant
Use of chewing gum.
Preventive measures can be prescribed based on the results of caries
activity test.
86 / Questions and Answers in Community Dentistry
ANSWER 3
Levels of Prevention for Dental Caries
Levels of Primary prevention Secondary Tertiary prevention.
prevention prevention
Preventive Health Specific Early Disability Rehabilitation.
services. promotion protection diagnosis limitation
and prompt
treatment
Services Diet Appropriate Self Use of Use of dental
provided by planning; use of examination dental services
individual demand for fluoride, and referral; services
patient preventive fluoridated use of
services; water, dental
periodic fluoridated services.
visit to dentifrice,
dental office fluoride
supplements,
oral hygiene
practices.
Services Patient Topical Complete Complex Removable
provided by education; application examination; restorative and fixed
the dental plaque of fluoride; prompt dentistry; prosthodontics;
professional control fluoride treatment of pulpotomy, minor tooth
program, supplements/ incipient root canal movement;
diet rinse lesions; therapy; implants.
counseling, prescription; preventive extraction.
recall pit and resin
reinforcement, fissure restoration;
dental caries sealants simple
activity test. restorative
dentistry;
pulp
capping.
ANSWER 4
Refer answer 1 (Diet counseling).
ANSWER 5
Sugar Substitutes
The sugar substitutes are generally sweeter than sucrose and hence only small
quantity is required. Some of the sugar substitutes which are shown to be safe
for the teeth are:
Sorbitol
Xylitol
High fructose corn syrup
Coupling sugar: Glycosylsucrose
Aspartame
Saccharin
Acesulfame-K
Cyclamate
Dulcin.
These have been used in chewing gums, mouthwashes, toothpaste, diet
drinks, dietetic foods and for table top use. However sucrose cannot be
replaced by these substitutes completely like in the baked products because it
becomes hard and tough and lacks bulk.
ANSWER 6
Xylitol
Xylitol can be used as a sugar substitute and is found to be safe for the teeth.
It is a pentose alcohol found naturally in variety of fruits and vegetables and
obtained commercially from birch trees, cottonseed husk and coconut shells.
Mechanism of action of xylitol:
Short term chewing of the gum significantly reduces salivary levels and
plaque proportions of streptococcus mutans
Because of its organoleptic property it stimulates salivation, thereby
increasing plaque pH and thus promotes remineralization.
Turku sugar study in Finland (1975) confirmed that xylitol is noncariogenic
in humans.
Most commonly used in chewing gums, mouthwashes, toothpaste, candies
and soft drinks.
Fluorides / 89
8 Fluorides
LONG QUESTIONS
1. Give a brief chemical description of fluoride and discuss the availability
and pharmacokinetics of fluorides.
2. History of fluoridation.
3. Describe in brief the importance of fluoride in dentistry. What are the
different types of fluorides used for local application in children? Write
the merits and demerits of each.
4. Describe the different uses of fluoride in dentistry. What is the mode of
action of fluoride in the prevention of dental caries? Which are the common
fluorides used in dentistry, mention advantages and disadvantages of
each.
5. a. Define water fluoridation.
b. Describe in detail the procedural steps taken in planning a water
fluoridation program in a city.
6. You have been appointed as a community inspector and are posted in a
city which has reported cases of fluorosis. Give your plan to solve this
health problem.
SHORT NOTES
7. Mechanism of action of fluoride.
8. 21 city study.
9. Shoe leather survey.
10. Knutsons technique.
11. Stannous fluoride topical application (Muhlers technique).
12. APF gel (Brudevolds technique).
13. Fluoride mouth rinses.
14. 0.2% sodium fluoride mouth rinse. (Refer Ans 13)
90 / Questions and Answers in Community Dentistry
ANSWER 1
Fluorine is the member of the halogen family with a relative atomic weight of
19 and an atomic number 9. The word fluorine is derived from the latin term
Fluore meaning to flow. At room temperature fluorine is a pale yellow
green gas. It is the most electronegative and reactive of all elements and thus,
in nature, is rarely found in its elemental form. The WHO expert committee
on trace elements has included fluorine as one among the 14 physiologically
essential elements for normal growth and development of human beings.
alkali rocks in geothermal waters and hot springs and volcanic gases. Examples
of minerals containing fluoride are:
Fluorspar (principle fluoride containing mineral) Fluorapatite and
Cryolite.
Biosphere
The normal level of fluoride in plants is about 220 mg/gm of dry weight.
Leafy vegetables such as cabbages, lettuce and Brussel sprouts contain about
1126 mg fluoride on dry weight basis. Tea plants have found to accumulate
high concentration of fluoride. Washing leafy vegetables reduces fluoride by
about 1/3 to 1/2. Plants growing in acidic solids, in vicinity of industries
show elevated fluoride concentration. The concentration of fluoride in various
animal products is approximately in the same range as the plants, e.g. sardines,
salmon, mackerel and other fishes contain 20 ppm of fluoride (High fluoride
level in fish is attributed to skin and bones).
Hydrosphere
Water contains fluoride in varying concentration. Highest of about 2800 ppm
is found in Lake Nakura in Kenya. Surface water has less fluoride compared
to ground water.
Atmosphere
Fluoride emissions are heaviest in the vicinity of industries in the production
of aluminum from cryolite, fertilizers, fluorinated hydrocarbons, etc.
The fluoride which is not absorbed from the stomach will be readily
absorbed through the microvilli in the intestine. The plasma peak usually
occurs in 30 mins. Half life is 410 hours.
Absorptiondistributionelimination is studied under the 2
compartment open model (Fig. 8.3).
Enamel
The enamel which is porous absorbs fluoride. The accumulation of fluoride
by enamel seems largely restricted to the surface than the interior.
Dentin
Dentin is like bone and cementum, it is a mesenchymal derivative unlike
enamel which is ectodermal in origin. Mesenchymal tissues have collageneous
matrix, increased surface area of the crystals, tubular structure and high degree
of tissue hydration which succumb to high fluoride absorption (fluoride
concentration is highest towards the pulpal surface).
Fluorides / 93
Cementum
Greater tissue porosity and poor crystallinity facilitate increased fluoride
uptake in cementum.
Absorption of fluoride in ascending order:
Cementum > bone > dentine > enamel
Excretion of Fluoride
Fluoride is excreted in urine, feces and is lost through sweat. It also occurs in
traces, in breast milk, saliva, hair and tears. About 1025% of the daily intake
of fluoride is excreted. Renal clearance is 35 ml/min and it is pH dependent.
ANSWER 2
Historical Evolution of Fluoridation
The history of fluoridation is more than 70 years old. It started with the arrival
of Dr Fredrick Mckay in Colorado springs, Colorado, USA in 1901, the year
following his graduation from the University of Pennsylvania Dental School.
He soon noticed that many of his patients had an apparently permanent stain
on their teeth, which was known to the local inhabitants as Colorado brown
stain.
1902: The first systematic endeavor to investigate this lesion was made by the
Colorado Springs Dental Society.
1905: Mckay moved to St. Louis to practice orthodontics. There he never saw
a case of mottled enamel and when he returned in 1908, the stain problem
struck him with more force than ever.
1908: El Paso county Odontological Society sent him, together with the patients
to the annual meeting for the state Dental Association in Boulder. Here he
learned of similar conditions in several other towns. The dentists here had
not bothered to report the stain. Dr Mckay approached Dr. G.V.Black for help
and he agreed to attend the Colorado state Dental Association meeting in
July 1909 and promised to spend some time in Colorado Springs.
In preparation for this visit and a first step in mapping out the entire
endemic area, Mckay and a fellow townsman, Dr Isaac Binton, examined the
94 / Questions and Answers in Community Dentistry
children in the public schools. 2945 children were examined. 87.5% of the
children native to the area had mottled teeth. For the first time the investigator
had statistical data. This information was given to Dr. Black when he arrived.
1912: Mckay found an article written by Dr J.M Eager in 1902 reporting the
unusual occurrence of brownish colored stains among majority of the residents
in Naples. Eager had termed these brownish discolorations as denti di chiaie.
1916: Mckay and Dr Black conducted studies on individuals living in 26
different communities in various parts of USA and they concluded that an
unidentified factor was responsible for the mottling of enamel. They assumed
that this unknown factor might has been present in the water consumed by
the individuals during the period of tooth calcification. They based this
assumption from the observation that the water supply of Britton was changed
from shallow wells to deep wells after 1898 and those people who were born
prior to 1898 had normal appearance of teeth while those born after 1898 had
enamel mottling.
1918: Mckay confirmed the presence of an unknown element in the water
supply to be the definite causative factor for enamel mottling. Similar findings
were reported in Bauxite with regard to change in water supply. In Oakley
and Idaho, Mckay found, the children living on the outskirts of the city, using
water from a private spring, were free of mottling. He advised the people of
Oakley to abandon their old water supply and tap their spring for a new
source, which the community did in 1925. Children born in Oakley, subsequent
to the change were free of mottled enamel.
1928: Mckay observed that in areas where the mottled enamel conditions were
found, the prevalence of dental caries appeared lower than would be expected.
1931: Mckay sent several samples of suspected water to Churchill H V, a
chemist employed with an aluminum company Alcoa. Spectrographic analysis
was done. The mysterious factor responsible for mottled enamel was thus
identified as Fluoride. The fluoride levels ranged from 1317 ppm.
Other important studies carried out were the 21 city study and the Shoe
Leather survey.
1931: US National Institute of Health appointed Dr, H. Trendly Dean, the first
dentist to study the fluoride-caries-mottled enamel relation. The term mottled
enamel was replaced to Fluorosis. Dean conducted a survey among 22 cities
in ten states of USA on a total population sample of 5824 children and gave the
following report on mottling of enamel at various concentration of fluoride:
1. A high concentration of fluoride in water is directly related to the severity
of enamel mottling
Fluorides / 95
ANSWER 3
Fluoride is used as a cariostatic substance. Depending on the fluoride delivery
method used it can be divided into two types:
1. Systemic fluorides
2. Topical fluorides
1. Different types of systemic fluoride supplementation:
Community water fluoridation
School water fluoridation
Dietary fluoride supplementation
Milk fluoridation
Salt fluoridation.
2. Different types of topical application:
Professionally applied Self applied
Also refer Answer: 5, 10, 11, 12, 13, 14, 15, 17, 19, 20, 21, 22, 27.
ANSWER 4
Refer answers 3 and 7.
ANSWER 5A
Water Fluoridation
This may be defined as the upward adjustment of the concentration of fluoride
ion in a public water supply in such a way that the concentration of fluoride
ion in the water may be consistently maintained at one part per million (1
ppm) by weight to prevent dental caries with minimum possibility of causing
dental fluorosis.
It has been found to be the least expensive and most effective way of
providing fluoride to large groups of people of all ages. The first community
water fluoridation scheme began in Grand Rapids, USA in 1945. This was
followed by other large scale studies in several countries in the world.
5060% caries reduction in permanent teeth and 4050% reduction in
deciduous teeth is earlier, not now observed by water fluoridation. 90% smooth
surfaces are the most benefited and the occlusal surfaces at 35%.
`
Important Studies on Water Fluoridation
ANSWER 5B
Planning a Water Fluoridation Program
1. Collect baseline information:
Conduct the survey:
To find out the number of people in the city
The water source used by them
Analyze the water to estimate the fluoride concentration
Find out whether there is centralized water facility.
2. Permission:
To be obtained from the higher authority.
Governmental clearance.
3. Resources: Funds for installation, maintenance, monitoring of water
fluoridation plant and other expenses.
Location: Place for installing the water fluoridation plant.
Personnel: Intersectoral co-ordination between the government,
community leaders, doctors, health authorities, engineer, scientific
workers, nutritionist, public health personnel, grass root level worker.
4. Type of method to be used and the chemical used:
Different types of equipments for water fluoridation: Three types of fluoridation
equipments are commonly used:
a. Saturator system
b. Dry feeder system
c. Solution feeder system.
The different fluoride compounds which can be used in water
fluoridation are fluorspar, Sodium fluoride (expensive), Silico-fluorides,
Sodium silico- fluorides(economical, low cost), Hydrofluosilic acid.
5. Estimation of the quantity of fluoride to be added to the water: (Depends
on the climatic condition) The empiric formula for estimating the fluoride
in water is given by Galagon and Vermillion in 1957.
ppm fluoride = 0.34/E
Where E= 0.038 + 0.0062 Temperature of the area in Fahrenheit
98 / Questions and Answers in Community Dentistry
ANSWER 6
Collecting Necessary Information
1. Identifying the water source in the community and estimation of water
fluoride concentration.
2. Decide on the type of the water sample whether: Grab or catch sample,
composite sample or integrated samples. Also decide the sampling
frequency.
3. To decide on the defluoridation method to be employed in the community
baseline information needs to be collected regarding the physico-chemical
property of water (turbidity, hardness, alkalinity, chloride and sulphate
concentration).
4. Home to home survey to identify the cases of fluorosis (examine only those
who are residents of the city by birth).
5. Manpower planning: For the survey, the community leader can be made
use of selection of a fluorosis index for estimating the dental fluorosis.
Intersectoral co-ordination with a medical professional to examine skeletal
fluorosis is required. Arrangement for instruments, its sterilization,
recording proforma, traffic arrangements, schedules, examiners and
recording clerk need to be planned and made available in advance.
Mode of Action
Prepare report of the survey to be submitted to the higher authority explaining
the problem. Include all the activities which need to be done at the individual
level and also at the governmental level.
Referral Services
Provision has to be made so that the people are referred to the medical or
dental center for the treatment of the severe form of fluorosis.
ANSWER 7
Mechanism of Action of Fluoride
A number of proposed mechanisms have been identified which are assumed
to work simultaneously and can be grouped as follows:
1. Increase the enamel resistance (reduced enamel solubility)
2. Increase the rate of post eruptive maturation
3. Remineralization of incipient lesions
4. Interference with Plaque Micro-organisms
5. Modification in tooth morphology.
ANSWER 8
21 City Study
To test the hypothesis that an inverse relationship exists between endemic
dental fluorosis and dental caries, a survey of four Illinois cities was planned.
Altogether 885 children, aged 1214 years, were examined. The results were
clear: Caries experience in Macomb and Quincy was more than twice as high
as that in Galesburg and Manmoth. This study paved way for a much larger
Fluorides / 101
ANSWER 9
Shoe Leather Survey
Dr. H. Trendly Dean, first dental officer to pursue full time research on mottled
enamel was appointed for the research unit within the US Public Health service.
His first task was to continue McKays work and to find the extent and
geographical distribution of mottled enamel in the USA. He sent a
questionnaire to the secretary of every local and state dental society in the
country, asking if mottled enamel existed in their area and if so how extensive
was it and from what source was the drinking water obtained. In all 1197 of
individual questionnaires were sent and 632 replies were received. As a result,
Dean reported that there were 97 localities in the country where mottled
enamel was said to occur and this claim had been confirmed by a dental survey.
There were further 28 areas referred to in the literature where mottled enamel
was said to be endemic, but no confirmatory dental survey had yet been carried
out and there were 70 areas which had been reported by questionnaire but
which had yet to be confirmed by extensive surveys. Many of the confirmatory
surveys were carried out by Dean himself. He started in Courtland, Virginia
and then followed with examinations in North Carolina, Tennesse and Illinois.
Dean and his colleague referred to the investigations as Shoe Leather
epidemiology. His travel gave, Dean a very clear picture of the variation in
mottling which could occur. He developed a standard of classification of
mottling in order to record quantitatively the severity of mottling within a
community, in 1934.
ANSWER 10
Knutsons Technique
It is a professionally applied topical fluoride.
Name of the fluoride agent used: Sodium fluoride.
Concentration of fluoride: 2% (9040 ppm fluoride).
102 / Questions and Answers in Community Dentistry
Method of Preparation
20 gms of sodium fluoride is dissolved in 1 litre of distilled water to obtain 2%
concentration. The resultant solution is stored in plastic container and not in
glass container because fluoride reacts with silica to form silico-fluoride and
reduces the availability of active fluoride ions required for anti-caries
mechanism.
Method of Application
Firstly oral prophylaxis is carried out. Isolation of the teeth quadrant or half
mouth using cotton rolls. Dry the teeth by using compressed air. Required
quantity of fluoride solution is taken in the plastic container. Apply solution
on the teeth using an application brush (Paint on technique) quadrant-wise or
half mouth. Repeat application every 1530 seconds so as to keep the teeth
moist with the fluoride solution. Solution is applied on the teeth for 4 minutes.
Procedure is repeated on all the other isolated segments until all the teeth are
covered. The 2nd, 3rd and 4th application is not preceded by oral prophylaxis
and the flouride application is done at an interval of one week.
Mechanism of Action
When sodium fluoride is applied on the tooth surface, it reacts with
hydroxyapatite crystals to form a thick layer of calcium fluoride. This calcium
fluoride will react with hydroxyapatite to form fluorapatite which is more
stable, less soluble, increases the rate of post-maturation of enamel and
interferes with microorganisms enzymatic action and, increases
remineralization of incipient lesion. The solution is applied for only 4 minutes.
If applied for more than 4 minutes, a thick layer of calcium fluoride is formed
which does not allow the diffusion of fluoride ions from the topical solution
to react with hydroxyapatite. This phenomenon is called choking mechanism.
Advantages
Both the dentitions are benefited.
Chemically stable(fresh solution need not be prepared every time)
Acceptable taste.
Non-irritant to oral tissues.
Does not discolor the restoration.
Fluorides / 103
Disadvantages
Time consuming and longer visits (total of 16 visits).
ANSWER 11
Muhlers Technique
Name of the fluoride agent used: Stannous fluoride.
Concentration of fluoride: 810 % (19,500 ppm fluoride).
Recommended age groups: Children and adults.
Recommended practice: Annual or semi-annual.
Method of Preparation
0.8 gms of stannous fluoride containing capsule is dissolved in 10 ml of distilled
water in a plastic container and shaken briefly. The solution is not chemically
stable, hence it requires fresh preparation every time. The solution becomes
cloudy and instable because of the formation of tin hydroxide.
Method of Application
Firstly, oral prophylaxis is carried out. Isolation of the teeth quadrant or half
mouth using cotton rolls. Dry the teeth by using compressed air. Required
quantity of fluoride solution is taken in the plastic container. Apply solution
on the teeths using an application brush (Paint on technique) quadrant-wise
or half mouth. Repeat application every 15-30 seconds so as to keep the teeth
moist with the fluoride solution. Solution is applied on the teeth for 4 minutes.
Procedure is repeated on all the other isolated segments until all the teeth are
covered. The patient is instructed to avoid eating or rinsing the mouth for 30
minutes.
Mechanism of Action
The stannous fluoride reacts with the enamel to form a new compound which
is tin-tri-fluorophosphate which is responsible to make the tooth structure
more stable and resistant to caries. The reaction of stannous fluoride with
hydroxyapatite shows that mainly 4 end products are formed. Tin
hydroxyphosphate is formed when stannous fluoride is applied in low
concentration and the second end product is tintri-fluorophosphate. At very
high concentration of stannous fluoride, calcium tri-fluoro-stannate gets
formed along with tintri-fluorophosphate. Calcium fluoride in low
quantity is also the end product in both low and high concentration. It further
reacts with hydroxyapatite and fluorhydroxyapatite gets formed. The other
104 / Questions and Answers in Community Dentistry
end product tin hydroxy phosphate which gets dissolved in oral fluid and is
responsible for the metallic taste in the mouth following the application of
stannous fluoride.
Advantages
Less time consuming.
Can be applied annually or semi-annually.
Disadvantages
Chemically instable (Fresh solution has to be prepared every time).
Metallic taste after application.
Discolor the restoration.
Irritant to the tissues.
ANSWER 12
Brudevold Technique
The disadvantages of the stannous fluoride application resulted in search of a
new compound which will have more anti-cariogenic property and which
can be applied annually. As a result of this, Brudevold dissolved sodium
fluoride in acid media and added phosphorus to it. The resulting solution
was acidulated phosphate fluoride. The objective of dissolving acid in fluoride
was that the enamel can absorb more fluoride in acid media.
Name of the fluoride agent used: Acidulated phosphate fluoride (APF).
Concentration of fluoride: 1.23% (12,300 ppm fluoride).
Recommended age groups: Children and adults.
Recommended practice: Annual or semi-annual.
Method of Preparation
20 grams of sodium fluoride is dissolved in 1 litre of 0.1 M phosphoric acid to
which 50% hydrochloric acid is added to adjust the pH to 3 and the fluoride
ion concentration to 1.23%. For preparing acidulated phosphate fluoride gel a
gelling agent is added methylcellulose or hydroxyethyl cellulose and the pH
is adjusted between 45.
Method of Application
Firstly oral prophylaxis is carried out. Isolation of the teeth quadrant or half
mouth using cotton rolls. Dry the teeth by using compressed air. The solution
Fluorides / 105
is applied by paint on technique. A cotton applicator is dipped in the solution
and is applied on the teeth for 4 minutes. Repeat application every 1530
seconds so as to keep the teeth moist with the fluoride solution.
The acidulated phosphate fluoride gel is applied by a tray technique. Select
the foam tray that fit the patients upper and lower arch. Patient is made to sit
upright in the chair. Load the tray with the gel (2 gm/tray, 40% of the tray).
Gel is thixotrophic and will only flow under pressure and hence, full mouth is
treated simultaneously. The tray is placed in the mouth for 4 minutes. After
the trays have been positioned in the mouth the saliva ejector is used to
evacuate the stimulated saliva. The patient is asked to expectorate the excess
fluoride and not to eat or drink for 30 minutes.
Mechanism of Action
When APF is applied on the teeth, it initially leads to dehydration and
shrinkage in the volume of hydroxyapatite crystals which further on hydrolysis
forms an intermediate product called dicalcium phosphate dihydrate (DCPD).
This DCPD is highly reactive with fluoride ion and starts forming immediately
when APF is applied. Fluoride penetrates into the crystals more deeply through
the opening produced by shrinkage and leads to formation of fluoroapatite.
The principal products formed are DCPD and calcium fluoride. The calcium
fluoride formed is partly lost by dissolution in the saliva and substantial
amount is retained by transformation to fluoroapatite.
Advantages
Less time consuming
Requires only two applications per year.
More effective.
Disadvantages
It is acidic, sour and bitter in taste.
Prolonged exposure of APF gel to composites and porcelain can result in
surface changes.
ANSWER 13
Fluoride Mouthrinses
The use of fluoride mouthrinse was first described by Bibby in 1946. The clinical
trials have shown that daily rinsing with fluoride mouthwash reduces the
caries by 35%. The different compounds used for mouthrinsing are:
106 / Questions and Answers in Community Dentistry
Mechanism of Action
Caries is prevented or arrested by an efficient delivery of ionic fluoride to the
site in adequate concentration and duration.
ANSWER 15
Dental Varnishes
With all the currently used topical fluoride reagents, about 2/3rd of the fluoride
acquired after treatment is lost within days. To prevent the immediate loss of
fluoride, fluoride was added to a varnish like coating material which has the
ability to adhere to the enamel surface for a longer period of time. There is a
slow release of fluoride and varnish acts as a fluoride depot. The dental varnish
can form an important and feasible element in school based preventive
program. For example, of varnishes:
1. Duraphat
2. Fluor protector
3. Carex
Duraphat
Duraphat is the first fluoride varnish introduced in Germany. It is a viscous
yellow material containing 22,600 ppm of fluoride as sodium fluoride in a
neutral colophonium base (2.265% fluoride in organic lacquer).
Fluor Protector
Fluor protector is a clear polyurethane based product containing 7000 ppm
fluoride from an organic compound diflurosilane (Polyurethane lacquer
dissolved in chloroform and difluorosilane at a concentration of 2% weight
equivalent to 0.32% fluoride in the liquid).
Fluorides / 107
Carex
Carex is another fluoride varnish similar to duraphat but contains lower
fluoride concentration of 1.8% fluoride.
Method of Application
After prophylaxis the teeth are dried, not isolated with cotton as varnish sticks
to cotton. A total of 0.30.5 ml of varnish equivalent to 6.911.5 mg fluoride is
required to cover the full dentition. Application is done on the lower arch
then on the upper arch . After application patient is made to sit with mouth
open for 4 minutes. Fluoroprotector sets faster than duraphat. Patient is asked
not to rinse or drink anything at all for one hour and not eat anything solid
but take liquid and semi-solid till next morning.
ANSWER 17
Fluoride Dentifrices
Toothpastes are valuable adjuncts to oral hygiene which makes toothbrushing
more pleasant. Attempts have been made from various times to add
therapeutic agents with a objective of interfering with bacterial flora and
limiting the plaque formation and making the tooth more resistant to initial
caries. However fluoride dentifrices with varying concentration have been
used since 1945. The caries reduction is upto 30%. In 1955 stannous fluoride
dentifrice became the first dentifrice recognized by the FDA.
The fluoride agents which are used in the dentifrices are: Sodium fluoride,
stannous fluoride, sodium monofluorophosphate and amine fluoride.
Composition of Dentifrice
Mechanism of Action
Physico-mechanical: It is the combined effect of the toothbrush and the
dentifrice which is responsible for removing the plaque from the
toothsurfaces and thus reducing the cariogenicity.
108 / Questions and Answers in Community Dentistry
ANSWER 18
Topical Fluoride Application
These are developed on the basis that fluoride will react with enamel to form
fluoroapatite crystals which makes the tooth more resistant to acid attack,
increases the rate of postmaturation of enamel and interferes with enzymatic
action, increases remineralization of early carious lesions and thus helps to
prevent new dental caries. Substances used for topical application contain
high fluoride concentration. Bibby in 1941 was the first one to use fluoride
solution on the teeth. He applied 0.1% of sodium fluoride solution 8 times in
a year and caries reduction was 1520%.
Also refer Answers 10, 11, 12, 13, 14, 15 and 17.
Fluorides / 109
ANSWER 19
Fluoride tablets are recommended for the infants and children residing in the
area with inadequate water fluoridation. The tablets are prescribed by the
dentist or pediatrician and are not available over the counter. Fluoride
supplement is usually available in the form of sodium fluoride, acidulated
phosphate fluoride, Potassium fluoride or Calcium fluoride. It is available as
0.25, 0.5 and 1 mg tablet. The 2.2 mg sodium fluoride tablet contains 1.0 mg
fluoride, and 1.1 mg sodium fluoride tablet contains 0.5 mg fluoride.
Fluoride Dosage
The correct dosage of fluoride supplement is based on the concentration of
fluoride in the drinking water, age and weight of the child and other available
fluorides.
The council on Dental Therapeutics of the American Dental Association
recommends the dosage schedule for dietary fluoride supplements.
Concentration of fluoride in drinking water
Age (Years) < 0.3 ppm 0.30.7 ppm > 0.7 ppm
ANSWER 20
Salt Fluoridation
Salt is freely available and is used on large scale all over the globe. With the
introduction of iodized salt, it was felt that salt can act as a vehicle for fluoride.
Therefore fluoridation of salt was seen as a useful mode of systemic
fluoridation. Fluoridation of salt was suggested more than 30 years ago.
Dr Wespi (Gynecologist) was responsible for its introduction in Switzerland
for the first time. Initially the fluoride supplement was 90 mg/kg of salt,
however recently it has been raised to 250350 mg/kg of salt.
Preparation
Sodium or calcium fluoride can be mixed with a slightly moist salt or mixed
with a flow conditioner such as tricalcium phosphate and then mixed with
dry salt.
110 / Questions and Answers in Community Dentistry
Advantages
1. It does not require a centralized community water supply.
2. It permits individuals to accept or reject.
Disadvantages
1. Fluoridated salt consumption is lowest when the need for fluorides is
greatest.
2. The current view that a high salt intake may contribute to hypertension.
3. Difficulty in controlling the fluoride intake (fluoride can be ingested
through various sources)
4. The amount of fluoridated salt ingested may decrease with increasing
consumption of processed foods.
Mode of Action
Fluoridated salt raises ambient oral fluoride concentration throughout life in
a manner similar to water fluoridation. Marthaler et al, has observed substantial
reductions in caries experience in teeth exposed only post-eruptively to
fluoridated salt. It has a topical as well as systemic action.
ANSWER 21
Milk Fluoridation
Milk is an essential component of the human diet throughout life. Ziegler in
1956 was the first one to mention milk fluoridation as a possible method of
systemic fluorides. Fluoridated milk can be produced in a number of different
forms- liquid and powder. Flouride compounds which have been used include
sodium fluoride, calcium fluoride, disodium monofluorophosphate and
disodium silicofluoride. WHO experts committee (1994) has recommended
upto 1 mg fluoride per day according to the age and fluoride concentration in
the water supply. Studies have shown 4050 % caries reduction. The
bioavailability of fluoride is not reduced by milk and a low accumulation of
fluoride is found in the enamel. It is found that fluoridated milk keeps a
permanently low level of ionized fluoride within the oral cavity promoting
remineralization. However the use fluoridated milk have confirmed fluorides
dual mode of action, i.e. topical and systemic. The preventive effects of
fluoridated milk was greater, the earlier in the childs life the consumption
commenced. The concentration of fluoride in milk is 515 ppm.
Fluorides / 111
Practical Aspects
Milk fluoridation was not very successful because of variable consumption
patterns of milk which cannot be controlled and depends on the socio-
economic status, religion and ethnic factors.
Children residing in rural areas cannot afford milk.
Controversy of fluoride binding and complexing to calcium and protein
of the milk.
ANSWER 22
School Water Fluoridation
Where community water fluoridation is not feasible school water fluoridation
is a suitable alternative because school age children during school days would
consume it, thus making it one of the several effective alternatives for
prevention of dental caries in children. The reduction is found to be 40%. The
optimum fluoride concentration recommended for school water fluoridation
is 45 times more then the optimal level.
ANSWER 23
Water defluoridation is the downward adjustment of the fluoride ion
concentration in a public drinking water supply so that the level of fluoride is
maintained at the normal physiological limit of 1 ppm to prevent dental caries
with minimum possibility of causing dental fluorosis.
ANSWER 24
Defluoridation of water using Nalgonda technique- After extensively testing
since 1961, NEERI (National Environmental Engineering Research Institute
at Nagpur) has evolved an economical and simple method for removal of
fluoride which is referred to as Nalgonda technique (Fig. 8.4). It involves
addition of aluminum salts, lime and bleaching powder followed by rapid
mixing, flocculation, sedimentation, filtration and disinfection.
Mechanism
Rapid Mixing
Aluminum salts added to water may be in the form of aluminum sulphate,
aluminum chloride or combination of these two. Aluminum salt is responsible
for removal of fluoride from water. The dose of aluminum salt increases with
increase in fluoride and alkalinity levels of raw water and also depends on
chloride and sulphate concentration in water. The dose of lime is empirically
1/20th that of of aluminum salts. Lime facilitates forming dense floc for rapid
Fluorides / 113
Flocculation
Flocculators provide subsequent gentle agitation before entry into the
sedimentation tank. The flocculation period permits close contact between
the fluoride in water and poly aluminic species formed in the system. The
chemical reaction is complex. It is a combination of polyhydroxy aluminum
species complexation with fluoride and their adsorption on polymeric
aluminum hydroxides (floc). Besides fluorides, turbidity, colour, odour,
pesticides and organics are also removed. The bacterial load is also removed.
All these are adsorbed on the floc.
Sedimentation
It permits settling of the floc loaded with all the impurities which will be
removed by the filters.
Filtration
Rapid, gravity sand filters are suggested to receive coagulated and settled
water. In this filters, unsettled gelatinous floc is retained. Residual fluoride
and bacteria are absorbed on the gelatinous floc retained on the filter bed.
ANSWER 25
Toxicity of Fluoride
Fluoride is always referred as a double edged sword, in low concentration it
helps reduce dental caries but in high concentration it produces harmful effects
on the system. The toxic effects of fluoride can be divided into two types:
Acute fluoride toxicity and chronic fluoride toxicity.
Dental fluorosis Greater than twice the optimal level Until 5 years of age
of fluoride
Skeletal fluorosis 1025 mg/day of fluoride. 1020 years
ANSWER 26
Intraoral Fluoride Slow Release Devices
The intraoral slow release device is being developed for caries control. The
therapeutic fluoride agent is sealed within a plastic core that permits a
Fluorides / 115
calculated amount to be continuously diffused to the surface and into the oral
environment. The resulting cariostatic benefits are mainly from the continuous
local availability of fluoride. The device is made in the form of a plastic capsule
8 mm long, 3 mm wide, 2 mm thick and is attached to the buccal surfaces of
both the upper first molars by direct bonding with a sealant, e.g: Copolymer
membrane device, fluoride glass device.
ANSWER 27
Dietary Fluoride Supplements
The fluoride supplements were first introduced in the late 1940 and were
intended as a substitute for fluoridated water for children in non-fluoridated
areas.
ANSWER 28
Systemic Fluorides
It provides a low concentration of fluoride to the teeth over a longer period. It
circulates through the blood stream and is incorporated into the developing
teeth. After teeth erupts, fluoride contacts teeth directly through salivary
secretion.
ANSWER 30
Newbrun in 1989 demonstrated the Halo effect of fluoride. This occurs when
the residents of non fluoridated communities are exposed to the benefits of
fluoridation by the consumption of foods and beverages containing fluorides
processed in the fluoridated communities.
ANSWER 31
Probably toxic dose (PTD) is defined as the threshold dose that could cause
serious or life threatening systemic signs and symptoms and that should trigger
immediate emergency treatment and hospitalization.
PTD for an individual = 5 mg fluoride/Kg body weight.
ANSWER 32
Certainly lethal dose (CLD) = 3264 mg fluoride/kg body weight.
ANSWER 33
Safely tolerated dose (STD)= 1/4th CLD = 816 mg fluoride/kg body weight.
Dental Caries Vaccines / 117
QUESTIONS
1. Write a note on pit and fissure sealants.
2. Write a note on preventive resin restoration (PRR).
ANSWER 1
Pit and Fissure Sealant
Definition
A cement or a resin material that is introduced into unprepared occlusal pits
and fissures of caries susceptible teeth forming a micro-mechanical retent and
physical protective layer that acts to prevent the demineralization of the enamel
by blocking the interaction of cariogenic bacteria and their nutrient substances,
thus eliminating the harmful acidic byproducts.
Indications
1. Sound deep pits and fissures
2. Recently erupted teeth
3. Patients who are highly susceptible to caries.
Contraindications
1. Carious pits and fissures
2. Caries exists on other surfaces of the same tooth
3. When large occlusal restoration is already present.
Based on filler
1. Free of fillers: Have better flow.
2. Semi-filled: More resistant to wear.
Based on color
1. Clear: Difficult to identify during follow up.
2. Tinted: Easily identified.
3. Opaque: Easily identified.
Based on materials
1. BIS GMA (Bisphenol- a glycidyl methyl acrylate).
2. Cyanoacrylates
3. Polyurethanes
4. GIC.
Procedure
1. Polish the tooth surfaces.
2. Isolation and drying of surfaces.
3. Etching by using 37% of orthophosphoric acid for 1530 seconds.
4. Rinsing the tooth surfaces for 15 seconds.
5. Isolation and drying of surfaces.
6. Apply bonding agent.
7. Material application: Care should be taken to prevent air trap.
8. Evaluate the sealants.
9. Check occlusion.
10. Recall and periodic maintenance.
ANSWER 2
Preventive resin restorations (PRR) are an extension of the sealant technique.
Unlike the old philosophy of Extension for prevention wherein excess of tooth
Pit and Fissure Sealants / 119
reduction existed, this is a method of caries control with minimal loss of tooth
structure. This is indicated when caries within a fissure has just reached dentin.
The procedure involves removal of only those areas of the tooth affected by
caries using dental hand piece followed by bonding resin restorative material
into them, and finally covering all restorative material and any remaining
fissured anatomy with sealant.
Advantage
Minimal intracoronal preparation
Minimal tooth structure loss.
120 / Questions and Answers in Community Dentistry
QUESTIONS
1. Caries activity tests.
2. Snyders test (Refer 5 in Ans 1)
3. Albans test. (Refer 6 in Ans 1)
ANSWER 1
A caries activity test facilitates the clinical management of patients for the
following reasons:
1. To determine the need and the extent of personalized preventive measures.
2. To serve as an index of the success of the therapeutic measures
3. To motivate and monitor the effectiveness of educational programs relating
to dietary and oral hygiene procedures.
4. To manage the progress of restorative procedures.
5. To identify high risk groups and individuals.
The different caries activity tests are:
For the collection of the stimulated saliva, the patient sits in an upright
position with the head bent forward. Chewing on a paraffin block for a
period of 5 min is recommended. The saliva produced is collected in a
graduated tube. The flow rate is expressed as ml/min.
The risk limit value is < 0.7 ml/min.
Low flow rate limit value is 0.71.0 ml/min
Medium flow rate limit value is 1.12.0 ml/min
High flow rate limit value is 2.1 3.0 ml/min.
Caries Activity Test / 121
Interpretation:
1 No color change -
2 Beginning color change (from top of the medium) +
3 One half color change ++
4 3/4th color change +++
5 Total color change to yellow ++++
7. Salivary reductase test (Susceptibility test): This test measures the activity
of the reductase enzyme present in the salivary bacteria. A kit is available
under the trade name Treatex. Saliva is collected in a plastic container
.The sample is then mixed with the dye diazoresorcinol, the color changes
and the caries conduciveness reading is taken after 15 mins. No incubation
procedures are required.
Interpretation:
8. Enamel solubility test (Susceptibility test): It is based on the fact that when
glucose is added to the saliva containing powdered enamel, organic acids
are formed, this in turn decalcify the enamel, resulting in an increase in
the amount of soluble calcium in the saliva-glucose-enamel mixture. The
extent of increased calcium is supposedly a direct measure of the degree
of caries susceptibility. However, this test is not generally suited for office
procedures.
124 / Questions and Answers in Community Dentistry
QUESTIONS
1. Write a note on dental caries vaccine.
2. Limitations of caries vaccine.
3. Discuss the public health aspects of dental caries vaccine.
ANSWER 1
Dental Caries Vaccine
Since dental caries fulfills the criteria for an infectious disease, the possibility
of vaccination have been considered. Goady was probably the first to advocate
caries control in 1910, by inoculation of the mouth with organisms which would
provide alkaline reaction. Thereafter many studies have been done and many
are still under progress. Most of the immunological studies in caries have
been concerned with the streptococcus mutans (organism responsible for caries
initiation) and to a lesser degree with lactobacilli (organism responsible for
progression of the caries). The subcellular units that are currently been studied
seriously as vaccine are:
Glucosyltransferase (GTF): These are group of extracellular enzymes
involved in the synthesis of polymer from sucrose.
Wall associated proteins: Two purified proteins from the surface of
streptococcus mutans are currently been suggested for use as caries vaccine
antigen A and antigen B.
Mechanism of Action
The immune response is through the saliva and systemic immune response.
In saliva, with the production of secretory IgA, which plays an important role
in preventing the colonization of streptococcus mutans by agglutination
Dental Caries Vaccine / 125
of the organism. The second mechanism involves the systemic immune system
and the production of IgG antibodies that travel through the gingival epithe-
lium into the gingival crevicular fluid (GCF) that bathes the tooth and the
plaque.
Route of Administration
1. Systemic
a. Periglandular salivary immunization.
b. Salivary gland immunization by combined periglandular injection and
installation of streptococcus mutans into the parotid duct.
c. Parental immunization.
d. Oral submucous immunization
2. Topical (painting the tooth with antibodies)
Type of Immunization
1. Active immunization: Causes host tissue reactivity.
2. Passive immunization: Direct introduction of specific pre-targeted
antibodies in the mouth, e.g. monoclonal/polyclonal antibodies topically
applied.
ANSWER 2
Limitations of Caries Vaccine
The following factors will explain why successful vaccine has not been
developed:
1. Partial protection: Only certain percentage of disease is due to strep-
tococcus mutans and vaccine are developed against streptococcus mutans,
which will provide only partial protection.
2. Tolerance development: Since the disease is life long, the constant exposure
to an antigen may lead to development of tolerance or to immune exclusion.
3. Disease of hard tissue: which does not bring contact of the organism with
the immune system. The organism does not come in contact with
phagocytes and complement system.
4. Cross reactivity: Antigen B has been suggested to have shown cross
reactivity with the heart cells.
5. Caries is a multi-factorial disease.
ANSWER 3
An important question always arises whether the search for a caries vaccine
is justified from a public health point of view. Two reasons for this can be
stated;
126 / Questions and Answers in Community Dentistry
12 Atraumatic Restorative
Treatment (ART)
QUESTION
Write a note on ART.
ANSWER
Dental caries is a widespread problem all over the world. In many developing
countries most of these cases are untreated leading to extraction. To meet this
problem, ART technique was developed mainly for the developing countries.
It was pioneered in the mid 1980s by Dr. Joe Frencken, in Tanzania as a part of
the community based primary oral health care program for the refugees by
the University of Dar es Salaam. In 1994, WHO introduced ART as a part of
oral health for healthy life.
This procedure involves excavating and removing caries with hand
instruments and restoring with adhesive filling like Glass Ionomer Cement
(GIC).
Advantages of ART
1. Non-threatening.
2. Non-painful.
3. Does not need local anesthesia.
4. Expensive electrically driven equipments are not used, so it is cost effective.
5. Only hand instruments are used.
6. Requires minimal cavity preparation, so conservation of sound tooth
tissues.
7. Easy sterilization of hand instruments.
Indications
1. It is indicated in teeth where caries is involving only dentin.
2. In those areas where hand instruments are accessible.
128 / Questions and Answers in Community Dentistry
Contraindications
1. Not used in cavities reaching pulp and with periapical abscess.
2. In those areas where hand instruments are not accessible.
Even non-dental professionals or primary health care workers can be
trained for this procedure. This technique can be carried out in schools, primary
health centers, villages and remote areas.
Procedure
1. Isolation of the tooth.
2. Removal of caries using excavators and prepare the cavity with other hand
instruments.
3. Dry the cavity.
4. Apply dentin conditioner.
5. Mixing of GIC powder and liquid.
6. Cavity and adjacent pits and fissures are overfilled.
7. Press the restorative material with petroleum jelly coated gloved finger.
8. Remove excess material with carver and apply varnish.
9. Check occlusion.
Limitations
1. Long term survival rates for glass ionomer ART restorations and sealants
are not yet available, the longest study reported so far is of three years
duration.
2. The techniques acceptance by oral health care personnel is not yet assured.
3. The use is limited to small and medium sized, one surface lesions because
of low wear resistance and strength of existing glass ionomer materials.
Atraumatic Restorative Treatment (ART) / 129
4. The use of hand instruments over long periods can lead to hand fatigue.
5. Unstandardized mix of the material because of hand mixing, variation
among operators and different geographical/climatic situations.
6. The apparent lack of sophistication of the technique.
7. The misconceptions by the public that the new glass ionomer white fillings
are only temporary dressings.
130 / Questions and Answers in Community Dentistry
13 Epidemiology of
Periodontal Diseases
QUESTIONS
1. Epidemiology of periodontal diseases.
2. Local factors in the etiology of periodontal diseases.
ANSWER 1
Epidemiology of periodontal disease is explained under host, agent and
environment factors:
Host Factors
Age
Survey data generally says that severity of the disease increases as age
advances. The prevalence of periodontal disease is approximately 45% at
10 years of age, 67% at 20 years, 70% at 35 years and 80% at 50 years. There is
a nine-fold increase in the prevalence of destructive periodontal disease with
pocket formation between 2070 years of age.
Sex
In general, males consistently have a higher prevalence and severity of
periodontal disease than females. The male enter the beginning phase of
destructive periodontal disease at approximately 35 years of age, while female
enter by 45 years of age. Day states that in India, females show significantly
lower bone loss than do the males.
Race
As per the studies done by Russell in United States, blacks showed high
prevalence and severity of periodontal disease than whites.
Epidemiology of Periodontal Diseases / 131
Intraoral Variations
The variations in the plaque, gingivitis, calculus and bone loss put together
produce the intraoral variation pattern of the periodontal disease in the
individual. The teeth most affected are upper molars, lower central incisors
and laterals. The teeth moderately affected are the lower molars, upper central,
lateral incisor premolar and lower canine. The teeth least affected are lower
bicuspids and upper canines. Bone loss and gingivitis is more severe in maxilla
compared to mandible/more severe in the interproximal area then buccal
and lingual.
Less periodontal disease is observed on the left side of the mouth as right
handed people brush left side better than right.
Endocrine Changes
Hormonal changes during puberty, pregnancy, menstruation and menopause
increases susceptibility for gingival disturbances and periodontal lesions.
Tobacco
There is a clear association between smoking and periodontal disease. There
is increasing scientific evidence that smoking has a detrimental effect on the
progression of periodontal disease and healing after periodontal therapy. Heat
and the accumulated products of combustion are particularly undesirable local
132 / Questions and Answers in Community Dentistry
Oral Hygiene
Poor oral hygiene is an important risk factor in highly susceptible individuals.
Improper or inadequate use of oral hygiene aids leads to accumulation of
plaque and calculus which increases the risk for the occurrence of gingival
and periodontal disease.
Iatrogenic Factors
Few iatrogenic factors may cause irritation to gingiva, acts as foci for plaque
formation, or leads to food impaction.
a. Margins of restoration which are over hanging.
b. ContoursOver contoured/under contoured crowns and restorations.
c. Inadequate proximal contacts.
d. OcclusionOver occlusion/under occlusion leads to traumatic occlusion
or food impaction.
e. Design of removable partial denturesFavors accumulation of plaque if
they cover gingival tissue or is impinging on the gingiva.
f. Improper use of rubber dam clamps, copper bands, matrix bands leads to
laceration and gingival inflammation.
Epidemiology of Periodontal Diseases / 133
Socioeconomic Status
Periodontal disease is inversely related to the increasing levels of income.
Study by Mehta et al in Bombay showed that periodontal disease increases
in low socioeconomic status and decreases in high socioeconomic status. In
high socioeconomic status people there is better oral hygiene, good educa-
tion and greater visits to dentist. Poor oral hygiene and gingivitis is related
to lower socioeconomic status. Few cultural factors associated with low
socioeconomic status people may also act as a predisposing factor for peri-
odontal disease.
Educational Background
Russel finds that periodontal disease is inversely related to degree of educa-
tion. This is because of more systematic home care, and dental maintenance
care among well educated people. Occupation along with education shows
relationship with periodontal disease e.g: The prevalence and severity of
periodontal disease are lower in office personnel than in factory workers.
Agent Factors
Plaque and Calculus
The most important local factors causing periodontal disease is bacterial plaque
and calculus. Various bacterial flora are responsible for gingivitis and various
periodontal diseases. Most widely accepted specific plaque hypothesis states,
specific micro organisms are responsible for specific periodontal diseases.
Supragingival plaque mainly constitutes gram positive cocci and rods
like outer surface, mature plaque contains gram negative rods, filaments and
Spirochaetes.
Sub gingival plaque has tooth attached and tissue attached plaque.
Tooth attached plaque mainly contains gram +ve rods and cocci like
streptococcus mitis, streptococcus sanguis, actinomyces viscosus.
Tissue attached plaque constitutes gram negative rods and cocci, filaments,
like porphyromonos gingivalis, prevotella intermedia, fusobacterium
nucleatum, campylobacter species, spirochaetes, peptostreptococcus micro
organisms.
134 / Questions and Answers in Community Dentistry
Chemicals
Certain chemicals like mercury, lead, bismuth phosphorus, arsenic, phenols,
silver nitrate, chromium, benzene, thallium are known to show harmful effects
on periodontal tissues. Drug like aspirin cause aspirin burns.
Environmental Factors
Geographic Areas
Russel found in few countries like Thailand, Burma, Malaya, Ceylon, India
and Jordon, a relatively high prevalence of periodontal disease. But there is a
weak generalization to say that underdeveloped and dentist deprived areas
show greater periodontal disease than developed countries.
Nutrition
There is no consistent association established between periodontal disease
and nutrition. It is a secondary factor in the etiology of periodontal disease.
There is a possibility that generalized malnutrition may influence its severity,
vitamin C deficiency causes scurvy, vitamin A deficiency has more chance of
developing deep periodontal pockets and vitamin D deficiency shows
osteoporosis and poor bone density. Vitamin B complex deficiency shows
gingival inflammation. Niacin deficiency shows necrotic gingivitis. In animal
studies shows that protein starvation and magnesium deficiency has effect
on periodontium.
Radiation
Radiation therapy develops erythema and desquamation of oral mucosa
including gingiva, leading to ulceration, and infection. Irradiated bone shows
acellularity and avascularity with loss of osteoclasts and osteoblasts which
makes bone more susceptible to infections. Periodontal disease is considered
as a portal of entry for infection and development of osteo radionecrosis after
radiation therapy.
Degree of Urbanization
In general, the prevalence and severity of periodontal disease is slightly higher
in rural areas than in the urban areas.
Epidemiology of Periodontal Diseases / 135
ANSWER 2
Classification of Etiological Factors
Local Factors
1. Deposits on teeth
a. Supragingival (salivary), calculus.
b. Subgingival (serumal) calculus.
c. Materia alba.
d. Mucinous plaque.
e. Protein pellicle.
2. Abnormal habits
a. Unilateral mastication.
b. Abnormal biting habits.
c. Clenching and bruxism.
3. Food impaction
a. Vertical.
b. Horizontal.
4. Non detergent diet
5. Other irritants
a. Mechanical irritants.
b. Chemical irritants.
c. Atmospheric irritants.
d. Improper orthodontic procedures.
e. Improper tooth brushing.
6. Abnormal anatomy
a. Hard tissue structures
i. Tooth form
ii. Tooth contour
iii. Proximal contact
iv. Tooth position
b. Soft tissue structures
i. Abnormal attachment of frenum
ii. Eruption of teeth
7. Factors of occlusal function
a. Overfunction
i. Excessive stress on teeth
ii. Insufficient periodontal support
iii. Too powerful masticatory musculature.
b. Underfunction
i. Premature wear
136 / Questions and Answers in Community Dentistry
Systemic Factors
1. Faulty nutrition.
2. Debilitating diseases.
3. Blood dyscrasias.
4. Endocrine dysfunctions.
5. Allergies and drug idiosyncrasies.
6. Roentgen, radium and atomic radiation.
7. Psychogenic factors.
8. Iatrogenic factors.
137 / Question andPrevention
Answers inand
Community
Control of
Dentistry
Periodontal Diseases / 137
Prevention and
14 Control of
Periodontal Diseases
QUESTIONS
1. Define plaque control and discuss plaque control methods.
2. a. Dental floss.
b. Interdental brushes
c. Wooden tips
3. Dentifrices.
4. Chlorhexidine mouthwash.
5. Tooth brushes.
6. Mechanical plaque control. (Refer Ans: 1, 2, 3, 5)
7. Chemical plaque control. (Refer Ans: 1, 4)
8. Level of prevention for periodontal disease.
ANSWER 1
Plaque control is the removal of microbial plaque and the prevention of its
accumulation on the teeth and adjacent gingival surfaces.
Plaque control is divided into mechanical and chemical plaque control.
Mechanical
1. Tooth brushes:
a. Manual tooth brushes.
b. Electrical tooth brushes.
2. Dentifrices
3. Interdental cleansing aids:
a. Dental floss.
b. Wooden tips.
c. Interdental brushes like
138 / Questions and Answers in Community Dentistry
i. Proxabrush.
ii. Unitufted brush.
iii. Miniature bottle brush.
d. Rubber tips.
e. Knitting yarn.
f. Pipe cleanser.
g. Gauze strip.
4. Oral irrigation devices
5. Prophylaxis by professionals.
Chemical
1. Enzymes:
Mucinase, dehydrated pancreas, mutanase, dextranase.
2. Antibiotics:
Penicillins, vancomycin, erythromycin, Kanamycin.
3. Phenols:
Thymol, triclosan.
4. Quaternary ammonium compounds:
Benzalkonium chloride, cetylpyridium chloride, benzethonium
chloride, domiphen bromide.
5. Bisbiguanides:
Chlorhexidine, Alexidine.
6. Bispyridines:
Octenidine.
7. Metallic salts:
Zinc, tin, copper.
8. Herbal extracts:
Sanguinarine.
9. Aminoalcohols:
Octapinol, decapinol.
10. Other surfactants:
Sodium lauryl sulphate.
ANSWER 2a
Dental Floss
This is made up of nylon thread used to remove plaque in the proximal surfaces
of the teeth.
Prevention and Control of Periodontal Diseases / 139
Uses
1. Used to remove plaque and food debris between the teeth or in
interproximal embrasures.
2. Remove plaque under pontics of the fixed partial denture.
3. Stimulating and massaging interdental papillae.
4. As a vehicle to carry therapeutic agents like fluoride solutions.
5. To locate subgingival calculus, overhanging margins of restorations, and
proximal carious lesions.
Types
1. Thick, medium, thin and exxtra-thin.
2. Twisted or untwisted.
3. Bonded or unbonded.
4. Waxed or unwaxed.
Method of Use
Stretch the floss between two forefingers or between thumb and forefinger.
Gently pass the floss into contact area by back and forth motion. Do not
snap the floss. Once it has entered into the contact area wrap it around the
proximal surface of the tooth, like semi-circle and move the floss down to
contact area. Repeat up and down strokes.
A dental floss holder is one in which floss is tied between two prongs and
it has a handle. It is designed to be used by patients like physically
handicapped patients, patients with restricted mouth opening and anyone
who would prefer to use it.
It is indicated for type-I embrasure when there is no gingival recession.
ANSWER 2b
Interdental Brushes
They are cone-shaped brushes made of bristles mounted on a handle, e.g.
Single tufted brushes, miniature bottle brush, cone shaped bristle brush and
cone shaped plastic brush. These are particularly suitable for cleansing large,
irregular or concave tooth surfaces adjacent to wide interdental spaces. They
are inserted interproximally and are activated with the short back and forth
strokes in between the teeth. For best cleaning efficiency the diameter of the
brush should be slightly larger than the gingival embrasure so that the bristles
can exert pressure on the tooth surfaces, working their way into concavities
on the roots. Interdental brushes are indicated in Type II embrasures
(moderate papillary recession) and unitufted brush is recommended in Type
III embrasure. These are useful in patients with open embrasures.
140 / Questions and Answers in Community Dentistry
ANSWER 2c
Wooden Tips
These are available with or without handle. Stim-U-Dent is triangle wooden
tip without handle. It is inserted into interdental space with base of the triangle
resting on the gingiva and the sides of triangle touching proximal surfaces of
the tooth. It is moved in and out of the embrasure. It removes plaque and also
stimulates gingiva. Perio-aid is a wooden tip with handle and used on the
facial or lingual surfaces throughout the mouth. This is efficient in cleaning
gingival margin and periodontal pockets.
ANSWER 3
Dentifrices (Dens = tooth, fricore = to rub)
They are the aids used for cleaning and polishing tooth surfaces. They are
usually available in the form of paste, also available in powder form and as
gel. Dentifrices are of two types: Cosmetic and therapeutic.
The ingredients are as follows:
1. Abrasives: Abrasive action eliminates plaque and removes stained pellicle
and polishes the teeth, e.g. Calcium carbonate, Dicalcium phosphate
dihydrate, etc.
2. Surfactants/detergents/ foaming agents: The foam produced helps in the
removal of debris and plaque, e.g. sodium laurylsulphate, sodium-N-
laurylsarcosinate.
3. Humectants: They preserve moisture and maintain the consistency of the
paste, e.g. Glycerine, Sorbitol, Polyethyl glycerol.
4. Binders: They bind the solid ingredients and form a homogenous paste,
e.g. Sodium carboxylmethylcellulose, alginates.
5. Flavouring agents: To provide flavour, e.g. Spearmint oil, peppermint oil,
oil of wintergreen.
6. Sweetening agents: e.g. Sorbitol, mannitol and saccharin.
7. Preservatives: To prevent microbial growth, e.g. benzoic acid.
8. Colouring agents.
Therapeutic Dentifrices
These contain the basic constituents of a dentifrice and also therapeutic agents
for specific purpose. They are as follows:
1. Anticaries dentifrices: Contains fluoride from 550 ppm to 3000 ppm. To
prevent dental caries, agents used are sodium fluoride, sodium mono-
fluorophosphate.
Prevention and Control of Periodontal Diseases / 141
ANSWER 4
Chlorhexidine Gluconate
It is used as one of the chemical plaque control agents which is classified
under cationic chlorophenyl bisbiguanide group. It has both bacteriostatic
and bactericidal action in low and high concentration respectively.
Instruction
1. Short term therapy: Rinsing with 10 ml of 0.2% aqueous solution, two
times daily for 3045 seconds.
2. Long term therapy: 1:1 dilution of chlorhexidine with water is used for
rinsing, twice daily for 3045 seconds.
Mechanism of Action
Chlorhexidine inhibits plaque formation by the following ways:
1. It effectively blocks acidic group of salivary glycoproteins which will reduce
their adsorption to hydroxyapatite and prevents formation of acquired
pellicle.
2. Chlorhexidine adsorbs to extracellular polysaccharides of bacterial capsules
or glycocalyx and prevents their adherence to the tooth surface.
3. Chlorhexidine may compete with calcium ions for acidic agglutination
factors in plaque.
Depending on the bacterial species and the amount of chlorhexidine
attached to the tooth surface, these microorganisms are either killed or are
simply prevented from multiplying.
Uses
1. After periodontal surgery.
2. As a prophylactic rinse before ultrasonic scaling, and extractions.
3. As a subgingival irrigation after scaling and polishing of periodontal
pockets.
142 / Questions and Answers in Community Dentistry
Adverse Effects
1. Discolors the teeth to yellowish brown extrinsic stains.
2. Painful desquamative lesions of oral mucosa.
3. Transient impairment of taste sensation.
ANSWER 5
Toothbrushes
The bristle toothbrush appeared about the year 1600 in China, was first
patented in America in 1857. Different types of toothbrushes available are as
follows:
1. Manual
2. Powered by battery or electricity.
3. Sonic and ultrasonic toothbrushes.
4. Ionic toothbrushes.
According to the size: Toothbrush should be selected according to age and
size of the jaws:
1. Large or adult size.
2. Medium size.
3. Small size.
4. Baby size.
According to the hardness: Stiffness and firmness of bristles:
1. Extra hard.
2. Hard.
3. Medium.
4. Soft.
5. Extra soft or super soft.
Pattern of the bristles: Multitufted regular or Crisscross pattern, with or
without indicator.
According to the Bistle material
1. Natural bristles (from hogs).
2. Artificial filaments (nylon).
Prevention and Control of Periodontal Diseases / 143
Powered Toothbrushes
In 1939, electrically powered toothbrushes were invented. There are many
types of toothbrushes, some with reciprocal or back and forth motions, some
with combination of both, some with circular and some with elliptical motion.
Regardless of type of device, best results are obtained if patient is instructed
to use properly. Placement of the moving bristles should be placed correctly
around the mouth. These are recommended for:
1. Individuals lacking fine motor skills.
2. Small children or handicapped or hospitalized patients who need to have
their teeth cleaned by someone else.
3. Patients with orthodontic appliances and
4. Patients who prefer them.
Ionic Toothbrushes
They change the surface charge of a tooth by an influx of the positively charged
ions. The plaque with a similar charge is thus repelled from the tooth surface
and is attracted by the negatively charged bristles of the toothbrush.
144 / Questions and Answers in Community Dentistry
ANSWER 8
Level of Prevention for Periodontal Disease
Epidemiology of Oral
15 Cancer/Prevention and
Control of Oral Cancer
QUESTIONS
1. Discuss the epidemiology of oral cancer.
2. Discuss the various contributing agent factor in the occurrence of oral
cancer (Refer Ans 1)
3. Describe the prevention and control of oral cancer.
4. Describe the various levels of prevention for oral cancer.
5. Toluidine blue staining.
6. Exfoliative cytology.
ANSWER 1
Oral cancer is one of the 10 most common cancers in the world. In the
industrialized countries it ranks second to cardiovascular diseases. In
developing countries it ranks third.
trigone (5%) grouped together as the gingivo- buccal complex can be called
Indian oral cancer as they constitute more than 60% of all cancers. In females
the most affected sight is buccal mucosa and palate.
Occupation: Textile workers show an increase risk of cancer in oral cavity.
Male leather workers show an increase risk of cancer of buccal cavity, larynx
and pharynx.
Ethnic variation: Ethnicity strongly influences prevalence as a result of social
and cultural practices, e.g. among the Indians living in Malay Peninsula, the
overall incidence of oral cancer has long been considerably higher than that
among the Malay or Chinese subjects. In US the incidence and mortality rates
for black Americans are substantially higher than those for white Americans.
Familial and genetic predisposition: There is little evidence of a strong effect
of familial and genetic predisposition to oral cancer. Of some relevant studies,
in Kerala a familial association was seen in 0.94% of total oral cancers that
occurred from January to June 1995, consistent with an autosomal mode of
inheritance.
Demographic shift: Urbanization, industrialization, changes in lifestyle,
population growth and increase in the age expectancy have contributed for
epidemiological transition in the country. Changes in the age expectancy alters
the disease pattern associated with the age and increases the burden of
problems such as cancer.
Agent (Etiology)
Tobacco: The role of tobacco in the etiology of oral cancer have been shown in
numerous studies. Data for India, says that 90% of oral cancer is directly
attributable to chewing and tobacco smoking. 70% smoke bidi, 10% smoke
cigarette and 20% use smokeless tobacco.
The various smoking habits prevalent arebidi, chillum, chutta, cigarettes,
dhumti, gudakhu, hookah, hookli.
The various smokeless varieties are khaini, mainpuri tobacco, mawa,
mishri, paan, snuff, jarda. Raw and processed tobacco has been shown to
have more than 2500 different chemical compounds. The most potent
carcinogen in tobacco are: tobacco specific nitrosamines, nicotine, phenol,
benzopyrene, carbon monoxide and polycyclic aromatic hydro carbons, tar,
etc.
Alcohol: A synergistic effect of tobacco and alcohol has been observed. They
account for 75% of all oral and pharyngeal cancers. Alcohol may promote
carcinogenesis by various mechanisms which may include dehydrating effects
Epidemiology /Prevention and Control of Oral Cancer / 147
Other Agents
All these factors can contribute towards increasing the risk of oral cancer.
Biological:
ViralHuman papilloma virus, herpes simplex virus (HSV-1), Epstein-
Barr virus
Immunological disorders
Fungal infection: Candida infections
Mechanical:
Irritation from jagged teeth or denture
Poor oral hygiene
Chemical:
Arsenic, dyes, nickel, aromatic amines, chromium.
Environmental Factors
Effects of solar radiation: Occupation like farming, fishing, forestry and postal
delivery are at risk due to long term exposure to UV radiation, e.g. lip cancer,
Solar keratosis leading to Squamous cell carcinoma.
Effects of atmospheric pollution: Air pollution caused by release of a number
of gases from factories, automobiles can act as a risk factor in the initiation of
the cancer.
148 / Questions and Answers in Community Dentistry
ANSWER 3
Prevention and Control of Oral Cancer
It has been estimated that 6580% of oral cancer is environmental, attributed
to lifestyle factors and thus can be prevented.
There are three main public health approaches:
Regulatory or legal approach
Service approach
Educational approach.
The prevention and control of oral cancer spans the spectrum from primary
prevention, through early detection, to treatment and after care.
Regulatory Approach
This applies to the governmental control of overuse of tobacco. As early as
1590, first governmental edict against tobacco use was declared in Japan where
users were penalized by having their property confiscated or were jailed. In
1604, King James in England, increased the tax on tobacco by 4000% and in
1605, organized at Oxford the first public debate concerning the effects of
tobacco. Similar edicts have been reported from the 17th century in Turkey,
Russia and China. In 1965, USA legislation was passed requiring cigarette
packages to carry a health hazard warning.
In India, the Cigarette Act, 1975 had made it necessary to print warning
Cigarette smoking is injurious to health on the cigarette packets. Banning
of advertisement on tobacco products has been undertaken. In 1985, National
Cancer Control program has been started, which gives high priority for
primary prevention of tobacco related cancers. Smoking in public places is
banned. Maharashtra has taken lead in formulating state policy to make
existing tobacco control legislature operative and use of governmental media
for educational program.
Legislation should be enacted to:
To prohibit the sale or handling over to minors of tobacco products for
chewing or smoking
Placing health warning on the cigarette packets and at places where it is
sold
Prohibiting advertisements of tobacco products
Restrict smoking of tobacco products in enclosed public places
Increase taxes on tobacco products
Regulate the content of tobacco products: to reduce tar, nicotine and other
carcinogenic agents.
Epidemiology /Prevention and Control of Oral Cancer / 149
Service Approach
This embodies screening of people for diagnosing cancer in its early stage.
The oral cavity is easily accessible and its examination poses relatively little
discomfort to the patient. It provides opportunity to identify and counsel
patients about habits that increase the risk of oral cancer. The techniques used
in screening are:
Toludine blue vital staining
Exfoliative cytology
Biopsy techniques.
Educational Approach
Education has a important role to play in discouraging people from starting
its use and helping people to stop the habit. Encouraging results with health
education to disuse from tobacco habits have been observed in a study of
12,000 adult rural population by Mehta et al.
Levels of prevention for oral cancer
Levels of Primary prevention Secondary Tertiary prevention
prevention prevention
Preventive Health Specific Early Disability Rehabilitation
services. promotion protection diagnosis limitation
and prompt
treatment
Services Periodic visit Avoidance Self Use of Use of
provided by to dental of known examination dental dental
individual office; irritants and referral; services services
patient demand for use of dental
preventive services
services.
Services Patient Removal of Complete Chemotherapy; Maxillo-
provided by education known examination; radiation facial and
the dental irritants in biopsy; oral therapy; removable
professional the oral cytology; surgery prosthodontics;
cavity complete plastic
excision surgery;
speech
therapy;
counseling
Services Dental Periodic Provision of Provision of
provide for health screening dental dental
community education and referral; services services
programs; provision of
promotion of dental
research services
efforts; lobby
efforts
150 / Questions and Answers in Community Dentistry
Secondary Prevention
At present in the developing countries, more than 50% of cancers are detected
only after they have reached an advanced stage. Treatment required will be
Epidemiology /Prevention and Control of Oral Cancer / 151
both extensive and expensive and the survival rate are low. Hence, early
detection can be very helpful.
Early detection: The natural history and anatomical site of oral cancer, provide
excellent opportunity for early detection. Efforts at early detection can take
many forms:
Educate and encourage individuals to examine their own mouths for early
signs of cancer.
Screening the patients, who visit for other reasons.
Organization and government can sponsor large scale efforts to seek out
and examine groups of the population at risk.
De-addiction program: The patient can be motivated to go in for a de-addiction
program.
Tertiary Prevention
Treatment modalities: The main treatment modalities are surgery, radio-
therapy and chemotherapy. Prognosis will depend on the stage of the cancer.
Additionally, supportive measures have an important impact on the
effectiveness of the therapy. Good nutrition, attention to oral hygiene and
dental care is especially important to prevent the adverse effects of the
treatment, like osteoradionecrosis.
Rehabilitation: The objective of rehabilitation is to restore the patient to as
normal a state of health. Reconstructive procedures may include correction
of cosmetic defects, speech, swallowing and respiration. The extent of
rehabilitation that will be needed is directly proportional to the extent of
surgical excision.
ANSWER 4
(Refer levels of prevention for oral cancer in answer 3)
ANSWER 5
Toluidine Blue Vital Staining
It is a technique which has been used as a diagnostic adjunct to biopsy which
can guide biopsy procedure by localizing small foci of tumor cells within the
larger area of inflammation. A 1% solution of toludine blue dye (A basophilic
vital nuclear dye) is used as a mouthwash and retained over the area of the
diffuse lesion for nearly one minute. The area is then irrigated with 1% acetic
acid. This stains the malignant lesions but not the normal tissues. It is
remarkably reliable. False negative and false positive rates are significantly
low with toluidine blue staining.
152 / Questions and Answers in Community Dentistry
ANSWER 6
Exfoliative Cytology
It has been advocated as an adjunct to biopsy. The surface from where the
specimen has to be taken must be first cleared of all debris and necrotic tissues.
The edge of a moistened tongue blade is used to scrape the suspected area.
Atleast, two samples should be taken. An adequate number of representative
cells are usually picked up. The sample is then transferred to a glass slide and
placed in 95% alcohol for 30 minutes, after this it is kept for fixation. The
slides can be removed and air dried before forwarding it for microscopic
evaluation in the laboratory. It is quick, simple, painless and bloodless
procedure. It is especially helpful in follow-up cases of recurrent carcinoma
in previously treated cases. The smear obtained is reported by cytologist as
falling in one of the five classes.
Class I: Normal
Class II: Indicates presence of minor atypia but no evidence of malignant
changes.
Class III: The cells display minor atypia that may be suggestive of cancer.
Class IV: A few cells with malignant characteristics. Biopsy is mandatory.
Class V: Cells are malignant. Biopsy is mandatory.
153 / Question
Epidemiology
and Answers
of Malocclusion/Preventive
in Community Dentistry Orthodontics / 153
Epidemiology of
16 Malocclusion/
Preventive Orthodontics
QUESTIONS
1. Etiology of malocclusion .
2. Preventive orthodontics.
3. Space maintainers .
4. Interceptive orthodontics .
ANSWER 1
Role of each factor in the development of malocclusion:
By Grabers classification:
General Factors
1. Hereditary: This factor is indicated as chief cause of malocclusion. This is
influenced by environmental nutritional disturbances and idiopathic
phenomenon. A child may have features resembling one of the parents or
a combination of both parents.
Hereditary plays a role in the following conditions like:
a. Congenital deformities: Cleft lip and plate.
b. Facial asymmetries.
c. Macrognathia and micrognathia.
d. Oligodontia and anadontia.
e. Tooth shape variations: Peg laterals, Carabellis cusp, etc.
f. Deep overbite
g. Mandibular retrusion and mandibular prognathism.
2. Congenital: Congenital defects have a strong genetic relationship. Few
congenital conditions associated with dental malocclusion are as follows.
a. Cleft lip and palate.
b. Cerebral palsy
154 / Questions and Answers in Community Dentistry
c. Torticollis
d. Cleidocranial dysostosis
e. Congenital syphilis.
3. Environmental:
a. Prenatal: The role of prenatal influences on malocclusion is said to be
small. But factors like posture of the foetus, fibroids, amniotic lesions,
maternal diet and metabolism, drug induced deformities as with
thalidomide, injury or trauma, German measles, etc. act as predisposing
factors for malocclusion, Congenital deformities like cleft lip and cleft
palate are mainly associated with German measles and medications
during pregnancy.
b. Postnatal and birth injuries: Injuries to infants cranium at birth with
high forceps delivery is an example for birth injuries. This can lead to
i. Hypoplasia of mandible.
ii. Ankylosis of TMJ joint which can inhibit growth of mandible.
iii. Cerebral palsy.
Other postnatal causes are condylar fractures which can lead to
facial asymmetries scar tissue of cleft palate surgery can affect normal
palate growth, prolonged Milwaukee brace wear can lead to restricted
mandibular growth.
4. Predisposing factors:
a. Endocrine imbalance: Endocrine glands have influence on formation,
calcification and eruption of teeth, growth pattern of jaws, face and
cranium. Any endocrinal imbalance can lead to malocclusion.
Example: In hypothyroidism there is delayed tooth eruption,
retardation of formation of bone, narrowing of dental arches and
submerging of teeth.
In hyperthyroidism we can see retardation of skeletal and bone
growth and osteoporosis.
During hypoparathyroidism there are irregular and accentuated
zones of under and over calcification of enamel and dentin.
Hyperparathyroidism shows dentin hypocalcification, osteitis
fibrosa, resorption of alveolar bone leading to tooth mobility.
b. Metabolic disturbances: The exact effects of the acute febrile conditions
on the development of occlusion is not known, but they can bring about
disturbances during the time of eruption, resorption, exfoliation, etc.
c. Infectious diseases: Diseases like poliomyelitis, disease with muscle
malfunction like muscular dystrophy and cerebral palsy can have
deforming effects on dental arch.
Epidemiology of Malocclusion/Preventive Orthodontics / 155
Local Factors
1. Anomalies in number of teeth: Under this we have supernumerary teeth
and missing teeth.
Supernumerary teeth are usually present in the midline, behind last
molars and in premolar region. They interfere with eruption of teeth or
may deflect the normal path of eruption of teeth. Most common
congenitally missing, teeth are upper laterals incisors, lower second
premolars, lower central incisors, which can cause spacing between teeth
and lead to migration of teeth.
2. Anomalies of tooth size: If the teeth size are large and arch size is small or
teeth size are small and arch size is large then it leads to crowding or
spacing respectively.
3. Anomalies of tooth shape: Abnormal tooth shapes are seen in case of peg
laterals, abnormal cingulum, fusion or gemination of a tooth which causes
localized malocclusion.
4. Abnormal labial fremum: High frenal attatchment leads to midline
diastema in the upper arch.
5. Premature loss of deciduous teeth: Premature loss of deciduous teeth can
result in loss of space for the succeeding permanent teeth because of
migration of adjacent teeth.
6. Prolonged retention of deciduous teeth: Prolonged retention of deciduous
teeth leads to altered path of eruption of permanent tooth.
7. Delayed eruption of permanent teeth: Delayed eruption of permanent tooth
results in impaction of underlying permanent tooth due to migration of
adjacent teeth into edentulous space.
156 / Questions and Answers in Community Dentistry
ANSWER 2
Preventive Orthodontics
The following are some of the procedures undertaken in preventive ortho-
dontics:
1. Parent education
2. Caries control
3. Care of deciduous dentition
4. Management of ankylosed tooth
5. Check-up for oral habits
6. Extraction of supernumerary teeth
7. Space maintenance
8. Management of deeply locked first molar
9. Management of abnormal frenum attachment.
ANSWER 3
Space Maintainers
These are the devices used to maintain space created by premature loss of
deciduous teeth.
Classification
According to Hitchcock
1. Removable or fixed, or semi-fixed.
2. With bands or without bands.
3. Functional or nonfunctional.
Epidemiology of Malocclusion/Preventive Orthodontics / 157
4. Active or passive
5. Certain combinations of the above.
2. Crown and loop: It is similar to band and loop except instead of band,
crown is given in cases where abutment tooth is highly carious, marked
hypoplasia or pulpotomized.
3. Lingual arch: It is the most effective appliance for space maintenance in
the lower arch. It is indicated when there are bilateral multiple loss of
primary molars. It helps in maintaining the arch perimeter by preventing
both mesial drifting of the molars and also lingual collapse of the anterior
teeth. Bands are cemented on first permanent molars or on the second
deciduous molars and joined by stainless steel wire contacting the lingual
surface of the four mandibular incisors.
4. Palatal arches: Also called Nance palatal arch. It is similar to the lingual
arch but wire does not contact maxillary incisors. It incorporates an acrylic
button in the anterior region that contacts the palatal tissue. It is designed
to prevent mesial migration of the maxillary molars.
5. Transpalatal arch: It has been recommended for stabilizing the maxillary
first permanent molars when the primary molars require extraction. (A
best example is when one side of the arch is intact and multiple primary
teeth on the other side are missing). It consists of a thick stainless steel
wire that spans the palate connecting the first permanent molar of one
side with the other.
6. Distal shoe space maintainers: It is also called intra-alveolar appliance. It
is indicated when primary second molars are extracted prior to the
eruption of first permanent molar. Band is placed on deciduous first molar
or canine and the horizontal bar is soldered to the band. The vertical
component of bar (intra-gingival extension) is placed in the bone mesial
to the permanent first molar. Depth of bone is calculated by the
radiograph. The vertical component guides the first permanent molar to
erupt into its position.
7. Band and bar/Crown and bar: Similar to the band and loop and crown
and loop instead of using loop, a bar is used to connect the abutment teeth
on either side of the extraction space.
ANSWER 4
Interceptive Orthodontics
It has been defined as that phase of science and art of orthodontics employed
to recognize and eliminate potential irregularities and malpositions of the
developing dentofacial complex.
The following measures are undertaken:
1. Serial extractions
Epidemiology of Malocclusion/Preventive Orthodontics / 159
Serial Extractions
These are done in the early mixed dentition, to recognize and anticipate
potential irregularities in dento-facial complex and corrected by planned
extraction of certain deciduous teeth and later specific permanent teeth in an
orderly sequence and predetermined pattern to guide the erupting permanent
teeth into a more favorable position.
Three step serial extraction procedure proposed by Dewel is extraction of
C D and 4. First deciduous canines are extracted to align incisors, then
deciduous first molars are extracted to allow eruption of first premolars and
lastly first premolars are extracted to allow permanent canines to erupt.
Space Regainers
If a primary molar is lost early and space maintainer is not used, a reduction
in arch length by mesial movement of the first molar occurs. This space can
160 / Questions and Answers in Community Dentistry
be regained by the distal movement of the first molar. Space regaining is done
preferably in early age prior to the eruption of second molar.
For example: Gerber space regainer, space regainer using jack screws,
Adams space regainer, space regainer using cantilever springs.
Muscle Exercises
It helps in improving aberrant muscle function
Exercise to strengthen the massetter muscle involves clenching of teeth
while counting upto ten and then repeated again for some more time.
Exercise for the lips (short hypotonic lips): Stretching the upper lip down
towards the chin, holding and pumping of water back and forth behind
the lips, massaging of the lips, button pull exercise and stretching of the
upper lip to maintain lip seal.
Exercise for the tongue (for correction of the improper positioning of the
tongue): One elastic swallow, two elastic swallow, tongue hold exercise
and the, hold pull exercise.
QUESTION
Disease the epidemiology of AIDS.
ANSWER
AIDS/HIV Impact on Nations World Wide
Approximately 65 to 70 million people infected with HIV; more than 25 million
have died. Six million people were infected with HIV globally in 2006. The
condition is worst in the Sub-Saharan Africa region followed by Caribbean.
There is a growing concern emerging in parts of eastern and central Asia.
India is one of the worst affected countries next only to South Africa in terms
of prevalence of HIV. In India, AIDS is into its second decade.
Based on sentinel surveillance, the HIV prevalence in adult population
can be broadly classified into three groups of states/union territories in the
country.
Group 1: High prevalence states
HIV infection has crossed 5% mark in high risk group.
1% or more among antenatal women.
Spreading from urban to rural areas.
States included are Maharashtra, Tamilnadu, Karnataka,
Andhra Pradesh, Manipur, Nagaland.
Group 2: Moderate prevalence states
HIV infection has crossed 5% mark in high risk group.
Less than 1% among antenatal women.
States included are Gujarat, Goa, Pondicherry.
Group 3: Low prevalence states
HIV infection in any of the high risk group is still less than 5%.
Less than 1% among antenatal women.
Includes remaining states.
162 / Questions and Answers in Community Dentistry
Epidemiological Features
1. Host factors
a. Age: Most cases have occurred among sexually active persons aged
between 20-49 years. Children below 15 years make upto less than 3%
of cases.
b. Sex: More commonly seen in homosexual and bisexual men, however
it is found to differ in different parts of the world. In Africa, women
outnumber the men. Certain sexual practices increase the risk of
infection more than others like multiple sexual partners, male
homosexuality but higher rate is found in prostitutes.
c. High risk groups: Sex workers, intravenous drug abusers, transfusion
recipients of blood and blood products, hemophilias and clients of
sexually transmitted disease (STD).
2. Agent factors
a. Agent: The causative factor involved is the virus by name human
immunodeficiency virus. It is a retrovirus; its diameter is 1/10,000th
of a millimeter, consists of a protein capsule containing two short
strands of RNA and enzymes. It replicates in actively multiplying T4
lymphocytes and can remain in lymphoid cells in a latent state that
can be activated. They destroy the human T-helper cells or T-4 cells
also called CD4+T lymphocytes/CD4+ cell. These cells play an
important role in immune response. HIV selectively infects T-helper
cells. They can spread throughout the body, also can pass blood-brain
barrier and destroy some brain cells.
b. Reservoir of infection: These are cases and carriers. The virus remains in
the body for life-long. HIV infection can take many years to manifest
itself, incubation period is uncertain may vary from few months to
10 years or more. The symptomless carrier can infect other people for
years.
c. Source of infection: Greater concentration of the virus is found in blood,
semen and cerebrospinal fluid (CSF), lower in tears, saliva, breast milk,
urine, cervical and vaginal secretions. To date, only blood and semen
have been conclusively shown to transmit the virus.
Mode of Transmission
1. Sexual transmission
2. Blood contact
3. Maternal-fetal transmission: Mother to child transmission.
Epidemiology of AIDS / 163
Clinical Manifestations
These are classified into four broad categories:
1. Initial infection with the virus and development of antibodies.
2. Asymptomatic carrier state.
3. AIDS-related complex (ARC).
4. AIDS.
1. Initial infection: About 70% of people show mild illness like fever, sore
throat and rash after initial infection but most of them show no symptoms
for first five years or so. HIV antibodies usually appear between 2 to 12
weeks in the blood stream. The period before the antibodies appear is the
Window period.
2. Asymptomatic carrier state: Infected people have antibodies, but no overt
signs of disease except persistent generalized lymphadenopathy.
3. AIDS-related complex (ARC): Person with ARC has illness due to damage
to the immune system but does not show opportunistic infections and
cancers associated with AIDS, but they exhibit one or more of the following
clinical signs; unexplained diarrhoea lasting longer than one month,
fatigue, malaise, loss of more than 10% body weight, fever, night sweats,
or other milder opportunistic infections such as oral thrush, generalized
lymphadenopathy or enlarged spleen. Some patients with ARC
subsequently develop AIDS.
4. AIDS: This is the end-stage of HIV infection. A number of opportunistic
infections and cancers are seen. Death is due to uncontrolled or untreatable
infection.
Few opportunistic infections and cancers commonly associated with
AIDS are:
Tuberculosis, persistent generalized lymphadenopathy, kaposis
sarcoma, oropharyngeal candidiasis, cytomegalovirus retinitis,
pneumocystis carinii pneumonia, toxoplasma encephalitis, hairy
leukoplakia, herpes zoster or shingles, severe prurigo or pruritic dermatitis,
severe or recurrent skin infections.
164 / Questions and AnswersPublic
in Community
Heath andDentistry
Denta Public Health / 164
18 Indices
QUESTIONS
1. a. Define index.
b. Define dental index.
2. Ideal requisites of an index.
3. Classify indices.
4. Uses of indices.
5. Name a few indices used for assessment of dental caries for permanent
dentition.
6. Decayed missing filled teeth index (DMFT).
7. Limitations of DMFT index
8. DMFS index.
9. Differences between DMFT and DMFS indices.
10. Name a few indices used for primary dentition and discuss about def
index. Modifications of def index.
11. Name a few indices used for assessment of periodontal diseases.
12. Russells periodontal index.
13. Ramfjords periodontal disease index.
14. Community periodontal index of treatment needs (CPITN).
15. Community periodontal index (CPI).
16. Name a few indices used for oral hygiene assessment.
17. Oral hygiene indexsimplified (OHI-S).
18. Discuss the differences between OHI and OHI-S.
19. Plaque index by Silness.P. and Loe.H.
20. Name a few indices used for assessment of gingival diseases.
21. Explain about gingival index by Loe.H. and Silness.J.
22. Name a few indices to measure fluorosis.
23. Deans fluorosis index.
Indices / 165
ANSWER 1A
Index is defined as a numerical value describing the relative status of a
population on a graduated scale with definite upper and lower limits designed
to permit and facilitate comparison with other populations classified by the
same criteria and methods (Russell AL).
ANSWER 1B
Dental index is an objective mathematical description of a disease or condition
based on carefully determined criteria under specified circumstances.
ANSWER 2
Ideal Requisites / Properties of an Index
Clarity, simplicity and objectivity: Should be clear, reasonably easy to
apply
Validity: Index should measure what it is intended to measure, should
correspond with clinical stages of disease under study
Reliability: Index should be able to measure consistently at different times
and each time the score should be the same
Quantifiability: Index must be amenable to statistical analysis, so that it
can be expressed by mean, median or other statistical measure
Sensitivity: Index must be able to detect clinically small shifts in condition
in either direction
Acceptability: Index must not be painful or offending to the subject.
ANSWER 3
Dental indices are classified as:
1. Depending on the condition measured
a. Reversible index: Measures conditions that can be changed, e.g. gingivitis-
gingival index
b. Irreversible index: Measures conditions that cannot be changed, e.g.
dental caries-DMFT index
c. Reversible and irreversible index: Measures both the conditions, e.g:
gingival and periodontal disease - Russels periodontal index.
166 / Questions and Answers in Community Dentistry
ANSWER 4
The uses of indices are:
1. For individual patients: An index can:
a. Provide individual assessment to help a patient recognize an oral
problem.
b. Reveal the degree of effectiveness of present oral hygiene practices.
c. Motivate the person in preventive and professional care for the
elimination and control of oral disease.
d. Evaluate the success of individual and professional treatment over a
period of time by comparing index scores.
e. Provide a means for personal assessment by the dental hygienist to
educate and motivate individual patients.
2. In research: An index is used to:
a. Determine baseline data before experimental factors are introduced.
b. Measure the effectiveness of specific agents for the prevention, control
or treatment of oral conditions.
c. Measure the effectiveness of mechanical devices for personal care, such
as toothbrushes, interdental cleansing devices or water irrigators.
3. In community health: An Index can:
a. Show the prevalence and trends of incidence of a particular condition
occurring within a given population.
Indices / 167
ANSWER 5
The following are few indices used for assessment of dental caries in permanent
dentition.
DMFT - Decayed, missing, filled teeth index
DMFS - Decayed, missing, filled surfaces index
Mollers index
Stones index
Czechoslovakian caries index
Caries severity index
Caries susceptibility index
DMF surface percentage index
WHO dentition status and treatment needs
Root caries index.
ANSWER 6
DMFTDecayed, Missing, Filled Teeth Index
Introduced by Henry T Klein, Carrole E Palmer and Knutson JW in 1938
Universally employed index for dental caries
It is a irreversible and cumulative index (it measures total life time caries
experience)
D- decayed teeth, M- missing teeth due to caries, F-filled teeth due to caries.
a. Purpose: To determine total dental caries experience past and present.
b. Selection of teeth
Select all the teeth except:
Third molars
Unerupted teeth
Congenitally missing and supernumerary teeth
Teeth removed for other reasons (orthodontic or prosthodontic)
Teeth restored for other reasons
When both primary tooth and its permanent successor are present,
primary tooth is not included.
3. Only carious cavities are considered as D and not chalky spots or stained
fissures etc.
Procedures
a. Instruments: Mouth mirror and explorer.
b. Criteria for identification of dental caries:
Lesion should be clinically visible and obvious.
Explorer tip can penetrate deep into soft yielding material.
Discoloration or loss of translucency, typical of undermined or
demineralized enamel is apparent.
Definite catch in a pit or fissure which resists removal of the probe
after moderate to firm pressure and when there is softness at the base
or wall of the area.
c. Criteria for recording or principles and rules governing DMFT index:
No tooth must be counted more than once
D, M and F teeth should be recorded separately.
Restorations with recurrent decay are considered as decayed.
Teeth which are badly carious, root pieces, non restorable carious teeth
that are indicated for extraction are considered as missing teeth.
A tooth having several restorations must be counted as one tooth.
Deciduous teeth are not included in DMF count.
Defective filling but without evidence of caries is considered as F tooth.
Permanent fillings are considered as F teeth.
Tooth is considered as erupted when there is total exposure of occlusal
surface or incisal edge or if the occlusal surface/incisal edge can be
exposed by gently reflecting the overlying gingival tissue.
Scoring
1. Individual DMFT: Each component is given a score of 1.
Add scores of each component separately
Total DT + MT + FT = DMFT. (DMFT score can range from 0-28/person
excluding the third molars and 0-32/person including the third molars).
2. Group average:
a. Add the D,M,F, Teeth scores for each individual.
b. Divide the total DMFT score by number of individuals in the group,
e.g. 30 individuals, a total of DMFT = 210.
210
Average DMFT = =7
30
Indices / 169
ANSWER 7
Refer Ans 6. (Limitation of DMFT Index).
ANSWER 8
DMFSIndex
DMF index when used to assess each individual surface of each tooth it is
termed as DMFS index.
Surfaces Examined
Posterior teethMesial, distal, buccal, lingual/palatal, occlusal.
Anterior teethMesial, distal, labial, lingual/palatal.
For 28 teethThe number of surfaces examined is 128.
For 32 teethThe number of surfaces examined is 148.
(Procedure/Principles/guidelines same as DMFT indexrefer Answer 6)
Scoring
Each surface is scored as 1. Total number of surfaces for anterior teeth are 4
and for posterior teeth are 5.
For Individual
DMFS = Sum of total D surfaces, M surfaces and F surfaces.
Average group DMFS = Total DMFS/Number of individuals.
Advantages
1. Sensitive index: A finer measurement is possible when compared with
DMFT index.
2. Index of choice in a clinical trial of caries preventive agent.
170 / Questions and Answers in Community Dentistry
Limitations
1. Overestimation of score:
Score to be allocated to extracted teeth, which may have been attacked
on one surface only and its extraction results in loss of 4 or 5 surfaces.
Score to be given to 2 surface fillings on posterior teeth, e.g. (MO),
where the attack may have been on only proximal surface and the
occlusal surface was involved later to provide an adequate class II type
of cavity for restoration.
2. Time consuming and more likely to produce inconsistencies in diagnosis.
3. May require the use of radiographs to be fully accurate.
4. It has wider range of values therefore a larger standard error.
ANSWER 9
Refer answers 6 and 8.
ANSWER 10
The following are a few indices used for assessment of dental caries for primary
dentition:
deft/defs
dmft/dmfs
dft/dfs
Mollers Index
WHO dentition status and treatment needs.
def Index
This index was given by Gruebbel AO in 1944
This is signified by lower case letters.
d- decayed teeth
e- carious teeth indicated for extraction
f- filled teeth.
Selection of Teeth
d= primary teeth with dental caries but not restored.
This code indicates the number of teeth those are decayed.
e= teeth indicated for extraction because of dental caries.
This code includes those teeth which are grossly destructed due to caries and
are indicated for extraction. Missing teeth are not recorded because of difficulty
in distinguishing between teeth exfoliated and extracted teeth. But, include
those teeth which give accurate history of missing due to caries.
Indices / 171
Principles
No tooth should be counted more than once. If the tooth has both filling and
decay it should be considered only once and decay has the first priority.
Number of teeth examined = 20.
The score can range from 020.
Modifications of this index are:
dmft/sFor children before age of exfoliation.
dmft/sIndex is performed only on the primary molars and canines (7 to
12 years).
dft/sHere the missing component is ignored (to avoid the confusion
arising from the tooth been naturally exfoliated or extracted). This index
is a choice of the WHO in the basic oral health survey. It can be applied to
the whole dentition as dft or dfs.
Mixed Dentition
DMFT/DMFS index for the permanent teeth and deft/defs for deciduous
teeth. The two scores should not be added and are represented separately.
ANSWER 11
The following are few indices used for assessment of periodontal disease:
1. Russells periodontal index (PI).
2. Ramfjords periodontal disease index (PDI).
3. Community periodontal index of treatment needs (CPITN).
4. Community periodontal index (CPI).
5. Gingival periodontal index (GPI).
6. Extent and severity index (ESI).
ANSWER 12
Periodontal Index by Russell AL (1956)
Selections of Teeth
All the teeth present in the mouth are examined.
Procedure
1. Instruments: Mouth mirror and periodontal probe.
172 / Questions and Answers in Community Dentistry
Scoring
1. Individual scoring: Add the scores for each tooth and divide by the number
of teeth present and examined
Interpretation:
Clinical condition Scores
Uses
1. Used in epidemiological surveys.
2. More data can be assembled using PI than any other index of periodontal
disease.
ANSWER 13
Periodontal Disease Index (PDI) by Sigurd P Ramfjord (1959)
It consists of 3 components:
Gingival and periodontal component.
Plaque component.
Calculus component.
Scoring Criteria
Scores Criteria
;
0 Absence of signs of inflammation.
1 Mild to moderate inflammatory gingival changes not extending around the
tooth.
2 Mild to moderately severe gingivitis extending all around the tooth.
3 Severe gingivitis characterized by marked redness, swelling, tendency to
bleed and ulceration, not necessarily extending around the tooth.
4 When the crevices (pockets) of any two recorded areas extend apically to
the CEJ not more than 3 mm (including 3 mm).
Contd...
174 / Questions and Answers in Community Dentistry
Scores Criteria
;
5 When the pockets of any two recorded areas extend apically to the CEJ from
3 mm to 6 mm.
6 When the pockets of any two recorded areas extend more than 6 mm.
Scoring
1. For individual: Add scores for individual teeth and divide by the number
of teeth examined. PDI score ranges from 06.
2. Interpretation:
03.9 indicates gingival involvement only.
46 indicate periodontal involvement.
3. PDI score for group:
Total individual PDI scores
Group PDI =
Number of individuals examined
0 No plaque.
1 Plaque present on some but not all interproximal, facial, lingual
surfaces.
2 Plaque present on all interproximal, facial and lingual surfaces,
but covering less than one half of these surfaces.
3 Plaque extending over all interproximal, facial and lingual
surfaces and covering more than one half of these surfaces.
d. Scoring: Add the plaque scores for each tooth and divide by the number
of teeth examined.
Indices / 175
Score Criteria
0 No calculus
1 Supragingival calculus extending slightly below the free gingival
margin (not more than 1 mm).
2 Moderate amount of supra and subgingival calculus or subgingival
calculus only.
3 Abundance of supra and subgingival calculus.
ANSWER 14
CPITN: Community Periodontal Index of Treatment Needs
(TRS 621 Method)
Developed by the joint working committee of WHO and FDI in 1982 by Jukka
Ainamo, David Barnes, George Beagrie, Terry Cutress, Jean Martin and
Jennifer Sardo-Infirri.
1. Purpose: To screen and monitor individual or group periodontal status
and treatment needs.
2. Selection of teeth:
Mouth is divided into 6 segments (sextants).
Below 20 years:
16 11 26
46 31 36
Molars are examined in pairs and only one score (highest) is recorded
Below 15 years, pockets are not recorded, only bleeding and calculus
are recorded
In epidemiological survey: For individuals of 20 years and above consider
10 index teeth; for individuals below 20 years consider only 6 index
teeth.
Procedure
1. Instrument used: CPITN probe
It has a ball tip of 0.5 mm diameter
Light weight probe weighing 5 grams.
Code Criteria
0 Healthy
1 Bleeding on probing (30 sec)
2 Calculus detected during probing or presence of plaque retentive areas (the
entire black band is visible).
3 4 to 5 mm of pocket (gingival margin within the black band on the probe).
4 Pocket 6 mm or more (black band on the probe not visible).
X Excluded sextant
9 Not recorded.
Scale Interpretation
ANSWER 15
CPI: Community Periodontal Index
This is the modification of the earlier used Community Periodontal Index of
Treatment Needs. Modification is done by the elimination of Treatment
Needs category and inclusion of Loss of Attachment.
178 / Questions and Answers in Community Dentistry
Selection of Teeth
Mouth is divided into six segments (sextants).
Index Teeth
Above 20 years:
17, 16 11 26, 27
47, 46 31 36, 37
Below 20 years:
16 11 26
46 31 36
Molars are recorded in pairs and only one score (highest) is recorded.
Below 15 years, pockets are not recorded, only bleeding and calculus are
recorded.
In epidemiological survey: For individuals of 20 years and above consider
10 index teeth; for individuals below 20 years consider only 6 index teeth.
Procedure
1. Instrument used: CPI probe (CPITN-C probe)
It has a ball tip of 0.5 mm diameter
Light weight probe weighing 5 gms.
Marking on the probe: Color coded band between 3.5 mm and 5.5 mm,
markings at 8.5 mm, and 11.5 mm. (CPITN-C- Probe)
2. How to use the probe: The probe tip is inserted gently into the gingival
sulcus or pocket and total extent of sulcus or pocket is explored and should
follow the anatomical configuration of the surface of the tooth root. Probe
should be parallel to the long axis of the tooth. Both buccal and lingual
surfaces are examined.
For checking bleeding on probing/pockets: The sensing force is 20 grams. (A
practical test to estimate this force is done; 20 grams force is equal to the
force applied by probe under the thumb nail to produce blanching in the
nail).
Indices / 179
Code Criteria
0 Healthy
1 Bleeding on probing
2 Calculus detected during probing (the entire black band is visible).
3 4 to 5 mm. of pocket (gingival margin within the black band on the
probe)
4 Pocket 6 mm. or more (black band on the probe not visible).
X Excluded sextant (less than two teeth present).
9 Not recorded.
Loss of Attachment
Code Criteria
0 Loss of attachment 03 mm. (CEJ not visible and CPI score 03).
1 Loss of attachment 4-5 mm. (CEJ within the black band).
2 Loss of attachment 6-8 mm. (CEJ between the upper limit of the black band
and the 8.5 mm. ring).
3 Loss of attachment 9-12 mm. (CEJ between the 8.5 mm and 11.5 mm rings).
4 Loss of attachment 12 mm. or more (CEJ beyond the 11.5 mm rings).
X Excluded sextant. (Less than two teeth present)
9 9Not recorded (CEJ neither visible nor detectable).
ANSWER 16
1. Indices used to measure oral hygiene and debris:
a. Oral hygiene index (OHI).
b. Oral hygiene index (OHI-S).
c. Patient hygiene performance index.
2. Indices used to measure plaque:
a. Plaque index by Silness.P. and Loe.H.
b. TureskyGilmoreGlickman modification of the quigley hein plaque
index.
c. Navy plaque index.
d. Shick and Ash modification of plaque criteria.
e. Glass index.
3. Indices used to measure calculus:
a. Calculus surface index.
180 / Questions and Answers in Community Dentistry
ANSWER 17
Oral Hygiene Index-Simplified
Given by John C Greene and Jack R Vermillion in 1964.
OHI-S is a simplified index of the original index OHI given by the same
authors in 1960.
Purpose
To assess oral hygiene by estimating the tooth surface covered by debris and/
or calculus.
Scoring
OHS-S for an individual:
Total debris scores
DI-S =
No. of teeth examined
Total calculus scores
CI-S =
No. of teeth examined
OHI-S = DI-S + CI-S
Interpretation
DI-S and CI-S values will range from 03
Rating Scores
Good 0.00.6
Fair 0.71.8
Poor 1.93.0
182 / Questions and Answers in Community Dentistry
ANSWER 18
Difference Between OHI and OHI-S
OHI OHI-S
Teeth examined All the teeth. (mouth is divided into Only index teeth
sextants and all the teeth in the
sextant are examined).
Surfaces scored 12 (2 scores per sextant, buccal and 6 (one surface per
lingual surface). index tooth)
DI and CI score range 0 6 03
Total DI+CI 012 06
ANSWER 19
Plaque Index (PI)
Given by Silness P and Loe H in 1964.
Selection of teeth: Entire dentition or selected teeth (index teeth=16, 12,
24, 36, 32, 44).
Surfaces Examined
Examine for plaque only in the cervical third areas of Distal, Disto-facial, facial
margin, mesial facial and lingual surface of the tooth.
Procedure
Dry the teeth and examine visually using adequate light, mouth mirror and
probe or explorer. Pass the probe or explorer across the tooth surface in the
cervical third and near the entrance to the sulcus.
Include plaque on the surface of the calculus and on the dental restorations
in the cervical third.
Use disclosing agent, if necessary to assist evaluation for the score 0 and 1.
Indices / 183
Scoring Criteria
Score Criteria
0 No plaque
1 A film of plaque adhering to the free gingival margin and adjacent area of
the tooth. The plaque may be recognized only after application of disclosing
agent or by running the explorer across the tooth surface.
2 Moderate accumulation of soft deposit within the gingival pocket that can
be seen with the naked eye or on the tooth and gingival margin.
3 Abundance of soft matter within the gingival pocket and/or on the tooth
and gingival margin.
Scoring
1. PI for tooth: Add score of each area: Distal, facial, mesial and lingual and
divide by 4.
2. Total PI score: Add scores of each tooth and divide by the number of
examined teeth.
Interpretation
Rating Score
Excellent 0
Good 0.10.9
Fair 1.01.9
Poor 2.03.0
ANSWER 20
The following are few indices used for assessment of gingival diseases:
For assessing gingival inflammation:
1. PMA (papillary marginal attached gingival) index by Maury Massler and
Schour I in 1944.
2. Gingival index by Loe H and Silness J in 1963.
3. PMI (papillary marginal index) by Muhlemann H.R. and Mazor Z.S.
4. Modified gingival index by Lobene R et al.
For assessing gingival bleeding
1. Sulcus bleeding index by Muhlemann HR and Mazor ZS.
2. Papillary bleeding index by Muhlemann HR (modification of sulcus
bleeding index in 1977).
3. Gingival bleeding index by Carter and Barness.
4. Modified sulcular bleeding index.
5. Eastman interdental bleeding index.
6. Gingival bleeding Index (GBI) of Ainamo J and Bay I
184 / Questions and Answers in Community Dentistry
ANSWER 21
Gingival index given by Loe H and Silness J in 1963
1. Purpose: To assess the severity of gingivitis based on color, consistency
and bleeding on probing.
2. Selection of teeth:
All teeth or selected teeth (index teeth = 16, 12, 24, 36, 32, 44).
Four gingival areas examined - Disto-facial papilla, facial margin,
mesio-facial papilla and entire lingual margin.
3. Procedure:
a. Teeth and gingiva are dried; using a mouth mirror and probe examine
the teeth, under adequate illumination.
b. Probe is used to press on the gingiva to determine the degree of
firmness.
c. To evaluate bleeding, pass the probe along the soft tissue wall of the
gingival sulcus.
4. Score and criteria:
Score Criteria
0 Normal gingiva.
1 Mild InflammationSlight change in color, slight edema, no bleeding on
probing.
2 Moderate inflammationredness, edema and glazing, bleeding on
probing
3 Severe inflammationmarked redness, edema, ulceration, tendency to
spontaneous bleeding.
Scoring
1. Each surface is given a score.
2. For each tooth: Add the scores of each surface and divide by four.
3. For individual: Add the scores of each tooth and divide by number of
teeth examined.
Interpretation
Rating Scores
Excellent (Healthy tissues) 0
Good 0.10.9
Fair 1.01.9
Poor 2.03.0
Indices / 185
ANSWER 22
The following are few indices to measure fluorosis:
1. Deans fluorosis index.
2. Community fluorosis index.
3. Tooth surface index of fluorosis (TSIF).
4. The Thylstrup-Fejerskov classification of enamel bluorosis.
5. Fluorosis risk index.
6. Youngs classification of enamel fluorosis.
7. Murray and Shaws classification of enamel fluorosis.
8. Simplified fluoride mottling index.
ANSWER 23
Deans Fluorosis Index
Given by Trendly H Dean in 1934.
Deans fluorosis index set criteria for categorizing dental fluorosis on a 7
point ordinal scale (normal, questionable, very mild, mild, moderate,
moderately severe and severe).
In 1942, he revised the index into 6 point scale as normal, questionable
very mild, mild, moderate and severe.
Selection of Teeth
Examine all the teeth. The score is based on the two most severely affected
teeth, but if the two teeth are not equally affected, then the score for the less
affected of the two is recorded.
Criteria
Code Criteria
Normal The enamel surface is smooth, glossy, and usually a pale creamy-white
color.
Questionable The enamel shows slight aberration from the translucency of normal
enamel which may range from a few white flecks to occasional spots.
Very mild Small, opaque, paper white areas scattered irregularly over the teeth
but involving less than 25% of the labial tooth surface.
Mild The white opacity of the enamel of the teeth is more extensive than for
code 2, but covers less than 50% of the tooth surface.
Moderate The enamel surface of the teeth show marked wear and brown stain is
frequently a disfiguring feature.
Severe The enamel surface are badly affected and hypoplasia is so marked
that the general from of the tooth may be affected. There are pitted
areas or worn areas and brown stains are widespread and teeth have a
corroded appearance.
186 / Questions and Answers in Community Dentistry
ANSWER 24
Normal 0
Questionable 0.5
Very mild 1
Mild 2
Moderate 3
Severe 4
Example
Normal 0 10 0
Questionable 0.5 2 1
Very mild 1 5 5
Mild 2 3 6
Moderate 3 4 12
Severe 4 1 4
25(n) 28
Indices / 187
f w 28
CFI = = = 1.12
n 25
Interpretation
ANSWER 25
The following are few indices to measure malocclusion:
Angles classification.
Dental Aesthetic index.
Handicapping labio-lingual deviation index.
Malocclusion severity estimate by Grainger.
Malalignment index by Vankirk.
Occlusal index by Summers.
Treatment priority index by Grainger.
Handicapping malocclusion assessment record by Salzmann Master and
Frankel.
Index of orthodontic treatment needs.
ANSWER 26
Dental Aesthetic Index
It was developed by N C Cons, J Jenny and FJ Kohaut in 1986. This index has
been adopted by the WHO in the basic oral health survey, 1997.This index is
performed only for the permanent teeth; 10 occlusal traits are recorded using
CPI probe and the DAI score is calculated using the occlusal traits in a
regression equation:
(missing visible teeth 6) + (crowding) + (spacing) + (diastema 3) +
(largest anterior maxillary irregularity) + (largest anterior mandibular
irregularity) + (anterior maxillary overjet 2) + (anterior mandibular
overjet 4) + (vertical anterior openbite 4) + (antero-posterior molar
relation 3) + 13.
The severity of malocclusion within a population is classified on the basis
of the DAI scores as shown in the table below:
ANSWER 27
Several kinds of scales for measuring intensity of a condition:
1. An ordinal scale: Lists the condition in order of severity without attempting
to define any mathematical relation between the categories, e.g.
Interpretation score of OHI-S index, good, fair or poor.
2. Nominal scale: It simply gives names to different condition and is strictly
not a scale, e.g. Kennedys classification of edentulousness, Angles
classification for malocclusion.
3. Interval scale: The numbers used in measuring scale purport to have
mathematical relation to each other. This scale does not have an true zero
point and hence is not used for dental indices, e.g. Temperature measured
in Celsius or Fahrenheit (here 0 degree does not mean absence of
temperature).
4. Ratio scale: The numbers used in measuring scale purport to have
mathematical relation to each other. This scale has a true zero point and
hence can be used in the dental indices, e.g. Gingival index:
Score Criteria
19 Planning and
Evaluation
QUESTIONS
1. Define the term planning/plan.
2. Discuss the planning cycle in detail.
3. Define evaluation and discuss the different types of evaluation.
4. Criterias for evaluation of dental services.
5. Evaluation. (Refer Ans 3 and 4)
6. Discuss the steps in evaluating a program.
7. How will you evaluate a dental health education program in school having
strength of 300 children?
8. Give your plan to evaluate the clinical trial of fluoride mouthwash
with a sample of 35 in the study group and 30 in the control group (with
placebo).
9. Write briefly how you will evaluate the water fluoridation program in the
school?
ANSWER 1
E.C Banfield defined plan as a decision about a course of action.
ANSWER 2
When planning, one needs to have a deep understanding and analyze the
system for which planning has been done. The planners who do the planning
are of two types:
1. External planners
2. Internal planners.
The planners may have training on the job in the organization or would
have undergone professional training.
190 / Questions and Answers in Community Dentistry
External Planners
The planner brought in from outside is usually an individual who contracts
to work for the company or agency on a consulting basis. The advantage of
this type of planner is that he or she potentially brings to the organization a
fresher look less bias and a greater sense of objectivity. However, the external
planner requires more time to reach a level of understanding of the system
sufficient to plan a appropriate course of action.
Internal Planner
A planner hired from within the system. He already has a true understanding
of the issues and operation of the system. The knowledge helps the planners
to begin making decisions more quickly regarding appropriate actions.
However the planner may already have acquired certain biases about the
system that could influence his or her objectivity.
Flow chart 19.1: Planning and implementation strategy
Planning and Evaluation / 191
ANSWER 3
Program Evaluation
The fundamental purpose of program evaluation is to provide information
for decision making. Evaluation is a judgment of merit or worth about a
particular person, place or thing.
Formative Evaluation
It refers to the internal evaluation of a program. It is an examination of the
processes or activities of a program as they are taking place. It is usually carried
out to aid in the development of a program in its early phases. It is used
primarily by program developers and program staff members concerned with,
whether various components of a program are workable or whether changes
should be made to improve program activities. If any sequence is found to be
incorrect, formative evaluation allows the program to make remedial changes
at that point and thereby improve the performance. Such strategy is much
better than waiting till the program is completed and then announcing that
there were procedural errors.
Four types of recommendations can be derived from formative evaluation.
a. Terminate the project
b. Reorganize
c. Fine tune
d. Continue with the project as it was implemented.
Summative Evaluation
It judges the merit or worth of a program after it has been in operation. It is an
attempt to determine whether a fully operational program is meeting the goals
for which it was developed. It is aimed at program decision makers who will
decide whether to continue or terminate a program and also at decision makers
from other programs who might be considering adoption of the program.
Formal Evaluation
An evaluation which is carried out in a structured manner in which there is
an exclusively designed program, with clear objectives and specific criteria to
measure the success of the program.
Informal Evaluation
An evaluation which is carried out in an unstructured manner, without any
exclusively designed program, unclear objectives and no specific criteria to
measure the success of the program.
194 / Questions and Answers in Community Dentistry
Relevance Evaluation
It is designed to determine whether the program is needed or whether the
program is targeting its efforts at the individuals in need.
Effectiveness Evaluation
It refers to whether program results meet predetermined objectives. Here the
emphasis is on immediate outcomes of the program activities and whether
these outcomes meet the objectives specified by the program planners.
Impact Evaluation
It refers to the evaluation of the long term outcomes of the program.
Efficiency Evaluation
It attempts to relate the results obtained from a specific program to the
resources used to maintain the program.
Progress Evaluation
It is also called as formative evaluation. A process of evaluation which is carried
out while the planning is taking place.
ANSWER 4
Criteria of Evaluation
1. Appropriateness: Is the program acceptable to both consumer and provider
and do the priorities reflect a proper interpretation of the needs of the
population?
2. Adequacy: Has the intended coverage of the target population being
achieved/ and are the services readily available?
3. Effectiveness: Have the tested objectives been achieved.
4. Efficiency: What has been the cost in manpower or finance in relation to
the output of the program?
ANSWER 6
Steps in evaluating a dental program are:
1. Determine the objectives.
2. Defining the instruments for evaluation.
3. Collection of data.
4. Presentation of results and recommendation.
20 Survey Procedures
QUESTIONS
1. Define survey.
2. Types of surveys.
3. Define basic oral health survey.
4. Pathfinder survey.
5. a. Describe the procedural steps in conducting the survey.
b. Discuss scientific method in dental epidemiology.
6. WHO index age and age groups.
7. Types of ADA examination.
8. Calibration. (Refer Ans 5)
9. Duplication. (Refer Ans 5)
10. Discuss how you will conduct a survey to find out the incidence of
periodontal disease in the community. (Refer Ans 5)
11. Describe the steps involved in conducting a survey to find out the
prevalence of dental caries among school children. (Refer Ans 5)
12. How would you plan to conduct a survey in rural area for assessing the
gingival disease? Describe the index you use for this purpose? (Refer Ans 5
and for gingival index refer chapter on indices)
ANSWER 1
A survey is an investigation in which information is systematically
collected, but in which experimental method is not used. There is no active
intervention by the investigators. It may be simply called as non-experimental
investigation.
ANSWER 2
Different types of surveys are:
1. Descriptive survey
a. Cross-sectional
b. Longitudinal
Survey Procedures / 197
2. Analytical survey
a Cross-sectional
b Longitudinal
3. Basic oral health survey
a Pathfinder survey
i. Pilot survey
ii. National pathfinder survey
1. A descriptive survey sets out to describe a situation, e.g. distribution of
disease in a population with respect to time, place and person.
2. An Analytic survey or exploratory survey tries to explain the situation or
prove a hypothesis.
Surveys descriptive or analytic can be cross-sectional or longitudinal
depending on the time period covered by the study.
ANSWER 3
Basic oral health surveys are defined as surveys to collect the basic information
about oral disease status and treatment needs that are needed for planning or
monitoring oral health care programs. They are not designed to collect
information about the etiological factors affecting disease distribution or
severity, or about the clinical effectiveness of different preventive or care
procedures or about etiological factors affecting disease distribution or severity.
However, the information obtained using basic oral health surveys can be
used to monitor aspects of the effectiveness of oral care services.
ANSWER 4
The most practical, economic survey sampling methodology to be used in
oral epidemiological survey is defined by the pathfinder method. The
pathfinder survey can be of two types depending on the number and type of
sampling sites and the age groups included.
1. Pilot survey
2. National pathfinder survey
The method used in selecting a sample is a stratified cluster sampling
technique, which aims to include the most important population subgroups
likely to have differing disease levels.
A pilot survey is the one which includes only the most important
subgroups in the population and only one or two index ages, usually 12 years
and one other age group. Such a survey provides the minimum amount of
data needed to commence planning.
A National Pathfinder survey incorporates sufficient examination sites
to cover all important subgroups of the population that may have differing
198 / Questions and Answers in Community Dentistry
disease levels or treatment needs, and at least three of the age groups or index
ages. This type of survey design is suitable for the collection of data for the
planning and monitoring of services in all countries what ever the level of
disease, availability of resources, or complexity of services.
ANSWER 5A
Steps of Survey
1. Pre-survey
a. Prepare survey protocol
Establish the objectives
Type of study
Sampling method
b. Organizing the survey
Obtaining permission from higher authority
Budgeting, schedules, emergency care and referral
Courtesy report
c. Reliability of the data
Examination method
Diagnostic criteria and aids
Selection of examiner
Calibration
Duplicating examination
d. Pilot survey.
2. Implementation of the survey
a. Contact person in authority
b. Continuous supply of schedules and instruments
c. Personnel (organizing clerk, recording clerk)
d. Traffic arrangement
3. Post-survey action
a. Analyzing the data.
b. Preparing the report.
Introduction
Aims and objectives
Material and methods
Results and findings
Discussion and conclusion
Summary.
Survey Procedures / 199
Pre-survey
1. Preparing the survey protocol: It is important to prepare written protocol
for the survey which will include the objectives of the study, the description
of the population to be studied, sampling methodology (e.g. Simple
random, stratified random, cluster or multistage sampling) , type of study
(e.g. Descriptive, Analytical, longitudinal or prevalence study), type of
data that will be collected, the personnel involved, about the budget, the
statistical methods used and the time table of the activities.
2. Organizing the survey: The permission from the authorities should be
obtained, like the official permission from the government if the survey is
for general population, from school principals and parents if it is for the
school children. The local community leaders have to be contacted and
also the health authorities. The dental organizations, local dental
practitioners and the organizers also need to be contacted. A budget has
to be prepared for the survey which will include all the resources required
including the personnel and all the activities of the survey. The time
schedule for the survey also needs to be decided. The planner must estimate
the time required for examination, e.g. 510 minutes for the child and 15-
20 minutes for the adults. The schedule should allow for some flexibility
so that unexpected delays do not cause major upsets in the survey time
table. In one half session, 2530 children can be examined by a single
examiner. Provision should be made for some medical facility at the survey
site or referral services to attend to any medical emergency or life-
threatening situation during the survey. Courtesy reporting should be done
wherein a report of the survey findings to the local authorities on day to
day basis should be done.
3. Reliability of the data: The examination method for data collection should
be decided. Usually ADA type 3 examination method is used. The data
collection can be done on the WHO health assessment form 1997 or can be
modified as per the requirement or a new proforma can be formulated.
Diagnostic criteria and aids used in assessment should be circulated among
all the examiners. The right decision about the type of index for recording
the disease should be made, e.g. dentition status and treatment needs/
DMFT/DMFS index for recording dental caries, gingival index by Loe
and Sillness/ Ramfjord index when assessing the gingival status, CPI/
Ramfjord index/extent and severity index for assessing the periodontal
condition.
a. Selection of examiner / training / calibration: In the epidemiological survey
it is essential that the participating examiners be trained to make
200 / Questions and Answers in Community Dentistry
Post-survey Action
The collected data is first arranged, edited and is analyzed manually or using
computer. The results are computed and statistical test are performed as is
required. The last step is preparation of the report which will contain the
following information:
Introduction
Purpose of the survey
Material and methods( will include the area and population surveyed,
the nature of information collected, sampling method, personnel and
physical arrangements, statistical analysis and computational procedures,
cost analysis, reliability and reproducibility of the results)
Results and findings
202 / Questions and Answers in Community Dentistry
ANSWER 5B
Scientific method in dental epidemiology.
An investigation should follow a logical scientific pattern:
1. Establishing the objectives*
2. Designing the investigation*
3. Selecting the sample*
4. Conducting the examination*
5. Analysing the data*
6. Drawing the conclusion*
7. Publishing the results*
For writing the answer in detail refer*.
1. (refer pre-survey in answer 5)
2. (refer answer 2)
3. (explain different sampling methods)
4. (refer pre-survey in answers 5 , 6 and 7)
5. (refer post-survey action answer 5)
6. (refer post-survey action answer 5)
7. (refer post-survey action answer 5)
ANSWER 6
WHO Index Ages and Age Groups
The following ages and age groups are recommended: 5 years for primary
teeth and 12, 15, 3544 and 6574 years for permanent teeth.
5 Years
The children can be examined between their 5th and 6th birthday. This age is
of interest because a complete complement of deciduous teeth is present. This
age reveals the levels of caries of the primary teeth. It is also the age at which
the child starts the schooling.
12 Years
This age is especially important as it is generally the age at which children
leave primary school, and therefore in many countries, is the last age at which
reliable sample is obtained easily through the school system. Also, it is likely
at this age that all permanent teeth, except third molars will have erupted.
Survey Procedures / 203
For this reason 12 years has been chosen as the global monitoring age for
caries for international comparisons and monitoring of disease trends.
15 Years
At this age permanent teeth have been exposed to the oral environment for
39 years. The assessment of caries prevalence is therefore often more
meaningful than at 12 years of age. This age is also important for the assessment
of periodontal disease indicators in adolescents.
ANSWER 7
There are four types of examination methods given by ADA.
1. Type 1 (used in intensive clinical study): This involves a very complete
examination using mouth mirror and explorer, good illumination, full
mouth radiographs and such additional diagnostic methods like study
models, pulp testing, transillumination and laboratory investigations.
2. Type 2 ( used in clinical trials): This is more limited examination, using
mirror and explorer, good illumination and bite wing radiographs.
Periapical radiographs are included where ever appropriate.
3. Type 3 (used in epidemiological surveys): Inspection using a mirror and
explorer. Examination is done under good illumination.
4. Type 4 (used in inspection and screening): This is a screening procedure
only using tongue depressor and available illumination.
204 / Questions and Answers in Community Dentistry
QUESTIONS
1. Define health education.
2. Aims of health education.
3. Methods of approaches to public health.
4. Contents of health education.
5. Principles of health education.
6. Barriers in health education.
7. Educational aids in health education.
8. Methods in health education for individual.
9. Methods in health education for group.
10. Methods in health education for public at large scale.
11. Methods in health education.
12. Panel discussion. (Refer Ans 9).
13. Group discussion. (Refer Ans 9).
14. Symposium. (Refer Ans 9).
15. Colloquy. (Refer Ans. 9).
16. Types of communication.
17. Socratic method of communication.(Refer Ans 16)
18. Didactic method of communication. (Refer Ans 16)
ANSWER 1
Health education is defined as Health education is a process that informs,
motivates and helps people to adopt and maintain healthy practices and
lifestyles, advocates environmental changes as needed to facilitate this goal
and conducts professional training and research to the same end.Adopted
by the National Conference on Preventive Medicine in USA.
Health Education and Communication / 205
ANSWER 2
Aims and Objectives of Health Education
1. To encourage people, to adopt and sustain health promoting lifestyle and
practices.
2. To promote the proper use of health services available to them.
3. To arouse interest, provide new knowledge, improve skills and change
attitudes in making rational decisions to solve their own problems; and
4. To stimulate individual and community self-reliance and participation to
achieve health development through individual and community
involvement at every step from identifying problems to solving them.
ANSWER 3
Different methods of approaches in public health are:
1. Regulatory approach /legal approach
This approach seeks change in health behavior and improvement in
health through a variety of external control or laws placed on people
Any governmental intervention direct or indirect, designed to alter
human behavior, e.g. child marriage restraint Act, pollution Act
This seems to be the simplest and quickest way to improve peoples
health but has some limitations like
i. The cause of the disease can not be eradicated.
ii. Involving personal choice like diet, exercise, smoking, etc. This
approach cannot pass legislation to force people to eat balanced
diet or not to smoke.
iii. People must be ready to accept a law.
2. Service approach/administrative approach
This approach was aimed to provide all the basic health services needed
by the people at their doorsteps on the assumption that people would
use them to improve their health
This approach may go failure if the services are not based on the felt
needs of the needs.
3. Health education approach
This approach is found to be most effective means for achievement of
changes in health practices and life-styles of the community
If the necessary behavior changes have to takes place, people must be
educated through planned learning, experiences, informed, educated
and encouraged to make their own choice for a healthy life. This does
not order the individual. The results are slow but are permanent
and enduring
206 / Questions and Answers in Community Dentistry
ANSWER 4
Contents of Health Education
1. Human biology.
2. Nutrition.
3. Hygiene
a. Personal.
b. Environmental.
4. Family health.
5. Disease prevention and control.
6. Mental health.
7. Prevention of accidents.
8. Use of health services.
ANSWER 5
Principles of Health Education
1. Interest: A health education program will be successful when the message
is based on felt needs of the people. People will participate with interest
when education is based on the needs of the people.
2. Participation: If interest is created in people, participation of people goes
simultaneously. Health education should aim at encouraging people to
work actively with health workers and others in identifying their own
health problems and developing solutions to solve them. Good
participation will provide maximum feedback.
3. Motivation: Every individual has a fundamental desire to learn,
awakening this desire is called motivation. Motivation is an important
factor, in health education we can make use of motivation to change the
behavior through incentives. There are two types of motives, primary
and secondary motives. Primary motives are inborn desires and
secondary motives are created by outside forces through incentives.
Health Education and Communication / 207
ANSWER 6
Barriers in Health Education
To have a better effect of health education it is necessary to identify and
overcome the barriers of communication, which can result in failure. These are:
1. Psychological barrier: They are emotional disturbances, depression,
neurosis, different levels of intelligence and any other psychosomatic
disorder causing barrier in communication. Special methods and utmost
care should be adopted while interacting with individuals with any
psychological problems.
2. Physiological barrier: These includes difficulties in hearing, seeing and
difficulties in expression and understanding.
3. Environmental barrier: These are due to excessive noise, improper vision/
invisibility, crowding, congested areas, etc.
4. Cultural barrier: They include illiteracy, levels of knowledge and under-
standing, customs, beliefs, religion, attitudes, patterns of behavior, habits,
economic and social class differences, language variations, and difference
between urban and rural education.
ANSWER 7
Educational Aids used in Health Education
1. Audio aids
2. Visual aids
3. Audio visual aids
Audio Aids
Most commonly used are:
1. Megaphones
2. Microphones
3. Amplifier
4. Radio
5. Tape-recorder
6. Gramophones records and discs.
These are useful in reproducing any kinds of words spoken and also
helps in repeating the same, can be used for entertainment and mass
communication.
Visual Aids
Visual aids helps people to understand better. These can be classified as:
1. Projected aids: These needs projection from a source onto a screen, e.g.
films or cinemas, film strips, slides, overhead projectors, epidiascopes,
Health Education and Communication / 209
ANSWER 8
Health Education for the Individuals
Individual health education can be possible through personal interviews in
the consulting room of the doctor, health centre or home. Topics of health
counseling may be selected according to the relevance of the situation. The
nursing staff also has opportunities to give health education. Public health
nurses, health visitors and health inspectors are visiting hundreds of homes,
they have plenty of opportunities for educating the people. The advantage
of this approach is that , the educator can have discussion, and persuade the
individual to change his/her behavior. It provides a two way communica-
tion. Disadvantage is that number of people we reach is small and is possible
only among those who come in contact.
ANSWER 9
Health Education for the Group
Group of many kinds like school children, industrial workers, mothers,
patients etc. can be educated through this approach. The subject must relate
directly to the interest of the group. A suitable method of health education
including audio-visual aids should be selected for successful health
education.
Group should not be more than 30 and lecture should not extend 15 to
20 minutes. The audio-visual aids can be combined along with lecture like
over head projector (OHP), powerpoint presentations, flip carts, flannel
graphs, models, charts, films, etc.
Disadvantages
Involvement of group to a minimum extent
Learning is passive
Does not stimulate thinking or problem solving capacity
Comprehension of a lecture varies with the individuals in the group.
2. Dialogue: Dialogue is another form of lecture where two people instead
of one present a discussion between themselves in front of the audience.
Since there are two people instead of one the audience reacts with much
greater interest than the lecture.
3. Group discussion: It is a group of people interacting in a face to face
situation. It is considered as effective method since there is free exchange
of knowledge, ideas and opinions.
Group should comprise of not less than 6 people and not more than 12
members. They should sit in a circle and there is a group leader who
initiates discussion and continues it without side conversations, encourages
every one to participate and summaries at the end.
Limitations of this may be unequal participation of members, one may
dominate the discussion and one may be shy and not participating.
The members have to follow few rules:
a. Ideas are clearly and concisely expressed
b. Listen to what others say
c. Not to interrupt when others are speaking
d. Make only relevant remarks.
4. Buzz session or small group discussion: It is the most informal way of
group discussion and allows for free expression of the ideas. Usually it is
followed in high school teaching where it is monitored by the class teacher
or the student monitor who will keep the discussion on track and control
the group.
5. Symposium: It is a series of speeches on a selected subject by speakers.
Each person will present an aspect of the subject briefly. There is no
discussion among speakers and at the end, the audience are invited to ask
questions and chairman gives summary at the end of the entire session.
6. Workshop: It consists of a series of meetings, usually four or more, with
emphasis on individual work, within a group with the guidance of
consultants and resource personnel. The total workshop is divided into
small groups with chairman and recorder for each group. Each person in
that group solve a part of the problem contribute for group work and group
Health Education and Communication / 211
discussion and leave the workshop with a plan of action on the problem.
Workshops are mainly advantageous for people with previous experience
on particular topics, for institutions and departments. It can be called as a
problem solving method.
7. Panel discussion: In panel discussion, there are 4 to 8 qualified people
who sit and discuss a given problem or topic before audience. The
Chairman opens the meeting and he has to keep the discussion going on.
After the discussion is over by panel speakers the audience are invited to
take part, but the participation is limited. It is an effective method of
education, provided it is properly planned and guided.
8. Conferences and seminars: These are good teaching methods that can be
employed by educational institutions. Education can be given to a large
number of people among the presence of persons qualified in topics of
interest or in allied disciplines. They provide opportunity to large number
of people to come together and exchange their ideas and views on the
topics of interest.
9. Colloquy: In this method of group health education, the audience gets the
opportunity for direct participation. Discussion/problems/questions are
put forward by few selected members of the audience. A group of experts
on the particular topic of discussion are selected and they listen to the
problems/questions raised by the members and give answers and
comments on them.
10. Programmed Instructions: In this method, teaching progresses step by step
called as instructional frames. It is based on Socratic method of advancing
in learning through easy stages or steps.
Advantage is that individual gets the opportunity to participate in the
program through practical experiences at different stages.
11. Simulation exercise: In this method individuals within the group are given
opportunities to participate in exercises that resembles real life situations,
e.g. demonstration of artificial resuscitation as a first aid measure on
dummies helps them to learn each step thoroughly.
Advantage is better understanding and visual impression is installed
in the minds of the participants.
12. Demonstrations: It is a carefully prepared presentation to show how to
perform a skill or procedure. The demonstrator involves audience in
discussion so they understand how to perform it. This is based on principle
of learning by doing, e.g. clinical teaching in hospitals, demonstration of
brushing technique to class of students.
13. Role playing: Role playing or socio-dramas are a form of dramatic
expression in health education. It is also called as psycho-dramas. It is a
form of demonstration where real life situations are acted out without any
212 / Questions and Answers in Community Dentistry
ANSWER 10
Health Education for Larges Masses/General Public
Mass media is useful in transmitting messages to people in large number
(millions) even from the remotest places. It is an effective method of health
education for the whole community. It is a one-way communication. Mass-
media alone is inadequate, in changing the human behavior but will be more
effective with other methods.
1. Television: It is most popular of all media. It is not only effective in creating
awareness but also has influence on people and introducing new ways to
life. It is one-way communication. It can only be an aid to teaching cannot
cover all aspects of learning. It covers large number of people and cater to
all groups of people.
Disadvantage: High cost of TV sets and not accessible by all people and is
one way communication.
2. Radio: In developing countries radio is more popular than TV. They can
reach illiterate population and also accessible to all socio-economic groups.
Health information can be conveyed in the form of talks, plays, question
and answer session, quiz programs, etc.
3. Internet: This is a fast growing communication media and has a large
potential to become a major health education tool. This is a computer based
communication system. There is vast communication through direct and
instant communication by means of e-mail discussion forums and other
online facilities.
Health Education and Communication / 213
ANSWER 11
Method in Health Education /Communication
These are grouped as:
1. Individual approach
2. Group approach
3. Mass approach.
(Refer Ans 8, 9 and 10).
214 / Questions and Answers in Community Dentistry
ANSWER 16
Types of Communication
1. One way communication: It is also called didactic method. Communication
is from the communicator to the audience. The example is lecture method
in the class room.
Drawbacks of this method are:
a. Knowledge is imposed.
b. Learning is authoritative.
c. Little audience participation.
d. No feedback.
e. Does not influence human behavior.
2. Two way communication: It is also called Socratic method. In this method
both educator and audience take part. The process of learning is active.
There will be exchange of ideas, views and opinions.
3. Verbal communication: This is the way of communication by word of
mouth.
4. Non-verbal communication: This is the method in which communication
is not through words but by actions, bodily movements, posters, gestures,
facial expressions, e.g. smile, raised eye brows, frawn, staring, gazing, etc.
5. Formal and informal communication
Formal communication is through normal channels.
Informal communication exists every where, e.g. gossip circle/grapevine
communication.
6. Visual communication: It is by seeing things like charts, models, posters,
graphs, etc.
7. Telecommunication: This is through electronic magnetic instrument like
TV radio, internet, telephone, telefax, telegram, etc.
215 / Questions and Answers in Community Dentistry
22 School Dental
Health Programs
QUESTIONS
1. Discuss the elements of school dental health program.
2. What are the objectives of the school dental program?
3. Name some school dental health programs.
4. Mention the aspects of school health program.
5. Learning about your oral health.
6. Askov dental program.
7. Tattle tooth program.
8. SHARP dental program.
9. North Carolina Statewide Preventive Dental Health Program.
10. Comprehensive dental care.
11. Incremental dental care.
12. Write in detail the steps in planning dental health education program for
controlling the dental disease in a school having 1500 children.
13. You are assigned the job of improving the dental knowledge of 500 school
children of your town by the department of community dentistry. Give
your detailed plan. (Refer Ans 12).
14. Prepare a dental health talk to be delivered on the radio.
15. Plan a comprehensive dental program for an orphanage school consisting
of 350 girls and 200 boys (Refer Ans 10 and 12).
ANSWER 1
The important elements of school dental health program are:
Improving school community relations
Conducting dental inspections
Conducting health education
Performing specific programs
216 / Questions and Answers in Community Dentistry
ANSWER 2
The ADA has given certain objectives of the school dental program:
To help every school child appreciate the importance of a healthy mouth
To help every school child appreciate the relationship of dental health to
general health
To encourage the observances of dental health practices, including personal
care, professional care, proper diet and oral habits
To enlist the aid of all groups and agencies interested in the promotion of
school health
To correlate dental health activities with the total school health program
To stimulate the development of resources to make dental care available
to all children and youth
To stimulate dentists to perform adequate health services for children.
School Dental Health Programs / 217
ANSWER 3
School Dental Health Programs
Learning about your oral health developed by ADA
Tattle Tooth Program Texas statewide preventive dentistry program
Askov Dental Health Program for the Danish population
North Carolina Statewide Preventive Dental Health Program
Preschool Dental Health Program initiated in US
New Zealand School Dental Service Plan
School Health Additional Referral Program(SHARP) institute in
Philadelphia
Love Teeth Day (LTD) campaign started in China
Bright Smile Bright Future Program-sponsored by Colgate Palmolive Ltd.
National Oral Health Care Program (NOHCP) initiated in India by
Directorate General of Health Services, Ministry of Health and Family
Welfare, Govt of India.
ANSWER 4
There are three main aspects of school health program:
1. School health services: These are procedures established to:
Appraise the health status of pupils and school personnel
To counsel pupils, parents and others concerning appraisal findings
To encourage correction of remedial defects
To assist in identification and education of handicapped children
To help prevent and control disease
To provide emergency service for injury or sudden sickness.
2. School health education: It is the process of providing learning experiences
for the purpose of influencing knowledge, attitudes or conduct relating to
individual or community health.
3. Healthful school living: It designates the provision of a safe and healthful
environment, the organization of a healthful school day and the
establishment of interpersonal relationships favorable to emotional, social
and physical health.
ANSWER 5
Learning About Your Oral Health
This program was developed by American Dental Association. The primary
goal of this program is to develop the knowledge, skills and attitude needed
218 / Questions and Answers in Community Dentistry
for prevention of dental diseases. The main aim of the program is to develop
adequate plaque control skills and knowledge among the school children.
Consideration is also given to increasing knowledge about diet and dental
caries. The other topics included in this program are the significance of fluoride,
oral safety, consumer health concepts, role of dental profession, relationship
of oral health with general health.
Program Evaluation
It was found that the program influenced favorably the oral health behavior
and affected favorable changes in the attitudes towards oral health practices.
ANSWER 6
Askov Dental Program
Askov is a small farming community with a population mostly of Danish
extraction. It showed very high dental caries in the initial surveys made in
1943 and 1946. During the period from 19491957 the section on dental health
of the Minnesota Department of Health supervised a demonstration school
dental health program in Askov, including caries prevention and control,
dental health education and dental care. There was no communal water
fluoridation; all other recognized methods for preventing dental caries were
used. Dental care was rendered by a group of 5 dentists.
10 year evaluation of the program reveal a 28% reduction in dental caries
in deciduous teeth of children aged 3 to 5 years. A 34% reduction in caries in
the permanent teeth of children 612 years and a 14% reduction in children
13 to 17 years old. Beyond these improvements in good health, dietary habits
for the children and improved filled teeth ratios were noticed. However, the
cost of the program was greater and caries reduction was smaller than are
now occurring with water fluoridation in the same community.
School Dental Health Programs / 219
ANSWER 7
Tattle Tooth Program
It was developed in 19741976 as a co-operative effort between Texas
Department of Health and the Texas Education Agency. The program was
pilot tested in 1975, field tested in 1976 to schools within the state of Texas. In
1985, the legislation stimulated a need for the Tattle tooth program statewide.
In May 1987 an advisory committee recommended that a new program be
developed to replace the existing Tattle Tooth Program. In 1989, the new
program Tattle Tooth II, A new generation Superbrush preschool
curriculum was intended for teachers and care givers who work with children
aged 3 and 4 years. The oral health curriculum consists of 7 units and the
primary purpose is to teach basic toothbrushing skills and to establish
toothbrushing as a daily routine in schools or day homes. The curriculum
includes children directed activities, which the children can do on their own
and teacher directed activities which the teacher does with the children. The
curriculum includes songs, games, stories, art work, a resource list and
videotapes to show the parents. Separate lesson plans were developed, 3
videotapes were produced as part of the teachers training package.
Program Implementation
The Texas Department of health employs 16 hygienists in the eight public
health regions to implement Tattle Tooth Program. They instruct the teachers
to conduct the program in the school. In 1987 it was decided to prepare the
college students in teacher preparation classes to implement the oral health
program. Topics covered in the curriculum were correct brushing and flossing
technique, awareness of the importance of safety and factual information
relating to dental disease, its causes and preventive techniques.
Program Evaluation
The results were positive. 94% of the teachers felt that teaching oral health
can have a positive effect on childrens dental health habits. Dental health
knowledge was significantly increased at all grade levels.
220 / Questions and Answers in Community Dentistry
ANSWER 8
SHARP (School Health Additional Referral Program)
A program called SHARP instituted in Philedelphia where the lowest rate for
correction of physical defects prevailed. The purpose of the program was to
motivate parents into initiating action for correction of defects in their children
through effective utilization for community resources. The project was carried
out by the district nurses with the co-operation of all school personnel. The
nurse made day time visits to the families in which the mothers were at home.
Working parents were contacted by phone.
ANSWER 9
North Carolina Statewide Preventive Dental Health Program
In 1973 Dr. Frank E Law initiated a 10-year program to reduce dental disease
problem in North Carolina It was the first statewide program. This project
included producing 19 videotapes for classroom teachers in teaching dental
health and conducting a statewide oral health survey of a representative
sample of children from Kindergarten to grade 12, during 198687.
Implementation
It reaches several segments of population young children, parents, teachers,
dental professionals and community leaders. Services delivered through the
program included fluoridation of water, weekly fluoride rinses, screening,
referral, dental health education and sealant program. Teachers were believed
to be the key in the educational programs. Classroom and teachers videos,
teachers guides for helping teachers to be effective while teaching are
available. Additional teaching aids like leaflets, worksheets and hand outs on
nutrition, fluoride, plaque control, routine dental visits, injury prevention and
smokeless tobacco is available.
Program Evaluation
Oral health surveys were conducted to evaluate the effectiveness of the
education program in changing knowledge, attitudes, values and practices of
students.
School Dental Health Programs / 221
ANSWER 10
Comprehensive Dental Care
It is the meeting of the accumulated dental needs at the time a population
group is taken into the program. Comprehensive dental care includes preven-
tive, therapeutic and maintenance care to the individual. Preventive care in
terms of educational motivation and other measures aimed at minimizing
the disease. Therapeutic care in terms of elimination of pain, restoration of
the carious lesion and replacement of the missing teeth. Maintenance care
includes recall visits and treatment of new increments of disease.
ANSWER 11
Incremental Dental Care
It may be defined as periodic care so spaced that increments of dental disease
are treated at the earliest time consistent with proper diagnosis and operating
efficiency, in such a way that there is no accumulation of dental needs beyond
the minimum. This concept is common at the school level. Here the youngest
available group (first year) is taken and is carried forward in the subsequent
years and every year adding a new class of children at their earliest age and
carrying them forward to as high as age available resources permit.
Advantages
Reduce economic burden, by treating small early increments of dental
disease
Inculcate a habit and awareness of dental care at an earliest age.
Disadvantages
Funds are sometimes exhausted before the child reaches the secondary
level of schooling
Parents and few dentists feel permanent teeth should be given more
importance then the deciduous teeth and also the child may not continue
the habits taught to them in the childhood and hence such program should
be targeted to the teenagers
Break in the continuity of the program if the child drops out of the school.
ANSWER 12
Planning a School Dental Health Program
Steps
1. Collecting information essential for planning.
2. Establishing dental health education objectives.
222 / Questions and Answers in Community Dentistry
QUESTIONS
1. Define dental auxiliary/ancillaries.
2. Classify dental auxiliaries.
3. Dental surgery assistant.
4. Four handed dentistry.
5. Dental laboratory technician.
6. Denturist.
7. a. New Zealand school dental nurse.
b. Saskatchewan nurse.
8. Dental therapist.
9. Dental hygienist.
10. Expanded Function Dental Auxiliary (EFDA)/techno therapist.
11. Newer type of dental auxiliaries.
12. Degree of supervision of dental auxiliaries.
13. TEAM (training in expanded auxiliary management).
14. Dental auxiliary in India.
ANSWER 1
A dental auxiliary is defined as a person who is given responsibility by a
dentist so that he or she can help the dentist render dental care, but who is not
himself or herself qualified with a dental degree.
ANSWER 2
WHO classification (1967)
1a. Non-operating auxiliary
1b: Clinical: This is a person who assists the professional (Dentist) in his clini-
cal work but does not carry out independent procedure in the oral cavity.
1c: Laboratory: This is a person who assists the professional by carrying out
certain technical laboratory procedures.
Dental Auxiliaries/Ancillaries / 225
ANSWER 3
Dental Surgery Assistant
Is a non-operating auxiliary who assists the dentist or dental hygienist in
treating patients but is not legally permitted to treat the patient independently.
Expert committee on auxiliary dental personnel of WHO gave the following
duties:
1. Reception of the patient.
2. Preparation of the patient for any treatment he/she may need
3. Preparation and provision of all necessary facilities such as mouthwashes
and napkins.
4. Sterilization, care and preparation of instruments.
5. Preparation and mixing of restorative materials including both filling and
impression materials.
6. Care of the patient after treatment until he/she leaves, including clearing
away of instruments and preparation of instruments for reuse.
7. Preparation of the surgery for the next patient.
8. Preparation of documents to the surgeon.
9. Assistance with radiography work and the processing and mounting of
radiographs.
10. Instruction of the patient, where necessary, in the correct use of the tooth
brush.
11. After-care of persons who have had general anesthetics.
Dental surgery assistant take on the job training or the training courses
are available which extend over a period of one year but may extend for two
226 / Questions and Answers in Community Dentistry
ANSWER 4
Four Handed Dentistry
It is an art of seating both the dentist and dental assistant in such a way that
both are within easy reach of the patients mouth. The patient is in fully supine
position. The assistant will hand the dentist, the particular instrument he needs.
Assistant will also perform additional tasks such as retraction or aspiration.
Thus the dentist keeps his hands and eyes in the field of operation and work
with less fatigue and greater efficiency.
ANSWER 5
Dental Laboratory Technician
This type of personnel are also called as dental mechanics. He/she is a non-
operating auxiliary who fulfills the prescriptions provided by dentists
regarding the extra oral construction and repair of oral appliances and
bridgework. They receive training through apprenticeship or formal training
at a dental school or technical college, which lasts from 3 to 5 years. Their
functions are casting of models from impression made by dentists, fabrication
of dentures, splints, orthodontic appliances, inlays, crowns and special trays.
They can be self employed or employed by the dentist or public health practice
or by commercial laboratories.
(also refer answer 6)
ANSWER 6
Denturist
They are dental laboratory technicians who fabricate dentures directly for
patients without dentists prescription. They may be licensed or registered;
they are permitted in few states of United States and elsewhere like Tasmania
and Denmark. This practice is called as denturism. WHO defines this as illegal
practice. In the state of Maine, denturist is permitted to take impressions and
fit dentures but only under the direction of the dentist.
Dental Auxiliaries/Ancillaries / 227
ANSWER 7A
The New Zealand School Dental Nurse
School dental nurse is a person, who is permitted to diagnose dental disease
and to plan and carry out certain specified preventive and treatment measure,
including some operative procedures in the treatment of dental caries and
periodontal disease in defined groups of people, usually school children.
Training is over a period of two years. A school dental nurse is assigned to
each school having its own dental clinic and with more than 100 children.
The dental nurse scheme was established in Wellington, New Zealand in 1921.
The man who influenced its formation was T.A. Hunter. In New Zealand, the
dental nurses are predominantly in the school-based salaried service, they
provide care for children at six months intervals. The duties for school dental
nurse are listed by New Zealand Department of Health Division of Dental
Health as follows:
1. Oral examination
2. Prophylaxis
3. Topical fluoride application
4. Advice on dietary fluoride supplements
5. Administration of local anesthesia.
6. Cavity preparation and placement of amalgam filling in primary and
permanent teeth
7. Pulp capping
8. Extraction of primary teeth
9. Individual patient instruction in tooth brushing and oral hygiene
10. Classroom and parent-teacher dental health education
11. Referral of patient to private practitioners for more complex services, such
as extraction of permanent teeth, restoration of fractured permanent
incisors and orthodontic treatment.
Other countries which have dental nurse services are Malaysia, Singapore,
Thailand, South Vietnam, Myanmar, Indonesia, Hong Kong, Australia, part
of Africa and South America.
ANSWER 7B
Saskatchewan Dental Nurse
In Saskatchewan, a Canadian province in North America is the only place
where the dental nurse is allowed to legally drill and fill the teeth. They are
trained under the direct supervision of the dentist for two months and then
work with a more experienced dental nurse for the third month. They are
presumed to provide care more cheaply than dentist.
228 / Questions and Answers in Community Dentistry
ANSWER 8
Dental Therapist (Dental dresser, New cross auxiliary)
This is a person who is permitted to carry out to the prescription of a
supervising dentist, certain specified preventive and treatment measures
including the preparation of cavities and restoration of teeth. Their function
is similar to New Zealand school dental nurse but they are not permitted to
diagnose and plan dental care. They have to work to written treatment plans
advised by the supervising dentist.
The training of these auxiliaries is about a period of 2 years including both
reversible and irreversible procedures. Their functions are:
1. Clinical caries diagnosis
2. Technique of cavity preparation in deciduous and permanent teeth
3. Material handling and restorative skills
4. Vital pulpotomies under rubber dam in deciduous teeth, but are not trained
to provide endodontic care
5. Extraction of deciduous teeth under local anesthesia.
6. They take radiographs under the supervision of dentist but have little
training in interpretation of radiographs.
UK and Australia were using the services of dental therapist, later other
countries like Hong Kong, Singapore, Vietnam and Tanzania started up with
this service.
ANSWER 9
Dental Hygienist
A dental hygienist is an operating auxiliary licensed and registered to practice
dental hygiene under the laws of the appropriate state, province, territory or
nation.
In 1905, Dr. Alfred Fones trained Mrs. Irene Newman for dental
prophylaxis. She worked with Dr. Fones and became the first dental hygienist.
Dr. Fones is called Father of Dental Hygiene. As per Indian Dentist Act of
1948, a dental hygienist means a person not being a dentist or medical
practitioner, who scales, cleans or polishes teeth or gives instructions in dental
hygiene. They have a training for 2 years.
ANSWER 10
Expanded Function Dental Auxiliary (EFDA)
They are also referred to as expanded function dental assistant, expanded
function dental hygienist, expanded function auxiliary, expanded duty dental
auxiliary and techno-therapist.
An expanded function dental auxiliary is a dental assistant or dental
hygienist in some cases, who have received further training in duties related
to the direct treatment of the patients, though still working under direct
supervision of a dentist.
They undertake reversible procedures like:
1. Placing and removing rubber dams.
2. Placing and removing temporary restorations.
3. Placing and removing matrix bands.
4. Condensing and carving amalgam restoration in previously prepared teeth.
5. Placing of acrylic restorations in previously prepared teeth.
6. Final finishing and polishing of the restorations.
Four levels of training and qualification were recognized in 1974s:
1. Certified dental assistant.
2. Preventive dental assistant.
3. Dental hygienist.
4. Dental hygienist with expanded duties.
ANSWER 11
New Auxiliary Types
The Expert Committee on Auxiliary Dental Personnel of the WHO has
suggested two new types:
Dental-aide
Their duties include elementary first-aid procedures for the relief of pain and
Extraction of teeth under local anesthesia
Control of hemorrhage
Recognition of dental disease important enough to justify transportation
of the patient to a center where proper dental care is available.
ANSWER 12
Degrees of Supervision of Auxiliaries
These levels are given by American Dental Association in 1998
1. Personal supervision: The dentist is personally operating on a patient and
authorizes the auxiliary to aid treatment by concurrently performing
supportive procedures.
2. Direct supervision: The dentist is in the dental office, personally diagnoses
the condition to be treated, personally authorizes the procedure and
remains in the dental office while procedures are being performed by the
auxiliary and before dismissal of the patient, evaluates the performance
of the dental auxiliary.
3. Indirect supervision: The dentist is in the dental office, has personally
diagnosed the condition to be treated, authorizes the procedures and
remains in the dental office while procedures are being performed by the
auxiliary.
4. General supervision: The dentist has authorized the procedure and they
are been carried out in accordance with the diagnosis and treatment plan
and the dentist is not required to be in the dental office while procedures
are provided.
ANSWER 13
Training in Expanded Auxiliary Management ( TEAM )
As dentists become more accustomed to employing hygienists, they realized
the advantages of doing so. The TEAM program includes training dental
students and the dental supervisory staff in the utilization of expanded
Dental Auxiliaries/Ancillaries / 231
ANSWER 14
Dental Auxiliaries in India
Non-operating Auxiliaries
Dental surgery assistant
Dental secretary/Receptionist
Dental laboratory technician.
Operating Auxiliaries
Dental hygienist.
232 / Questions and Answers in Community Dentistry
Provision of Dental Care/
Structure of Dental
24 Practice/Delivery
of Dental Care
QUESTIONS
1. Different methods in delivery of dental care/provision of dental
care/structure of dental practice.
2. Private practice/solo practice
3. Group practice.
4. Closed and open panel.
5. Health Maintenance Organizations (HMOs).
6. Mobile dental clinics/mobile dental van.
7. Portable equipments.
8. Hospital dentistry.
9. Franchised practices.
10. Neighborhood health centers.
11. Different methods of dental care delivery in India.
ANSWER 1
The following are the different methods by which dental care is provided:
1. Private practice
2. Solo practice.
3. Group Practice: Close panel and open panel
4. Health Maintenance Organization (HMO)
5. Preferred Provider Organization (PPO)
6. Contract Provider Organization (CPO)
7. Provision made by the government.
8. Neighborhood health centers.
9. Mobile dental clinics.
10. Hospital dentistry.
11. Franchised practice- Department store clinics
12. Part time practice.
Provision of Dental Care / 233
ANSWER 2
Private Practice
Traditionally, dental care has been delivered by independent private
practitioner. Solo practice is the most common form with two-third of the
dentists in private practice.
Advantages
Flexibility to both provider and patient
Earning capacity is increased
Dentist has a freedom to treat or not to treat anyone
Working hours can be decided by both
Choice of equipment, materials is decided by dentist.
Disadvantages
Maldistribution of the dentists
Some groups are not readily treated like uncooperative preschool child,
chronically ill, mentally retarded, physically handicapped, etc.
Many elderly and poor people can not afford
Dentists may have to meet with expenses like utilities, rent, equipment,
supplies, staff payroll, etc. regardless of whether patient visits the clinic or
not
Inconvenience to the patients when dentist is on vacation.( No associate
to cover when on vacation as in Group practice).
ANSWER 3
Group Practice
It is called non-solo practice.
Definition by ADA states that a non-solo dentist works in a practice
with at least one other dentist. Some of these dentists may be employed by
the owner dentist in the practice.
Dentists are involved in many large group practices ( including general
dentists/specialists/semi-specialists) covering all the major phases of
comprehensive dental care.
Convenience: As all the types of treatment are available under one roof
Economy: May reduce overhead costs
Security: The patient feels more secure as good specialized care and good
continuity of care are available.
Advantages to Dentist
Can improve his own performance
Can go for vacations
Financial outlook is better as more patients are treated per year
Can serve more patients in a year
Gains security
Reduction of overhead cost compared to solo practice.
Disadvantages
Personal conflicts
Location and business procedures may not please all members
Patient is feared being shuffled from one operator to another.
ANSWER 4
Open Panel
Any licensed (registered) dentist may participate
The beneficiary may receive treatment from among all licensed (registered)
dentists, with the corresponding benefits being payable to either the
beneficiary or dentist
The dentist may accept or refuse any beneficiary.
Closed Panel
It is a practice that is set up by an employer or union for the treatment of the
employees and staffed by salaried dentists who treat only the employees and
their dependents.
ANSWER 5
Health Maintenance Organizations (HMOs)
HMO is defined in 1973 act as a legal entity which provides a prescribed
range of health services to each individual who has enrolled in the organization
in return for a prepaid, fixed and uniform payment. HMO is a large group
practice with a number of services available under one roof. The advantage
of HMOs is, it reduces the cost of care for those enrolled. HMO uses a prepaid
Provision of Dental Care / 235
ANSWER 6
Mobile Dental Clinics
They are also referred to as the clinics on wheels. They provide dental services
to the people at their doorstep. Mobile dental clinics can be used in frontier
and rural areas, in cities by saving in-patients transportation time. A mobile
dental van can be parked in a schoolyard and provide screening, preventive
236 / Questions and Answers in Community Dentistry
care and even comprehensive dental care. Mobile dental clinic are of two
types:
1. Large mobile dental clinic
2. Small mobile dental clinic.
ANSWER 7
Portable Equipments
Portable equipments are designed for variety of community uses:
For home bound patients, for extraction, denture and fabrication work
Provision of Dental Care / 237
ANSWER 8
Hospital Dentistry
Dental care is provided in the hospitals. Many dentists affiliated with these
and other educational programs have full time or part time commitments to
hospital based care. Dental care provided in hospital is often in those situations
in which general anesthesia and other resources of hospital are required like
treatment of rampant caries in young children, surgery of carcinomas, cleft
palate repair, maxillofacial prosthetic treatment for victims of burns or trauma
of head and neck, routine dental care for patients suffering from severe
systemic diseases.
ANSWER 9
Franchised Practices
The concept of franchises is common in the United States. The dental clinics
are opened in the departmental stores, which are operated during usual store
hours and perceived by the stores management as further step in one stop
shopping. They are viewed as an extra service for their customers. These dental
clinics can also be practiced in restaurants, automobile servicing, retail stores,
child care services, etc. The franchisor, for some combination of initial fees
provides name and advertising, training, coordinated purchasing and
management services. The franchisee runs the individual practice and except
for the agreed payments to the franchisor, retains the profit from the business.
238 / Questions and Answers in Community Dentistry
ANSWER 10
Neighborhood health centers are a modern attempt to provide health
services to group of disadvantaged people, where private medical and
dental practitioners are not found. These centers are established where the
low income people live in a place that will seem homelike to them. Certain
services are provided in the homes and good primary medical and dental
care is provided in the center; the center acts as a referring agency to sources
of specialized care or hospitalization. It has a real function in vocational
rehabilitation. It also trains and employs local people; by doing these the
centre becomes more personalized. Supportive services offered at these
centers are usually by the public health nurses, social workers and home
counselors.
ANSWER 11
The following are the different methods by which dental care is provided in
India:
1. Private practice/solo practice.
2. Part time practice.
3. Group practice: Close panel and open panel.
4. Provision made by the government
5. Mobile dental clinics.
6. Hospital dentistry.
7. Private/governmental dental institutions.
Finance/Payment in Dental Care / 239
25 Finance/Payment in
Dental Care
QUESTIONS
1. Classify methods/mechanism of payments of dental care.
2. Fee-for-service.
3. Post-payment plans.
4. Pre-payment plans/Third party payment plans.
5. Reimbursement in third party payment plans. (Refer Ans 4)
6. UCR fee. (Refer Ans 4)
7. Delta dental plans/dental service corporation.
8. 90th percentile.
9. Blue cross and blue shield.
10. Prepaid group practice.
11. Medicare.
12. Medicaid.
13. Mode of financing in India.
ANSWER 1
Different methods of payment for dental care are:
1. Private fee-for-service
2. Post payment plans
3. Private third party prepayment plans
a. Commercial insurance companies
b. Non-profit health service corporations, e.g. delta dental plans blue
cross/ blue shield
c. Prepaid group practice
d. Capitation plans
4. Salary
5. Direct reimbursement
6. Public programs.
240 / Questions and Answers in Community Dentistry
ANSWER 2
Private Fee-for-Service
Two party arrangement
In this, patient decides to visit any dentist and dentist suggests appropriate
treatment and informs the fee for that service. If patient accepts the service,
service is provided by the dentist and fee for that service is paid by the
patient to dentist
It is a traditional form of reimbursement and culturally acceptable
This system is flexible and simple to administrate.
ANSWER 3
Post-payment Plans or Budget Payment Plans
Under this plan the patient borrows money from a bank or finance company
to pay the dentist fee. The amount is repaid to the bank or finance company
in budgeted amount. This plan was primarily used by the people in the middle
income group rather than the lower income group.
ANSWER 4
Third Party Payment
a. In this system payment for dental services, i.e. the payment to the dentist
is done by an agency rather than directly by the patient and the patient
pays to the agency (Third party).
b. The patient and the dentist are the first and second parties and the
administrator of the finance is the third party. The third party is also called
as the carrier, insurer or administrative agent.
(Refer Ans 1 for types of third party payment).
UCR Fee
1. Usual fee: This is that type of fee that an individual dentist most frequently
charges for a given dental service.
2. Customary fee: This is the fee that is decided by the administrator of a
dental benefit plan from actual submitted fee for a procedure to establish
maximum benefit payable under a given plan for that procedure.
3. Reasonable fee: This fee is charged by a dentist for a specific procedure
that is modified by nature and severity of condition being treated and by
medical or dental complications or unusual circumstances.
Table of Allowances
It is defined as list of covered services with an assigned amount that represents
the total obligation of the plan with respect to payment for such service, but
that does not necessarily represents the dentists full fee for that service.
Example: If dentists usual fee for extraction is Rs 100 and plan lists a fee
of Rs 90 as payable for that service, to make up the difference dentist will
collect Rs 90 from the carrier and charges Rs 10 to the patient.
In this, a dentist should explain the patient the limited nature of the
insurance payment because some patients are unaware that their plan may
not cover them full.
Fee Schedule
It is a list of charges established or agreed by a dentist for specific dental
services and is usually taken to mean payment in full.
Capitation
A capitation fee is usually a fixed monthly payment paid by a carrier to a
dentist based on the number of patients assigned to the dentist for treatment.
This requires patients to be assigned to specific dentist or practice so that
payment can be paid to appropriate dentist or practice. Dentist receive fixed
sum of money per head per month regardless of whether participant in the
plan receive care in that particular month.
ANSWER 6
Delta Dental Plans
A dental corporation is a legally constituted not for profit organization,
incorporated on state by state basis, that negotiates and administers contracts
for dental care. In June 1954, the Seattle district Dental society in Washington
242 / Questions and Answers in Community Dentistry
ANSWER 8
90th Percentile (Fig. 25.1)
It is one of the methods employed for reimbursing the dentist fees.(e.g. in
delta dental plan, Blue cross and Blue shield). It is calculated as follows: First,
obtain the usual fees of all the participating dentist, divide the total frequency
into hundredths, so that the 90th percentile is that value below which 90% of
the observations lie.
For example, if 100 dentists are there in a given area, and the filed fee for
a particular service range from Rs 30 to Rs 100, spread out these filed fees on
a cumulative frequency distribution table. The results may show 10% of
dentists charge Rs 30, 50% charge Rs 55 or less, 80% charge Rs 68 or less and
90% charge Rs 85 and less. The 90th percentile fee is Rs 85.
In this method of reimbursement 90% of the dentist will get their usual fee
but the remaining 10% dentist who charged above Rs 85 will be paid at 90th
percentile (Rs 85) which will be less than their usual fee.
Finance/Payment in Dental Care / 243
ANSWER 9
Blue cross and Blue shield is a non-profitable health service corporation which
offered limited coverage for dental services under their main part of hospital-
surgical-medical policies. In this the dentists are reimbursed like in the Delta
dental plan or dentist prefiled UCR fee is used to create fee screens as a
basis for reimbursement.
ANSWER 10
Pre-paid Group Practice
Here a group of dentists practice under one roof. The net income in this is
provided equally or according to patient load, years of service, speciality
and in some group practices dentists are salaried. Majority of the patients
receive services on the usual private fee-for-service basis, larger group
practices have resources and personnel that make it feasible for them to offer
contracts to consumer groups on a pre-paid, capitation basis. The group
practice may be OPEN PANEL (where any licensed dentist may participate,
dentist may accept or refuse any beneficiary and the beneficiary has the choice
to select among the dentist) or CLOSED PANEL (where the patients can
receive dental service only at specified facilities from a limited number of
dentists).
ANSWER 11
Medicare
Title XVIII of the social security amendment of 1965 is the program known as
Medicare. It is funded wholly by federal government, US. This program
removes all the financial barriers for hospital and physician services for all
245 / Questions and Answers in Community Dentistry
26 Social Sciences
QUESTIONS
1. Culture and dental practices.
2. Social stratification.
3. Social class and dental health.
4. Write a note on social sciences.
5. Society. (Refer Ans 4)
6. Norms. (Refer Ans 4)
7. Folkways. (Refer Ans 4)
8. Taboos. (Refer Ans 4)
9. Anthropology. (Refer Ans 4)
10. Indigenous oral hygiene practices. (Refer Ans 1)
ANSWER 1
The word culture is derived from a latin word colere means to cultivate or
to instruct. Culture is a learned behavior which has been socially acquired. It
plays an important role in human societies. It is transmitted from generation
to another generation through learning process both formal and informal. It
is a dynamic force of the society. It is the cumulative experience of mankinds
history from origin to the present. Culture influences the beliefs, behavior,
perception, emotions, language, religion, family, diet, dressing, personality
and also health.
d. Burnt charcoal, tobacco, paddy husk, coconut hush ash, salt have been
used for teeth cleaning.
4. Taboos (Medical superstitious): Regarding tooth and toothache there have
been various superstitions. The ancestors related miracle cure of toothache
to the workship of sun. In some parts of India, Brahmin priest clean their
teeth with cherrywood invoking heavenly blessings to keep toothache
away from them. In Switzerland, space between the teeth was considered
to indicate that the child will be a good singer. In some tribes in Africa, a
baby born with prenatal teeth was believed to be a threat to the tribe.
5. Beliefs (Misconception) that the diseases are caused due to the:
a. Supernatural causes
b. Wrath of god or goddess
c. Breach of Taboo
d. Past sins
e. Evil eye
f. Spirit of ghost.
For example:
1. Diarrhea is associated with teething, but there are different beliefs:
a. Some feel that it is a natural process and treatment is not required
b. Some believe that it is dangerous to control it and the heat would get
trapped in the body
c. While some believe that it is due to the evil eye.
2. Superstitions regarding fluorosis:
a. It is caused by biting on the banana leaf
b. It is caused by biting on the palm leaf
c. It is caused by eating brinjal.
3. Scalling leads to tooth loosening.
4. Extraction of tooth causes loss of eye-sight.
ANSWER 2
Social stratification is the classification of a group based on the socioeconomic
status. Socioeconomic status (SES) is an important determinant of health. The
different scales for measuring social status are:
1. Superior/Inferior.
2. a. Ascribed: Determined at birth, e.g. age, caste.
b. Achieved: Is gained during the lifetime of the person.
3. a. Open: Form of stratification in which there is a change of rank and is
related to the age.
b. Closed: It is a permanent rank and determines ones whole lifestyle. There
is no movement in any direction.
248 / Questions and Answers in Community Dentistry
4. SES scale for rural Indian family: Developed by Pareek based on 9 items:
Caste, occupation, education, level of social participation, land holding,
housing, farm, material possession and family. The combined score for
the 9 items is graded to indicate 5 SES categories.
5. SES for urban family developed by Kuppuswamy. It is based on 3 variables:
Education, occupation and income.
6. SES based on Per capita income suggested by Prasad.
7. Social class: by British Registrar-General.
S.no. Social class Occupation
ANSWER 3
Social Factors and Dental Health
1. Upper middle class: The professional and business executive group, well
educated, living in a preferred areas in well maintained, usually spacious
homes. The members of this class seek out expert advice and follow the
advice, with considerable religiosity. They value their teeth and are
interested in preventive dentistry and actively pursue various types of
dental care. The dentist is visualized as a professional who not only repairs
teeth and stops pain but also prevents decay and loss of teeth and makes
persons teeth more attractive and useful. The members of this class are
much impressed with the desirability of having their own teeth for as long
as possible.
2. Lower middle class: These include the small business, minor executives,
teachers, salesman and white collar workers. They are highly moralistic
group. They are the most compulsive in their dental care attitudes and
Social Sciences / 249
ANSWER 4
The five branches of social sciences include:
1. Sociology
2. Social or cultural anthropology.
3. Social psychology.
4. Economics.
5. Political sciences.
Sociology
It is the science concerned with the organization or structure of social groups.
It is the science of behavior of man in a society or group of human beings.
Society may be defined as an organization of member agents having social
relations amongst themselves.
Cultural Anthropology
Anthropology is the study of man and his work. It has two main divisions:
1. Physical anthropology
2. Cultural anthropology
Social Sciences / 251
Physical Anthropology
It is the study of man as a biological organism.
Cultural Anthropology
It is the branch dealing with mans behavior and products. Its main theme is
culture. The branches of cultural anthropology are:
1. Ethnology: It is the comparative study of culture
2. Archeology: It is study of past cultures and civilizations and uses their
remains as the principal source of information
3. Linguistics: It is study of speech patterns of man, i.e. study of languages
and dialects
4. Social anthropology: It is a specialized branch of cultural anthropology
dealing with comparative study of kinship and non kinship organization
patterns in different societies.
Social Psychology
It deals with human nature and attitudes in general. It explains how and why
perceptions, thoughts, opinions, attitudes and behavior vary in different
groups and societies.
Economics
It studies the economic aspects of man, i.e. production, distribution and
consumption of the three basic essentials for his living namely food, shelter
and clothing. Scarcity or excess of these are found to affect human behavior.
Political Science
It deals with the constitution, government and the laws of the state which
impose some sort of discipline on mans movements or behavior.
252 / Questions and Answers in Community Dentistry
27 Dental Ethics
QUESTIONS
1. Define ethics.
2. Define dental ethics.
3. Principles of ethics.
4. Unethical practices.
5. Ethical practices.
6. Informed consent.
7. Nuremberg code. (Refer Ans 6)
ANSWER 1
Ethics is defined as the science of the ideal human character and behavior in
situations where distinction must be made between right and wrong, duty
must be followed and good interpersonal relations maintained.
ANSWER 2
It is the moral obligation (duties) of the dentist towards the patient, his
professional colleagues and to the society at large.
ANSWER 3
Principles of Ethics
1. Non-maleficence (To do no harm): Practitioners should not harm his
patients.
2. Beneficence (To do good): Attempts must be made to maximize the benefits
and minimize the harm.
3. Veracity or truthfulness: The doctor-patient relationship is based on trust;
failure of this can result in disrespect to the patient and threatens
relationship.
Dental Ethics / 253
ANSWER 4
Unethical Practices
1. Dental Practice by unregistered practitioner.
2. Styling dental clinics as dental hospitals.
3. Issuing bogus/false certificates.
4. Practicing or aiding in any illegal practice.
5. Promise of radical cure by the employment of secret methods of treatment.
6. Employing any agent for the purpose of obtaining patients.
7. Using sign boards larger than 0.9 m by 0.6 m and writing things like
painless extraction or any attractive words to attract patient.
8. Placing sign boards on a chemist shop or any other place where the dentist
does not reside or work.
9. Advertising in press about practice for the purpose of increase in flow of
patients.
10. Using abbreviations after dentists name except indicating dental
qualifications like RDP, MIDA, MRSH, FICD, MICD, FACD.
ANSWER 5
Ethical Practices
1. Duties of doctors in general
a. A doctor must always maintain the highest standards of professional
conduct
b. A doctor must not allow himself to be influenced merely by motives of
profit.
254 / Questions and Answers in Community Dentistry
ANSWER 6
Consent: Patients right to self-determination.
Types of Consent
1. Implied consent: If a patient enters the dental clinic and sits on the dental
chair and opens his/her mouth for examination then it is implied consent.
Other forms of implied consent are in cases of emergency and accidents.
2. Informed consent/express consent: It is first stated and by far the largest
principle of Nuremberg Code which identifies four attributes of consent
that must be Voluntary, legally competent, informed and
comprehending. This consent is a statement documented and recorded
in writing and assigned by the signature of the person. Informed consent
plays a vital role in the ethical justification of research involving human
subjects.
Other forms of informed consent
a. Proxy consent: In case individuals form a part of collective group then
informed consent can be obtained from one of the members of the group
who is the leader.
For example: obtaining informed consent from the principal of the
school on behalf of school children.
b. Consent of minors
i. Emancipated minor: is the one who is not subject to parental control
or regulation and can give consent himself/herself independently
ii. The mature minor rule: Here, the minor (in the absence of parental
consent) who is capable of appreciating the nature and
consequences of the surgery to be done on the body, usually in the
age group of 1418 years gives the consent
iii. Child of divorced parent: In this case, the parent of the child with
legal custody have the right to give the consent of the child
iv. When a minor or mentally incompetent patient is been treated than
the consent must be obtained by parent or guardian.
3. Telephone consent: If the consent is taken on the telephone the patient
should be informed that a third party is listening on the extension. After
the consent is obtained appropriate notes should be made on the patient
chart and signed by the one who obtained the consent and countersigned
by the third party.
256 / Questions and Answers in Community Dentistry
1. I agree to give my personal details like name, age, sex, phone no., address,
occupation and other details required for the study to the best of my knowledge.
2. I will co-operate with the investigators for my oral examination.
3. I will follow the instructions given by the investigators during the study.
4. I will visit the investigators as and when required for the study, at the given
appointments (date and time).
5. I permit the investigators to utilize the information given by me and results
obtained from this study for presentation and publication.
6. The investigators have assured me, that the information given by me will be
kept confidential.
7. I will not claim any returns for my co-operation in the study, even if it is being
sponsored by agency.
8. I am participating at my own wish and will.
I have read, gone through and understood the above information given by the
doctor about my study. I have entered and signed this application.
28 Dental Jurisprudence
QUESTION
Define dental jurisprudence.
ANSWER
Dental jurisprudence (Flow chart 28.1) is the science of law as applied to the
practice of dentistry.
29 Consumer Protection
Act (CPA)
QUESTION
Write a note on Consumer Protection Act.
ANSWER
Consumer Protection Act was passed by parliament in 1986, and came into
force on 1987. Under this act, the provision was made for the establishment of
Consumer Protection Councils and Consumer Dispute Redressal Forums at
National State and District levels for quick and simple settlement of consumer
disputes.
It was passed with a view to:
Provide for a better protection of interest of the consumer
Creation of authorities for the settlement of consumer dispute
Establish consumer councils to educate the public
To provide speedy and inexpensive settlement within a limited time frame
as against civil action which are expensive and takes long years.
The Consumer Protection Act is eventually envisaged to cover business
and trade, but in a landmark judgment the professional services was brought
into the ambit of the Consumer Protection Act .The supreme court ordered
professional services rendered by professionals like doctors and dentists to
be included into the definition of Sec 2 (o) of the Consumer Protection Act.
a. District forum: One district judge (sitting or retired) and two members
of repute and integrity, one of whom shall be a women. The forum can
entertain complaints where the compensation claimed does not exceed
five lakhs.
b. State commission
One judge (sitting or retired) of High court and two members of
repute and integrity, one of whom shall be a women.
Jurisdiction above 5 lakhs upto 20 lakhs
Also appeals against the order of District Forum
Always has revisional powers and appellate jurisdiction.
c. National commission
One judge (sitting or retired) of Supreme Court .
Four members and two members of repute and integrity, one of
whom shall be a woman.
Jurisdiction above 20 lakhs
Also appeals against the order of the State Commission
Always has revisional powers and appellate jurisdiction.
30 Dental Council
of India (DCI)
QUESTIONS
1. Dentist Act.
2. Dental Council of India.
3. State Dental Council.
4. The Dentist Amendment Act 1993.
5. Part A/Part B registration.
ANSWER 1
Dentist Act
This act came into force on 29th March 1948. It is an act to uphold dignity,
prestige and honor of the dental profession and to regulate dental profession
in India. This act contains the following chapters with their sub-sections as
contents:
CHAPTER I: INTRODUCTORY
1. Short title and extent
2. a. Interpretation
b. Construction of references to laws not in force in Jammu and Kashmir.
CHAPTER V: MISCELLANEOUS
47. Penalty for falsely claiming to be registered
48. Misuse of titles
49. Practice by unregistered persons
50. Failure to surrender certificate of registration
51. Companies not to engage in dentistry
52. Cognizance of offences
53. a. Payment of part of fees to council
b. Accounts and audit
54. Appointment of commission of enquiry
55. Power to make rules.
ANSWER 2
The Dental Council of India was formed on 12th April 1949 under the provision
of Dentist Act, 1948.
Functions of DCI
1. Basic principles for the maintenance of minimum education standard for
the BDS degree.
2. Minimum physical requirements of a dental college.
3. Minimum staff pattern for under-graduate dental studies in colleges with
40, 60 and 100 number of admissions.
4. Basic qualifications and teaching experience required to teach BDS and
MDS students.
5. General establishment of dental facilities, its duration of course, select on
of students.
6. Migration and transfer rules for students.
7. Regulations of scheme of exam for BDS and MDS
264 / Questions and Answers in Community Dentistry
Incorporation of Council
The council shall be a body corporate by the name of the dental council of
India having perpetual succession and a common seal.
Mode of Elections
Election shall be conducted in the prescribed manner and where any where
any dispute arise regarding any such election, it shall be referred to central
government whose decision shall be final.
Dental Council of India (DCI) / 265
Effect of Recognition
1. Any recognized dental hygiene qualification shall be a sufficient
qualification for enrolment in the approximate register of any state.
2. No person shall be entitled to be enrolled in any register as dental hygienist
unless he holds a recognized dental or dental hygiene qualification or as a
dental mechanic unless he has undergone training which satisfied the
prescribed requirements.
Withdrawal of Recognition
1. When upon report by the executive committee it appears to the council:
a. That the courses of study and training or the examinations to be
undergone or the conditions for admission to such courses are not in
conformation with regulations made under this act or fall short of the
standards required thereby, or
b. That an institution does not satisfy the requirements of the council. A
statement to the effect may be sent by the council to the Government
of the State in which the authority or institution concerned with an
intimation of the period within which the authority or institution may
submit its explanation to the governments.
2. On receipt of the explanation or on the expiry of the fixed period, the state
government shall, after consulting the state council, forward, its
recommendations to the council.
268 / Questions and Answers in Community Dentistry
Mode of Declarations
All declarations shall be made by a resolution passed at the meeting of the
council and shall be published in the official gazette.
Professional Conduct
1. The council may prescribe standards of professional conduct and etiquette
or the code of ethics for dentists.
Dental Council of India (DCI) / 269
ANSWER 3
State Dental Councils
Constitution and Composition of State Councils
The state government shall constitute a state council consisting of the following
members:
a. Four members elected from among themselves by dentists registered on
Part A of the state register.
b. Four members elected from among themselves by dentists registered in
Part B of the state register.
c. The heads of dental colleges in the state which train students for any
recognized dental qualification included in Part I of the schedule.
d. One member elected from amongst themselves by the members of the
medical council.
e. Three members nominated by the state government and,
f. The chief medical officer of the state.
Interstate Agreements
1. Two or more state governments may enter into an agreement, for a joint
state council.
2. The agreement may
a. Provide for the appointment between the participating states of the
expenditure in connection with the state council or joint state council.
b. Determine which of the participating state governments shall exercise
the functions under this act.
c. Provide for consultation between the participating state governments.
d. Make such incidental and ancillary provisions, not inconsistent which
this act, as may be deemed necessary for giving effect to the agreement.
270 / Questions and Answers in Community Dentistry
Mode of Elections
Elections shall be conducted in the prescribed manner and where any dispute
arises regarding any such election, it shall be referred to the state government
whose decision shall be final.
Executive Committee
1. The state council shall constitute among its members an executive
committee consisting of the president and vice-president ex-officio and
the chief medical officer (CMO) of the state or the states concerned.
2. The president and vice-president of the state council shall be chairman
and vice-chairman respectively of the executive committee.
3. A member of the executive committee shall hold office until the expiry of
his term of office as a member of the state council, but subject to his being
a member of the state council, he shall be eligible for re-election.
4. The executive committee shall exercise and discharge such powers and
duties as may be prescribed.
ANSWER 4
Dentist Amendment Act 1993 can be retrieved through the internet at
http://www.dciindia.org/dentist_act1993_pages/dentistact1993.html?
indexposition=1
ANSWER 5
To uphold the dignity and honour of the dental profession and to regulate it,
the 1948 Dentist Act was formed. It stated that only graduated qualified
dentist should deliver Dental Care to the public at large and those graduated
were registered in Dental Council and were placed in Part A registration.
Those unqualified persons who were practicing before 1948 were also allowed
to continue their practice in order not to deprive their livelihood and they
were place in Part B registration in the Dental Council.
(More details of this chapter can be got on www.dciindia.org).
272 / Questions and Answers in Community Dentistry
31 Indian Dental
Association (IDA)
QUESTIONS
1. Functions of IDA.
2. Office bearers of IDA.
3. Memberships of IDA.
4. IDA Emblem.
5. IDA.
ANSWER 1
Functions of IDA
1. Holding periodical meetings and conferences for the IDA members and
dental professionals in general.
2. Publishing and circulating a journal of the association specially adapted
to the needs of dental profession and undertake publicity and propaganda
of the work of the association.
3. Encouraging opening of libraries and buy books from funds.
4. Publishing time to time papers related to dental researches by the
members.
5. Encouraging research in dental and allied sciences by the funds and
establishment of scholarships and maintain international contacts with
foreign dental associations.
6. Conducting educational campaign amongst masses related to oral hygiene
by cooperating with public bodies working for same.
7. Protects public from unethical practice by unqualified practitioners.
8. Trying to set exemption from custom duty for essential dental materials
and instruments.
Indian Dental Association (IDA) / 273
ANSWER 2
Central Council
1. Members as office bearers of IDA.
2. Members without portfolios.
a. Immediate past president.
b. Representative from state branches.
ANSWER 3
Memberships of IDA
1. Honorary members
a. Persons of high scientific or literacy attainment
b. Persons who have rendered conspicuous services to the association
c. Persons whose connections with the association may be deemed
desirable and want to become honorary members are elected according
to the rules of the association.
2. Ordinary members: Dental practitioners and other members of dental
profession are eligible to become members.
3. Direct members: Persons eligible for membership but are not residing or
practicing in the area of local branch, these members shall be attached to
the state branch or to the central head quarters.
4. Student members: Only under-graduate students of recognized dental
institution are eligible as student members.
274 / Questions and Answers in Community Dentistry
ANSWER 4
IDA Emblem (Fig. 31.1)
ANSWER 5
1. IDA was formed in 1949.
2. Before it was known as All Indian Dental Association.
3. IDA was registered in 1967 in New Delhi (Reg. No.S/265).
(Also add Ans 1, 2, 3 and 4)
Occupational Hazards in Dentistry / 275
32 Occupational Hazards
in Dentistry
QUESTION
Discuss the occupational hazards in dentistry.
ANSWER
The occupational hazards can be studied under the following headings:
1. Biological health hazards
a. Infections:
i. HIV/AIDS
ii. Tuberculosis
iii. Hepatitis
iv. Parotitis
v. Syphilis
vi. Gonorrhea
vii. Sore throat
viii. Herpes simplex
ix. Pneumonia.
b. Hypersensitivity reactions
i. Urticaria
ii. Conjunctivitis
iii. Mucous rhinitis
iv. Bronchial-asthma
v. Anaphylactic shock
vi. Allergic contact dermatitis
Due to latex allergy or acrylic monomer.
c. Intoxication (Mercury toxicity)
i. Gastric disturbances
276 / Questions and Answers in Community Dentistry
ii. Diarrhea
iii. Excitability
iv. Insomnia
v. Headache
vi. Mental depression
vii. Ptyalism
viii. Metallic taste
ix. Enlarged salivary gland and tongue
x. Pigmentation of gingiva.
d. Ergonomic (Musculoskeletal disorders):
i. Spondylitis
ii. Back pain syndrome
iii. Pain of wrist and elbows
iv. Varicose veins.
e. Auditory defects
i. Temporary/permanent hearing defects
f. Radiation hazards
i. Somatic effects
Radiation sickness, acute radiation sickness
Leukemia, carcinogenesis
Genetic defects.
2. Psychological factors
a. Hazards related to work load
i. Frustration, emotional tension
ii. Hypertension
iii. Depression, insecurity
iv. Insomnia
v. Lack of job satisfaction.
3. Litigation
Health Care System in India / 277
QUESTIONS
1. Discuss the health system in India.
2. Discuss the health problems in India.
3. Define primary health care.
4. Elements of primary health care.
5. Principles of primary health care.
6. Levels of health care.
7. Health care system in India.
8. Primary health care in India.
9. Primary health center. (Refer Ans 8)
10. Community health center. (Refer Ans 8)
ANSWER 1
Health System in India
Under the constitution of India, the states are largely independent in matters
related to the delivery of health care to the people. Each state has therefore
developed its own system of health care delivery, independent of the central
government. The central responsibility consists mainly of policy making,
planning, guiding, assisting, evaluating and coordinating the work of the State
Health Ministries, so that health services cover every part of the country and
no state lags behind for want of these services. The health system in India has
three main links:
1. Central.
2. State.
3. Local or peripheral.
The official organs of the health system at the various links are as follows:
278 / Questions and Answers in Community Dentistry
At the Center
1 The Ministry of Health and Family Welfare
2 The Directorate General of Health Services
3 The Central Council of Health and Family Welfare.
At the State
1. State Ministry of Health
2. State Health Directorate.
ANSWER 2
Health Problems in India
The health problems in India may be conveniently grouped under the
following heads:
1. Communicable disease problems
2. Nutritional problems
3. Environmental sanitation problems
4. Medical care problems
5. Population problems.
Nutritional Problems
From this point of view, the Indian society is a dual society, consisting of
small group of well fed and large group of undernourished. The high income
groups are showing diseases of affluence. The specific nutritional problems
are protein energy malnutrition, nutritional anemia, low birth weight,
xeropthalmia (nutritional blindness), Iodine deficiency disorders and others
like lathyrism and endemic fluorosis.
Environmental Sanitation
The most difficult problem to tackle in India is the sanitation problem. The
twin problems are lack of safe drinking water and management of excreta
disposal. Population explosion, industrialization and urbanization are creating
greater impact on the sanitation problem.
Population Problems
The population problem is one of the biggest problems facing the country,
with its inevitable consequences on all aspects of development, especially
employment, education, housing, health care, sanitation and environment.
The population size plays an important role and is the single factor among
other factors which influences the economic development of the country.
ANSWER 3
The Alma-Ata Conference defined primary health care as follows:
Primary Health Care is defined as Primary health care is essential health
care made universally accessible to individuals and acceptable to them through
their full participation and at a cost the community and country can afford.
280 / Questions and Answers in Community Dentistry
ANSWER 4
ANSWER 5
ANSWER 6
There are three levels of health care:
1. Primary care level
2. Secondary care level
3. Teritary care level
ANSWER 7
Health care systems in India are represented by five major sectors:
1. Public health sector
a. Primary health care
Primary health centers
Sub-centers.
b. Hospitals/health centers
Community health centers
Rural hospitals
District hospital/health centers
Specialist hospitals
Teaching hospitals.
c. Health insurance schemes
Employees state insurance
Central government health scheme
d. Other agencies
Defence services
Railways.
2. Private sector
a. Private hospitals, polyclinics, nursing homes and dispensaries.
b. General practitioners and clinics.
3. Indigenous systems of medicine
Ayurveda and Siddha
Unani and Tibbi
Homeopathy
Unregistered practitioners.
4. Voluntary health agencies
5. National health programs.
Health Care System in India / 283
ANSWER 8
Primary Health Care in India
In 1977, the government of India launched a rural health scheme, based on
principle of placing peoples health in peoples hands. recommended by
Shrivastav committee in 1975. Keeping in view of Health for All by 2000 AD,
Govt. of India evolved a National Health Policy based on primary health care
approach and was approved by parliament in 1983.
1. Village level: One of the principles of Primary Health Care is universal
coverage and equitable distribution of health resources, Health care must
penetrate into the farthest reaches of rural areas so that everyone can access
it. To implement this the following schemes were made at the village level.
a. Village Health Guides Scheme.
b. Training of Local Dais.
c. ICDS (Integrated Child Development Scheme) Scheme.
a. Village health guide is a person for social service not a full time
government employee. It was introduced in 2nd Oct. 1977. These are
mostly women. They are trained for 200 hours over 3 months in Primary
Health Center or subcenters, paid a stipend of Rs.200/month during
training. Their duties are treatment of simple ailments, activities in
first aid, mother and child health including family planning, health
education and sanitation.
b. Training of local dais: Most of the deliveries in rural areas are handled
by untrained dais. Under Rural Health Scheme, these dais are trained
in Primary Health Center, subcenter and MCH center for 30 working
days and paid a stipend of Rs. 300 during training. These are trained
for maternal and child health, sterilization besides obstetric skills.
c. Anganwadi worker: Under the (Integrated child development scheme)
ICDS project, there is one Anganwadi worker for 1000 population. She
is selected from the community, she is expected to serve and is trained
in various aspects of health, nutrition and child development for 4
months. Her services include health education, non formal pre school
education and referral services. Target population are nursing mothers,
children below the age of 6 years and women between (1545 years).
2. Sub-center level
One sub-center is established for every 5000 population in general and
one for every 3000 in hilly, tribal and backward areas
Functions are: Mother and child health care, family planning and
immunization. But proposed to extend for IUD insertion, simple
laboratory investigations like urine albumin and sugar
284 / Questions and Answers in Community Dentistry
Staff
Medical officer -4
Pharmacist -1
Nurse mid-wives -7
Lab. Technician -1
Dresser -1
Radiographer -1
Ward boys -2
Dhobi -1
Sweepers -3
Mali -1
Choukidar -1
Aya -1
Peon -1
286 / Questions and Answers in Community Dentistry
34 Environment and
Health
QUESTIONS
1. Potable water.
2. Water borne diseases.
3. Different methods of water purification.
4. Water purification on large scale.
5. Rapid sand filtration. (Refer Ans 4)
6. Differences between rapid sand filtration and slow sand filtration.
7. Vital/biological/zoogleal/schmutzdecke layer. (Refer Ans 4)
8. Chlorination. (Refer Ans 4)
9. Break point of chlorination. (Refer Ans 4)
10. Water purification on small scale.
11. Sound/noise pollution.
12. Radiation pollution.
13. Methods of solid waste disposal.
14. Hospital waste management.
15. Incineration. (Refer Ans 13)
16. Composting. (Refer Ans 13)
17. Dental waste management.
ANSWER 1
Potable Water
The water that we consume should be both safe and wholesome. Potable water
is defined as the water with the following qualities:
Should be free from pathogenic agents,
Should be free from harmful chemical substances,
Pleasant to taste, i.e. free from color and odor,
Usable for domestic purposes.
Environment and Health / 287
ANSWER 2
Water Borne Diseases
Water borne diseases are mainly seen in developing countries most common
been diarrheal diseases. These are classified as Biological and Chemical.
1. Biological diseases are classified as:
a. Presence of an infective agent
288 / Questions and Answers in Community Dentistry
ANSWER 3
Methods of water purification:
1. Large Scale
Rapid sand filtration
Slow sand filtration.
2. Small scale:
Household
Boiling
Chemical disinfection
Filtration.
Disinfection of wells.
(For detailed description refer Ans 4 and 10).
Environment and Health / 289
ANSWER 4
Purification of Water on Large Scale
There are three stages:
1. Storage
2. Filtration: It is of two types
a. Slow sand filtration
b. Rapid sand filtration.
3. Disinfection
Storage
Storage of water has three functions:
1. Physical: It allows the suspended particles to settle down in 24 hours.
2. Chemical: Content of free ammonia is reduced and rise in nitrates because
of aerobic bacteria which oxidizes the organic matter occurs.
3. Biological: Bacterial count is dropped down.
Filtration
Two types of filtration process are available:
1. Rapid sand filtration.
2. Slow sand filtration.
1. Rapid sand filtration (Flow chart 34.1): The following steps are involved:
a. Coagulation: Raw alum is added to raw water of about 540 mg or more/
litre depending upon the color, turbidity, temperature and pH.
b. Rapid mixing: Water is subjected to violent agitation in mixing chamber
for few minutes so that alum is properly disseminated in water.
c. Flocculation: In flocculation chamber water is stirred slowly and gently
which results in formation of flocs of aluminum hydroxide.
d. Sedimentation: The coagulated water is allowed to settle the precipitated
flocs in sedimentation chamber for 26 hours. 95% of the precipitate is
allowed to settle before it is subjected to filtration. Then the supernatant
water subjected to filtration.
e. Filtration: The water is passed through the filter beds. The alum floc,
which is not removed by sedimentation, settles on the sand bed. It
forms a slimy layer, which is similar to zoogleal layer in slow sand
filters which helps to adsorb bacteria. Even oxidation of ammonia also
takes place. As this process proceeds the bacteria and suspended
impurities clogs the surface of the filter beds and reduces its filtration
capacity. When the loss of head approaches 78 feet, filtration is stopped
and the filters are subjected to Back-washing.
f. Back-washing: This is a washing procedure accomplished by reversing
the flow of water through the sand bed, which helps to dislodge the
impurities and cleans up the sand bed. Compressed air is sometimes
used along with the reversing of water flow. The whole process of
washing takes about 15 minutes and is stopped when clear sand is
visible and the wash water is sufficiently clear.
2. Slow sand filtration/Biological filtration: It includes:
a. Supernatant (raw) water.
b. A bed of graded sand.
c. An under-drainage system; and
d. A system of filter control valves.
a. Supernatant (raw) water: It is the water above the sand bed whose depth
varies from 1 to 1.5 m and level is always kept constant. It serves two
purposes: it provides constant head of water and secondly, it provides
waiting period of some hours and allows partial purification by
sedimentation, oxidation and particle agglomeration.
b. Sand bed (Fig. 34.1): The thickness of the sand bed is about 1 m. The
sand grains are preferably rounded with the diameter of 0.2 to 0.3 mm.
It should be free from clay and organic matter. A layer of graded gravel
of 3040 cm deep supports the sand bed , which prevents the fine grains
being carried into the drainage pipes. Water is passed very slowly
through the sand bed during which water is subjected to mechanical
straining, sedimentation, adsorption, oxidation and bacterial action.
Normally the rate of filtration lies between 0.1 and 0.4 m3/hour/per
square meter of sand bed surface.
Vital layer: Initially filter acts as a mechanical strainer, but soon the
surface is covered with a slimy growth known as Vital/Biological/
Zoogleal/Schmutzdecke layer. Formation of this layer is also known
as ripening of the filter. This layer is slimy and gelatinous and consists
of threadlike algae and numerous forms of life including plankton,
diatoms and bacteria. It takes several days to form and fully formed
Environment and Health / 291
layer extends for 2 to 3 cm on the sand bed. This layer removes organic
matter, holds back bacteria and oxidizes ammoniacal nitrogen into
nitrates. The first few days filtrate is usually run waste till vital layer is
fully formed.
c. Under drainage system: Under drainage system lies below the filter bed
which cannot be seen. It consists of porous or perforated pipes which
provides an outlet for filtered water and also supports the filter medium
above.
d. Filter control: The filter is equipped with certain valves and devices
that are incorporated into the outlet pipe system. The purpose of these
devices is to maintain a constant rate of filtration. The important part
in this system is Venturi meter which measures bed resistance or
loss of head. If loss of head exceeds 1.3 m it is uneconomical to run the
filter. When bed resistance increases it reduces filtration rate, so it has
to be cleaned. To clean the filter bed, first drain the supernatant water
and the sand bed is cleaned by scraping off the top portion of the
sand layer to a depth of 1 or 2 cm. After 20 30 scrapings, the thickness
of the sand bed reduces and new bed is constructed.
Disinfection
Chlorine is widely used for disinfection of water. It is used as chlorine gas,
chloramines or perchloron. Chlorine kills pathogenic bacteria and also oxidizes
iron, manganese, hydrogen sulphide, destroys some taste and odor producing
constituents, controls algae and slime organisms and aids in coagulation.
292 / Questions and Answers in Community Dentistry
ANSWER 6
Differences between Rapid sand filtration and Slow sand filtration
ANSWER 10
Purification of Water on Small Scale
1. Household purification of water: This can be done by following methods:
a. Boiling: It is effective when water is brought to rolling boil for
510 minutes. It kills bacteria spores, cysts, ova and also removes
294 / Questions and Answers in Community Dentistry
ANSWER 11
Noise Pollution
Noise is often defined as unwanted sound .It is defined as wrong sound, in
the wrong place, at the wrong time. Sources of noise is from automobiles,
factories, industries, aircraft, etc. Noise levels are acute near railway junctions,
bus terminuses and airports. Other domestic noises are from radios, transistors,
and TV sets. A daily exposure upto 85 dB is the limit. People can tolerate
without substantial damage to their hearing
The recommended maximum loudness is 85 dB and frequency is from
2020,000 Hz.
Environment and Health / 295
Non-auditory Effects
1. Interference with speech: Noise interferes with speech communication.
2. Annoyance: It is primarily a psychological response. Neurotic people are
more sensitive to noise. They often get irritated, short tempered and
impatient.
3. Efficiency: Reduction in noise has been found to increase work output.
4. Physiological changes: Rise in blood pressure, an increase in heart rate
and, breathing, and increase in sweating, a rise in intracranial pressure.
General symptoms like giddiness, nausea and fatigue and may also cause
visual disturbance.
5. Noise is also a significant factor in economic losses.
Control of Noise
1. Careful planning of cities
a. Separation of cities from industries and transports.
b. Separation of residential areas from main streets.
c. Widening of main streets to prevent penetration of noise into dwellings.
2. Control of vehicles:
a. Heavy vehicles should not be routed into narrow streets.
b. Vehicular traffic on residential streets should be reduced.
3. To improve acoustic insulation of buildings.
4. Industries and railways: Special areas must be earmarked for industries
and railways outside residential areas, if not possible green belts must be
laid down between such installations and residential areas.
5. Protection of exposed persons with use of earplugs, earmuffs.
6. Legislation: Many states have adopted legislation providing for controls
which are applicable to a wide variety of sources.
7. Education of the people through media and their participation is needed
to highlight the importance of noise as a community hazard.
296 / Questions and Answers in Community Dentistry
ANSWER 12
Radiation Pollution
Sources for radiation are of two types:
1. Natural sources
a. Cosmic rays: which originate in outer space.
b. Environment:
i. Terrestrial radiation: like thorium, uranium, radium present in soil,
rocks and buildings.
ii. Atmospheric radiation: radioactive gases radon and thoron in
atmosphere.
iii. Internal radiation: these are radioactive matter stored in body tissues.
These are in minute quantities like uranium, thorium, potassium,
strontium (Sr 90) and carbon (C 14).
2. Man-made sources
a. X-rays
b. Radioactive fall-out like nuclear explosions.
c. Miscellaneous, e.g. TV sets, luminous wrist watches.
Types of Radiation
1. Ionizing radiation is harmful as it penetrates through tissues and deposits
its energy within them. They are of two types:
a. Electromagnetic radiation: X-rays and gamma rays.
b. Corpuscular radiations: -particle, -particle and protons.
2. Non ionizing radiation refers to several forms of electromagnetic radiation
of wavelength longer than those of ionizing radiation.
For example: UV radiation, visible light, infrared radiation, micro-
wave radiation and radio frequency radiation.
The amount of radiation received from natural sources is estimated to be
0.1 rad/yr. which at present is not hazardous. Additional permissible dose
from man-made sources should not exceed 5 rad/yr.
ANSWER 13
Solid Waste Disposal
Different methods of solid waste disposal
1. Dumping
2. Controlled tipping or sanitary landfills
3. Incineration
4. Composting
5. Manure pits
6. Burial.
Dumping
Refuse is dumped in low-lying areas partly as a method of reclamation of
land, but mainly as a method of disposal of dry refuse.
Disadvantages
Waste is allowed to accumulate, it decomposes and favors fly breeding, attracts
rodents and vermin, mans food is contaminated by pathogens through flies
and dust, possibility of water and soil pollution, produce bad odors and
unsightly appearance.
Controlled Tipping
This method is suitable for disposal when suitable land is available. In this,
material is placed in a trench or prepared area, adequately compacted and
covered with earth. There are three methods.
1. Trench method: Trench of 2 to 3 m deep and 4 to 12 m in width is dug
where level ground is available. Refuse is dumped and covered with
excavated earth. It is estimated that one acre of land/per year will be
required for 10,000/- population.
2. Ramp method: This method is chosen when land is moderately sloping
and some excavation is done to cover the material.
3. Area method: This method is used for filling land depressions, disused
quarries and clay pits. The refuse is packed in uniform layers upto 2 to 2.5 m
deep and each layer is sealed on its exposed surface with mud cover at
least 30 cm thick.
Incineration
It is widely used method of waste disposal especially for most hazardous
health care wastes. This method is selected when wastes cannot be recycled,
reused or disposed-off in a landfill site. It is a high temperature dry oxidation
process that reduces organic and combustible waste to inorganic incombustible
matter with significant reduction of waste volume and weight.
298 / Questions and Answers in Community Dentistry
Types of Incinerators
Incinerators should be chosen on the basis of available resources, the local
situation and the risk-benefit consideration.
1. Double chamber pyrolytic type: Mainly designed to burn infectious health
care waste. It needs a fuel burner to initiate the process. It comprises of
pyrolytic chamber where, waste is thermally decomposed in an oxygen
deficient medium temperature combustion process (800-900 C) producing
ashes and gas. The gases (Flue gas) which are produced are burnt at high
temperature (9001200C) in post-combustion chamber by a fuel burner,
using an excess of air to minimize smoke and odor. The by-products are
exhaust gas released into the atmosphere and ashes disposed by burial/
landfilling.
2. Single chamber: Used when pyrolytic type are not affordable. This should
be used as a last option as it is difficult to burn the waste completely
without generating potential harmful smoke. It consists of a steel drum
with both ends removed and fine screen is placed on the top to prevent
ash blowing out. Fine screen is also placed at the bottom and a chimney is
placed on the top. Good fire is generated underneath the drum, wood is
used to the fire till the waste is completely burnt. After burning is complete
the ash both from fire and waste is buried safely. Loading and de-ashing
operations are performed manually.
3. Rotary kilns: Operated at high temperatures, can decompose genotoxic
substances, sharps , pathological wastes and heat resistant chemicals. It
consists of a rotating oven and a post- combustion chamber.
Rotary kiln is inclined to an single angle to the vertical (35% slope).
Waste is charged from the top of the kiln and kiln rotates at 25 times/
minute. Ash is collected from the bottom and gases which are produced
are burnt at high temperature in post-combustion chamber.
Composting
In this method combined disposal of refuse and night soil or sludge is used.
The organic matter breaks down under bacterial action resulting in formation
of stable humus like material called compost. Because of the heat (60o C or
higher) which is produced as a by-product, makes this compost sterile with
few or no microorganisms.
There are two methods:
1. Bangalore method: Also called hot fermentation process. This was
developed by Indian Council of Agricultural Research at the Indian
Institute of Science, Bangalore recommended for disposal of town wastes
and night soil.Trenches are dug of 90 cm deep and 1.5 to 2.5 m in width
and 4.5 to 10 m long depending upon amount of refuse and night soil.
These trenches are located about 800 m away from city limits. First 15 cm.
of refuse in spread out and above that give 5 cm night soil, put same amount
of refuse and night soil alternately and top layer should be of refuse with
25 cm. thickness and covered with excavated land. Within seven days,
decomposition of material starts by bacterial action and heat in generated
over 60 C. This heat persists over 23 weeks and decomposes night soil
and refuse and also destroys all pathogenic and parasitic organisms. After
four to six months decomposition is complete and manure developed is
used for cultivation.
2. Mechanical composting: In this method compost is manufactured on a
large scale. The refuse is cleared of with salvageable materials such as
rags, bones, metal, glass and any other materials, which interferes with
grinding operation. Then it is pulverized in a pulverizing equipment in
order to reduce the particle size to less than two inches and mixed with
sewage, sludge or night soil in a rotating machine and incubated. The
entire process is complete in 4-6 weeks. The Government of India is
considering the installation of mechanical composting in selected cities
like Delhi, Nagpur, Mumbai, Chennai, Pune, Allahabad, Hyderabad,
Lucknow and Kanpur. This method is already installed in developed
countries like, Holland, Germany, Switzerland and Israel.
Manure Pits
In this method, pits are dug by individual householders. Refuse like garbage,
cattle dung, straw and leaves are dumped into the pit and covered with earth
after each days dumping. Two pits are dug, one can be in use and one be
closed. After five to six months time refuse is converted into manure and can
be used in fields. This is most effective and simple method to be used in rural
areas in India, where there is no system for collection and disposal of refuse.
300 / Questions and Answers in Community Dentistry
Burial
This method is suitable for small camps. A trench 1.5 m wide and 2 m deep
is excavated, refuse is dumped and covered with 20 to 30 cm of earth after
each day. When the level of trench is 40 cm from the ground level, it is filled
with earth and compacted and a new trench is dug out for dumping the
waste. The contents may be taken out after four to six months and used in
the fields.
ANSWER 14
Hospital Waste Management
Biomedical waste (Management and Handling) Rule 1998, prescribed by the
Ministry of Environment and Forests, Government of India, came into force
on 28th July 1998.This is applied to those who generate, collect, receive, store,
dispose, treat or handle bio-medical waste in any manner.
According to Biomedical waste (Management and Handling) Rule 1998
of India, Biomedical waste means any waste, which is generated during
the diagnosis, treatment or immunization of human beings or animals or in
research activities pertaining thereto or in the production or testing of
biologicals and including categories as mentioned below:
Option Waste category Treatment and disposal
Category No.1 Human anatomical waste Incineration2/ deep burial
(human tissues, organs, body parts)
Category No.5 Discarded medicines and cytotoxic drugs incineration @ destruction and
(wastes comprising of outdated, contami- drugs disposal in secured
nated and discarded medicines). landfills
Contd...
Environment and Health / 301
Option Waste category Treatment and disposal
ANSWER 17
Dental Waste Management
Dental waste disposal.
QUESTIONS
1. Classify health agencies.
2. World Health Organizations (WHO). ( Ans 2, 3, 4 and 5)
3. Functions/work of WHO.
4. WHO Regional Organizations/Centers.
5. WHO Oral Health Unit.
6. Colombo plan.
7. Rockefeller Foundation.
8. Ford Foundation.
9. CARE.
10. UNICEF.
11. ILO.
12. FAO.
13. USAID.
ANSWER 1
Health agencies are classified into:
1. International health agencies.
2. Voluntary health agencies (in India)
6. World Bank
7. ILO.
Bilateral Agencies
1. USAID
2. Colombo Plan
3. Public Law Scheme.
Non-governmental Agencies
1. Ford Foundation
2. Rockefeller Foundation
3. CARE (Co-operative for Assistance and Relief Everywhere)
Voluntary Agencies
Voluntary Agencies involved with Maternal and Child Health
1. Indian Council of Child Welfare
2. Family Planning Association of India
3. Kasturba Memorial Fund.
ANSWER 2
World Health Organization (WHO)
Non-political and specialized agency under United Nations
Officially born on 7th April 1948 and since then 7th April every year is
celebrated as World Health Day with a theme for global focus.
Memberships in WHO
Open to all countries
Territories as associate members
In 1948, there were 56 members and in 1996, there were 190 member states
and two associate members. India became a member of WHO on 12th
January 1948.
Objective of WHO
The attainment by all people of the highest level of health.
ANSWER 3
The Work of WHO
Broadly classified into three divisions:
1. The first division: Work which caused International Health Organizations
to come into existence, such as, epidemic intelligence and quarantine and
standardization work in biologicals, statistics and nomenclatures.
2. The second division: Direct services to the governments.
3. The third division: Education and information.
Work of WHO
Prevention and control of specific diseases
Development of comprehensive health services
Family health
Environmental health
Health statistics
Biomedical research
Health literature and information
Co-operation with other organizations.
Publications includes:
Handbooks on Basic Documents and Resolutions and Decisions
Monthly Chroniclecurrent activities
The Bulletinscientific articles on subjects with which WHO is concerned
The Monographs and Technical Report Seriescontains scientific studies
and report of expert committees and study groups
Public Health Papers occasional papers prepared as contribution to the
study of a particular subject by WHO
International Digest of Health Legislation
A series of weekly, monthly and annual Epidemiological Records
World Healthnews sheet published
The first ten years of WHO.
Structural Organization
Consists of:
1. World Health Assembly (or Parliament).
2. The Executive Board (or Cabinet).
3. The Secretariat (or Civil Service).
Functions
To give effect to the decisions and policies of the assembly
Has power to take action itself in an emergency, like epidemics,
earthquakes, floods where immediate action is necessary.
The Secretariat
Headed by Director General (chief technical and administrative officer)
assisted by one Deputy Director General
Six Regional Directors
Main function is to provide Member States with technical and managerial
support for their national health development programs.
At WHO Headquarters in Geneva, there are five Assistant Director
Generals responsible to look after divisions as assigned by Director General.
ANSWER 4
WHO Regional Organization
Region Headquarters
1. South East Asia Region New Delhi (India)
2. African Region Harare (Zimbabwe)
3. Regions of America Washington DC (USA)
4. European Region Copenhagen (Denmark)
5. Eastern Mediterranean Region Alexandria (Egypt)
6. Western Pacific Region Manila (Philippines)
ANSWER 5
The WHO Oral Health Unit
Established in 1956
Postgraduate education and training at advanced institutions all over the
world
WHO consultants are sent to countries requesting technical assistance
Reports of expert committees on various topics of oral health are published
in the form of WHO Technical Report Series
Standard methods of collection of data on global basis have been developed
WHO Global Oral Epidemiology Programdesigned to facilitate
comparison of data
Global Oral Epidemiology Data Bank
WHO International Collaborative Study on Dental Manpower Systems
Establishment of WHO Oral Disease Preventive Program in 1976.
308 / Questions and Answers in Community Dentistry
Publications
Oral Health Surveys: Basic Methods
Guide to oral health epidemiological investigations
Application of the international classification of diseases to dentistry and
stomatology
The theme for the World Health Day on 7th April 1994 was: Oral Health
for a Healthy life.
ANSWER 6
ANSWER 7
Rockefeller Foundation
Founded in 1913, by Mr. John D Rockefeller
In the early years, was active chiefly in public health and medical education
then included the advancement of life sciences, the social sciences, the
humanities and agricultural sciences
In India, began in 1920, with a scheme for control of hookworm disease.
Establishment of All India Institute of Hygiene and Public Health at Kolkata
Training of competent teachers and research workers
Training abroad of candidates from India through fellowships and travel
grants
Sponsoring of visits of a large number of medical specialists from USA
Development of medical college libraries, population studies, assistance
to research projects and institutions [National Institute of Virology at Pune,
Setting up of field demonstration area (Ballabhgarh) in connection with
Department of Preventive and Social Medicine and AIIMS]
Health Agencies / 309
ANSWER 8
Ford Foundation
Mainly involved with the development of rural health services and family
planning
Ford foundation has helped India in the following projects:
1. Orientation training centers: At Singur, Poonamalle, NajafgarhProvide
training courses in public health for medical and paramedical personnel
from all over India.
2. Research cum action projects: Projects mainly aimed to solve basic
problems in environmental sanitation.
3. Pilot project in Rural Health Services, Gandhigram (Tamil Nadu) attempt
was made to develop co-ordinate type of health services.
4. Establishment of NIHAE: National Institute of Health administration and
Education at Delhi.
5. Calcutta water supply and Drainage Scheme.
6. Family planning programs.
ANSWER 9
CARE: (Co-operative for Assistance and Relief Everywhere)
Began in India in 1950
In the 1980s, the primary objectives was to provide food for children in
age group of 611 years
Then focused its food support for the Integrated Child Development
Scheme(ICDS) program
Helped in following projects: Integrated nutrition and health project, Better
health and nutrition project, Anemia control project, Improved health care
for adolescent girls project, Improving womens health project, Child
survival project, Konkan integrated development project.
ANSWER 10
United Nations International Childrens Emergency Fund (UNICEF)
Origin: Created by United Nations General Assembly in 1946.
Purpose: To meet the emergency needs of children around the world.
Headquarters is in New York
South Central Asian RegionHeadquarters is in New Delhi.
310 / Questions and Answers in Community Dentistry
Functions of UNICEF
Content of services
1. Child health
2. Maternal health
3. Nutrition
4. Water and sanitation
5. Education
6. Children in especially difficult circumstances
7. Advocacy and peoples participation
8. Promotion of GOBIFF campaign for a child health revolution.
GGrowth charts to better monitor child development.
OOral rehydration.
BBreastfeeding.
IImmunization against DPT, TB, Polio, measles.
F- Family planning
F- Food supplements.
ANSWER 11
International Labor Organization (ILO)
Formed in 1919
Headquarters in Switzerland, Geneva
Purpose: Improving the living and working conditions of the working
population in different parts of the world.
Functions
1. Establishment of peace by promoting social justice.
2. To improve the living standards and labor conditions of working people
around the world.
3. To promote economic and social stability.
ANSWER 12
Food and Agriculture Organization (FAO)
Formed in the year 1945
Headquarters in Rome
Concerned with human diseases of animal origin, with nutrition and with
rural hygiene.
Most important aspect is towards ensuring that the food is consumed by
the people who need it, in sufficient quantities and in right proportions, to
develop and maintain a better state of nutrition throughout the world.
Health Agencies / 311
Functions of FAO
To improve nutrition of the people of all countries
To help nations raise living standards
To increase the efficiency of farming, forestry and fisheries
To better the condition of rural people and widen the opportunity of all
people for productive work
Campaigning for the freedom from hunger in all nations.
ANSWER 13
United States Agency for International Development (USAID)
Was created in 1961
Incharge of activities previously administered by the Technical
Co-operation Mission (TCM)
USAID Mission functions in New Delhi.
36 Survey/National Oral
Health Care Program
QUESTIONS
1. Write a report on the National Oral Health Survey.
2. Write a note on National Oral Health Care Program.
ANSWER 1
To formulate the Oral Health Policy and implement appropriate programs, to
improve the awareness and knowledge of general public about the preventive
aspects of oral health, to create the required services and to train the necessary
dental manpower to meet these needs gave rise to the national level
epidemiological study called as National Oral Health Survey and Fluoride
Mapping 20022003. This was undertaken by Dental Council of India,
Ministry of Health and Family Welfare and the project was supported by
Colgate-Palmolive Ltd. The scope of the survey was to collect information
about the following dimensions of health:
1. Prevalence of oral health problems
2. Fluoride levels in drinking water
3. Eating habits affecting oral health
4. Dental cleaning practices
5. Awareness and knowledge of people on factors affecting oral health
6. Treatment seeking behavior of people for their oral health problems.
This survey was conducted among people of 5 years, 12 years, 15 years,
3544 years and 6574 years. This study was conducted in 16 states and 3
union territories.
Sample Selection
Each state was divided into few homogenous regions based on agro-climatic
and physio-geographic factors, 315 households out of which 210 from rural
National Oral Health Survey/National Oral Health Care Program / 313
and 105 from urban were selected from each homogenous area, with equal
distribution of males and females was done. 315 people in each age-group
were proposed for the examination . In total 19,845 households and 92,225
examinations were done. WHO(1997) proforma and individual questionnaire
were used in the study. Training and calibration of the manpower was carried
out before the survey. The summary of the findings are given in the following
Table.
ANSWER 2
National Oral Health Care Program
Oral health is an integral part of general health. In developing countries, there
is increase in oral health problems like dental caries, periodontal diseases,
malocclusion, dental fluorosis and oral cancer. In India, prevalence of oral
disease is very high. Majority, of population in the country lack knowledge
about dental diseases and its relation to general health. There is maldistribution
of dentists ( 80% of the dentists are crowded in urban areas where 20% of
population resides and 80% of the population resides in rural areas where
there are only 20% of dentists available), lack of manpower in primary health
centers, lack of equipments in community health centers and district hospitals,
no organized data recording system for proper oral health care planning and
no specific oral budget. Keeping all these problems in mind, the Ministry of
Health and Family Welfare, Govt. of India accepted the principle of National
Oral Health Policy in 1995 to be included in National Health Policy.
Director General of Health Sciences and Ministry of Health and Family
Welfare in collaboration with All India Institute of Medical Sciences,
New Delhi implemented National Oral Health Care Program as a pilot
program in five states, i.e. Kerala, Maharashtra, Delhi, Punjab and Eastern
countries.
Preventive Programs
Promotion of fluoride toothpaste
Legislation against tobacco products
Manufacturing of sugar-free chewing gums
Sugar substitutes in medicinal syrups.
37 Computers in
Dentistry
QUESTION
Write a note on uses of Computers in Dentistry.
ANSWER
Computers have become an indispensable tool in virtually every conceiv-
able field and dentistry is no exception. Dentistry has kept itself abreast of
these advances and has made use of its information and technology. The
first computer program on a large scale in dentistry was started in 1981 by
SCICON and was commissioned by British Dental Association. The purpose
of using computers was to store a large amount of data, process and retrieve
the accurate and reliable data in no time.
Uses of Computers
Administrative Services
1. Patients appointments and recalls (Computerized scheduling)
2. Missed appointment follow-up.
3. Billing accounting correspondence.
4. Purchase and supply order
5. Dental insurance claims
6. Referral information
2. Presentations.
a. Teaching/Lectures
b. Health education
c. Continuing dental education
d. Research records
e. Conferences
3. Review of literature
4. Research
5. Medlars services to retrieve literature data.
3. Clinical applications
a. Patients records
i. Storage, retrieval, evaluation, examination, diagnosis, treatment
planning and motivation
b. Diagnostic tool.
CAD/ CAM
1. Computerized Imaging
2. Computerized cephalometrics (e.g. JOE, Rocky Mountain Orthodontics
[RMO] digigraph, por dios)
3. Computerized growth prediction.
4. Computerized designing of Prosthesis and Restorations.
5. Computerized endodontic apex locators.
6. Diagnosis and treatment planning of orthognathic and other oral and
maxillofacial surgeries.
7. Radio visiography.
8. Forensic odontology
Internet Applications
1. Creating homepage
2. Marketing services
3. Journal clubs
4. Discussion groups.
5. Video conferencing.
6. Use of Pubmed and other sites to obtain data and literature instantaneously.
318 / Questions and Answers in Community Dentistry
38 The Oral
Physician
QUESTION
Write a note on oral physician
ANSWER
39 Dental Clinic
Setup
QUESTION
Write a note on establishing a dental clinic.
ANSWER
Several factors are taken into consideration while setting up a private dental
clinic.
Selection of Place
The selection of the place is depended on the following factors:
1. Place which can offer good facility for setting the clinic.
2. Select the place depending on the number of dental clinics in that area.
Financial Assistance
There are many nationalized banks, private sector and state financial
corporation which render financial help for setting up a clinic.
Equipments
Basic instrument to run the dental office should be present.
Prime importance should be given to the company brand and quality of
the instruments.
Make alternate arrangement of the generator in case of the power shut
down.
Manpower
1.Dental surgeon/In-house or on-call Specialist Dentist.
2.Receptionist
3.Dental attender
4.Dental surgery assistant/Dental hygienist/Lab technician
Apart from setting up a clinic, the other important things includes clinic
administration, manpower, financial and patient management (Practice
management).
Dental Clinic Setup / 321
Operational System
1. Scheduling
2. Recall system
3. Checking recall effectiveness
4. Broken appointments and purging of patient charts
5. Production and collection
6. Payment policy
7. Dental insurance and other third party plans
8. Insurance assignment
9. Insurance reference guide
10. Predetermination
11. Filing claims
12. Quick claim forms
13. Pending and paid insurance files
14. Direct reimbursement
15. Managed care
16. Dental management companies
17. Fiscal management
18. Billing and accounts
19. Fees
20. Setting a budget
21. Practice-monitors
22. Daily statistics.
Personal System
1. Personal needs
2. Interviewing and hiring
3. Orientation and training
4. Wage and benefit administration
5. Performance and appraisal
6. Personal records
7. Dismissal
8. Communication.
322 / Questions and Answers in Community Dentistry
40 Miscellaneous
QUESTIONS
1. Tooth brushing techniques.
2. Most of the periodontal diseases are preventable. Discuss.
3. A clean tooth never decays.
4. Psychological development of the child from birth to adolescence.
5. Behavior management.
6. Disclosing agent.
7. Taboos related to oral health.
8. Misconception in relation to dentistry.
9. Tell show do technique.
10. Tobacco related cancer.
11. Hand over mouth exercise (HOME).
12. Towel over mouth exercise (TOME).
13. Hand over mouth exercise and restriction (HOMAR).
14. Towel over mouth exercise and restriction (TOMAR).
15. Child management in dental clinic.
16. Fear in children.
17. Parent counseling.
18. Oral hygiene habits among Indian people.
19. Prepare a TV talk for improving the oral health of the school children.
20. Health education methods used for the rural population.
21. Plan a health education program for the rural community taking into
consideration the barriers in communication and discuss how you will
overcome those barriers.
22. Parts of the computer.
23. Difference between Health Education and Propaganda.
24. History of Dentistry.