Contents

No. Subject Page

1 Retention of Complete denture 1
2 Posterior Palatal Seal 10
3 Stability of Complete Dentures 17
4 Support of Complete Denture 23
5 Concept of Neutral Zone 26
6 Denture adhesive 32
7 Occlusion in Complete Denture 35
8 Insertion of the complete denture 49
9 Oral mucosal Lesions induced by removable 64
dentures
10 Immediate Dentures 67
11 Single Complete Denture 81
12 Relining and Rebasing of complete denture 90
13 Tooth supported overdenture 95
14 Dental Implant 108
15 Bone graft 128
16 Complete Edentulism 132
 Retention of Complete denture
Outcome of complete denture treatment depends largely, on the degree
of retention and stability of the dentures. Good retention causes the
denture to remain in place when the jaws are apart, as in laughing and
speaking. Good stability prevents the dentures from skidding when the
jaws are brought together, as in chewing or swallowing. Successful
integration of the prosthesis with the patient’s oral functions depends
largely on denture retention. Integration means that the patient feels that
the denture as part of his body. A retentive denture contributes severely
to patient acceptance of the finish denture.

Definitions :
Retention of the denture can be defined as :
✓ The resistance of a denture to dislodgment.
✓ The quality of a denture that holds it to the tissue foundation.
✓ The resistance to the movement of a denture away from its tissue
foundation especially in a vertical direction.
✓ The resistance to removal in a direction opposite to that of insertion.
✓ The attachment of the denture to the underling soft tissue and it is the mean
by which the denture holds in position in mouth at rest.

It is checked by firmly seating the denture in the mouth and trying to displace
it wi It is checked by firmly seating the denture in the mouth and trying to
displace it with force at right angle to its occlusal surface, if the denture resist
displacement it is said that it has retention.th force at right angle to its occlusal
surface, if the denture resist displacement it is said that it has retention.

There are several forces that try to displace the denture away from its foundation;
retention is the ability to resist all these forces. Dentures stay in place if the retentive
forces acting on the dentures go over the displacing forces.

Retentive forces offer resistance to vertical movement of a denture away from the
underlying mucosa and act through the three surfaces of a denture. These surfaces
may be defined as follows :
1. Occlussal surface : that surface of a denture which makes contact or near
contact with the corresponding surface of the opposing denture or dentition.
 2. Polished surface : that portion of the surface of a denture which extends in
an occlussal direction from the border of the denture and which includes the
palatal surface. It is that part of the denture base which is usually polished,
includes the buccal and lingual surfaces of the teeth, and is in contact with
the lips, cheeks and tongue.

3. Impression surface : that portion of the surface of a denture that had its shape
determined by the impression. It includes the borders of the denture and
extends to the polished surface.

The retentive forces that act upon each of these surfaces are of two main types,
muscular forces and physical forces.

Retaining forces acting on a denture: (1) force of the muscles of mastication acting
through the occlussal surface; (2) muscular forces of lips, cheeks and tongue acting
through the polished surface; (3) physical forces acting through the impression
surface.

Muscular forces : These forces are exerted by the muscles of the lips, cheeks and
tongue upon the polished surface of the denture and by the muscles of mastication
indirectly through the occlusal surface.
The successful muscular control of dentures depends on two factors :
✓ The design of the dentures.
✓ The ability of the patient to acquire the necessary skill.
The design of the dentures
The oral and facial musculature supply supplementary retentive forces, provided :
1. The denture bases must be properly extended to cover the maximum area
possible, without interfering in the health and function of the structures that
surround the denture.
2. The polished surfaces of the dentures are properly shaped.
The buccal flanges of the maxillary denture slope up and out from the
occlusal surfaces of the teeth and the buccal flanges of the mandibular denture
slope down and out from the occlusal plane, the contraction of the buccinators
will tend to seat both dentures on their basal seats.
The lingual surfaces of the lingual flanges should slope toward the center of
the mouth so the tongue can fit against them and perfect the border seal on
the lingual side of the denture.
For Orbicularis oris muscle if we did not give the lower labial flange the
correct thickness and shape (concave) to receive this muscle, it will try to
dislodge the denture.
3. Occlusal plane is the average plane established by the incisal and occlusal
surfaces of the teeth; it is not a plane but represents the planar mean of the
curvature of the surfacesThe occlusal plane must be at the correct level;
externally should it be with the relaxed lower lip level or with commissures
of lips and internally with the lateral border of the tongue and slightly below
the superior portion of the tongue. The position of occlusal plane in denture
wearers should be as close as possible to the plane, which was previously
occupied by the natural teeth [6]. Such position of the occlusal plane provides
normal function of the tongue and cheek muscles, thus enhancing the denture
stability

4. The arch form of the teeth must be in the "neutral zone” between the tongue
internally and the cheeks and lips externally.

Conversely an incorrectly shaped denture results in the muscular force dislodging

that denture. In short, the muscles can either help or hinder denture stability and
retention.

Influence of muscles forces on dentures: (a) seating the dentures when the
polished surfaces are correctly shaped; (b) displacing the dentures when the
polished surfaces are incorrectly shaped.
Patient’s skill
The patient’s ability to acquire the necessary skills to control new dentures is related
to biological age. In general, the older the patient, the longer the learning period. In
the extreme case, the elderly or senile patient may not be able to acquire this skill at
all and so new dentures may fail even though they are technically satisfactory.
It is for this reason that replacement dentures for an older patient should be
constructed in such a way that the patient’s skill in controlling the previous denture
shapes can be transferred directly to the replacements. This is achieved by copying
the old dentures as closely as possible. When dentures are first fitted, muscular
control takes some time to develop and is therefore likely to be inefficient. Thus, it
is during this initial learning period that the physical forces of retention are
particularly important.

Physical forces
1. Interfacial force is the resistance to separation of two parallel surfaces that is
imparted by a film of liquid between them. These forces act to keep the denture
inside the patient’s mouth because of thin film of saliva between the denture and
mucosa. Interfacial forces depends on : Interfacial surface tension and Viscous
tension.

Interfacial surface tension is the tension or resistance to separation possessed by

the film of liquid between two well adapted surfaces. This acts with the air-liquid
interface acting between two surfaces where a thin film of liquid holds the surfaces
on the either sides. Thin film of saliva resists the displacing forces, and this aids in
retention.
It is dependent on the ability of the fluid to “wet” the rigid surrounding material For
retention to happen effectively, there needs to be a thin film of saliva, and as there
is excess saliva in the borders of a mandibular denture, there is minimal interfacial
surface tension seen.

Wettability
Wetting is the ability of a liquid to maintain contact with a solid surface, resulting
from intermolecular interactions when the two are brought together.
If the surrounding material has low surface tension, as oral mucosa does, fluid will
maximize its contact with the material, so wetting it readily and spreading out in a
thin film. If the material has high surface tension, fluid will minimize its contact
with the material, with the result that it will form beads on the material’s surface.
Most denture base materials have higher surface tension than oral mucosa, but once
coated by salivary pellicle they display low surface tension that promotes
maximizing the surface area between liquid and base. The thin fluid film between
denture base and the mucosa of the basal seat therefore furnishes a retentive force
by virtue of the tendency of the fluid to maximize its contact with both surfaces.
Capillarity
Capillary action, or capillarity, is the ability of a liquid to flow against gravity
where liquid spontaneously rises in a narrow space such as a thin tube, or in porous
materials such as paper or in some non-porous materials such as liquified carbon
fibre.
Is the penetration of liquids into narrow crevices, is what causes a liquid to rise in a
capillary tube, because in this physical setting the liquid will maximize its contact
with the walls of the capillary tube. When the adaptation of the denture base to the
mucosa on which it rests is sufficiently close, the space filled with a thin film of
saliva acts like a capillary tube in that the liquid seeks to increase its contact with
both the denture and the mucosal surface in this way, capillarity will help to retain
the denture.
Surface tension at the periphery of the saliva film will produce a slight negative
pressure beneath the denture

Interfacial viscous tension refers to the force holding two parallel plates together
that is due to the viscosity of the interposed liquid. The viscous force increases
proportionally to increases in the viscosity of the interposed fluid, and decreases as
the distance between the plates (i.e., the thickness of the interposed medium)
increases. The interfacial viscous tension depends on saliva viscosity.
Thick, high-mucin saliva is more viscous than thin, watery saliva—yet thick
secretions usually do not result in increased retention for the watery, serous saliva
can be interposed in a thinner film than the more cohesive mucin secretions.

2. Adhesion
Adhesion is the physical attraction of unlike molecules for each other. Adhesion of
saliva to the mucous membrane and the denture base is achieved through ionic
forces between charged salivary glycoproteins and surface epithelium or acrylic
resin. By promoting the contact of saliva to both oral tissue and denture base,
adhesion works to enhance further the retentive force of interfacial surface tension.
In patients with xerostomia (sparse or absent saliva), the denture base materials
seem to stick to the dry mucous membrane of the basal seat and other oral surfaces.
Such adhesion is not very effective for retaining dentures, and predisposes to
mucosal abrasions and ulcerations due to the lack of salivary lubrication. So saliva
substitute can be helpful in this situation.

The most adhesive saliva is thin serous but contains some mucous components.
Thick and ropy saliva is very adhesive but tends to build up so that it is too thick in
palatal area and interferes with oral adaptation, in this situation patient should rinse
out ropy saliva every tow or three hours.
3. Cohesion
Cohesion is the force of attraction between like molecules, which maintains the
integrity of the saliva film. It occurs within the layer of fluid (usually saliva).
That is present between the denture base and the mucosa, and works to maintain the
integrity of the interposed fluid. Normal saliva is not very cohesive, so that most of
the retentive force of the denture-mucosa interface comes from adhesive and
interfacial factors unless the interposed saliva is modified (as it can be with the use
of denture adhesive

The chain of intermolecular forces between the denture and the mucosa
contributing to retention.

In general, the retention force directly proportional to the surface area of the surfaces
and inversely proportional to the distance or space between the surfaces.

4. Atmospheric pressure Atmospheric pressure can act to resist dislodging forces

applied to dentures, if the dentures have an effective seal around their borders. This
resistance force has been called “suction”. When a perpendicular force is exerted on
a properly extended complete denture to dislodge it, pressure between the prosthesis
and mucosa drops below the outside pressure thus resisting displacement. Retention
due to atmospheric pressure is directly proportionate to the area covered by the
denture base. For atmospheric pressure to be effective, the denture must have a
perfect seal around its entire border. Proper border molding with physiological,
selective pressure techniques is essential for taking advantage of this retentive
mechanism.

Obtaining optimum physical retention

The aspects of complete dentures that influence the amount of physical
retention obtained are :
✓ border seal
✓ area of impression surface.
✓ accuracy of fit.
Border seal
For optimum retention, the denture border should be shaped so that the channel
between it and the sulcus tissues is as small as possible.
It is not possible to maintain a close approximation between the border of a denture
and the mucosal reflection in the sulcus at all times because the depth of the sulcus
varies during function.
The denture has to be constructed so that the border conforms to the shallowest point
that the sulcus reflection reaches during normal function. This means that for some
of the time when the patient is at rest the denture will be slightly underextended. If
the denture were extended further in an attempt to produce a more consistent seal in
this area, displacement might occur when the sulcus tissues moved during function.

The problem of achieving a constant border seal is overcome by extending the

flanges of the denture laterally so that they contact and slightly displace the buccal
and labial mucosa to produce a facial seal.
Along the posterior border of the upper denture as it crosses the palate, another
approach to creating the smallest possible space between denture and mucosa is
adopted.
A groove known as a post-dam is cut into the working cast so that the posterior
border of the finished denture has a raised lip which becomes embedded a little way
into the palatal mucosa. However, although an enhanced posterior seal is achieved
with a post-dam it differs from the facial seal against the flanges in that even a small
downwards movement of the posterior border of the denture is likely to break the
seal with a resultant loss of retention. If the post-dam has width as well as depth the
basic retention of the denture will be improved.

Lateral extension of the buccal flange to produce a facial seal

Right : denture poorly retained because the thin flanges failed to create a facial seal
and the palatal coverage did not make the most of the area available.
Left : the replacement denture corrected these errors and as a result had excellent
retention.
Area of impression surface
The degree of physical retention is proportional to the area of the impression
surface. It is important therefore to ensure maximum extension of the dentures so
that the optimum retention for a particular patient may be obtained.

Accuracy of fit
The thinner the saliva film between the denture and underlying mucosa, the greater
the forces of retention; therefore it is important that the fit of the dentures is as
accurate as possible. A poor fit will increase the thickness of the saliva film and
increase the likelihood of air bubbles occurring within the film. These bubbles will
further reduce the retention of the denture. In addition, as the pressure of the saliva
film drops due to displacing forces acting on the denture, the air bubbles will expand
and may extend to the border area, resulting in a breaking of the border seal.

Other factors affect on retention of complete denture

Bony undercuts (mechanical factor)
If bony undercuts exist, retention may be enhanced by designing a denture that
utilises these undercut areas. In order to achieve this without traumatising the
mucosa on insertion and removal of the denture, special care is required in planning
the path of insertion.
The resiliency of the mucosa and submucosa overlying basal bone allows for the
existence of modest undercuts that can enhance retention. Exaggerated bony
undercuts or ones covered by thin epithelium may compromise denture retention by
necessitating extensive internal adjustment of the denture, less severe undercuts of
the lateral tuberosities, maxillary premolar areas, distolingual areas, can be
extremely helpful to the retention of the prosthesis. Modest undercuts can help in
retention of complete denture because it will keep the denture in its place
(mechanically) and prevent vertical displacement of the denture.

Selection of path of insertion to improve retention by utilising undercuts: (a) single path of
insertion to engage labial undercut; (b) dual path of insertion to engage unilateral undercut.
Modest undercuts are very helpful in the retention of complete denture especially
when they present in the upper anterior region, so in this case you should have
rotational path of insertion and the undercuts will prevent vertical dislodgment of
the denture. This is the most common undercuts in the upper ridge, also we may
have undercut in the tuberosities.
In the lower jaw we should use the available undercuts in the retromylohyoid space
which give good retention and stability of the lower denture and in this case insert
the denture first in retromylohyoid eminence and then put the denture forward.

Parallel wall
Prominent alveolar ridges with parallel buccal and lingual walls provide significant
retention by increasing the surface area between the denture and the mucosa thus
maximising interfacial and atmospheric pressure forces.

Gravity
When a person is in an upright posture, gravity acts as a retentive force for the
mandibular denture and a displacive force for the maxillary denture. In most cases,
the weight of the prosthesis constitutes a gravitational force that is in significant in
comparison with the other forces acting on the denture. But if a maxillary denture
is fabricated wholly or partially of a material that increases its weight considerably
(e.g., a metal base or precious metal posterior occlusal surfaces), the weight of the
prosthesis may work to unseat it if the other retentive forces are themselves
suboptimal. Increasing the weight of a mandibular denture (through the addition of
a metallic base, insert, or occlusal surfaces) may seem theoretically capable of
taking advantage of gravity.

Surgical factors :
Usually we use these factors to increase the retention of the dentures through various
procedures, like vestiobuloplasty, ridge augmentation, frenectomy & dental
implants.

Psychological factors :
The role of psychological factor on denture retention depends on several
considerations related to the patient himself which include :
1. Intelligence
2. Expectations
3. Apprehension
4. Gagging reflex
5. Previous denture experience.
 Posterior Palatal Seal
Posterior Palatal Seal (PPS) area : the soft tissue area at or beyond the junction
of the hard and soft palates on which pressure, within physiologic limits, can be
applied by a complete denture to aid in its retention. Posterior palatal seal area is
frequently referred also as postdam area, vibrating line and vibrating area.
This soft tissue seal around the posterior border of maxillary complete denture
requires special consideration during denture extension determination because of
the range and extent of the soft tissue activity along this border.
By utilizing the retentive function of atmospheric pressure. Presence of intact border
seal is necessary for the retentive function of atmospheric pressure. Posterior palatal
seal complements the buccal and labial border seal.

Functions and importance of the Posterior Palatal Seal

1- The primary function is that of completing the peripheral seal and enhancing
the retention of complete denture by utilizing the retentive function of
atmospheric pressure.
2- Diminishes the gag reflex by making the posterior border less noticeable to
the tongue.
3- The proximity of the tissue contact prevents food from getting under the
denture base.
4- Decreases the forces on the residual ridge by increasing the denture bearing
area
5- Strengthens the maxillary denture due to the additional bulk at the posterior
border
6- Compensates for polymerization shrinkage of acrylic resin.
Anatomical Considerations

The seal area extends from around the hamular notch on one side across the junction
of hard and soft palate to the hamular notch on the other side. The seal area narrows
down in the mid palatine area due to the lack of connective tissue and the
prominence of posterior nasal spine.
Posterior palatal seal : it is a seal area at the posterior border of maxillary denture.
It can be divided into 2 areas – pterygomaxillary seal, Posterior palatal seal

Pterygomaxillary seal extends through pterygomaxillary notch continuing 3-4mm

anterolaterally, approximating the mucogingival junction. It occupies entire width
of hamular notch (loose connective tissue lying between pterygoid hamulus of the
sphenoid bone and distal portion of maxillary tuberosity). The notch is covered by
pterygomaxillary fold (extend from posterior aspect of tuberosity to pad). This fold
influences the posterior border seal if mouth is wide open during final impression
procedure.
Post palatal seal : is an area between anterior and posterior vibrating line found
medially from one tuberosity to other. It appears to be a cupids bow.
posterior palatal seal area encompass
✓ maxillary tuberosity & hamular process of medial pterygoid plate,
✓ posterior part of hard palate, Hard palate anterolaterally, the submucosal
contains adipose tissue, and posterolaterally it contains glandular tissue, this
tissue is displaceable and
✓ soft palate which is a movable, muscular fold, suspended from the posterior
border of the hard palate. It separates the nasopharynx from oropharynx.

The range of soft palate movement and the degree of displaceability of the seal area
differ in every individual. House proposed three classes of palatal throat forms
based on the angle, the soft palate makes with the hard palate and the soft palate
muscle activity that will be necessary to establish velopharyngeal closure.
The mucosa of the seal region shows a transition from a fixed to loosely attached
tissue beginning from its anterior extent on the glandular region of hard palate to its
posterior extent on the soft palate.

As the seal zone contains varying thickness of loose connective tissue covered by
mucous membrane, it shows differing areas of tissue vibration which are referred to
as anterior and posterior vibrating lines with the seal area stretching out between the
lines. These lines are defined as follows

Anterior vibrating line : it is an imaginary line, lying between immovable tissue

over hard palate & movable tissue of the soft palate. It is generally cupid bow-
shaped, visualized while the patient is instructed to say ';ah' with short vigorous
bursts. Ask patient to blow air gently through nose with nostrils closed with fingers.

Due to the projection of the posterior nasal spine, the anterior vibrating line is not a
straight line between both hamular processes. The anterior vibrating line is always
on soft palatal tissues.

Anterior vibrating line

Posterior vibrating line : it is also an imaginary line, located at junction of soft
tissue that show limited movement & the soft palate that show marked movement.
It is usually straight & generally having slight curvature anteriorly. The posterior
vibrating line is an imaginary line at the junction of the aponeurosis of the Tensor
veli palatini muscle and the muscular portion of the soft palate.

It represents the demarcation between that part of the soft palate that has limited or
shallow movement during function and the remainder of the soft palate that is
markedly displaced during functional movements.

Posterior vibrating line

Relationship of vibrating line with fovea palatine

Fovea palatines are two indentations à oval to round in shape & unique to human
race located approximately1.3 mm anterior to anterior vibrating line.

Types of Palates :
✓ Hard palate – Anterior part.
✓ Soft palate - Posterior part.

Classification of Hard Palates :

Class A - broad, shallow, and flat palate, & least beneficial.
Class B - v-shaped, medium vaulted palate. It gives intermediate quality of PPS.
Class C - high vaulted & U-shape, it gives best retention and stability so most
helpful PPS.

Classification of Soft Palates : ( House classification)

Class I - it is horizontal & makes 10° angle to the hard palate & allowing more than
5 mm of seal area most advantageous. Ideal retention.
Class II - soft palate makes a 45° angle to the hard palate, 1 to 5 mm of seal area
depending on the muscular activity of the soft palate. Good retention
Class III soft palate makes a 70° angle to the hard palate. The soft palate is more
acute in relation to the hard palate, permitting a narrow seal of less than 1 mm. poor
retention.
Designs of the posterior palatal seal
The most common Posterior palatal seal configurations are :
1. A bead posterior palatal seal.
2. A double bead posterior palatal seal.
3. A butterfly posterior palatal seal.
4. A butterfly posterior palatal seal with a bead on the posterior limit.
5. A butterfly posterior palatal seal with the hamular notch area cut to half
the depth of a #9 bur

Locating Posterior Palatal Seal Region :

As tissues of this area are displaceable, the seal area can be identified when the
movable tissues are functioning.
Methods that can be employed are as follows :
1. Palpation method using a ';T burnisher.
2. Nose blow method closing both nostrils of the patient and asking him to blow
gently through the nose.
3. Phonation method-visualizing the vibrating lines as the patient says 'ah'

Different methods of recording PPS :

1. Conventional method.
2. Fluid wax technique.
3. Arbitrary scraping of the master cast.

Conventional method :
1. Gently dry the tissues in the posterior palatal seal and pterygomaxillary notch
with a gauze sponge.

2. Locate the pterygomaxillary (hamular) notches with a T burnisher by passing it

posteriorly along the crest of the ridge until it drops into the notch. Mark the
notches with the indelible marker.

3. Locate the vibrating line by having the patient say a series of short "ahs" and
mark it in the mouth with the indelible marker. Mark the area of the soft palate
where movement just begins.

4. Insert the dried maxillary record base in the patient's mouth and seat it
fully. Visually observe the relationship of the record base to the line marked in
the patient's mouth. Ask the patient to tilt his head down and swallow and/or say a
series of short "ahs."
5. Remove the maxillary record base. The indelible marking may have transferred
to the record base. If the line has not transferred to the record base, reinsert the
base and instruct the patient to blow through his or her nose while you gently
pinch it shut. Look in the patient's mouth. You may be able to see the indelible
marker line through the translucent record base.

6. Trim the posterior border of the record base to the transferred marking using a
bur designed for trimming acrylic. Reinsert the record base in the patient's mouth
and evaluate the relationship of the posterior border to the vibrating line. Adjust
until the correct length is obtained. The fovea palatine are not reliable indicators
of the location of the vibrating line.

7. Place the maxillary record base on the cast. Scrape a line into the cast, marking
the posterior border of the record base using a sharp instrument. Extend this line
approximately 3 mm beyond the crest of the pterygomaxillary notch continuous
with the disto-buccal border. This marks the posterior limit of the denture.

8. Palpate the tissue anterior to the vibrating line with the ball end of the T-
burnisher. Examine the thickness and displaceability of the tissue. Using a pencil,
outline the posterior palatal seal on the cast. The generally accepted outline is a
butterfly or mustache pattern. The average dimensions are 2-3 mm in the midline
and distal to the tuberosities. A width of 4-6 mm is appropriate for the intervening
areas between the midline and pterygomaxillary notches. The seal should be
deeper posteriorly becoming more shallow as it extends anteriorly. It should be
rounded and smooth in contour.

9. Scrape the master cast using a discoid/cleoid to the proper depth. This is
usually one-half the depth the ball of the T-burnisher displaces the tissues. The
deepest part of the posterior palatal seal usually is placed on either side of the
midline where the seal approaches the hamular notches. This is generally in the
range of 1.0 - 1.5 mm in depth. It should be .5 mm deep in the middle of the
posterior palate, 1 mm deep in the hamular notch area, and 1.5 mm deep in the
glandular area between the hamular notch and the middle of the posterior palate.

Advantages :
1. Highly retentive trial bases make recording jaw relations easier and precise.
2. Give psychological confidence to patient that retention will not be a problem
in complete denture.
3. Dentist is able to determine the retention of final denture.
4. Patient will be able to realize the posterior extent of denture, which may ease
the adaptation period.
Disadvantages :
1. Not a physiological technique and therefore depends upon accurate transfer
of vibrating line and careful scrapping.
2. Potential for over compression is more.

Fluid wax technique :

Start with locating and transfer of anterior and posterior vibrating line similar to
conventional approach. Then with markings made, final impression is made using
ZOE/impression plaster (not with elastomeric impression material as they are
resilient, non adherent to wax and distort wax when reseated into oral cavity).

The melted wax is painted into the impression surface (within the outline of the seal
area). The wax is applied slightly in excess of the estimated depth and allowed to
cool below mouth temperature to increase its consistency and make it more resistant
to flow. This impression is carried to the mouth and held in place under gentle
pressure for 4-6 minutes plane to be at 30° to the horizontal plane) excess (or) if no
tissue contact is established then add and redo the procedure. Ask the patient not to
rinse with cold water, between the procedures (contraction of tissues and act to
decrease flow properties of wax).Examine the surface morphology of wax at
anterior vibrating line. It should be a brief edge, if a step is found this indicates poor
flow of material.

Advantages :
A. It is physiologic technique of displacing tissues.
B. No over compression of tissues.
C. PPS is incorporated into trial denture base for added retention.
D. No mechanical scraping of cast.

Disadvantage :
A. Time consuming.
B. Difficulty in handling material and additional care to be taken during boxing
procedure.

Arbitrary scrapping of the master cast

In this technique, the anterior and posterior vibrating lines are visualized by
examining the patient's mouth and approximately marked on the master cast.
Scrapes 0.5 to 1mm of stone in the posterior palatal seal area of the master cast and
fabricates the denture.
This technique is inaccurate and not physiological and should be avoided.
 Errors in recording the posterior palatal seal
Underextension : Most common cause. May be produced due to following reasons.
1. When the denture does not cover the fovea palatina, the tissue coverage is
reduced & the posterior border of the denture is not in contact with the denture
border during functional movements.
2. Improper delineation of the anterior and posterior vibrating lines.
3. Excessive trimming of the posterior border of the denture by the dental
technician.
4. 4There are patients who inform the dentist on the very first visit for complete
denture therapy that they are gaggers. The dentist intentionally leave the
posterior borders underextended in order to reduce the patients’ anxiety in
gagging…

Overextension : Overextension of the denture base can lead to ulceration of the soft
palate and painful deglutition. Covering of the hamular process can lead to sharp
pain in that region. In order to relieve these areas ,indelible pencil markings are
made on them (hamular process, ulcers, etc) and transferred to the denture.These
regions are trimmed and polished.

Underpostdamming : This can occur due to improper head positioning & mouth
positioning, e.g. when the mouth is wide open while recording the posterior palatal
seal the mucosa over the hamular notch becomes taut. This’ll produce a space
between the denture base and the tissues.
1. Inserting a wet denture into a patient’s mouth and inspecting the posterior
border with the help of a mouth mirror can identify underdamming.
2. If air bubbles are seen to escape under the posterior border,it indicates
underdamming.
3. To correct underdamming, the master cast can be scraped in the posterior
palatal area or the fluid wax impression can be repeated with proper patient
position.

Overpostdamming : This commonly occurs due to excess scraping of the master

cast.
It occurs more commonly in the hamular notch region
Mild overdamming in the hamular notch region can lead to tissue irritation of the
mucosa and excessive postdamming produces downward displacement of the
denture posteriorly.
Selective reduction of the denture border with a carbide bur, followed by lightly
pumicing the area while maintaining its convexity will remedy the problem.
 Stability of Complete Dentures
Stability
1. That quality of maintaining a constant character or position in the presence
of forces that threaten to disturb it; the quality of being stable; to stand or
tolerate.
2. The quality of a removable dental prosthesis to be firm, steady, or constant,
to resist displacement by functional horizontal or rotational stresses.
There is a very interdependent relation between retention and stability because the
factors that affect retention are also involved in the stability.

A stable denture is one that moves little in relation to the underlying bone during
function. It is perhaps surprising that dentures stay in place at all, as they simply rest
on mucous membrane and lie within a very active muscular environment.

Denture stay in place if the retentive forces acting on them exceed the displacing
forces and the dentures have adequate support

Forces acting on a denture :

1. Force of the muscles of mastication acting through the occlusal surface.
2. Muscular forces of lips, cheeks and tongue acting through the polished
surface.
3. Physical forces acting through the impression surface.
Forces acting through the occlusal surface
Force of Mastication
During mastication, pressure exerted by the food on the teeth tends to displace the
denture. Successful dentures require that the artificial teeth be placed in the position
occupied by the natural teeth. Although the natural teeth were situated in the centre
of the alveolar ridge, following their loos much bone resorption occurs and the
position of the crest of the residual ridge may bear little relation to that of the
original alveolar ridge. It is suggested that optimum denture stability is obtained
when the artificial teeth are placed on, or lingual to the residual ridge.

If the artificial teeth are arranged on A, the occlussal load placed on A will serve as
the tilting force with a fulcrum on the ridge crest. I f arranged on B or C, the
occlussal load will serve to place the denture in position leading to stability of the
denture.

The vertical position of the teeth are usually determined by the level of the
occlusal plane which is determined by the position and functional movements of
the tongue angled parallel to the maxillary and mandibular residual ridges for
maximum stability.
The occlusal plane should be the same as that present before the loss of natural teeth
in the resting position the occlusal plane of teeth should be with the level of the
lateral border of the tongue which is determined by the junction of the specialized
and non-specialized mucosa. The presence of inappropriate and adverse occlusal
planes may result in stability problems.
If the occlusal plane is higher than that level of the tongue it will interfere with the
stability at the denture because the tongue will move too far high to bring the bullous
of food between the teeth from the lingual vestibule which lead to dislodgment of
the denture. In this situation the tongue will need a big amount of movement in
upward and forward direction to get freedom during speech or eating which result
in elevation of the floor of the mouth (alveolingual sulcus) and finally displacement
of the denture.
We can use the retromolar pad to determine the level of occlusal plane because this
plane should never pass the lower 2/3 of the retromolar pad.
Incisal plane; the inter-pupillary line is an acceptable guideline for this plane. Right
and left occlusal planes; Standard guidelines for these planes are that they should
be parallel to the ala-tragus line and instruments such as Fox's occlusal plane guide
may be used to confirm these planes . Inappropriately formed planes may result in
occlusal errors that may result in denture instability.

Forces related to the posterior teeth

As a general guide to (lower) complete denture stability, the palatal
cusps of the maxillary premolar and molar teeth should lie over the
mandibular ridge, the central fossae of the lower posterior teeth should overlie the
straight edge (this represents the zone occupied by the palatal cusps of the maxillary
posterior teeth in retruded contact position.

Relationship of maxillary palatal cusps to the mandibular ridge. It is recommended that these cusps are placed over
the lower ridge crest and thus occlude with the central fossae of the mandibular posterior teeth.

It is generally accepted that, in the interests of (lower) denture stability, the central
fossae of the lower posterior teeth and the necks
of the lower anterior teeth should lie over the residual mandibular crest.
Stability of the lower denture can be improved by careful consideration of the
posterior extension of the occlusal table. If that table extends to the steeply sloping
part of the ridge posteriorly, pressure from the bolus will cause the denture to slide
forwards. Therefore the occlusal table should terminate on the relatively horizontal
part of the ridge where effective support is available and displacement prevented. It
may be necessary to reduce the number of posterior teeth to achieve this aim.

Pressure from the bolus on the posterior part of the lower occlusal table, which
overlies a sloping part of the ridge, causes the lower denture to slide forwards.
Do not place the posterior teeth over the ascending portion of the ramus. Functional
forces will cause the denture to tilt or shift. Causing looseness and/or discomfort.
Instead, eliminate the 2nd premolars from the set up if necessary.

The presence of molar teeth over the ascending portion of the mandibular ramus
tends to encourage displacing movements of the lower denture and this practice
should be avoided.
Following the loss of the natural teeth the buccinators mucle moves inwards and the
tongue outwards. Accordingly, it is necessary, particularly in the lower jaw and
particularly with the older patient, to use posterior teeth that are considerably
narrower bucco-lingually than the natural teeth.

Forces related to the anterior teeth

Occasionally, the problem of occlusal displacement can create a confl ict of interests
between the requirements of optimum appearance and denture stability.
Upper anterior teeth placed close to the crest of the ridge where strong incising
forces can be applied with minimal leverage effects, despite the fact that lip support
and appearance would be compromised.
No matter what skeletal relationship exist, the labial surface of the mandibular
incisors should not protrude beyond the labial vestibule. This horizontal limit
applies even in a sever Class 11 jaw relationship with large overjet of the maxilla,
unless, of course, the patient insists that the aesthetics advantages of protruding
incisors are more valuable than the stability of the lower denture.

Distal displacement of the lower denture caused by placing teeth too far labially.
If the teeth are arranged by referring to the natural tooth Position. The anterior teeth
will be placed much more anterior to the alveolar crest. If food is bitten using these
anterior teeth. The posterior border of the denture is likely to drop easily due to the
leverage. With the fulcrum at the alveolar crest The direction of the force applied
when biting food with the anterior teeth is similar to that of removing the denture,
so the antagonizing force is small. Thus patients are instructed about the above
mentioned mechanism and told not to bite with the anterior teeth

When food is incised with the anterior teeth which have been arranged much more
anterior to the alveolar crest. The posterior border of the denture is likely to drop
easily due to the leverage with the fulcrum at the crest of the ridge. The antagonizing
force is also small.

While incising food with the anterior teeth, the upper denture is supported by the
dorsum of the tongue and the lower denture is pressed downward by the tip and
ventral surface of the tongue. Leading to stability of the denture.

A reduction in displacing forces to bring them within the ability of the patient to
control the dentures can be achieved by offering advice, for example, cutting food
into smaller pieces before inserting them into the mouth, chewing on both sides of
the dental arch simultaneously and starting with softer ‘easier’ foods before
progressing to more challenging morsels.
Sticky foods tend to move the dentures away from the mucosa.

Tipping of the denture due to an unbalanced occlusal contact.

Occlusal imbalance
If, when the dentures occlude, tooth contact on one side of the dental arch is not
balanced by contact on the other side the dentures will tip, causing the border seal
to break with consequent loss of retention When the mandible moves into lateral or
protrusive occlusal positions, interference between opposing teeth resulting from
interlocking cusps or an excessively deep overbite will cause horizontal
displacement and tipping of the dentures. This type of instability can be minimised
by producing balanced occlusion It should be borne in mind that occlusal displacing
forces can be severely increased in patients exhibiting parafunctional activity such
as bruxism.
Forces acting through the polished surface
During mastication the muscles of the cheeks, lips and tongue control the bolus of
food, move it around the oral cavity and place it between the occlusal surfaces of
the teeth. In so doing, they press against the polished surfaces of the dentures. If
these surfaces are correctly shaped with the buccal and lingual surfaces converging
in an occlusal direction, this muscular force will seat the dentures on the underlying
mucosa

The muscles of the lips, cheeks and tongue, in addition to being of fundamental
importance in the retention of dentures, are also capable of causing denture
instability. Displacement will occur, if the polished surfaces have an unfavourable
slope and also if the denture interferes with the habitual posture and functional
activity of the surrounding musculature.

Between the tongue on one side and the cheeks and lips on the other where the
muscular displacing forces acting on a denture are least. This area is known as the
neutral zone or zone of minimal conflict. Positioning a prosthesis within this zone
is most important for the lower denture as the physical retentive forces are normally
small and can do little to resist muscular displacement.

The polished surfaces of the denture should be carved during waxing procedure in
such a way that these surfaces will act in harmony with the oral; and facial
musculature.

For the stability , as we know during various functions the muscles surrounding the
denture will contract from outside and inside so the denture should design in such a
way that will not interfere with the movement of these muscles. I.e. the polished
surface of the upper labial flange should not interfere with the action of the
orbicularis oris also for the lower this surface should have a slight concavity to
receive this muscle.

We give a concavity for the palatal surface of the upper denture to increase the space
for free tongue movement also the lingual flanges of the lower denture should have
some sort of concavity to give a sufficient room for the tongue and some sort of
extension toward the midline to create a type of seal between the lower border of
the tongue and the denture.

For the posterior flanges of the denture, it should have some concavity to receive
the buccinator and in the lower most posterior region of the buccal flange should
eliminate any interference with the masseter.
Impression surface
For the impression surface to get benefit of stability the impression surface of the
denture we should have correct registration of the denture stabilizing borders, also
it should have the maximum extension within the limits of health and function of
the tissues.

Factors affecting stability of complete denture

1. Round, parallei ridges offer better stability than flat ridge
2. fibrouse connective tissue that is firm aids in stability more than flabby
tissue.
3. An accurate impressin with maximum coverage increase stability.
Impressions should recored the stress- bearing areas under stress and
relief respectively.
4. A well contoured occlusal rims with the occlusal plane oriented parallel
to the ridge posteriorly and parallel to the interpupillary line anteriorly
stabilizes the denture.
5. if the teeth arranged in a well contured occlusal rim, balanced occlusion
and neuteral zone is achieved easilly which again aids in stability of the
denture.
6. the polished surfaces should be countured in regared with neuteral zone
or the action of various muscles tend to displace the denture.

Support of Complete Denture

Support is the resistance to the vertical forces exerted on the denture.
Support the quality of a denture that resists movement of a denture toward the
tissues.

Denture bearing area : is the surfaces of the oral structures available to support a
denture or those areas of the maxillary and mandibular edentulous ridges that are
considered best suited to carry the forces of mastication when the dentures are in
function.

The denture bearing area becomes progressively smaller as the underlying residual
ridge resorbs over time.
The greater the coverage of the supporting areas by the denture base, the less the
force per unit area will be transmitted.
Many complete dentures are seen with inadequate extension of the bases and this is
due to a mistake that the extended bases will be more difficult to tolerate by the
patient whereas the contrary is true. The extension of the base must be within the
functional and morphological limits of each particular mouth. With correct
extension the patients.
Understanding of the structure and characteristics of the mucosa and the underlying
bone of the denture bearing area is important in determining the primary and
secondary support areas.

In maxilla, the primary stress-bearing areas are the residual ridge and most of the
hard palate.
The firmness and resiliency of keratinized mucous membrane covering the compact
bone of the crest of the ridge forms the most favourable primary support area.
The presence of palate in the maxilla increases the surface area of the denture-
bearing area.

In the rugae area, the overlying tissue is fairly thin but set at an angle to the ridge
and this area provides secondary support area.

In the region of midpalatal suture, the mucosa is extremely thin so it is often

necessary to provide some relief in this area to prevent rocking of the denture base.
The incisive papilla should usually be relieved because it covers the emerging
nasopalatine nerve and vessels.
Anterolateral palatal region contains adipose tissue and posterior laterral
palatal tissue is glandular in nature .These tissues are displaceable and provide
primary support area.

In mandible, the much reduced area for the denture base increases the importance
of correct selection of the most appropriate stress –bearing areas The bone beneath
the mucosa is often of a cancellous nature and not of the compact bone encountered
in the maxilla, making it less suitable for primary support.
The mucosa covering the crest of the ridge is of adequate thickness but the
underlying bone is cancellous without a good cortical plate covering it, so it is not
favorable as the primary support area.

The mucosa overlying the buccal shelf area is loosely attached and less keratinized
but the underlying bone is covered by smooth cortical plate .This ,in addition to the
fact that the shelf area lies at right angle to the vertical occlusal forces , makes shelf
area the most suitable primary stress-bearing area for a lower denture .The buccal
shelf area is bounded medially by the crest of residual ridge ,laterally by external
oblique ridge , anteriorly by buccal frenum and posteriorly by retromolar pad .The
total width of bone in this area becomes greater as residual ridge resorption
continues due to that the width of the inferior border of the mandible is greater than
the width at the alveolar process .

So the primary support area in the mandible is the buccal shelf and the secondary
support areas are the crest of the ridge and the slope of the ridge.

The retro molar pad is covered by a thin non-kerainized mucosa .It should not be
used as support and it should be relieved by taking impression mucostatically in that
region.

Ps: primary stress bearing area,Ss: secondary stress bearing area

A reduction in support promotes instability, as indicated in the following

examples :
1. Instability of an upper denture follows resorption of the supporting bone. This
resorption is largely confined to the region of the alveolar ridges, as there is
remarkably little resorption of bone in the centre of the palate. Thus, after a period
of time, the denture will be well supported by the hard palate, but there will be
limited contact between the impression surface of the denture and the alveolar
ridges. In these circumstances, occlusal contact readily produces tipping, with the
denture pivoting about the mid-line of the palate.

2. Support will be inadequate if the ridges are small because resistance to lateral
displacing forces will be poor.

3. Support will be reduced if the ridges are flabby, the denture will move
considerably during function even though the retention may be good and contact
with the mucosal surface is maintained.

Relationship of factors contributing to denture stability.

 Concept of Neutral Zone
The objectives of any prosthodontic service are to restore the patient to normal
function, esthetics, and health. The design of prostheses to replace lost teeth and
resorbed ridges is largely determined by the position and amount of morphological
change in the denture bearing area of the jaws. These changes dictate artificial tooth
positions in complete denture patients. The arrangement of teeth must be
physiologically and esthetically acceptable.

1. Dislodging forces,
2. Discrepancies in residual ridge,
3. Maxilla-mandibular relationships,
4. Residual ridge relationships,
5. Functional and para-functional mandibular movements,
6. Esthetic requirements and
7. Preferences of patients

The eruption of the teeth in the oral cavity is influenced by the forces exerted by
tongue, cheeks and lips. These muscular forces collectively determine the final
dental arch form and position of the tooth in the oral cavity. This muscular
environment continues throughout life, even after teeth have been lost and greatly
influences this potential space.

After the loss of natural teeth, it is difficult to ascertain the exact position due to
varying pattern of alveolar bone resorption in different segments.
The concept of “teeth over the residual ridge” is based on the mechanical principle
of ensuring stability by directing the forces at right angle to supporting tissues.
Mandibular posterior teeth are placed with their central fissures coinciding with a
line joining the cuspid tip and the middle of retromolar pad. Bucco-lingually narrow
teeth when placed closer to ridge offer additional lever balance. Crests of the
residual ridge may be used as a biometric guide.

Unfortunately the crests do not remain in same antero-posterior and medio-lateral

position. Viewing from the occlusal aspect, the crest of the residual alveolar ridge
shifts lingually in maxilla and buccally in mandible. Both arches are resorbed in
vertical and horizontal direction.

The alveolar ridge crest changes its location in a bucco-lingual direction after
resorption. The probable cause of this resorption pattern may be eruptive pathway
of teeth, development pattern of alveolar processes or muscularor myodynamic
forces. So arrangement of artificial teeth strictly over the crest of residual ridge may
emphasize facial deformity, aggravate phonetic problems and affect deglutition.
Generally, loss of bone occurs from the lingual plate of mandibular arch and buccal
aspects of maxillary arch. This allows more space for tongue movement and hence
tongue enlarges over the years. This results in exertion of force more towards buccal
and labial sides. Cheeks and lips may not respond in the same fashion due to loss of
tonicity of muscles, with advancing age. Therefore neutral zone may not lie at the
place where it was, when teeth were present.

Complete dentures are primarily mechanical devices, but since they function in the
oral cavity, they must be fashioned so that they are in harmony with normal
neuromuscular function.

Neutral zone may be defined as the space where during function the forces of the
lips and cheeks pressing inwards neutralize the forces of the tongue pressing
outwards. The neutral zone concept involves acquired muscle control especially by
tongue, lips, and cheeks towards denture stability. Believersof neutral zone agree
that lack of favourable leverage is observed when teeth are positioned directlyover
the ridge. As in this case teeth are not positioned in harmony with the surrounding
musculature.By employing neutral zone concept, the dislodgingmuscle energy can
easily become a retentive and stabilizing force.

After loss of natural teeth, a space or void exists within oral cavity called the
potential denture space. It is bounded by maxillaand soft palate above, by
mandible and floor of mouth below, by tongue medially or internally and bymuscles
and tissue of lips and cheeks laterally or externally. Within the denture space, neutral
zonelies. Denture teeth should be arranged in the neutral zone, where during
function the forces of the tongue pressing outward are neutralized by the forces of
cheek and lips pressing inward.
The central opinion of the neutral zone approach to complete dentures is ‘to locate
that area in the edentulous mouth where the teeth should be positioned so that the
forces exerted by the muscles will tend to stabilize the denture rather than unseat it’.
When the residual alveolar ridges have resorbed significantly, denture stability and
retention are more dependent on correct position of teeth and contour of the external
surfaces of dentures.
Failure to recognize the importance of tooth position, flange form and contour often
results in dentures which are unstable and unsatisfactory. This potential space is
known as neutral zone, which is bounded by the tongue medially, and the lips and
cheeks laterally.
In the highly atrophic mandible muscular control over the denture is the main
retentive and stabilizing factor during function. A denture shaped by the neutral
zone (NZ) technique will ensure that the muscular forces are working more
effectively and in harmony.
Historically, different terminology has been loosely associated with this concept,
including :
1. dead zone
2. stable zone
3. zone of minimal conflict
4. zone of equilibrium
5. zone of least interference
6. biometric denture space
7. denture space
8. Reciprocal space
9. Potential space
10.Reciprocal zone
11.Zone of neutralmuscular forces

Boundaries of denture space

It is bonded by the upper ridge, hard and soft palate from above, the lower ridge
from below, tongue medially and cheek and lip externally.

Anatomy of soft tissue boundaries :

1. maxillary and mandible buccal region : in this region, the buccinators
considered as the main boundaries of the denture space .it originates from
pterygomandibular raphe and area opposite to maxillary and mandible molar and
fibers goes anteriorly to converge with other muscles at the modulus .The role of
buccinators is to position the food between teeth in coordination with tongue .
Because of the direction of muscle fibers (which is parallel to the border of the
denture and not at right angle to it), the contraction of the muscle has a slight
displacing action to the denture and we may have a possibility of over extension
with the limit of function and health.

2. Anterior margin of buccal region : in this region, the modulus is a strong knot
that alter the position of the mouth angle .it is composed of intersection of
buccinators ,orbicularis oris, zygomaticus major and elevator and depressor
angulioris.
The modulus determines the position of premolar and the shape of the polished
surface in that region. This produces narrowing of the denture so that the polished
surface doesn't interfere with the modulus movement during function.

3. Labial region : it extends from one modulus to the other. Its boundaries in the
maxilla are formed by elevator labiisuperioris and in the mandible by depressor
labiiinferioris and mentalis. The origin of these muscles determines the length of
labial flange but the degree of ridge resorption and the tonicity of muscle determine
the thickness of the flange. Anterior portion of the labial region is bounded by
orbicularis oris.

The movement of the lip and tongue determines the position of lower anterior teeth,
if they are positioned too far labially, the contraction of lip will displace the denture
posteriorly.

4. Palatal region : it is bounded by the upper residual ridge, hard palate and anterior
part of soft palate .It is very important during phonation of words

5. Mandibular lingual region : It is the most important region. It is formed mainly

by tongue which is a powerful group of muscles (17 muscle) and it is in contact with
denture during rest and function .The polished surface and position of teeth are
critical in this region .

If the interior or posterior teeth are set too lingual, the tongue will displace the
denture during function .Also the occlusal plane should not be high to allow the
tongue to lie on the occlusal surface during rest.

6. Floor of mouth : the composition of this region is mainly the mylohyoid muscle
arising from mylohyoid line. The direction of the muscle fibers is different in
various regions.
In the anterior part of floor of mouth, the fibers extend almost horizontally while
posteriorly, it extends obliquely to the hyoid bone. So anteriorly the mylohyoid
muscle is considered as the limit of the denture while posteriorly the denture flange
is extended sometimes below the mylohyoid line depending on the direction of the
muscle fibers.
Methods of assessing the neutral zone :
1. Conventional method : it based upon the arrangement of artificial teeth
following certain anatomical guides and then waxing and carving of trial denture in
the conventional way. Incisive papilla is thought to be a fixed anatomical landmark
and it is not affected by resorption of bone. It is a good guide for anteroposterior
positioning of the anterior teeth. The labial surfaces of the central incisors are
usually 8-10 mm in front of the papillae. Also the line bisecting the midline at the
center of the incisive papilla should pass through the tips of the upper canines.

For arrangement of lower posterior teeth, we have the retromolar pad which is also
a fixed anatomical landmark and not affected by bone resorption. Arrangement of
teeth is done according to aline passing from the center of the retromolar pad to the
tip of the lower canine. This line is passing through the central grooves of the lower
posterior teeth.

After arrangement of teeth, we do corrections inside the patient's mouth according

to esthetic, phonetic and functional needs.
Then waxing and carving are performed in a conventional way (the labial and buccal
flange is given a concavity and sometimes a convexity at the anterior segment to
receive muscle action).

2. Functional methods
These are many but all of them try to register the neutral zone through molding of
soft material by the action of tongue, lips, cheeks and floor of mouth by specific
oral functions. Material of impression used is impression compound, soft wax,
silicon or tissue conditioning material.
This method may registrate the neutral zone at rest or function (swallowing,
phonation, sucking, whistling). The impression material will capture in greater
detail the action of the lips, cheeks and tongue and determine the thickness, contours
and shape of the polished surface of the denture to be functionally compatible with
muscle action.

Neutral zone Technique

1. Maxillary and Mandibular primary impressions are made in stock trays using
Impression compound. Custom trays are fabricated in autopolymerizing resin and
final impression taken in zinc oxide eugenol impression paste after border
moulding. Jaw relation records are then recorded using conventional occlusal rims
made of modelling wax and occlusal blocks are mounted on semiadjustable
articulator.
2. An additional autopolymerizing resin mandibular denture base is fabricated and
is attached with retentive loops made of thin orthodontic wire in the centre. Two
vertical pillars made of low fusing compound (Tracing Sticks) areplaced in First
molar region at established vertical dimension. This autopolymerizing resin base is
placed in the mouth, checked for stability and ensured that loops and vertical pillars
do not interfere with muscle movements during function. Maxillary occlusal rim is
placed back in the mouth.

3. Poly ether impression material of medium-bodied consistency is placed over the

base and inserted in the mouth and patient is instructed to perform all muscle
functions by sucking and swallowing movements and by producing exaggerated
‘EEE’ and ‘OOO’ sounds. Excess material if any will be displaced upward in the
upper denture space from where it can be easily removed. In case of insufficient
material, additions can easily be made using extra material and the process is
repeated. The final record should be perfectly stable in place.

4. The impression of denture space is placed over the mandibular master cast.
Indexing is made on side and center of the land area of cast. Lingual matrices of this
denture space is made using silicone putty. Putty is adapted into the tongue space of
the neutral zone record so that it is in level of occlusal plane of record and extends
over the posterior land area of cast.

Likewise facial matrices is developed along the facial contours of the neutral zone
record. Once polymerized, putty matrices is sectioned and removed from the cast
Poly ether material is removed from the base and replaced with wax using putty
matrices.

5. Arrangement of Teeth
All of the lower teeth are set first. This is done by removing just enough wax to set
one tooth at a time, constantly checking its position with the index. When all of the
lower teeth have been set, the upper teeth are arranged. They must be positioned
within the neutral zone and to the proper height of the occlusal plane as established
on the polyether occlusion rim with the Putty matrices in position. However position
of maxillary anterior teeth can be modified based upon the esthetic and phonetic
requirements of the patient.

6. Flasking, processing, finishing and polishing of denture is then done using

conventional method.
 Denture adhesive
Denture adhesive : is a material used to adhere a denture to the oral mucosa.
A commercially available, nontoxic, soluble material (powder, liquid or cream) that
is applied to the tissue surface of the denture to enhance denture retention, stability,
and performance.

There are two main types of denture adhesives

1. The old generation : which is vegetable gums based adhesives such as(e.g.
karaya, xanthan, and acacia) that display modest, non ionic adhesion to both denture
and mucosa and possessed very little cohesive strength ,in addition, gum based
adhesives are highly water soluble particularly in hot liquids such as coffee, tea.
And soups, and therefore wash out readily from beneath dentures. Allergic reactions
have been reported to karayia, and formulations with karayia impart a marked odor
indicative of acetic acid. Overall, the adhesive performance of vegetable gum-based
materials is short-lived and relatively unsatisfactory.

2. The new generation which is a synthetic materials, the most popular product
consist of mixtures of the salts of short acting Carboxy Methyl Cellulose (CMC)
and long acting polymers(polyvinyl methyl ether maleate or gantrez).
In the presence of water, Carboxy methyl cellulose hydrated and displays quick-
onset ionic adherences to both denture and mucosa, the original fluid increases its
viscosity and carboxymethyl cellulose increases in volum, thereby eliminating
voids between prosthesis and its basal seat.Thesetwo actions markedly enhance the
interfacial forces acting on the denture. The long acting polymers (gantrez salts) are
less soluble, it also displays molecular cross- linking resulting in a measurable
increase in cohesive behaviour.

Mechanisms of action
Denture adhesives augment the same retentive mechanisms already operating when
a denture isworn they enhance retention through optimizing interfacial forces by:
1. Increasing the adhesive and cohesive property and viscosity of the medium lying
between the denture and its basal seat.

2. Eliminating voids between the denture base and its basal seat.
When an adhesive come into contact with saliva or water a hydrated material is
formed, which is more cohesive than saliva, physical forces intrinsic to the
interposed adhesive medium resists the pull more effectively than would similar
forces within saliva. So it sticks readily both the tissue surface of the denture and
the mucosal surface of the basal seat.
The material increases the viscosity of saliva with which it mix and the hydrated
material swells in the presence of saliva / water and flows under pressure, voids
between the denture base and bearing tissue are therefore obliterated.

Indications of denture adhesive

It must be emphasized that denture adhesive is not indicated for the retention of
improperly fabricated or poorly fitting dentures.
1. In addition to enhancing patient satisfaction with a properly constructed
denture, denture adhesives can be particularly beneficial to patients who place
severe demands on their prostheses, such as: Musicians, Public speakers,
and those who feel the need for the additional sense of security conferred by
use of the product.
2. Denture adhesives are particularly useful form aladaptive patients who have
severely compromised residual ridge morphology.
3. Patients suffer from xerostomia.
4. Have undergone maxillofacial jaw resection.
5. Are neurologically compromised due to stroke, multiple sclerosis, or closed-
head injury.
6. psychologically compromised ( over expected) patients .

Contraindications
The following are contraindications to the use of denture adhesive:
1. A patient with open cuts or sores in mouth.
2. An ill-fitting denture.
3. A patient who cannot or will not maintain adequate oral and prosthesis
hygiene.
4. A patient with a known allergy to any product .ingredient

How to Apply the Denture Adhesive

The four rules to follow for the application of adenture adhesive are :
1. Use the minimum amount necessary to provide the maximum benefit.
2. Distribute the adhesive evenly in the tissuebearingsurface of the denture.
3. Apply or reapply when necessary to providethe desired effect—only after
following rule4.
4. Always apply the denture adhesive to a thoroughly clean denture.
Cream Adhesive Application
Maxillary Denture
On a clean denture (wet or dry) three short stripsof product are applied: one at the
crest of eachof the ridge areas and one down the center. Analternative is to apply a
series of very small dotsof product, evenly spaced. Material should beplaced no
closer than 5 mm to a denture border.The patient should the insert and press
thedenture firmly in place and hold briefly.

Mandibular Dentures
For the lower prosthesis, a short strip is placed inthe depth of the left, right, and
anterior rid areas;or small dots are evenly spaced. As with theupper denture, the
prosthesis must be clean butthe product can be applied to either a wet or a dry
surface. The patient should the insert and pressthe denture firmly in place and hold
briefly.

The recommended method for applying powderadhesive is to sprinkle a thin

uniform layer throughout the moistened tissue-bearing surfaceof the clean denture.
Excess powder is shaken offand the denture is pressed into place.
Whether using a cream or powder dentureadhesive, the patient should wait briefly
(10-20minutes) before drinking hot liquids or beforechewing in order to allow the
adhesive to attain itsfull cohesive and adhesive strength.

Denture Hygiene when Adhesive is being Used

Daily removal of the denture adhesive from the denture is important for tissue
health. Soaking the prosthesis overnight in water will loosen the adhesive material
and allow it to be readily rinsed off. Alternatively, scrubbing the tissue
surfaces of the denture under warm water will remove adherent product. Finally,
when adhesive is supplemented in the course of the day, all remaining material
should be thoroughly removed prior to adding additional material.
 Occlusion in Complete Denture
Occlusion in complete denture must be developed to function efficiently and with
the least amount of trauma to the supporting tissues.

Occlusion : Occlude means ‘to close’. This words is used to describe the static
contact relationship between the incising or masticating surfaces of the maxillary or
mandibular teeth or tooth.
It is the static contact of the teeth that exist after the jaw movements have stopped.
it is the contact relationship of the upper and lower teeth. All occlusal forms should
at least have a tripod contact in centric relation.

Centric occlusion : the occlusion of opposing teeth when the mandible is in centric
relation. This may or may not coincide with maximum interception.

Centric relation :
✓ The most posterior relation of the lower to the upper jaw from which lateral
movements can be made at a given vertical dimension.
✓ The most retruded physiological relation of the mandible to the maxillae to
and from which the individual can make lateral movements. It is a condition
that can exist at various degrees of jaw separation. It occurs around the
terminal hinge axis.
✓ Centric relation is the most posterior relation of the mandible to the maxilla
when the condyles are in the most posterior unstrained position in the glenoid
fossa from which lateral movements can be made at any given degree of jaw
separation.

✓ The maxillomandibular relationship in which the condyles articulate with the

thinnest avascular portion of their respective disks with the complex in the
anterior-superior position against the shapes of the articular eminencies. This
position is independent of tooth contact. . It is restricted to a purely rotary
movement about the transverse horizontal axis.

It is a significant jaw position in prosthodontics and especially in complete denture

construction.
1. It is a reproducible and recordable position, which can be repeatedly arrived
at and thus serves as a reliable guide to develop centric occlusion in
complete dentures.
2. Centric relation become starting point to plan and execute the occlusion.
 3. Centric relation is related to terminal hinge axis. In centric relation, condyles
exhibit pure rotation without any translation.
4. This position is more definite than the vertical relation and is independent of
the presence or absence of teeth.
5. The final act of masticatory stroke ends in centric relation. It is a functional
position.
6. It is a border position and the posterior limit of the envelope of motion

The transverse horizontal axis : An imaginary line around which the mandible
may rotate within the sagittal plane.
Maximal Intercuspal Position : The complete intercuspation of the opposing teeth
independent of the condylar position.

Occlusal Pattern : The form or design of the masticatory surfaces of a tooth or

teeth based on natural or modified anatomic or non anatomic teeth.

Occlusal Interference : Any tooth contact that inhibits the remaining occluding
surfaces from achieving stable and harmonious contacts.

Articulation : Refers to the static and dynamic contact relationship of maxillary

and mandibular teeth as they move against each other during function.

Free Mandibular Movement : Any mandibular movement without interference.

Balanced Occlusion : It refers to the bilateral, simultaneous, anterior, and posterior

occlusal contact of teeth in centric and eccentric position.

Objectives
The basic principles to be achieved by any occlusion concept are :
✓ Preservation of the remaining tissues.
✓ Proper masticatory efficiency.
✓ Enhancement of denture stability.
✓ Enhancement of phonetics and esthetics.
Difference between Natural and Artificial Occlusion
1. The teeth in natural dentitions are retained by periodical tissues that are
uniquely innervated and structured. In complete artificial occlusion all the
teeth are on bases seated on slippery tissues.
2. In natural dentitions the teeth receive individual pressures of occlusion and
can move independently.
3. Malocclusion of natural teeth may be uneventful for years.
4. Non vertical forces on natural teeth during function affect only the teeth
involved and are usually well tolerated, whereas in artificial teeth the effect
involved all of the teeth on the bases. It is usually traumatic to the
supporting structures.
5. Incising with the natural teeth does not affect the posterior teeth. Incising
with artificial teeth affects all of the teeth on the base.
6. In natural teeth the second molar is the favored area for masticating hard
foods.
7. In natural teeth bilateral balance is rarely found; If present it is considered
balancing side interference.
8. In natural teeth proprioception gives the neuromuscular system control
during function.

Fundamentals for Artificial occlusion

1. The smaller the area of the occlusal surface acting on food, the smaller will
be the crushing force on food transmitted to the supporting structures.
2. Vertical force applied to an inclined occlusal surface causes non vertical
force on the denture base.
3. Vertical force applied to a denture base supported by yielding tissue causes
the base to slide when the force is not centered on the base.
4. Vertical force applied outside (lateral to) the ridge crest creates tipping force
on the base.

Requirement of Complete Denture Occlusion

1. Stability of the denture & its occlusion when the mandible is in both
centric & eccentric relations.
2. Balanced for all eccentric contacts bilaterally for all eccentric mandibular
movements.
3. Unlocking [removing interference] the cusps mesiodistaly so that the
denture can settle down when there is ridge resorption.
 4. Control of horizontal forces by buccoligual cusp height reduction according
to the residual ridge resistance and inter ridge space.
5. Functional lever balance by favorable tooth to ridge crest position.
6. Cutting and shearing effeciancy of the occlusal surface (sharp cusps or
ridges)
7. Anterior clearance of teeth during mastication. Minimum occlusal contact
between the upper and lower teeth to reduce pressure during function
(linguilized occlusion).

Concepts of occlusion :
There is no scientific proof that any one concept of occlusion will satisfy all of the
requirements of complete denture in all patients also there is no scientific proof that
one tooth form is more efficient than other tooth forms.

1 - Spherical concept of occlusion; [monson] ; proposed that the lower teeth move
over the surface of upper teeth as over a surface of sphere with a diameter of 8 inches
The center of the sphere is located in the region of glabella .The surface of the sphere
passed through the glenoid fossa and along with the articulating eminences
According to this concept the anterioposterior and mesiodistal incline of artificial
teeth should be arranged in harmony with a spherical surface .

2 - Organic concept of occlusion : the aim of this concept is to relate the occlusal
surface of the teeth so that the teeth are in harmony with the muscles and joints
during function. The muscle and joint determine the mandibular position of
occlusion without any tooth guidance .So the muscle and joints should determine
the mandibular position of occlusion without tooth guidance .The mandibular
position of occlusion is terminal hinge position .In function the teeth should always
be passive to the paths of mandibular movement .

3 - Neutrocentric concept of occlusion : According to this concept the

anteroposterior plane of occlusion should be flat and parallel to the residual
alveolar ridge and not dictated by the horizontal condylar guidance, the form of
posterior teeth is devoid of cusp and there is no projection above or below the
occlusal plane .This concept is similar to the monoplane occlusion used to set non-
anatomical teeth.

Occlusion in Complete Denture

Types of Occlusion
1. Balanced occlusion
2. Monoplane occlusion
3. Lingualised occlusion
Balanced occlusion
Balanced occlusion in complete dentures can be defined as:
The simultaneous contacting of the maxillary and mandibular teeth on the right and
left side and in the posterior and anterior occlusal areas in centric and eccentric
positions, developed to lessen or limit tipping or rotating of the denture bases in
relation to the supporting structures

Bilateral Balanced Occlusion

This is a type of occlusion that is seen when a simultaneous contact occurs on both
sides in centric and eccentric positions. Bilateral balanced occlusion helps to
distribute the occlusal load evenly across the arch and therefore helps to improve
stability of the denture during centric, eccentric or parafunctional movements.

Protrusive balanced Occlusion

This type of balanced occlusion is present when mandible moves in a forward
direction and the occlusal contacts are smooth and simultaneous anteriorly and
posteriorly. There should be at least three points of contact in the occlusal plane.
Two located posteriorly and one anteriorly. Absent in natural dentition.

Lateral Balanced Occlusion

In lateral balance there will be a minimal simultaneous three point contact present
during lateral movement of mandible. This is absent in natural dentition. Teeth
should be arranged such that there is simultaneous tooth contact in balancing side
and working side.

Parts of the occlusal scheme

Occlusal scheme has three units
1). Incising units
2). Working units
3). Balancing units

Incising units : include all the four incisors.

A. These units should be sharp in order to cut efficiently..
B. The unit should not contact during mastication except during protrusion.
C. They should have as flat an incisal guidance as possible considering esthetics
and phonetics.
D. They should have horizontal overlap to allow for base settling without
interference.
E. They should contact only during protrusive incising function.
Working units : Include the canine s & the posterior teeth of the side towards
which the mandible moves.
A. They should be efficient in cutting and grinding.
B. They should have decreased buccal-lingual width to minimize the work
force directed to the denture foundation.
C. They should function as a group with simultaneous harmonious contacts at
the end of the chewing cycle and during eccentric excursions.
D. The occlusal load should be directed to the anterioposterior center of the
denture.
E. Plane should be parallel to mean foundation of the ridge.

Balancing Units : includes canines & posterior teeth opposing the working side.
A. They should contact on the second molars when the incising units contact in
function.
B. They should contact at the end of the chewing cycle when the working unit
contact.
C. They should have Smooth gliding contacts for lateral and protrusive
excursions..

In natural teeth when the mandible is protuded so that the incisal edges of the upper
& the lower teeth contact, there is a gap between the upper & lower posterior teeth,
this is termed as “Christensen’s phenomenon”.

Factors affecting balanced occlusion (Laws of Articulation) (Hanau quint)

There are five factors involved in eccentric occlusal balance in complete dentures.
1. Condylar guidance.
2. Incisal guidance.
3. The occlusal plane.
4. The compensatory curves.
5. Cusp angulation. Relative Cusp Height.

1 - Condyler Guidance :
The angle between the protrusive condyle path [down the eminence) and a
horizontal reference plane. It is definite anatomic feature that depends on the
inclination of the floor of the glenoid fossa. It should be determined on the patient
and set on the articulator by eccentric records so that the patients TMJ is in harmony
with the occlusion programmed on the articulator. The steeper the condylar
guidance, the more separation of the teeth that will occur when the mandible moves
in a protrusive or lateral movement (Christensen’s phenomenon).
If the condylar angle (angle between the path of condyle and the Frankfort
horizontal plane) is steep, it's difficult to produce balance occlusion because when
the condyle travel downward and forward large space is created posteriorly when
the anterior teeth are edge to edge, So compensation should be made by altering the
other factors to obtain the desired balance. It is the only factor which can be recorded
from the patient, the dentist has no control over the condylar inclination and cannot
change or modify it to fit particular occlusion.

Components of condylar guidance

Horizontal condylar guidance: guides the forward movement for protrusive
balance.
Lateral condylar guidance: guides the sideward or lateral movement of the
mandible.

2 - Incisal Guidance
Defined as : The influence of the contacting surfaces of the mandibular and
maxillary anterior teeth on mandibular movements. During protrusive movements
mandibular teeth move downward & forward called as incisal guidance. Incisal
guidance influenced by esthetic, phonetic, ridge relations, arch shape, and inter
ridge space.
If the incisal guidance is steep, steep cusps or occlusal plane or steep compensatory
curve is needed to balance occlusion. It is determined by the dentist & customized
during anterior try-in desired overjet &overbite are determined. If overjet is
increased, the inclination of incisal guidance is decreased. Incisal guide angle
should be acute with suitable vertical overlap and horizontal overlap to achieve
balanced occlusion.

Component of incisal guidance :

Horizontal component (overjet)
Vertical component (overbite).

3 - Plane of Occlusion or Occlusal Plane

Defined as “An imaginary surface which is related anatomically to the cranium and
which theoretically touches the incisal edges of the incisors & the tips of the
occluding surfaces of posterior teeth. It represents the mean curvature of the surface.

The occlusal plane is established in the anterior by the height of the lower cuspid,
which is nearly coincident with the commissure of the mouth, and in the posterior,
by the height of the retromolar pad. It is also related to the ala-tragus line. It should
be nearly parallel to the ridges, raising the occlusal plane in the posterior will
minimize the vertical separation of the teeth in eccentric movement and aid in
balancing denture occlusion. Tilting of the plane >10o is not advisable.
4 - Compensating Curve
“The anterioposterior and lateral curvatures in the alignment of the occluding
surfaces and incisal edges of artificial teeth which are used to develop balanced
occlusion”. Determined by inclination of posterior teeth and their vertical
relationship to occlusal plane. There are two types of curves :
a. Anterioposterior compensating curve- Curve of spee
Anatomic curvature of the occlusal alignment of teeth beginning at the tip of lower
canine and following the buccal cusps of the natural premolars and the molars,
continuing to the anterior border of the ramus” as described by Graf Von Spee.
When the patient moves his mandible forward, the posterior teeth set on this curve
will continue to remain in contact. Thus avoiding disocclusion.
b. Lateral compensating curves Compensating curve for Monson curve
The curve of occlusion in which each cusp and incisal edge touches to a segment of
the sphere of 8” in diameter with its center at glabella”

5 - Cuspal Angulation
“Angle made by the average slope of a cusp with the cuspal plane measured
mesiodistally or buccolingually”. It is an important factor that modify the effect of
plane of occlusion & the compensating curves. Mesiodistal cusps are reduced to
prevent the locking of cusps.In shallow bite cases- cuspal angle should be reduced
to balance the incisal guidance. In Deep bite cases with steep incisal guidance, the
jaw separation is more during protrusion .Teeth with high cuspal inclines are
required for these cases

Interaction of the five factors

Of the four that he (the dentist) can control two of them (the incisal guidance and
the plane of occlusion) can be altered only a slight amount because of esthetic and
physiologic factors.
The important working factors for the dentist to manipulate are the compensating
curve and the inclinations of cusp on the occlusal surfaces of the teeth.

Types of posterior teeth

1. An anatomic tooth is one that is designed to simulate the natural tooth form. The
standard anatomic tooth has inclines of approximately 33 degree or more.

When the cusp incline is less steep than the conventional anatomic tooth of 33
degree it can be classified as a modified or semianatomic tooth. It can be
considered basically anatomic and will articulate in three dimensions.

2. A non-anatomic : Tooth is flat and has no cusp heights to interdigitate with an

opposing tooth and has sulci to enhance its comminuting effect on food. They
articulate in only two dimensions.
Selection of Posterior Tooth Forms
Factors affecting the selection of posterior teeth forms:
1. The capacity of the ridge to receive and resist forces of mastication.
2. Inter ridge distance.
3. Ridge relationship
4. Esthetics
5. Patients age and neuromuscular coordination

Requirements of balanced occlusion :

1. All the teeth on the working side should glide evenly against the opposing
teeth.
2. No single tooth should produce any interference or disocclusion of the other
teeth.
3. There should be contacts in the balancing side but they should not interfere
with the smooth gliding movements of the working side.
4. There should be simultmeous contact during protrusion.

General considerations for balanced occlusion :

1. The wider and larger the ridge & the teeth closer to the ridge, the greater the
lever balance.
2. Conversely, the smaller and narrower the ridge and the farther the teeth from
the ridge, the poorer the lever balance.
3. Wider the ridge & narrower the teeth buccolingually, greater the balance.
4. The more lingual (inside) the teeth are placed in relation to the ridge crest,
the greater the balance.
5. The more centered the force of occlusion anteriopsosteriorly, the greater the
stability of the base.
6. Previous denture wearing experience.

Advantages of Balanced Occlusion

1. Distribution of load
2. Stability
3. Reduced trauma
4. Functional movement
5. Efficiency
6. Comfort.

Disadvantages of Balanced Occlusion

1. More occlusal disharmony during setting of teeth and difficult to correct by
djustment.
2. Stable bases and precise jaw closer is required.
3. Increased horizontal forces due to the presence of incline plane of the cups.
4. Difficult to adapt in jaw relation other than class l.
Evaluation
There is an ideas questioning the validity of balanced occlusion in full denture from
the point of view that:
✓ During rest position teeth are not in contact.
✓ During chewing the food separating the teeth.
✓ So balanced articulation appears to be more important when no food in the
mouth so it may be of value in nonfunctional activities when the patient is
bruxing.

Significance :
Normal individual makes masticatory tooth contact only for 10 minutes in one day
compared to 4hrs of total tooth contact during other functions. So, for these 4hrs of
tooth contact, balanced occlusion is important to main denture stability.
Prime gave the concept of “ENTER BOLUS EXIT BALANCE” which implies
that introduction of food on one side will prevent the teeth of opposite side from
contacting and hence occlusal balance is impossible during mastication.

However Sheppard (1964) later gave the concept of ENTER BOLUS ENTER
BALANCE according to which even while chewing, the teeth cut through the bolus
and come in contact with each other, for few fractions of a second. Hence the
stability of the denture is maintained during various movements of mandible during
chewing.

Normal individual makes masticatory tooth contact only for 10 mines in one day
compared to 4hrs of total tooth contact during other functions. So, for these 4hrs of
tooth contact, balanced occlusion is important to maintain denture stability
It improves the stability of denture, reduce resorption of the residual ridge and
soreness and improve oral comfort & well-being of the patient

Balanced Occlusion with Non Anatomic or Flat Teeth

Balanced occlusion with cuspless teeth can be achieved by several ways:
1- Zero-degree teeth with inclination of the lower second molar.

Tilting the second molar

2- Zero-degree teeth with balancing ramps placed posterior to the most distal molar.

3. Zero-degree teeth set to steep compensatory.

Monoplane or None balanced Articulation

It is also called neutrocentric occlusion .In this type of occlusion
✓ This concept of occlusion assumes that the anterior-posterior plane of
occlusion should be parallel to the denture foundation area and not dictated
by condylar inclination.
✓ The plane of occlusion is completely flat and level. There is no curve of
Wilson or curve of Spee (no compensating curve) incorporated into the set
up.
✓ There is no vertical overlap of the anterior teeth.
✓ When setting these teeth the horizontal and lateral condylar guidances should
be set at zero.

✓ non-anatomical cuspless teeth (zero degree) are used.

✓ The occlusal plane flat and parallel to the upper and lower residual ridges.
✓ No compensating curves are created
✓ The teeth are set flat with no medial or lateral inclination, elimination of
inclined plane therefore more stability,
✓ The patient is instructed to avoid incising with anterior teeth to avoid
displacement of the denture.
✓ The teeth are arranged without vertical overlap.
✓ The buccolingual width of the teeth is reduced.
✓ The number of teeth is reduced to direct the forces in the molar and bicuspid
area of support to avoid placing a tooth on the ridge incline in the second
molar area.
✓ With this concept of occlusion, there is no attempt to eliminate deflective
occlusal contacts in lateral or protrusive excursions, the condylar inclinations
on the articular are set at 0 degrees.
When the foundation tissues is compromised, i.e. is severely resorbed ridge, knife-
edge, thin wiry ridge or one that covered with thick movable flabby tissues,
favorable control of occlusal forces can be utilized by the use of non-anatomic teeth
arranged following the monoplane occlusion concept

Indications of the monoplane occlusion (neutrocentric concept)

1. Flat ridge(s).
2. Class II jaw relations.
3. Class III jaw relations.
4. Maxillofacial patients.
5. Handicapped patients.
6. Cross bite.
7. Doubtful or without any perfect centric relation records.

Advantages of Monoplan (Neutrocentric) Occlusion

1. simple and less time consuming.
2. less precise jaw relation records.
3. lateral forces are reduced by eliminating (neutralizing) cuspal inclines.
4. simpler and easier occlusal adjustments.
5. occlusion is not locked .
6. good for patients with Class II (Retrognathic), Class III (Prognathic) and
crossbite ridge relations.
7. for the geriatric patient

Disadvantages of Neutrocentric Occlusion

1. least esthetic
2. Poor bolus penetration
3. Cannot be balanced in eccentric excursions.

Lingualized Occlusion
The lingualized occlusion concept is a variation of the bilaterally balanced occlusion
concept. The premolars and molars are arranged so that only the lingual cusps of
the upper posterior teeth make contact with the central fossae of the lower posterior
teeth. This type of occlusion involves :
✓ The use of a large upper palatal cusp against wide lower central fossa,
✓ The buccal cups of the upper and lower teeth do not contact each other.
✓ It is identified by the occlusal contacts of the maxillary lingual cusps of the
posterior teeth initially with occlusal surfaces of the mandibular teeth in
maximum intercuspitation, and
✓ The continuous contacts of the lingual cups with mandibular teeth during
various movements of the mandible.
 ✓ This concept also can be considered as a balanced articulation, the teeth
are anatomical or semi anatomical teeth with some modification :

1- Sharp maxillary lingual cusp in the posterior teeth opposing a widened central
fosse on the occlusal surface of the mandibular antagonists in maximum
intercuspitation and the buccul cusp is out of occlusion.

2- The mandibular teeth have a reduced facial and lingual cusps and widened central
fosse.

Advantages of Lingualized Occlusion

1. Esthetics
2. Better penetration of the food bolus
3. Decrease of vertical and lateral forces
4. Simpler technique. less precise CR records
5. Useful in a wide variety of patient
6. Added stability is gained during parafunctional movements with a balanced
occlusion.
7. Easier to adjust occlusion
8. May be used in Class II, Class III and crossbite
9. may be used to incorporate many of the advantages but few of the
disadvantages of other occlusal schemes.

Characteristic Anatomic Lingualized Neutrocentric

1. Denture stability during + + -
parafunctional movement.

2. Simpler technique, less precise - + +

records
3. Decreased lateral forces - + +
4. Ease of adjustment - + +
5. Good for Class II and Class III - + +
jaw relation.
6. Better esthetics + + -
7. Ease of penetration + + -
(decreased vertical stress
8. Good stability, forces centralized - + +
and neutralized
Factors affecting the selection of the occlusion concept
1. Age of the patient
2. Condition of oral health (soft tissue and residual ridge).
3. Social status and demand of the patient esthetic and function.
4. Skill and philosophy of the dentist in occlusion concept, the dentist must
really on clinical skill and experience when selecting an occlusal scheme for
the patient.
5. The availability of the material and dental laboratory efficiency.

Factors effecting accurate start for denture occlusion

1. Accurate measurement of vertical dimension of occlusion
2. Accurate recording of centric jaw relation
These two factors depend on skill of the dentist and clinical judgment
3. Properly constructed bit rim (strong, polished, smooth, round equal thickness
border resemble finished denture).

In general all complete denture occlusions have certain comman factors in their
design for example most occlusion require that the teeth in the upper and lower
dentures contacts in centric occlusion when the mandible is in centric jaw relation
to the maxilla. Tooth contacts in this relationship are established to distribute
stresses evenly over the entire denture base supporting area to preserve the
supporting structure that must carry the load during function.

Conclusion
✓ There is no one ideal occlusal scheme to fit all the variety of patient situations
and requirements.
✓ There is not clear cut research in occlusion to support one occlusal scheme
over another.
 Insertion of the Complete Denture
The overall objective when fitting complete dentures is to ensure that the patient is
given the best possible start with the new prostheses. This may be achieved by
checking that :
✓ There is no pain when the dentures are inserted and removed from the
mouth, or when the teeth are brought into occlusal contact.
✓ The teeth meet evenly.
✓ The dentures stay in place when inserted and during normal opening of the
mouth.
✓ The patient understands :
➢ How to control the dentures.
➢ What to expect of them.
➢ How to clean them.
The patient should have been instructed to keep any previous dentures out of the
mouth for 12-24 hours immediately before the insertion appointment this is essential
because the new dentures should be seated on healthy and undistorted tissue ,this is
also important before the final impression.

Checking the finished denture :

A - Checking the polished surface and peripheries of the denture which should
be rounded and polished. Checking the polished surface it should be well polished
smooth highly lustered free from porosity because it will decrease the denture
strength and breaks easily also porosity will act as area of food and bacterial
stagnation.

B - Assessment of the impression surface

Inspection of the tissue surface of the denture by passing the little finger on the
tissue surface of the denture and detect any rough or sharp edges, air bubble in the
cast may lead to a sharp projection on the tissue surface of the finished denture after
processing.
Before inserting the new dentures for the first time the impression surface must be
carefully checked for any potential causes of pain. If found these must be eliminated
to ensure patient comfort and also to avoid the adoption of abnormal paths of closure
of the mandible. Such abnormal paths are followed to avoid occlusal pressure at the
site of discomfort.

The common causes of pain arising from the impression surface of a denture
are :
1. An undercut flange which traumatizes the mucosa when the denture is inserted
and removed. The part of the flange causing discomfort is identified by direct
observation and by the use of a disclosing material such as soft wax. A thin, even
layer of the disclosing material is applied to the suspect area and the denture is
inserted and removed. The precise location of undercut producing the pain is shown
up as an area of acrylic from which the wax has been displaced.

2. Acrylic spicules : These are produced by acrylic resin being processed into
indentations on the cast which are the reproductions of surface irregularities in the
mucosa. These spicules, together with the acrylic nodules mentioned below, can be
detected by observation of the dried denture surface and by passing a gauze napkin
or cotton wool roll over the surface so that the threads catch on the offending areas.
3. Acrylic nodules : Nodules occur commonly and are the result of acrylic resin
being processed into small air blows in the cast.
4. Sharp acrylic margins : Sharp edges are associated with the presence of a tin-
foil relief on the cast. The relief area if present, should be rounded, especially in the
area of the midpalatine suture or torus palatinus.

C - Checking of retention : which is the quality of the denture that resists

dislodgement in a vertical direction. This quality is checked by putting our finger
on the central incisors of the denture and try to dislodge the denture upward and
downword.

D - Checking the stability : which is the resistance to denture movement against

horizontal forces. It is checked by pressing on the premolars area, if there is any
rocking when pressing on one side more than the other this is an indication for the
lack of stability.
E - Checking the esthetic and facial contour : As the complete denture support
the overlying muscles and facial tissues of an edentulous patient, it should restore
not distort the muscle support of the face.
This natural appearance of the complete denture is obtained by :
1- Proper positioning of teeth.
2- Proper contouring of denture flanges.
3- Correct height, thickness and shape of the flanges.

F- Assessment of the occlusal surface

The occlusion of the dentures is checked once completion of the initial adjustments
mentioned above have ensured that :
✓ Each denture can be inserted and removed from the mouth without
discomfort.
✓ Firm pressure can be applied to the occlusal surface without eliciting pain.
A- The centric occlusion of the artificial teeth should be coincide with the centric
jaw relation.

B- Checking the vertical dimension by measuring the distance between two points
one above the mouth and the other on the chin in physiological rest position and
reducing 2-4mm will be the correct measurement of centric occlusion also asking
the patient to speak and count from 1-10 as the phonetic is affected greatly by the
space between the teeth so all the letters should be pronounced correctly, the facial
appearance of the patient are checked. An increase or a decrease of the vertical
dimension should be corrected if an increase of 2mm selective grinding may solve
the problem while with reduction in V.D. one of the dentures should be repeated.

Sources of errors in finished complete denture :

1. Technical errors (errors in judgment made by the dentist) ex. centric off.
2. Technical errors developed in the laboratory, ex. broken cast
3. Inherent deficiencies of the material used in the construction of the denture,
ex. expired acrylic.

Clinical errors
Incorrect registration of the centric jaw relation, may be due to difference in
compressibility between the soft tissue and that of the stone cast. This is true
specially when the record bases are not correctly and accurately fit on the ridges.
This error may appear as a premature contact in the finished denture.

Errors in registering maxillomandibular relation may be the result of one or

more factors :
A. Record bases that do not fit accurately.
B. A shifting of the record bases over displaceable tissues
C. Excessive pressure exerted by the patient during the registering of
maxillomandibular relations.
D. Unequal distribution of stress during the registering of maxillomandibular
relations.
E. Record bases placed on soft tissues that have been deformed by ill- fitting
dentures.
F. Patients not registering centric relation because of systemic factors, such as
muscle spasm, abnormalities of the tempromandibular joints, and impairment
of muscle tonus.
Laboratory Occlusal Errors
Causes of errors
Poor laboratory technique can result in the movement of individual teeth or in an
increase in occlusal vertical dimension of the denture.

1. If the acrylic resin has reached an advanced dough stage and thus offers increased
resistance to closure of the flask. Excessive pressure will then be needed to bring
the two halves of the flask together.
2. Normal packing pressures breaking the investing plaster and causing movement
of the teeth when the layer of investing plaster is weakened as a result of the use of
an incorrect powder/water ratio.
3. Excessive packing pressures resulting in the artificial teeth being forced into the
investing plaster.
4. Separation of the two halves of the flask by a layer of excess resin, this results in
an increased occlusal vertical dimension of the denture.

In spite of taking all due precautions to prevent the errors just described, small
occlusal inaccuracies invariably occur.
During insertion of the dentures, It is important to start first with the lower denture
because it is smaller and cause less gagging reflex. So it is psychologically more
acceptable by the patient.
We have to check the retention, stability and the peripheries of the denture . if there
is any discomfort or pain , it should be relieved first before checking the occlusion
otherwise the patient will never give you proper centric occlusion.

Secondly we have to check the upper and lower dentures together :

Methods to check premature contact :
Is done by a method called selective grinding which is defined as modification of
occlusal surfaces of the teeth by grinding at selected places, this procedure done to
correct minor errors and to establish proper smooth occlusion during centric and
eccentric relations. The portions of the teeth maintaining centric occlusion will not
be destroyed. There is 2 types of the selective grinding:

Intraoral selective grinding : this is done by using

1 - The articulating paper : it is an acceptable method but has many
disadvantages:
A. Cusps who are not in premature contact may be colored also.
B. don't record the fossa.
C. Difficult manipulation, as we have to put the articulating paper
simultaneously on both sides otherwise it lead to inaccurate record.
2 - Occlusal indicator wax : horse –shoe shaped wax placed on the occlusal surface
of the teeth, so any premature contact result in perforation of the wax.

Disadvantages of intraoral selective grinding :

1. Because of the presence of compressible tissue, we may have incorrect
registration.
2. presence of Saliva may distort the color of the articulating paper.
3. Difficult procedure in case of severely resorbed ridges (very old patient).
4. Cannot be used in case of gross changes in occlusion more than 3 mm space.
5. Psychological point of view since the patient get better if the denture is given
to him without any correction.

Extraoral selective grinding : Some dentists prefer to do corrections of occlusal

errors in the clinic at the time of denture insertion, this is also correct, but it might
take time and some patients may think that these errors could be due to work,
therefore it is advisable to do correction in the laboratory on the articulator, and if
further adjustments are required, dentist can do it in the clinic.
It is done just after deflasking and before polishing .this is when we use a
semiadjustable or 3 plane articulator, so we remount the casts with the dentures and
detect any processing changes in occlusion by using of articulating paper.
We should check the centric occlusion, working and balancing occlusion and
protrusive movement.

Rules of selective grinding :

1. Vertical dimension is maintained by occlusion of the functional cusps
which are upper palatal cusps and lower buccal cusps so never grind from
them.
2. if it is necessary, we can grind from the inclines of the cusps.
3. We have to deepen the fossa rather than removing the cusp unless it
interfere with the balancing and working occlusion.
4. For protrusive movement, we grind from the mesial and distal surface of the
artificial teeth.
Occlusal Errors in Centric Occlusion and their Correction
A. Premature contacts, holding remaining teeth out of occlusion, i.ea any pair of
opposing teeth can be too long and hold other teeth out of contact.
Solution: Fossae of the teeth in question are deepened. The cusp tips should not be
shortened. (rule 3).

B. The cusp tips of opposing teeth appear to be nearly tip to tip.

Solution: Grind on the inclines so as to move the upper cusp inclines buccally and
the lower cusp inclines lingually. In so doing the central fossae are made broader,
the lingual cusp of the upper teeth narrowed, and the buccal cusp of the lower teeth
are also narrowed.
The cusp tips should not be shortened. (rule 2).

C. Upper teeth too buccal in relation to the lower.

Solution: Broaden the central fossae, and the buccal cusps of the lower teeth are
moved buccally by broadening the central fossae. The cusp tips should not be
shortened.

Balance in working side

Most occlusal discrepancies found on the working side can be corrected by reducing
premature contacts on the buccal cusps of the maxillary teeth and the lingual cusps
of the mandibular posterior teeth (non-centric holding cusps) known as the rule of
BULL (Buccals of the Uppers and Linguals of the Lowers).
Occlusal Errors and corrections on working side :
a) If lingual cusp made contact but the buccal is not, begin grinding by removing
any contacts that are present on the inclines of the lower lingual cusps as shown in
the diagram.

b)if buccal cusp made contact but the lingual is not, the upper buccal cusp is shorten.

c) Both of upper buccal cusp and the lower Lingual cusp are too long. For correction
the cusp's length must be reduced.

d) No contact between teeth on the working side, the cause of this error, is excessive
contact on the balancing side.

Balance in balancing side

Bull rule does not work. Reduce interceptive cusp.
Slide the articulator through working again and
observe the contacts on the balancing side.

Occlusal Errors and corrections on balancing side :

a) Premature balancing side contacts are reduced by grinding on the lingual inclines
of the lower buccal cusps.

b) If there are no balancing side contacts, the working side contacts should be
reduced until balancing side contacts appear. Continue until working and balancing
contacts are about equal. Repeat the same sequence on the opposite side
Balance in protrusive
a) This may require grinding of the anterior teeth (We grind the labial surface of the
lower teeth and lingual portion of the upper anterior teeth,
this grinding should be done carefully to prevent any damaging
to the shape or form of the teeth and destroy esthetic requirements)

b) Equilibration in protrusive movement also require selective

reduction of the posterior teeth (distal inclines of upper buccal
cusps and mesial inclines of the lingual cusp of the lower teeth)
until free smooth balanced protrusive movement is resulted.

Upon completion of the selective grinding, the articulator should slide easily from
working to balancing to protrusive side and back, this indicates that a perfect
balanced occlusion is established, otherwise further corrections should be done.

Instructions to Denture Patients

A. What To Expect From Your New Dentures
1. You must learn to manipulate your new dentures. Most patients require at
least three weeks to learn to use new dentures, and some patients require more
time.

2. Dentures are not as efficient as natural teeth so you should not expect to chew
as well with dentures as with your natural teeth. Dentures are better than no
teeth at all. Start with small bites of easy to manage foods. Do not try to bite
with your front teeth. Use the area of the canine teeth to bite foods, but it is
even better to cut the food into small pieces before attempting to chew.

3. Speaking will feel awkward for a while. Hardworking practice usually

enables a patient with new dentures to speak clearly within a few days.

B. Adjustments

1. You must return to your dentist for follow-up treatment after the dentures
have been inserted. In nearly ever) instance, it is necessary to make some
minor adjtistments to the denture.
2. Most patients must make some adjustments in their attitude and habits in
order to wear dentures successfully.
3. If you develop soreness, do not become alarmed. Call your dentist for an
appointment. Do not expect soreness to go away by itself.
4. If you are unable to reach your dentist during weekends or holidays, remove
your dentures to prevent excess tissue damage.
C. Cleaning
1. Your dentures and supporting ridges must be cleaned carefully after each
meal. "Denture breath" is a result of dirty dentures.
2. Clean your gum with a soft brush.
3. Clean your dentures with liquid detergent, and gently brush with a soft
denture brush. Many types of toothpaste are too abrasive to use on the
polished denture surface.
4. Soak your dentures at night in a denture cleaner or a water mouth wash
solution.
5. Always keep your dentures wet when not wearing them to prevent warping.

D. Your Oral Health

1. Nature did not intend for people to wear dentures. You must, therefore, be
very careful of the supporting tissue.
2. In addition to keeping the dentures meticulously clean, you must rest the
tissues at least eight hour a day. Most patients find it convenient to leave their
dentures out at night.
3. The tissues that support your dentures are constantly changing. This will
result in denture looseness. However, looseness can result from many causes
with time, your dentures will tieed either refitting or replacement. at any
event, you should call your dentist for an appointment when you notice
excessive looseness.
4. Annual examinations of the supporting tissue for abnormalities and to assess
the function and fit of the denture are important for your overall dental health.

Post Insertion Denture Problems

Post-insertion treatment is that phase of the complete denture procedure that
involves any necessary alteration of the dentures, tissue treatment and patient
education, to provide patients with comfortable dentures that provide maximum
function without irritation to the oral tissues and further educate the patient to
successfully master them.

Ideally, the first post-insertion visits should be approximately 24 hours after

insertion of the dentures. In this situation, the patient is instructed not to remove the
dentures during this period. If the patient cannot be seen for several days after the
first insertion, he should be instructed to remove the dentures if there is any severe
discomfort. However, he should reinsert the dentures for at least 6-8 hours before
the next appointment.
At the first post-insertion appointment, the patient is asked to relate his experience.
The operator should then remove the dentures and examine the tissues, especially
those areas noted by the patient. Observe for inflamed or ulcerated areas and areas
painful to palpation. After correcting any problems the patient should be given an
appointment at the 72-hour post insertion point (48 hours after first appointment).
Successive visits should be encouraged at the discretion of the patient until all
problems are corrected as determined by the dentist

For many patients, three adjustments are sufficient to make them comfortable with
their new denture.
Patients must understand that even the best dentures are only about 30% as efficient
as natural teeth. It is the patient's responsibility to learn how to use them efficiently
within their limits of performance.

The usual areas liable for ulceration are :

In the upper jaw
1. Hamular notch.
2. Post-dam area.
3. Labial frenum.
Ulceration in the hamular notch and post dam area causes sore throat.
In the lower jaw
1. Lingual pouches of the mylohyoid region because of the presence of
muscles & undercuts. The patient may complains from sore throat.
2. Labial frenum.
3. Sublingual region since it is a movable area.

Classification of Post-Insertion Denture problems :

I. Complaints about comfort of the denture :
1. Sore spots
2. Burning sensation
3. Redness
4. Pain in TMJ
5. Tongue & cheek biting
6. Swallowing & sore throat
7. Nausea & gagging
8. Clicking of teeth
9. Deafness
10.Fatigue of the muscles of mastication.
II. Complaints about function of the denture :
1. Poor fit.
2. Instability.

III. Complaints about esthetics :

1. Fullness under the nose
2. Depressed philtrum or naso-labial sulcus
3. Upper lip sunken in
4. Too much of teeth exposed
5. Artificial look

IV. Complaints about phonetics :

1. Whistle on “S” sounds
2. Lisp on “S” sounds
3. Indistinct “TH” & “T” sounds
4. “T sound like “TH”
5. “F” & “V” sounds indistinct

I. Complaints about comfort of the denture

1. Sore spot
1- Sore spots in the vestibule.
a- Overextension .Adjust denture (disclosing wax).
b- Unpolished or sharp edge. Polish denture borders.
2- Sore spots posterior limit of the maxillary denture
a- Posterior palatal seal too deep. Identify area with pressure indicating paste
and relief high pressure area.
b- Sharp posterior palatal seal. Round off sharp areas.
c- Overextension. Adjust peripheral extension
3- Single sore spots over ridge.
a- High occlusion in that area Check with articulating paper& adjust the
occlusion.
b- Bubbles of acrylic Inspect the denture under good light to detect surface
roughness then remove & polish lightly.
4- Soreness under labial flange
a- Excessive overbite Reseat maxillary anterior teeth.
b- Habit-mastication in protrusive relation .Train the patient to masticate in
centric relation
c- Overextended labial flange. Adjust peripheral extension.

5- Soreness under lingual flange of mandibular denture

a- CO not on harmony with CR (drives mandibular denture forward) If only
slight, if can be corrected, record, remounting & selective grinding
b- Overextended lingual flange Apply pressure indicating paste to denture
periphery, adjust peripheral extension.

6- Generalized soreness over the alveolar ridge.

a- Excessive vertical dimension.If the occlusal plane of the upper is judged to
be correct, make a new lower denture to the decreased vertical dimension,
otherwise, new upper and lower dentures.
b- Inaccurate denture base. Dentures can be rebased if the occlusion is adequate.

2. Burning sensation :
a- Anterior hard palate & anterior alveolar ridge Pressure over the anterior
palatine foramen. Relief over the foramen.
b- Premolar to molar area, Pressure on the posterior palatine foramen, Relief
area over the foramen.
c- Lower anterior ridge, Pressure on the mental foramen. Relief over the
foramen.

3. Redness
a- Fiery redness of all tissues contacted by denture, including tongue & cheeks.
Denture base allergy (uncommon) Remake the denture & use metallic
denture base.
b- Redness of the denture bearing tissues. Ill-fitting denture Remake or rebase
the denture
c- Avitaminois. Employ vitamin therapy regime.

4. Pain in TMJ
1. Insufficient vertical dimension of occlusion. Increase vertical dimension.
2. CO not in harmony with CR. Correct occlusion by selective grinding
3. Arthritis. Treat with analgesics.
5. Tongue and cheeck biting
1. Posterior teeth edge to edge (insufficient horizontal overlap). Re-contour
buccal surface of mandibular molars & premolars to increase the horizontal
overlap
2. Over-closure. Restore the vertical dimension
3. Changes in the occlusal plane leading to cheek & tongue biting. New denture
with proper occlusal height
4. Posterior teeth too far buccal leading to cheek biting. Re-contour buccal
surface of the upper molars.
5. Posterior teeth too far lingual (reduction of tongue space) leading to tongue
biting. Re-establish adequate tongue space.

6. Swallowing & sore throat

A. Maxillary denture
1- Over extension of posterior border. Adjust posterior border extension.
2- Too thick posterior border. Thin posterior border.
B. Mandibular denture
1- Overextension of the posterior lingual flange area.
2- Too thick lingual posterior flanges.
Reduce thickness or adjust posterior lingual flange area.
C. Insufficient vertical dimension of occlusion. --- Increase vertical dimension.
D. Excessive vertical dimension of occlusion --- Reduce vertical dimension.
E. Posterior teeth set inside the ridge (tongue is crowded). Re-set teeth in correct
position.

7. Nausea and gagging

1- Immediately upon denture placement.
A- Maxillary denture:
1. Overextension
2. Too thick posterior border.Adjust denture or thin posterior border
B- Mandibular denture : Distolingual Flange too thick. Reduce thickness of disto-
lingual flange.
C- Psychogenic factors.

2- Delayed (2 weeks to months) after denture placement.

A. Incomplete border seal allowing saliva under the denture Improve border
seal.
B. Faulty occlusion causing denture to loosen & allowing saliva under the
denture. Correct occlusion.
8. Clicking of teeth
The possible causes :
A. Increased vertical dimension
B. Cuspal interference.
C. Poor retention of the lower denture
D. Using porcelain teeth

9. Fatigue of the muscles of mastication

1. Excessive vertical dimension of occlusion. Reduce vertical dimension.
2. Insufficient vertical dimension of occlusion. Increase vertical dimension.

10. Deafness
Over closure of vertical dimension. Increase vertical dimension.

II. Complaints about function of the denture

1- Loose denture (poor retention)
A. Inadequate border seal. Test with green stick. Add to or reline denture.
B. Overextension of denture flange.
C. Excessively thick denture flange. Reduce and raconteur to permit normal
function.
D. Underextention of denture flange.
E. Inadequate post dam (for the upper denture). Test with green stick. Add to or
reline denture.
F. Perforated denture base. Repair by addition.
G. Flabby tissues displaced when making impression.
H. Dehydration of tissues due to lack of saliva.

2- Unstable denture
A. Under-extension of denture. Test with green stick. Add to or reline denture.
B. Excessively increased vertical dimension. Reduce or reset teeth or remake
denture.
C. Improper placement of occlusal plane. Remake denture.
D. Errors in occlusion.

3- General feeling dentures are not right, but with absence of pain
1. Patient has high pain tolerance.
2. Mal-occlusion
3. Centric occlusion is not in harmony with centric relation
4. Incorrect vertical relation of occlusion
III. Complaints about esthetics
1. Fullness under nose. Labial flange of upper too long or too thick. Reduce length
or thickness of labial flange.
2. Depressed philtrum and/or nasolabial sulcus. - Labial flange too short, too thin.
3. Upper lip sunken in. upper anterior teeth too far lingual.
4. Shows too much of the teeth
a- Vertical dimension too great
b- Incisal plane too low
5. Artificial look
a- Technique set-up, the teeth are in too regular alignment (individualize by
rotating and shortening some teeth)
b- All teeth same shade.
c- Lack of grinding incisal edges and angles. Grind incisal edges & angles to
give a more individualized appearance.
d- Lack of individualizing gingival contours and color of denture base

IV. Complaints about phonetics

1. Whistles on “S” sounds. Too narrow an air space on the anterior part of the
palate.
2. Lisp on “S” sounds. Too broad and air space on the anterior part of the palate
3. “Th” and “T” sounds indistinct.-Inadequate inter-occlusal distant
4. “T” sounds like “Th”. - Upper anterior teeth too far lingual
5. “F” and “V” sounds indistinct. Improper position of upper anterior teeth
either vertically or horizontally.
Oral Mucosal Lesions Induced by Removable Dentures
Lesions of the oral mucosa associated with the wearing of removable dentures may
represent acute or chronic reactions to microbial denture plaque, a reaction to
constituents of the denture base material or a mechanical denture injury.

Causes of Mucosal Irritation

1. Mechanical irritation by denture
2. Accumulation of microbial plaque on denture
3. Toxic or allergic reaction to constituents of denture material
Local irritation of mucosa, increase mucosal permeability to allergens or microbial
antigen.

Types of these lesions :

1. Denture stomatitis : also termed :
✓ Denture sore mouth
✓ Denture- induced stomatitis
✓ Chronic atrophic candidiasis
✓ Candida-associated denture induced stomatitis
✓ Denture-associated erythematous stomatitis

Is a common condition where mild inflammation and redness of the oral mucous
membrane occurs beneath a denture. In about 90% of cases, Candida species are
involved. This is normally a harmless component of the oral microbiota in many
people.

It is usually painless and asymptomatic. The appearance of the involved mucosa is

erythematous (red) and edematous (swollen).

Classification
The Newton classification divides denture-related stomatitis into three types based
on severity. Type one may represent an early stage of the condition, whilst type two
is the most common and type three is uncommon.

Type 1 - Localized inflammation or pinpoint hyperemia

Type 2 - More diffuse erythema (redness) involving part or all of the mucosa which
is covered by the denture

Type 3 - Inflammatory nodular/papillary hyperplasia usually on the central part of

hard palate and the alveolar ridge. This type often is seen in association with type 1
or type 2.
This condition is multifactorial, the causes include :
1. Ill fitted denture.
2. Disharmonious occlusion.
3. Nutritional deficiencies.
4. Poor oral hygiene.
5. Candidal infection.
6. Wearing the denture continuously.

2. Angular Cheilitis
Angular cheilitis also called (angular stomatitis) is inflammation of one or both of
the corners (angles) of the mouth. There are many possible causes, including:
✓ Nutritional deficiencies (iron, B vitamins, folate)
✓ Contact allergy
✓ Infection (Candida albicans, Staphylococcus aureus or β-hemolytic
streptococci, often with overclosure of the mouth and associated with
denture-related stomatitis.

3. Flabby ridge
Also called alveolar fibrosis i.e. removable and extremely resilient alveolar ridge,
is due to replacement of bone by fibrous tissue, in a generalized and localized form,
it is seen most commonly in the anterior part of the maxilla, particularly when there
are remaining anterior teeth in the mandible, flabby ridges provide poor support for
the denture, so the tissue should be removed surgically to improve the stability of
the denture and to minimize alveolar ridge resorption.

4. Denture irritation hyperplasia

A common tissue reaction to ill-fitting denture is the occurrence of tissue
hyperplasia of the mucosa in contact with denture border. They includes :

A- Epulis fissuratum : usually asymptomatic and clinically appear as numerous

folds or highly vascular tissue in the labial or buccal vestibule and ulceration might
occur at the mucobuccal fold commonly in the maxillary arch. Usually it occur as
a result of reduction of the residual alveolar ridge especially in case of immediate
denture when bone loss is rapid and the patient fail to make a new denture or relining
within 6 months and due to the overextended flanges of the denture.
Its treatment include conservative or surgical treatments. The conservative
treatment include :
1- Using of tissue conditioning material with shortening & smoothening the
overextended denture border.
2- Construction of a new denture with relief of pressure areas on these lesions.
3- Massage of the tissue with apiece of gauze.
B- Papillary hyperplasia : or nodular hyperplasia appears as multiple nodules in
the palate under maxillary denture. This lesion usually occur in the lower labial
sulcus due to overextension of the denture border. The causes are:
1- in patients having a relief chamber for retention.
2- if the patient wearing the denture continuously.
The treatment include :
a- using tissue conditioning material.
b- Construction of a new denture with relieve of pressure areas on these lesions.

5- Traumatic ulcer
Or sore spots, most commonly develop within 1-2 days after insertion of new
denture.
Appear either as red area (erythema) or with even break of continuity of the
epithelium, the associated symptom is slight to sever pain depending on the pain
threshold of the patient.
The possible causes are :
a. overextended denture.
b. When the mucosa is squeezed between spinus bone and denture base
(pressure area).
c. Rough surface of the denture.
d. Inharmonious occlusion may cause scattered traumatic ulcers.

6- Burning Mouth Syndrome

Burning mouth syndrome (BMS) is a chronic, painful condition characterized by
burning sensations in the tongue, lips, palate (roof of the mouth), gums, inside of
the cheeks and the back of the mouth or throat. Oral mucosa appear healthy , Feeling
of dry mouth with persistent altered taste perception , Headache , irritability,
depression burning mouth syndrome appears to affect women seven times more
often than men. Often appears for the first time in association with the placement of
new denture

7- Hypersensitivity
Very rare, induced by continuous or frequent repeated exposure to an allergic
substance. The patient complains from swollen tissue underneath the denture,
sometimes accompanied by a metallic taste. This allergic reaction may be early (
anaphylactic reaction )or delayed reaction. To diagnose this condition we do the
patch test for the skin. The condition is treated by change the denture base material
other than methacrylate like (Cr/ Co) base denture.
 Immediate Dentures
When several teeth are loose or badly caries and are beyond saving, this condition
is usually caused by advanced periodontal disease or decay. Periodontal disease
causes bone resorption if not treated properly in time so the involved teeth should
be removed. Removing the teeth and replacing them with denture in the same visit
is called immediate denture.
An immediate denture is a complete denture or removable partial denture
fabricated for placement immediately after the removal of natural teeth.

Definition
Immediate denture is a dental prosthesis constructed to replace the lost dentition
and associated structures of the maxilla and or the mandible and inserted
immediately following removal of the remaining teeth. An immediate denture may
replace one tooth or16 teeth in either the maxillary or the mandibular arch or in
both arches .The latter should be made together to ensure optimal esthetic and
occlusal relationship, it can be a complete denture or an over-denture.

Indications for immediate dentures

a. Patient is socially active.
b. Wishes to retain their natural appearance.
c. Good health (Medically fit patients).
d. Available time and can afford multiple visits.
e. Hopeless remaining teeth due to:
1- Advanced periodontal condition.
2- Advanced caries, non vital tooth.
3- Severely tilted teeth, mal occlusion.

Contra indications for immediate denture

A few patients are not good candidates for immediate dentures they include :
1. Patient is debilitated.
2. Patient who are in poor general health or are poor surgical risks due to
advanced or complicated systemic diseases that affect healing or blood
clotting ( e.g., uncontrolled diabetic patients) , cardiac or endocrine gland
disturbances, post irradiation of the head and neck regions. Systemic
conditions preclude multiple extractions.
3. Emotionally disturbed or diminished mental capacity.
4. Uncooprative patient who is not willing to accept the treatment mentally
and psychologically they cannot understand and appreciate the scope,
demands ,and limitations to the course of immediate denture treatment.
5. Indifferent patients.
6. Patient is unavailable for appointment or financially underpriviledged.
Advantages :
1- The primary advantage of an immediate denture is the maintenance of a patients
appearance , the patient psychological and social well being is preserved so he
does not have to go without teeth and there is no interruption of a normal life-style
of smiling talking ,eating and socializing .
2- Circum oral support , muscle tone , vertical dimension of occlusion ,jaw
relationship and face height are preserved ,the tongue will not spread out as a
result of tooth loss .
3- Less post operative pain because the extraction sites are protected .
4- It is easier to duplicate the natural tooth shape and position plus arch form and
width, the horizontal and vertical position of the anterior teeth can be more
accurately duplicated
5-The patient adapt more easily to the dentures at the same time that recovery
from surgery is progressing .Speech and mastication are not affected , and
nutrition can be maintained .
6- Post operative hemorrhage and infection are also prevented due to the
protective action of the denture it acts like a splint for the tissues to help control
bleeding, to protect against trauma from the tongue, food, or teeth if present in the
opposing arch also to keep mouth fluids and particles of food from entering the
tooth socket and to protect the blood clot and thus promote rapid healing.

7- There is less difficulty in making the polished surface of the dentures

compatible with the surrounding structures, the tongue lips, and checks have not
altered their positions because of lack of tooth support.

Disadvantages
1- Immediate denture is more difficult and demanding procedure, more time
additional appointment and increased cost.
2-There is no opportunity to observe the anterior teeth at the try-in appointment ,
therefore the esthetic result cannot be evaluated until the denture are inserted
careful planning ,operator experience ,attention to details of the technique and
explanation to the patient can solve this problem .
3- Retention problems because some time it is difficult to accurately capturing a
posteriorly located undercut area caused by the presence of anterior undercut area
because of the presence of the remaining anterior teeth.
4- The presence of different number of remaining teeth in various locations
frequently leads to incorrect centric occlusion position or planning improperly the
appropriate vertical dimension of occlusion,an occlusal adjustment or even
selective pre-treatment extraction may be needed to record an accurate centric jaw
relation at the proper vertical dimension of occlusion.
5- The resorption of bone and the shrinkage of unhealed soft tissue are greater and
faster than the changes of healed tissue These changes require new impressions to
keep the denture base adapted to the basal seat .The remounting of the dentures to
refine the occlusion is necessary whenever the denture base is altered .
6- Functional activities (speech and mastication) are likely to be impaired but this
is temporary inconvenience .

Requirements
Patients vary greatly in what they want, expect, and demand.
To attain the maximum degree of success in immediate denture the following
requirements should be satisfied
1. Compatibility with the oral environment
2. Restoration of masticatory efficiency within limit
3. Harmony with functions of speech respiration and deglutition
4. Esthetic acceptability
5. Preservation of the remaining tissues
The patient should be properly informed and educated by the dentist in order to
satisfy their requirement.

Types of Immediate Dentures

1- Interm immediate dentures (transitional or nontraditional denture)
Is a dental prosthesis to be used for a short interval of time for reason of aesthetics
, mastication ,occlusal support ,or convenience or to condition the patient to the
acceptance of an artificial substitute for missing natural teeth until more definitive
prosthetic therapy can be provided.

These immediate dentures used temporarily during the healing period of the
patient to preserve ridge contour until the permanent denture can be fabricated ,
they are mainly indicated in patients with periodontal disease when anterior and
posterior teeth are remaining or full arch extraction and these teeth support a
removable partial denture that the patient desires to retain until insertion of the
complete denture .When healing is completed a second new denture is fabricated
as the long term prosthesis .
2- Conventional immediate dentures (classic)
It is an immediate denture which can be later modified (refitted or relined) to serve
as the permanent prosthesis.
The CID is usually selected when only anterior teeth remain or if the patient is
willing to have the posterior teeth extracted before immediate denture procedure
begin .

Comparative Advantages and Disadvantages between Interim and

Conventional immediate denture :
1. CID is Intended as definitive or long term prosthesis after healing complete, it is
relined. IID is transitional or short term prosthesis after healing a second denture is
made.

2. At patients initial presentation in CID usually only anterior teeth are remaining
or few posterior teeth remain that do not support an existing removable partial
denture while in IID usually both anterior and posterior teeth are remaining or full
arch extractions or these teeth support a removable partial denture that the patient
desires to retain until insertion.

3. CID usually has good retention and stability at placement which is possible to
maintain during healing.
The IID has only a fair retention and stability at insertion which must be improved
by relines (tissue conditioning) during healing.

4. The overall cost of CID treatment is less than IID treatment because it is the
cost of the CID plus a reline . The overall cost of IID treatment is greater than CID
treatment because it includes the cost of the IID denture and a second denture.

5. Treatment process in CID takes longer than IID because there is a delay of 3-4
weeks for posterior teeth extraction areas to heal partially before making the final
impression.
In IID treatment process takes less time than the CID as denture fabrication
procedures can begin right away.

6. CID is indicated when two extraction visit is feasible while the IID is indicated
when only one surgical visit is preferable.

7. Esthetics of the CID cannot be changed, with IID allows an alteration of

esthetic and any other factors if indicated.

8. At the end of the treatment the patient has one denture in CID with IID at the
end of the treatment the patient has a spare denture to use.
9. If all the posterior teeth are initially removed the vertical dimension of
occlusion is not preserved in CID ,while in IID posterior teeth not be removed
before fabrication of the IID the vertical dimension of occlusion may be preserved.

10. CID is contraindicated for a patient who has a complex treatment

plan(periodontal therapy, crowns, fixed partial dentures and removable partial
dentures in the opposing arch) or for changes in the vertical dimension of
occlusion.

IID is indicated when a complex procedures are needed or changes in vertical

dimension of occlusion an upper IID against a transitional lower partial denture
can be made ,then any periodontal procedures ,crowns, and fixed partial dentures
during the initial healing stage.

11. CID is not useful for converting existing prostheses such as removable partial
dentures. The IID can be useful in converting existing prostheses to an IID.

Diagnosis And Treatment Planning

The diagnostic findings are determined by investigating the local oral conditions,
the patients mental attitude ,systemic status ,and past dental history the diagnostic
procedures can be divided into two phases

1- Patient examination :
The examination should include finding of local and systemic conditions
The local factors are evaluated by full mouth radiographs should be taken,
periapical radiograph may be useful for localized area,OPG give general view for
both jaws in single image. Head and neck examination is performed, accurately
articulated study casts, and visual and digital examination.
The local factors which are important in complete immediate denture treatment are
1. The condition of the teeth to be extracted such as endodontically treatment
roots ,multiroots, ankylosed roots, hypercementosis, hooked or curved root
may require extensive surgery.
2. The positions of the teeth .
3. The presence of foreign bodies, tissues or bony undercuts or exostosis that
requires extensive surgical procedures at the time of insertion of the denture
may result in condition unfavorable to a good prognosis .

Periodontal probing ,full charting of the teeth ,and a note of need for frenum
release or tori reduction if necessary .when possible ,teeth should be selected for
retention as over denture abutments , visual and digital examination of the denture
supporting tissues and the posterior palatal seal area should be carried out . The
shade and mold of the existing teeth should be determined Patient should be asked
if they like their current shade and tooth position and what changes they would
like to make patient existing midline and need for modification of its position, the
patient existing vertical dimension of occlusion and the amount of interocclusal
distance, the present amount of horizontal and vertical overlap of anterior teeth.
Examination of any existing prosthesis for shade mold tooth position, lip support
and smile line
Systemic status : for the partially edentulous patients any systemic complication
that adversely affected the formation of the essential component of healing and of
tissue regeneration both soft and hard will offer a poor prognosis for immediate
complete denture.

2- Consultation interview : A careful explanation to the patient of the limitations

of immediate denture service should be given
Preparing the patient and proper selection of the patient is the main factor to
successful immediate dentures . The patient should understand all the sequences of
the treatment , cost ,time and number of visits.

The treatment plan includes :

1- Oral prophylaxis
The patient should have a general scaling of the teeth to minimize calculas
deposits this will reduce post operative edema and chance of infection .
2- Tooth modification
Many immediate denture will require modification of opposing teeth to correct the
occlusal plane or to eliminate prematurities in centric relation which affect the
registration of centric relation when they interfere with guiding the patient into the
centric relation position .These tooth modification should be done on the patient in
advance of the final impressions .

3- Diagnostic mounting of pre-extracting cast : The analysis of the occlusion

and the plane of occlusion is best done by performing a diagnostic casts and
carefully evaluating the planned changes also it can serve to plane the treatment
and as pre-extraction record and to construct special tray .It is also best to include
photographs of the patient as a part of permanent record . Evaluation of the lip
support ,position of high lip line low lip .line , and amount of tooth exposure in
function as during normal speech is important .Tooth mold and shade selection
should be done at this stage of treatment .

Prognosis : All of the foregoing feature will allow the dentist to determine a
prognosis for immediate denture.
At this point there will be a good indication of which type of immediate denture is
best for the patient, the anticipated difficulties, esthetic demands on the part of the
patient, once the patient understand and accept the diagnosis and treatment plan
and prognosis, the actual treatment can begin .
Clinical Procedures
The procedures for fabrication of conventional immediate denture are similar to
these for making complete denture with some modifications.

1- Extraction visit : if multiple extraction is needed [posterior and anterior ]

usually post teeth removed as soon as possible opposing bicuspids maybe retained
to preserve the vertical dimension of occlusion .These posterior areas are allowed
to heal usually 3-4 weeks .

Any other required hard and soft tissue operation is usually done at this first
surgical visit (tori reduction, tuberosity reduction and frenectomy and if any
posterior teeth are proposed as overdenture abutments the endodontic treatment
can be done earlier and the abutmtments can be morphologically modified when
the denture is ready to be inserted. Final preparation of overdenture abutments and
placement of any coping or attachments should be done after the immediate
denture is inserted and patients ridge healing is complete.

2- Preliminary impression and diagnostic casts : Impression are made with

alginate [irreversible hydrocolloid ] in stock metal or plastic tray the tray should
reach all peripheral tissue borders and posterior extension such as the retromolar
pad on the mandibular arch and the posterior limit on the maxillary arch [hamular
notches and postdam area ] periphery wax is adapted to the borders of the tray to
reach towards the vestibule and the undercuts accentuated by the presence of teeth
The palatal surface of the upper tray need to have wax added to reach the palatal
tissues .Location of the posterior limit can be marked in the patient mouth with an
indelible pencil ,this will transfer to the impression surface ,the impression should
record the full extensions planned for the denture prosthesis .

Loose Teeth
When the teeth were so loose that it was feared that it would extract during
impression it can be blocked out by adding periphery wax at the cervical areas or
by applying a lubricating medium to the teeth or by placing copper bands over the
loose teeth or by placing a vacuum-formed plastic over the teeth or by placing
holes in the tray and using an amalgam condenser to release the tray over loose
teeth.
These impressions are poured in stone and are used to make custom trays for the
final impressions .If an IID is planned the preliminary impression and cast will
contain all of the remaining teeth .If a CID is planned these will contain only
anterior teeth
3- Custom trays and final impression
Different tray design and impression techniques were described for final
impression; these techniques may range from simple to more complicated in the
tray design and materials used.
Selection of a suitable technique depending on :
A. Case difficulty
B. Teeth and tissue undercut.
C. Number and location of teeth included in the immediate denture treatment.
D. Type of the planned surgical operation, impression material.
E. Dentist skill and experience.

The objective of the final impression is to record the tissue in maximum accuracy
that minimize the insertion, post-insertion adjustment and maintenance phases as
possible.

There are two ways to fabricate the final impression trays :

A- Single full arch custom impression tray :
This method more closely resembles a routine custom tray for removable partial
denture, it can be used in CID technique .It is the only tray that can be used for the
IID technique, complete denture border molding is accomplished, and a final
impression is made in any elastomeric material .It can be used both when only
anterior teeth are remaining and when anterior and post teeth are remaining.
In IID the teeth area are blocked out with two sheet wax thicknesses. In CID the
edentulous area are blocked out and treated like a complete denture impression
tray stop effect is established by providing holes through the wax anteriorly and
posteriorly ,the tray is out lined to be 2-3 mm short of the vestibular roll and to
extend and include the posterior limit [posterior palatal seal and hamular notch
areas ]

Autopolymerising acrylic resin or light cured resin try is fabricated, border

moulding by tracing compound is achieved and the final impression is made in
any elastomeric material [irreversible hydrocolloid, polysulfide rubber base,
polyvinyl silicone or polyether ].

B- Tow tray or sectional custom impression tray :

This method is used only when posterior teeth have been removed (CID) it can not
be used in IID technique because usually there are posterior teeth present .It
involves fabricating two trays on the same cast one in the posterior which is made
like an edentulous tray it cover the edentulous area up to the incisal edges of the
anterior teeth,out line the borders of the tray 2-3 mm shorter of the vestibule but
covering the posterior limit with wax block out tissue undercut area and
interdental spaces and undercuts around the teeth, adapt autopolymerizing acrylic
resin to the posterior edentulous areas .The tray should cover the lingual surfaces
of the teeth only and extend up beyond the incisal edges of the teeth to include a
handle .

For the anterior section either adapt a custom tray or we can cut and modify plastic
stock tray ,this tray should cover the labial surface of the teeth and the vestibule .
Some prefer not to use a tray they adapt a heavy mix of an elastomeric impression
material directly in the mouth ,the impression must cover the labial surface of the
teeth and the vestibule .

The tray is tried and border moulded with tracing stick compound and then
posterior impression is made in any impression material desired [zinc oxide-
euginol past ,polysulfide rubber base ,polyvinyl silicone, polyether ] ,the posterior
impression is removed and inspected ,then it replaced in the mouth then insert the
second tray with alginate impression material to cover the anterior teeth and the
labial vestibule when it set remove both tray together ,the most important
consideration in sectional tray technique is the careful proper reassembly of the
two separate impression and care must be taken not to distort this assembly during
pouring the impression

4- Vertical dimension and centric jaw relation :

A. If all teeth present or enough teeth to be articulated as in some patient with IID
no need to construct a record base and occlusal rim.

B. If remaining teeth are scattered or only few upper and lower teeth are present
and in all patient with CID autopolymerizing resin is adapted to the edentulous
areas of the cast as for complete dentures ,wax occlusal bite rim is constructed the
occlusal rims are added to the proper height and width .The remaining teeth and
anatomical landmarks such as the retromolar pad can serve as a guide to the height
of the rim .It is important that the record bases be stable and strong to record
centric jaw relations .

An evaluation of the patients existing vertical dimension of occlusion is recorded

determining if one wishes to retain it .on occasion one wishes to increase it
because the patients uneven tooth loss ,loosening of the remaining teeth ,and tooth
wear created overclosure .some time the vertical dimension of occlusion will have
to be closed because of teeth drifting and extrusion opened it this can be done by
grinding the natural or stone teeth on the master cast .The occlusion rims are
trimmed to the desired vertical dimension of occlusion and a recording of centric
jaw relation are made ,the casts are mounted on the articulator and send to the
laboratory for setting of the teeth with complete information about the teeth to be
extracted pocket depth and tooth mold and shade
Setting the dentures teeth :
The articulated casts are used for setting any anterior or posterior teeth that are
missing so that a try-in can be accomplished on the patient, a try- in is not always
possible when all teeth in the arch are present as in IID, when the posterior teeth
are missing (CID) so that a try-in is possible .Set the teeth in centric occlusion.
Acrylic teeth are the recommended type.

The trail denture bases are tried in the mouth and used to verify vertical dimension
of occlusion and centric relation as with complete dentures .If necessary the lower
cast is remounted with new centric relation record until the articulator mounting
and the patient centric relation coincide .It is important at this visit to take time
with the patient to record landmarks on the casts and to confirm the patients
esthetic desires .The midline or newly selected midline is recorded on the base
area of the master casts the anterior plane of occlusion using the inter pupillary
line as a guide is determined and marked on the base of the cast .If posterior teeth
are still present intra oral land marks that correspond to the ala-tragus plane should
be located and can be used as an aid to draw an ala-tragus line on the base of the
cast .The high lip line should be determined .

A discussion of placement of diastema ,rotated teeth ,notches and other contouring

should be done at this visit, some patient want perfect looking teeth where as other
patients will not want friends and colleagues to know any thing has changed and
want more natural appearance.
On the cast marks of the pocket depths , free gingival margins and a drawing of
where the new tooth position should be , a discussion of surgical and denture
placement procedure should be discussed to prepare the patient then the cast can
be send to the laboratory for setting of the anterior teeth .

Setting anterior teeth for immediate dentures more than one method can be
used to trim the teeth in immediate denture cases depend on :
1- if the teeth are need to be changed in location or alignment to improve the
aesthetic.
2- The teeth are well aligned aesthetically and functionally acceptable then we
can reproduce same alignment in the denture.

An alternative tooth setup is suggested setting every other tooth in the maxilla first
leaving at least one canine, central incisor and lateral incisor then the mandible,
then remove the remaining teeth and complete the set up using the pocket depth as
a guide for the trimming , the facial portion of the extraction site can be trimmed
to the pocket depth line the lingual tissues will not collapse to the pocket depth
after extraction the extraction site should be convex .
An extra visit to recall the patient for a look at the final wax up is good at this time
to reassure some apprehensive patient.
The wax contour is similar to that for complete denture except we need to increase
the thickness of the labial flange anteriorly to provide room to trim from inside to
relieve the sore spots or to seat the dentures which can be later reduced after the
removal of all sore spots .

Immedaite denture can be classified according to flange design :

1. flanged type.
A. Complete Flange
B. Partial Flange.
2. flangless type.

In case of flangless denture [gum fit , socket fit] which is indicated when the
premaxilla is prominent prepare root socket[5mm depth]on the stone model in the
direction of the root at the place of anterior teeth ,the neck of the artificial tooth is
placed in the preparation at the time of insertion the neck of artificial tooth will
just enter socket of extracted tooth.

There are certain differences between types of immediate denture regarding

to flange extention :
1. The flange denture cover the clot completely and protect the area, also the
flange denture exert equal pressure on both lingual and labial side reducing
post extraction hemorrhage.
2. appearance of flanged denture does not changed after fitting where the
appearance of open face (socket type) although good initially can
deteriorate rapidly as resorption create a gap between the necks of the teeth
and ridge.
3. The flanged denture allows freedom in the positioning of teeth, where as in
open face denture teeth have to be positioned in the sockets of the natural
teeth therefore on case of malpositioned teeth in flanged denture the tooth
position can be ultered while in socket type it will difficult.
4. In upper denture ,a flange on an upper denture creat a more effective
borders seal,better retention than is achieved with an open face denture .
5. The presence of labial flange produces a stronger denture labial flange will
make the denture stiffer so the midline fatigue fracture cause by repeated
flexing across the midline is reduced.
6. the presence of labial flange make it easier to add tissue conditioner
.Furthermore as the color of some reline materials is not always ideal or
changed with time.
7. Socket fit lower denture is not usually constructed because of poor stability
of lower denture during function.
Try In
1. If remaining [anterior and posterior teeth IID] try-in cannot be made
2. If only anterior teeth remaining try-in for centric relation and vertical
dimension can be made as In CID

Surgical Template
Is a thin transparent form duplicating the tissue surface of an immediate denture
fabricated from clear acrylic, constructed on the cast after it is shaped to normal
contour [duplicated cast] and is used as a guide for surgically shaping the alveolar
process at the time of extraction .When any amount of bone trimming is necessary
to improve the shape of the alveolar bone then the template is seated when it fit
properly this mean the shaping of the bone is adequate.

Fabrication of surgical template : Take alginate impression for the master cast
after the cast has been trimmed at boil –out stage then pour the impression with
stone then make a clear resin template on this duplicated cast by any one of these
methods
a. vacuum form method : a hole is placed in the center of the cast and a clear
sheet is vacuumed onto the cast .
b. sprinkle-on technique a clear acrylic resin is used
c. process template in a clear acrylic resin
d. fabricate the template in light-cured clear material

Processing and finishing : The immediate dentures are processed and finished in
the usual manner of complete denture ,keep the undercut areas of the denture
slightly thick at this stage to allow for insertion over the undercuts ,it is best to
keep all posterior undercuts at this point they do not need reduction ,but it can be
well managed by selecting an upward and backward path of insertion and of the
denture .Any bumps inside the immediate denture resulting from over trimming of
the cast should be reduced to allow for a convex ridge healing, these procedures
are duplicated on the surgical template. Both the immediate denture and the
surgical template should be placed in a chemical sterilizing solution in a bag for
delivery .

Placement And Post Oprative Care

Surgery and insertion of the dentures : The patient can see the practioner first
for reduction of any overdenture abutments or sectioning of any preexisting fixed
partial dentures, then extract the remaining teeth.

Incase of multiple extraction start with post teeth to prevent damaging the
wound taking care to preserve the labial plate of the bone no bone trimming is
done , the surgical template is used as a guide to ensure that bone trimming is
done adequately the template should fit and be in contact with all tissue surfaces
Inadequately trimmed areas planned for bone reduction will blanch from the
pressure and be seen through the clear template. The template is removed and the
bone or soft tissue trimmed until the template seats uniformly and completely .
This indicates that the dentures will seat as it was originally intended to ensure
proper occlusion and minimally induced discomfort . Sutures are placed where
necessary.

The denture should have good bilateral occlusion and no gross deflective contacts
pressure areas on the denture can be located with pressure indicating paste and
trimmed ,if the occlusion is not correct the denture should be rechecked for seating
particularly distally in the denture heel areas , a quick occlusal correction is done
to allow simultaneous bilateral contact further refinement of occlusion usually is
done at a later date ,the frena should be checked for proper relief

When both Ant and post teeth were extracted tissue conditioning liner can be used
to increase retention and for faster healing ,but the material should not be allowed
to get into the extraction sites it should be trimmed by rounded hot instrument .

Postoperative Care and Patient Instruction

First 24 Hours
1. The patient should avoid rinsing and avoid drinking hot water and not remove
the denture during the first 24hrs to reduce bleeding and pain because
inflammation ,swelling and discoloration are likely to occur their partial
control can be helped with ice packs for 20 minutes on,20 minutes off on the
first day .
Because of swelling premature removal of the immediate denture could make
its reinsertion impossible for 3-4 days or until reduction of swelling the
patient should be reminded that the pain from the trauma of extraction would
not eliminated by removal of the denture from the mouth .
2. The diet for the first 24hrs should be liquid or soft.
3. Analgesic medication are prescribed as required
4. Patient is seen after 24hrs for sore spots ,commonly these areas include cuspid
eminences ,lateral to tuberosities, posterior limit areas and retromylohyoid
undercuts, the related areas are relieved in the acrylic resin and also border
extension are checked and relieved by using pressure indicator paste .
5. Adjust any gross occlusal discrepancy in centric relation or excursion .If the
retention is not adequate tissue conditioning material may be used to improve
the retention. After the 24 hours visit the patient should be shown how to
remove the denture after eating to clean it and to rinse the mouth at least 3-4
times daily to keep the extraction site clean .
For the first post operative week the patient should continue to wear the immediate
denture at night for 7days post extraction or until the swelling resolved .
6- After 1 week remove the sutures and change the tissue conditioner if it has been
used During the first month after insertion the patient is seen on request or weekly
as required for sore spot adjustment .Denture adhesives can be used during this
period as an aid if retention is lost between visits .
After 2 weeks remount casts are poured and centric relation registered and
adjustment of occlusion is performed .If the opposing arch is not denture a cast of
apposing arch is made in an irreversible hydrocolloid impression and related to the
immediate denture on the articulator .

Subsequent service for the patient with an immediate denture :

After the sore spots are eliminated and tissue have healed ,a recall program for
changing the tissue conditioner liner is organized .Ridge resorption is faster
during the first 3 months, the frequency of changing the liner depend on the rate
and amount of bone resorption, denture hygiene frequency and methods, diet and
smoking habits.

Researches shows that complete socket calcification is complete at 8-12 months

following tooth extraction and the bone volume of the ridge is reduced 20-30%
during the first 12 months ,the resoption in the lower ridge is about twice that for
the upper ridge ,and so the immediate denture should be relined after that time to
improve the retention of the denture after remodeling of the residual ridge during
this period practically patient will prefer to have reline within the first 3-6 month
but they should be told that their denture supporting area will continue to remold
and further reline will be necessary .

When patients with immediate overdentures have an indication for an overdenture

attachment it should be accomplished after healing and before the definitive
prosthesis so that attachment components can be processed into the second denture
or reline.

Immedaite denture can be classified according to type of restoration into :

1. Immedaite complete dentute
2. Immedaite partial denture.
3. Immedaite overdenture.

Immediate Partial Denture

It could be either new or adding teeth to the existing denture normally made of
acrylic with ball clasps ,it is transitional and should be replaced after healing with
cast removable partial denture, the clinical procedure include :
 1. Put the partial denture in the patient mouth
2. Take alginate impression
3. Remove the impression with the partial and pour a cast
4. Break teeth to be extracted and place artificial teeth and process

Advantages of adding teeth to existing partial denture

1. quick
2. economic
3. no need for adjustment or change in esthetic

Single Complete Denture

The prevalence of the condition where one edentulous arch opposes a natural or
restored dentition is quite common. It has been estimated that for some patient
populations the mandibular canines are retained four times longer than other teeth
followed by the mandibular incisors. This documented arch discrepancy in tooth
survival suggest that the maxillary arch exhibits earlier tooth loss, the reasons for
the loss of the maxillary teeth prior to the mandibular teeth is unclear and are
influenced by a combination of factors, one major f actor might be the professions
perception of the ease of construction of maxillary dentures compared with
mandibular ones and comparative functional success of maxillary versus
mandibular complete dentures.

Among the reasons for this occurrence is that a maxillary complete denture is
more stable, easier to retain in position and tolerated better by patients than a
mandibular denture, therefore many are less reluctant to allow the loss of the
maxillary teeth and at times insist upon their removal.
Single Complete Denture
Is a complete denture that occludes against some or all of the natural teeth, a fixed
restoration, or a previously constructed removable partial denture or a complete
denture.
A single complete denture may be desirable when it is to oppose any one of
the following :
1- Natural teeth that are sufficient in number not to necessitate a fixed or
removable partial denture.
2- A partially edentulous arch in which the missing teeth have been or will be
replaced by a fixed partial denture.
3- A partially edentulous arch in which the missing teeth have been or will be
replaced by a removable partial denture.
4- An existing complete denture.
In the first three situations the maxillary arch is usually the edentulous arch.

Single complete dentures making is more complicated than the conventional upper
and lower complete denture procedure. The reasons for this :
1. The ability of the patient to generate heavy occlusal forces, due to the
existence of opposing natural teeth.
2. The high occlusal forces from the opposing natural teeth, results in
advanced bone loss of the residual alveolar ridge.
3. Supra-eruption of the opposing natural teeth produces an unharmonious
occlusal plane. And minimizes the vertical space for setting the opposing
denture teeth.
4. Mesial drifting of the opposing natural teeth results in an increased mesial
axial angulation (tilting) which produce an unharmonious occlusal plane.
5. Esthetic problems due to the fixed position of the mandibular teeth.
6. Abrasion of the artificial teeth if acrylic is used or the abrasion of the
natural teeth if porcelain is used.
7. Increase the tendency of fracture of maxillary denture due to occlusal
stresses exerted by natural teeth.
In these situations, it is necessary to consider the to all patient, three factors in
particular must be carefully evaluated,
1. Preservation of the residual alveolar ridge.
2. Necessity for retaining apposing teeth and
3. Mental trauma.

Single complete maxillary denture

Single complete maxillary denture to oppose natural mandibular teeth
More frequently encountered than the single mandibular denture is the single
maxillary denture. The diagnostic procedures should determine that there are
sufficient teeth in the mandibular arch. Periodontal health is acceptable, and there
are no missing teeth to be replaced. The number of mandibular teeth considered
sufficient should include the first molars in jaws that have a class I or class III
relation. In class II related jaws, the anterior teeth and premolars bilaterally may
sufficient.

When cusp form posterior teeth are used, balanced occlusion enhances the
stability and retention of the dentures. Balanced occlusion should be provided
when the jaws are in terminal relation and the teeth are brought together.
The occlusal forms of the natural teeth usually act as the guide in selecting the
occlusal form for maxillary posterior teeth. In most situations this would be a cusp
tooth, however if the natural teeth are abraded and are not restored prior to
treatment, the monoplane form may be the choice for the occlusal surfaces of
posterior teeth.
One of the five requirements of a denture is its esthetic acceptability. Sometimes
the positions of mandibular anterior teeth will not allow the maxillary anterior
teeth to be positioned in an esthetically acceptable manner or for balanced
occlusion. This problem may be resolved as follows :
1. Alter the clinical crowns of the teeth by grinding or with restorations
2. A accept balanced occlusion with the jaws in centric relation and not in the
eccentric positions.

The mandibular posterior teeth may be malposed or missing and the ideal
direction of the forces of occlusion to the maxillary teeth may be lacking. Abused
mucosa over the maxillary residual alveolar ridge is frequently encountered when
a complete single denture opposes malpositioned natural teeth. The mandibular
teeth should then be altered either by selective grinding procedures or by placing
restorations to establish a more ideal occlusal plane and compensating curve.

When the occlusal surfaces of the natural teeth, the food tables are considered to
be to large in the buccolingual dimension, they can be altered by removing some
but not all of the enamel from both buccal and lingual surfaces. After the grinding,
the enamel should be polished with pumice in a rubber cup.

Another unusual problem with patients who have neglected their dental care is the
prior loss of all maxillary posterior teeth and remaining anterior maxillary teeth
that are not restorable. For some unexplainable reason the mandibular teeth have
not been lost and are restorable , the mandibular arch will then present two planes
of occlusion , an anterior plane from canine to canine and a much lower posterior
plane. The mandibular posterior teeth have extruded and not only is the occlusal
plane objectionable but interring tooth space is at a premium .To prepare this
mouth to receive a single complete maxillary denture require extensive restorative
procedures in the mandibular arch and possible surgery in the maxillary arch.

Complete maxillary denture oppose a partially edentulous mandibular arch

with fixed prosthesis
When a complete maxillary denture is to oppose a partially edentulous mandibular
arch in which the missing teeth have been or will be replaced, the problems
presented are usually in the diagnostic procedures related to the existing
restorations. At that time it must be determined if the fixed restorations are
acceptable, if they can be made acceptable or if they must be rejected.

When the restorations are acceptable one must then decide what occlusal concept
will be pursued. It must be remembered that the teeth in the single complete
denture are on a movable base and even though they function against natural teeth,
they will function as a unit. The same principles of occlusion apply to complete
denture apply to the single complete denture.
Another consideration is the material composition of the artificial teeth to be used.
When the occlusal surfaces of the teeth and fixed prosthesis are made of porcelain,
the artificial teeth of choice are porcelain or acrylic resin. When the occlusal
surfaces are mixed enamel and gold or gold alone, the occlusal surfaces of the
artificial teeth are preferably gold however acrylic teeth are acceptable.

Complete maxillary denture oppose a partially edentulous mandibular arch

and a removable partial denture
The most frequent encountered situation for a single complete denture is opposite
a partially edentulous arch in which the missing teeth have been or will be
replaced with a RPD. As with the mandibular arch with fixed prosthesis, there
should be no other diagnostic complications. And no contraindications for using a
complete denture to oppose a RPD in the mandibular arch.

The remaining mandibular teeth should be in an acceptable state of dental health.

When there is a RPD it must be evaluated critically, the partial denture must meet
the requirements of an acceptable prosthesis. The occlusal plane, tooth
arrangement for occlusion, esthetics and the material composition of teeth must be
such that an accepted complete denture can be constructed to oppose it, because of
the considerable time and effort that will expended in the procedures to supply a
complete denture to oppose that which remain, it should not be embarrassing to
condemn the existing prosthesis if it will not be suitable opposite a complete
denture. When the RPD is to be supplied, there should be no problems related to
the complete denture construction, since the treatment plane is or should be
formulated for both arches at the same time.

Combination syndrome (Single complete denture syndrome)

Combination Syndrome as a set of characteristics that occur when an edentulous
maxilla is opposed by mandibular anterior teeth.
Patients wearing complete maxillary denture and removable partial denture in
mandible with posterior lack of teeth show very often the group of symptoms
called Combination Syndrome or Anterior Hyperfunction Syndrome.

The characteristic features that occur when an edentulous maxilla is opposed by

natural mandibular anterior teeth, including losses of bone from the anterior
portion of the maxillary ridge, overgrowth of the tuberosities, papillary
hyperplasia of the hard palate's mucosa, extrusion of the lower anterior teeth and
loose of the alveolar bone and ridge high beneath the mandibular removable dental
prosthesis denture base.
Combination syndrome has six associated changes
1. loss of vertical dimension of occlusion.
2. Occlusal plane discrepancy.
3. Anterior spatial resumption of the mandible.
4. Development of epulis fissuratum.
5. Poor adaptation of the prosthesis.
6. Periodontal changes.

This syndrome is a result of great magnitude of force, the unsuitability of the

denture foundation to resist them, and the unfavorable occlusal relationship.

Single complete denture to oppose an existing complete denture The decision

to construct a single complete denture against an existing complete denture can be
approached in a systemic manner by analyzing the following :
a. How long has the existing denture been in use?
b. Was the denture an immediate insertion at the time of tooth removal?
The answers for these two questions have a direct relation to the extent of bone
resorption one may expect to find. The loss of bone determines the accuracy of
adaptation of the denture base to the basal seat and should be thoroughly
investigated. The patient may not be experiencing a feeling of loss of retention and
a cursory examination may not reveal the necessary information because:
1- The muscles of the lip, tongue and cheeks may have adapted to retain the
denture in place
2- Edema is not always accompanied by hyperemia.
The first of these factors can be investigated by the use of pressure disclosing
paste and disclosing wax in the same manner as when new dentures are checked
for accuracy of adaptation and border extension. The second may require that the
denture be left out of the mouth for a period of 12 to 24 hours.
c. Does the denture meet the requirements of an acceptable denture? , there are
no shortcuts in determining the answer to this question. Some of the
principles that are accepted as essential for denture acceptance may be
difficult to analyze and may require an extensive examination unless the
existing denture was constructed by the examiner, in addition to the
accuracy of tissue adaptation and border extension, one must evaluate the
tooth position esthetic acceptance, condition of the polished surfaces ,
including contour and finish and the occlusal plane.
d. Has the denture opposed another complete denture , a partially edentulous
arch that supported a removable partial denture , restored natural teeth, a
fixed partial denture , or natural teeth , each of these different situations
influenced the arrangement , size , shape , form and color of the teeth used
in the existing denture.
 e. Is the operator satisfied to institute complete denture procedures utilizing
the existing denture, rarely this situation is satisfactory solution, a most
serious consideration is the fact that the dentist assumes the responsibility
for both dentures when accepting the patient for treatment of the single
denture, few old dentures fulfill the ideal requirements in all areas.
One type of dentures is defined as additive transitional, or treatment dentures.
These dentures evolve into complete dentures inserted at the time of the removal
of the last teeth or tooth. This type of single complete denture has been used with
success, however it must be understood that within a period of 6 to 8 months they
will be replaced with a new denture.

Single mandibular denture

Although the mandibular arch is seldom the edentulous one, this condition does
occur. It usually happens as a result of either surgical or accidental trauma.
The mandibular teeth may be lost as a result of fall, vehicle accident or gunshot.
Frequently the remaining maxillary teeth and periodontium are free of disease and
the teeth are cosmetically attractive. The teeth may or may not be supporting a
fixed or removable restoration, however the situation are comparable.

In these situations, it is necessary to consider the to all patient, three factors in

particular must be carefully evaluated,
1. Preservation of the residual alveolar ridge.
2. Necessity for retaining maxillary teeth and
3. Mental trauma.

When all factors have been evaluated and it is decided to prescribe a complete
mandibular denture. The patient should be well educated to the possible
consequences. If this is done seriously and sincerely the treated patient will
understand the consequences and help to minimize them.

The single mandibular denture opposing restored complete or partial maxillary

dentition poses an even greater challenge to the clinician. The situation often is
compounded by the finding of sever residual ridge resorption of the edentulous
mandible making conventional treatment nearly impossible.

The edentulous mandible is always at a disadvantage because of a limited quantity

of mucosa, the amount of denture border adjacent to movable mucosa, and the
impact of occlusal forces from mandible contacting the static dentate maxillary
arch.
These conditions frequently make conventional treatment unwise and have been
best addressed through :
 ✓ The use of endosseous dental implants to provide retention and support for
the mandibular complete denture and to retard residual bone resorption,
however many clinicians feel that
✓ The use of a resilient soft liner in the mandibular denture is of benefit. With
such a procedure the dentist attempts to provide a stress reducing element in
the denture base to resist the forces of functional and parafunctional loads.

Preservation of the residual alveolar ridge :

For the continued satisfactory use of a mandibular denture, the residual alveolar
ridge must be preserved in the mandibular arch .researches shown that the force of
jaw closure with natural teeth is greater than that with complete dentures. It is
known that the greater the force, the more the pressure and pressure is contributing
factor to bone resorption.
The mandible is the movable member of the stomatognathic system; therefore it is
more difficult to stabilize the mandibular denture. Another factor involved in
stabilizing the mandibular denture is its proximity to the tongue.one of the most
active muscles in the body. Which in activity may displace the denture. This
denture movement increases the pressure and stress on the mucosa and bone. This
is detrimental to comfort for the patient and to preservation of the support.

Another factor is the minimal availability of mucosa with tightly attached

submucosa for mandibular denture support. The more concentrated the stress the
more damage to the supporting structures results.
The young patients who insist on this treatment must know that there may come a
time in their life when not being able to tolerate dentures as a result of support loss
will be a disastrous situation.

Necessity for retaining maxillary teeth

The maxillary dentition may be needed to retain a prosthesis. This situation is
usually associated with congenital defects, such as cleft palate or stoma resulting
from surgical or accidental trauma. The primary considerations for these patients
is the ability to speak clearly enough to be understood and to swallow food and
fluids without their passing into the nasal cavity.

Mental trauma
The loss of teeth is such a traumatic mental experience for some persons that they
become depressed. Their depression may lead to more complicated psychological
problems. If this mental state exists when the patient loses the mandibular teeth.
Removal of the remaining maxillary teeth may be more than he or she can endure
mentally. It must be remembered that that the face is the most exposed part of the
body, and it is usually the first part of the body that the individual scrutinizes each
morning and is usually the first part of the body that others see. Change in the
appearance of the face is a factor that all dentists must consider when treating the
total patient.
Even though the potential for the destruction of the mandibular residual ridge is
great. The necessity for retaining maxillary teeth for retentive purposes and the
mental trauma created by the loss of the mandibular teeth may be the deciding
factors for prescribing a complete mandibular denture to oppose natural teeth in
the maxillary arch. With patient education and at times psychiatric help, the
problem may be resolved in a different manner at a later date.

Clinical and laboratory procedures :

In the case of single maxillary denture, a final impression is made of the maxillary
arch and an opposing impression is made of the mandibular arch. If a cast metal
base (non-precious or gold alloy) is prescribed, this is now made in a full palatal
coverage design with mesh extensions over the edentulous ridges and extending to
the posterior palatal seal area .a maxillary occlusion rim is fabricated and centric
relation record is made in wax or fast setting plaster. The teeth are arranged with
the proper inclinations and vertical overlaps but without following the exact
occlusal plane of the opposing natural teeth when their arrangement is not ideal.

The teeth placed in the hard baseplate –wax occlusion rim are then evaluated on
the articulator in eccentric positions. Modifications to tooth position are made to
provide stable cross –arch balance with functional range of eccentric movement.
In deciding the best possible denture tooth position, given the opposing tooth
positions, it may be found that the best option is to alter the natural tooth contours
through selective tooth reduction.
The denture arrangement is completed and the necessary natural tooth
modifications are accomplished on the opposing stone cast, taking care to mark
the location and extent of modifications. When it is clinically determined that
natural tooth modification can be carried out.
The modification is accomplished at the final prosthesis insertion. If however it is
determined that the natural tooth modification that is required to ensure stable
denture prosthesis would result in perforation of the enamel, and a restoration of
the natural tooth is necessary.
Discussion with the patient as part of overall treatment plan will be required. it
also may be observed that the required tooth positions will place the maxillary
prosthesis at risk of fracture due to required occlusal relations coupled with
prosthesis design , if this is suspected , a cast metal base should be recommended
for the patient.
After denture tooth placement is accomplished, if an opposing fixed or removable
partial denture is part of the treatment, it is finalize at this stage, the most
predictable control of the occlusion can be provided if the prosthesis are fabricated
and inserted at the same time. Following verification of the occlusal requirements
on the articulator and the wax trial denture stage. The prosthesis is processed and
completed.
At insertion, the tissue surface is checked for proper extension and the occlusion is
checked for duplication of the articulator mounting. Significant occlusal
discrepancies should be adjusted following a clinical remount procedure. Any
necessary minor adjustment of the natural dentition is accomplished using the
adjusted stone cast and or record of adjustment as a guide. Using thin articulating
paper to record the steep inclines that require adjustment, the teeth are marked,
checked against the cast markings, and reduced to the predetermined inclination.

Potential adverse treatment outcomes :

Two of the most common adverse sequelae to single complete denture treatment
include natural tooth wear and denture fracture. The use of maxillary porcelain
denture teeth especially when adjusted during the occlusal correction phase, can
lead to rapid wear of the opposing natural or restored dentition. Teeth restored
with various cast restorations often are less resistant to the wear from unglazed
porcelain.

Because the single denture often is opposed by a full or near full complement of
natural teeth , a common complication is fracture of the denture base, specific
conditions that encourage such fracture include heavy anterior occlusal contact ,
deep labial frenal notch especially when in conjunction with midline diastema.,
and high occlusal forces due to strong mandibular elevator musculature. Careful
attention to the occlusion and adequate denture base thickness and control of the
denture labial notch are frequently all that is required to protect from fracture.
When the clinicians is unable to control these factors or suspicious that fracture
potential is high. A cast metal base is best use to resist deformation and fracture.
Considerations during maintenance visits for the single complete denture patient
include verification of the occlusal contacting relationships that provide stable
occlusal forces in centric relation and eccentric contact positions. Also the
condition of the supporting tissues should be evaluated, and when found to exhibit
changes that would encourage excessive movement. Measures should be taken to
reduce movement and the potential for dislodgment.

Edentulous maxilla opposed by natural mandibular anterior teeth is a considerable

challenge for many clinicians. These cases pose many potential problems,
including loss of bone from the anterior edentulous maxilla and super-eruption of
unopposed mandibular anterior teeth. Kelly (1972) proposed the term combination
syndrome for this oral condition and its resultant clinical features. The Glossary of

Prosthodontic Terms has defined combination syndrome as : the characteristic

features that occur when an edentulous maxilla is opposed by natural mandibular
anterior teeth, including loss of bone from the anterior portion of the maxillary
ridge, overgrowth of the tuberosities, papillary hyperplasia of the hard palatal
mucosa, extrusion of mandibular anterior teeth, and loss of alveolar bone and
ridge height beneath the posterior mandibular removable dental prosthesis bases –
also called anterior hyperfunction syndrome.
Prevention of syndrome
1. Try and retain weak posterior teeth by means of endodontic.periodontal
therapies.
2. Using lower anterior roots and giving overdenture.
3. Giving bilateral balanced occlusion.

Management of combination syndrome

✓ Diagnosis of cause and its correction.
✓ Use of Tissue conditioners
✓ Surgical correction of changes in basal seat flabby tissues, papillary
hyperplasia, enlarged tuberosities.
✓ Restorative treatment of remeaning teeth

Relining and Rebasing of Complete Denture

Both biological supporting tissues and materials used in complete denture
fabrication are vulnerable to time dependent changes, the denture base material
may discolor or deteriorate also the artificial teeth may discolor, fracture or
become abraded, also there are irreversible changes in the tissues supporting the
prosthesis .The clinical efforts to prolong the useful life of complete denture
involve a refitting of impression surface of the denture and occlusal correction by
two techniques.

Relining : is the process of resurfacing the tissue side of the denture with new
base material that provides accurate adaptation to the changed foundation area
without changing its occlusal relation.

Rebasing : it is the process of readaptation of the denture to the underlying tissues

by replacing the denture base material with a new one without changing its
occlusal relation.

Treatment Rationale
The foundation that support a denture changes adversely as a result of varying
degrees and rates of residual ridge resorption so the dentures need regular
attention for maintenance purpose this can be achieved by patients education and
regular recall visit to the dentist .
A number of changes can occur in these tissues and they more common under the
mandibular denture than the maxillary dentures ,they are also common in
maxillary dentures opposing natural teeth , these changes are progressive and
inevitable and are accompanied by one or more of the following clinical changes :
1. Loss of retention and stability
2. Loss of vertical dimension of occlusion
 3. Loss of support for facial tissues
4. Horizontal shift of the denture (incorrect occlusal relationship)
5. Reorientation of occlusal plane

These changes in the denture will effect on the circum –oral support and
consequently in the patient's appearance .Changes in the occlusal relationship also
induce more adverse stresses on the supporting tissues, which increases the risk of
farther ridge resorption.

Every denture patient should be examined periodically on an annual basis .Rate of

osseous changes can be retarded when complete dentures are readapted at the first
sign and symptoms of loss of adaptation .when such changes are observed the
dentist may choose to reline or rebase the dentures .The magnitude of the observed
changes allows a decision to be made as to whether the resurfacing will necessitate
a laboratory reline or rebase

Minimal to moderate changes : reline

Moderate to maximal changes : rebase

Rebasing involves all the problems of making new dentures and the teeth cannot
be moved around as easily as when a new denture is made.
In this case the procedure should compensate for ridge resorption and also
reorientation of the vertical and horizontal position of the denture leading to bulky
denture base, and this necessitates the rebasing procedure at the laboratory.
Maximal to sever changes : remake new denture
Relining is the most common procedure which will not affect occlusal relationship
or aesthetic support of the lip and face .It is indicated in minimal to moderate
changes by taking impression to compensate the ridge resorption and in the
laboratory the impression material is replaced by acrylic.

Resorption of the bone of the maxillae usually permits the upper denture to move
up and back in relation to its original position .Patient may complain of pain in the
anterior vestibule below the nose .However. The occlusion also may force the
maxillary denture forwards .The lower denture usually moves down and forward.

The mandible moves to a higher position when the teeth are in occlusion than the
position it occupied before resorption .This leads to a decrease in the inter-arch
space .This movement is rotatory around a line approximately through the
condyles because the occlusal plane and the body of the mandible are located
below the level of this axis of rotation, the mandible moves forward as the space
between the maxilla and mandible is reduced from that existing when the dentures
were constructed Originally.
Indications for Relining and Rebasing
1. Loss of retention in immediate denture [3-6 months after placement]
2. Loss of retention and stability in patient who have worn dentures
successfully for long time due to resorption in the residual ridge mostly in
the lower denture
3. Geriatric or chronically ill patients who cannot withstand physical and
mental stress of construction of new dentures.
4. Economic reason where the patients cannot afford a new dentures.

Contra indications of relining and rebasing [Indications for making new

dentures]
1. Sever bone resorption and the presence of abused or inflamed soft tissue
due to an ill-fitting denture it should be treated by tissue conditioner
material ,in severe cases surgery may be indicated and making new denture
2. Sever occlusal disharmony or too much decrease in occlusal vertical
dimension
3. Poor esthetic dentures specially the anterior teeth [shape, color, position]
4. Dentures with phonetic problem [difficult to pronounce words or letters]
5. Sever osseous undercuts.

Advantages :
1. Restoration of retention and stability
2. Restoration of occlusal vertical dimension and centric jaw relationship
3. Cost of the prosthesis is less than making a new denture
4. Eliminates frequency of patient's visits.

Materials used in relining and rebasing :

l - Soft liner ; these used to refit the surface of complete denture and to condition
traumatized tissues providing long or short term cushion like effect .These are
classified into;
A. Short term soft liner [tissue conditioner]
B. Long term soft liner
These soft liner used only for relining only.

2 - Hard liner these are considered as permanent lining materials and are
represented by polymethylmethacrylate and its types which are heat, chemically,
and light activated acrylic.
Tissue conditioner
It is a soft resilient material that flows under pressure these properties enable the
material to readily adapt to the basal mucosa and the basal denture surface to form
an intervening cushion, so the transmission of masticatory forces to the supporting
mucosa are equalized thereby eliminating isolated pressure spots of a loose ill-
fitting denture, it permit wider dispersion of forces and aids to decrease the force
per unit area transmitted to the supporting tissues.

Composition : tissue conditioner are composed of powder

[polyethylmethacrylate] and liquid I ethanol, ester plasticizer and flavoring agent]

On mixing it forms a soft gel which will pass into the following stages
l- Plastic stage : It starts from time of loading the material in the denture .During
this stage the denture base responds to functional and parafunctional stresses and
fit of the denture will improve .

2- Elastic stage : It starts from few hours to few days during this period stresses
cushioned and tissue recovery will take place and retern to normal healthy
condition .The denture should not be removed for the first 24 hours because the
material will shape itself to the oral tissue .After that the denture could be removed
and rinsed only by warm water so as not to cause deterioration.

3- Firm stage : The material reach this stage because of leach out of plasticizer
from the tissue conditioner, this may take l-2 week, at this stage the surface of the
material is similar to polymerized resin surface except it is vulnerable to
deterioration .

The viscoelastic and elastic properties of tissue conditioner results in even

distribution of the load of mastication on the underlying mucosa and it will act like
a cushion and absorb the force of mastication, thus allowing the traumatized
mucosa to recover and return to normal healthy condition.

The rehabilitating effect is limited to tissue changes that are reversible such as
tissue displacement, abrasion, ulceration, swelling due edema and reduction in the
inflammatory response.

Indications of tissue conditioner

1. Treatment and conditioning of abused, irritated denture supporting tissues
of ill-fitting denture, they are also used to heal irritated hypermic tissues
prior to denture fabrication
2. Correction of vertical dimension of occlusion and also occlusion of old
dentures before relining or rebasing.
 3. Temporarily relining of immediate denture and surgical splints after
extraction of the teeth.
4. Temporary obturator ; tissue conditioner may be added as temporary
obturator over the existing complete or partial dentures .This may be done
directly in the mouth or indirectly after an impression of the surgical area
has been made
5. Tissue conditioning during implant healing.
6. As functional impression material.

Long term soft liner

These are mostly used for patients who cannot tolerate stresses induced by
dentures due to chronic pain, soreness or discomfort due to prolonged contact
between rigid denture base and underlying mucosa.
Such cases are seen in patients with sharp bony spicules on the crest of the ridge
and covered by thin atrophic mucosa, heavily resorbed ridges, sever bony
undercuts also it can be used in prosthetic restorations for congenital or acquired
oral defects, soft lining materials allow the dentist to utilize undercuts in the defect
for retention without traumatizing the soft tissue lining the defect .

Composition of soft denture liner :

They are classified into two types
1. Plasticized acrylic
2. Silicon rubber
Both are either chemically or heat activated

Disadvantages of soft denture liner :

Despite the clinical benefits of soft liner their efficacy and life expectancy are
limited to a maximum of one year of serviceability due to leaching out of
plasticizer and other soluble materials resulting in a progressive loss of
resiliency and cushioning effect, this will end with hard rough surface which will
cause food accumulation and growth of microorganisms like candida albicans
because of porosity and difficulty of cleaning the liner with routine mechanical
methods .
The cleaning should be performed by antimicrobial agent and using soft brush
with non-abrasive dentifrices to minimize fungal colonization in the liner .

The major disadvantage of silicones is their inability to bond with acrylic denture
base . This can be overcome by adding bonding agent or confining the borders of
the liner to end within the denture border rather than extending it to the periphery
of the denture base
 Tooth Supported Overdenture
Overdenture : a removable partial or complete denture that covers and rests on
one or more remaining natural teeth, the roots of natural teeth, and/or dental
implants;
A dental prosthesis that covers and is partially supported by natural teeth, natural
tooth roots, and/or dental implants.

Tooth supported overdenture : a complete or partial denture supported both by

mucosa and by a few remaining natural teeth that have been altered to permit the
denture to fit over them.
A complete or partial removable denture supported by retained roots or teeth to
provide improved support, stability, and tactile and proprioceptive sensation and
to reduce bone resorption.

Terminology
Overdenture
Overlay Denture
Overlay prosthesis
Superimposed prosthesis
Hybrid Prosthesis
Telescoping Denture
Tooth Supported Denture
Preventive prosthodontics
Common to all is the combined periodontal and mucosal support and the similarity
of the external form to that of complete or partial dentures.
"Overdentures," and "Hybrid Prosthesis” both terms mean dentures that are
partially supported by natural teeth. The first term describes the outer covering,
while the latter refers to the dual nature of the construction. Both express the
essential concept. Also have been described as hybrid dentures or teeth supported
complete dentures. The treatment strategy is to share stress concentration between
teeth abutments and denture supporting tissues.

In fact it is reasonable to suggest that the technique may be regarded as a form of

preventive therapy, as everything should be done to prevent a patient from
entering into an edentulous state, hence the popular term preventive
prosthodontics applied to the overdenture prescription.
The idea of leaving roots of teeth in the jaw and constructing a complete denture
over them is more than 100 years old. The objective was to slow down or prevent
the resorption of the residual ridge, which inevitably follows extraction of the
teeth. This is still one of the basic concepts today.
It appears that the presence of a healthy periodontal ligament maintains alveolar
ridge morphology. Whereas the diseased periodontal ligament or its absence, is
associated with variable but inevitable time- dependant reduction in residual ridge
bulk.

Advantages of preserving teeth or roots

1- Psychological benefits to the patient
The loss of remaining teeth can be a disturbing and emotional experience for
many. It may well be that loss of teeth is associated with ageing and this could be
a depressive factor in some. Certainly the effects of body image, together with the
emotions associated with the oral area, should not be underestimated.

2- Effects upon the edentulous ridge

When the teeth are retained, the alveolar bone integrity is maintained as it supports
the abutment teeth, therefore there is decrease in the rate of resorption of alveolar
bone. However when teeth are removed then the alveolar bone resorption process
begins. 7-years studies of alveolar bone loss around mandibular natural teeth in
patients with partial dentures showed the vertical loss to be only 0.8 mm,
compared with a 6.6 mm loss in those wearing complete dentures. Another 4-years
study, claimed that the retention of mandibular canines for overdentures helped
preserve the remaining edentulous ridge. figures showed an average of 0.6 mm of
ridge reduction in the anterior part of the mandible for patients with overdentures.
whereas patients with complete dentures lost an average of 5mm.

3-Tactile discrimination
Tactile discrimination is the ability to differentiate information received through
the sense of touch .When patients are anesthetized by local agents, they have
diminished tactile sense and frequently bite their lips rather severely without being
aware of it. Thus patients should be instructed not to eat or chew until the
“numbness” has completely gone and full tactile sense has retained.
With the preservation of the teeth, there is also the preservation of the periodontal
membrane and this in turn preserves the proprioceptive impulses. Over the last 30
years a wide range of reports have all confirmed far greater discriminatory ability
in dentate subjects compared with edentulous. As effective mastication which
requires tactile discrimination relies upon feedback. The extraction of teeth result
in loss of mechano-receptors from associated perio-dontal ligaments. A study has
shown that the ability to distinguish thin test foils placed between the artificial
teeth of root supported mandibular overdentures was greater than those supported
by implants. While receptors in the mucosa, proprioception in the muscles and
TMJ may all influence discrimination, the periodontal receptors appear to play a
significant role.

4- Improved stability and retention of the denture

The vertical walls of the remaining root will provide some additional stabilisation
for the overlying prosthesis. The greater the vertical space occupied by the root
preparation, the greater the stabilisation provided. Implants produce stabilisation
in a very similar manner, and the effect of this stabilisation along with a well made
prosthesis can be quite surprising.
✓ The roots of the tooth offers the best available support for occlusal forces.
✓ Accelerated rate of bone resorption is prevented.
✓ It increases pt.'s manipulative skills in handling the denture. (periodontal
membrane is preserved ,thus proprioceptive impulses, Extraction of teeth is
followed by continuous ridge resorption and poor denture foundation
✓ Loss of periodontal receptors responsible for proper masticatory function
and accurate jaw movements.
✓ Retention of few remaining teeth will preserve alveolar bone and preserve
periodontal receptorspart of myo-facial complex are retained.)

Advantages of overdenture
Based on above, overdentures. With their combination of periodontal and mucosal
support, have a significant number of advantages compared with complete
dentures. The most important of these are :
✓ Preservation of the Alveolar bone.
✓ Harmony of arch form – By preserving the teeth the alveolar bone loss will
be prevented/ delayed therefore maintaining the original arch form.
✓ Support for the overdentures.
✓ Greater functional stability due to preservation of residual ridge contours
near the abutment teeth
✓ Better retention, especially when retentive attachments are used in
mandibular prostheses.
✓ Preservation of the proprioceptive response. This may translated into better
occlussal awareness, biting force, neuromuscular control .
✓ Greater chewing efficiency because of better stability and retention.
✓ Less pressure on the mucosa.
✓ Reduced extension of the denture base in the maxilla. The palate need only
be partially covered when retentive elements are utilized. This is often very
important psychologically for the patient.
✓ Convertibility: if any problem occurs with the existing overdenture
abutments, the teeth can be extracted and the Overdenture can be converted
to a conventional complete denture.
✓ Patient acceptance – patients accept overdentures more fast and better than
the conventional dentures.
✓ Training effect for complete dentures that may become necessary later, by
preparing the neural pathways for appropriate reflex patterns. This takes
place while the occlusion and denture bases are similar to those of complete
dentures,
✓ Simple approach to the problem patient; i.e. patients with congenital defects
such as cleft palate, partial anodontia, microdontia, amelogenesis imperfect
etc can all be given overdentures which will be relatively fast and
inexpensive mode of treatment.
✓ Cost : despite the increased initial costs, mainly due to periodontal and
endodontic treatment and also cast copings, are ,however, justified because
overdentures are a superior health service compared to the standered
complete denture.

✓ Ridge preservation
✓ Proprioception

✓ Superior patients acceptance

✓ Open palate possible

✓ Definitive vertical stop for denture base

✓ Support, stability and retention are improved

✓ Less trauma to supporting tissues

✓ Fever post insertion problems than conventional complete denture

✓ Conversion to complete denture

✓ Increased biting force (Pacer FJ, Bowman DC. Occlusal force

discrimination bydenture patients. J Prosthet Dent 1975;33:602–9)

✓ Physiological Advantage
Disadvantages
1. An overdenture covers the soft tissues surrounding the root. The potential
for plaque retention on the denture base is considerable which increase
Caries Susceptibility and periodontal disease. An effective plaque control
regime will be required to ensure a reasonable prognosis for the prosthesis
and of its supporting structures. -Patient with poor oral hygiene is not
indicated for overdenture because of high possibility of caries and
periodontal condition.
2. Esthetic problems ;this is due to over contouring of the flange especially in
the canine eminence area due to the presence of undercut area.
3. Overdenture needs a sufficient interridge space.
4. More complex clinically.
5. More maintenance required.
6. Costly compared with conventional complete denture.

Indications for overdenture

1. When we have a good prognosis Motivated patient with good oral hygiene
2. Congenitally missing teeth.
3. Highly worn teeth ( sever attrition or bruxism) .
4. Congenital deformity in case of Cleft palate extend posteriorly.
5. Xersotomic patient.
6. Absence of alveolar residual ridge in the edentulous areas.
7. Overdentures are particularly useful for lower complete denture because of
decrease retention and stability and increase rate of mandibular resorption.
8. Patient with badly worn teeth.
9. Pt. with few natural remaining teeth.
10.Poor prognosis for routine complete denture.
11.Congenital or acquired intra oral defects.
12.Mandibular arch where loss of bone is more rapid
13.Edentulous maxilla opposing intact mandibular dentition.
14.Post traumatic or post surgical cases.
15.Severe attrition and loss of vertical dimension.
16.Young patient.
17.Cleft palate causing large free way space.
18.Hypodontia
19.Tooth wear cases
Contraindications :
1. High caries index.
2. Poor oral hygiene.
3. Poor prognosis of abutment.
4. Reduced inter-arch space.
5. Undercuts.
6. Sufficient attached gingiva not present.
7. Where endo and perio treatment can not be performed satisfactorily.
8. Grade III mobility
9. Mentally or physically handicapped patients

Selection of abutments
1 - Periodontal considerations
Periodontal and mobility status: - Periodontally compromised teeth with a good
treatment prognosis are probably regarded as suitable candidates even when
horizontal bone loss is present, on the other hand significant vertical bone los
particularly if a companied by type 2 or 3 mobility, generally precludes a tooth's
selection, slight tooth mobility is not a contraindication because a favorable
change in the crown- root ratio may improve this sign. a circumferential band of
attached gingival, although a narrow one , is popularly regarded as a mandatory
requirement for abutment selection.
2- Abutment location :
Because the anterior mandibular alveolar ridge appears to be most susceptible to
time- dependent oclusal stresses .cupids and or bicuspids are regarded as the best
overdenture abutments. This applies to maxilla as well. The later is particularly
frequent employed if the mandibular arch is intact or naturally restored one.
Clinical experience supports the recommendation of at least one tooth per
quadrant. If this recommendation is exceeded, retained teeth should preferably not
be adjacent ones, this will minimize the risks of compromise in soft tissue health.
Canines and premolars are regarded as the best overdenture abutment in mandible.
This is also for maxilla, although incisors are frequently used especially if the
mandibles teeth are natural. It is recommended that at least one tooth per quadrant
is present.

3- Endodontic status :
Anteroir single rooted teeth are easier and less expensive to prepare . whenever
pulpal recession to the extent of calcification has occurred , endodontic treatment
usually can be avoided .

4- Sufficient coronal tooth substance to maintain integrity

5- No gross bony undercuts [unless no flange required ].

6- Ability to have positive retention on abutments.

7- Adequate inter ridge space to have minimal interference with placement of

artificial teeth.

Various techniques in overdenture construction :

1. Simple tooth modification and reduction.
2. Tooth reduction with cast coping.
3. Endodontic therapy with amalgam or composite plug.
4. Endodontic therapy with cast coping only.
5. Endodontic therapy with cast coping utilizing some form of attachments.

1- Simple tooth modification and reduction :

In this procedure remaining teeth are reshaped to eliminate undercuts and reduced
in vertical height to create more interridge space for the overdenture and then
contoured to a convex or dome-shaped surface. this type require maintenance of
good oral hygiene this type of preparation is used in :
 A. An old patient and whose general health precludes several dental
appointments
B. partially anodontia patients
C. patient with sever abrasion of the teeth

2- Tooth reduction with cast coping :

This technique used when more preparation is to be carried out this will increase
the sensitivity and caries susceptibility so we do cast coping .Cast metal copings
with a dome- shaped surface and a chamfer finish line at the gingival margin are
fabricated and cemented. This approach is possible only when the teeth have
A. Adequate bone support.
B. good periodontal prognosis.
C. Adequate inter occlusal distance.

3- Endodontic therapy with amalgam or composite plug : Used when we

have insufficient interocclusal space, so we need to cut more from the occlusal
surface of abutments which causes pulp exposure and require endodontic therapy
and in the final step are prepared conservatively o receive an amalgam or
composite type restoration the remaining dentin is smoothed and polished to
prevent recurrence of caries.
4- Endodontic therapy with cast coping only : when much interocclusal space
is required , we cut the crown and do a post in the canal and coronal cast to act as
abutment. Short cast copings are 2 to 3 mm long and normally require endodontic
therapy because the required coronal root reduction would expose the pulp.
attached to the cast coping is a post fitted to the canal, for this reason canals
should be obturated with soft gutta percha –like material rather than with metal
points. when there is a history of caries and improper home care the coping is
made dome shape with the margin slightly supragingiva.

Short copings Long copings

2‐3mm long. 5‐8 mm long
RCT done. RCT is not a must
Copings are with a post. Copings are long Canals filled with gutta perca
5- Endodontic therapy with cast coping utilizing some form of attachments :
Attachment
a mechanical device for the fixation, retention, and stabilization of a prosthesis.
An interlocking device, one component of which is fixed to an abutment or
abutments, while the other is integrated into a removable prosthesis to stabilize
and or retain it, they are required where additional mechanical retention is needed
to overcome problems where prognosis of retention is poor.

Functions of attachments
Overdenture attachments have basically the same functions as the clasps of a
partial denture :
✓ Securing the prosthesis against forces that tend to lift it
✓ Providing periodontal support for the prosthesis
✓ Transferring the forces of the muscles of mastication from the prosthesis to
the periodontium in as nearly axial a direction as possible
✓ Distributing shearing forces
✓ Stabilizing and/or splinting the abutment teeth.
They are useful for increase retention of the dentures especially in cases with
tissue loss[trauma or cleft lip and palate patients] but this type of technique has
certain disadvantages

Disadvantages :
1. Increased cost.
2. Technical difficulties in construction and repair.
3. Oral hygiene maintenance requirement may be more demanding.
4. It require more inter arch space.
5. The bone support of the abutment teeth should be adequate due to increase
loading on the abutment teeth.
6. Increased bulk may weaken denture base.
7. Several of these attachments are available in rigid and non- rigid designs.

Rigid attachments
A retentive attachment is considered to be rigid if it grasps the abutment tooth
bodily and permits no movement between anchor and prosthesis except for
rotation around the long axis of the element in the case of a single tooth. Even
with rigid attachments there is a minimal amount of movement or "play", which
can increase as the attachment wears.
Advantages
Reduction of the load on the edentulous ridge during function and parafunction
Minimum tipping of the abutment teeth when subjected to lateral forces.

Disadvantage
Applied forces and movements of the denture are transmitted almost entirely to
the abutment teeth.

Non rigid attachments

Non rigid retentive attachments permit rotational movements of the denture
around the anchor in one or more planes.
Advantage
Reduced effect of tipping force on the abutment teeth.

Disadvantages
✓ Greater stress on the tissues supporting the denture (ridge resorption).
✓ Greater tipping of the teeth under lateral forces.

Types
1- Stud Attachment
1. Intraradicular like Zest anchor attachment
2. Supraradicular attachments like resilient gerber attachment, dalbo
attachment , rotherman attachment.

Zest anchor system : it is a type of intra-radicular attachment compose of matrix

[above the root] and batrix[inside the root]so they engage each other to increase
retention of the prosthesis
Post preparation is done within the root and a female sleeve is cemented in the
root canal male portion is a nylon post attached to the overdenture

Disadvantages
1. Posibility of dental caries due to dissolution of cement, plaque
accumulation, loss of root and loss of abutment so periodic recall is very
important
2. Possibility of fracture of the root due to occlusal force
3. The polymer part of the batrix will have fatigue failure and it needs
replacement frequently
Dalbo attachment : it is supraradicular type of attachment it compose of ball and
socket unit with spring action attached to the fitting surface of the denture by cold
cure acrylic, this type of design provide good retention and stability

2- Bar attachment : it is connection between two abutment teeth either soldered

or casted together, they are used more than other type of attachment because they
are simple and produce good retention and support used mostly in dental implants,
they are either prefabricated or custom made there should be sufficient space
between the bar and the gum to maintain good oral hygiene

Hader bar : this system consist of preformed bar and clips, the bar resembles a
keyhole in cross section with superior ( occlusal ) round end attached to the coping
and creates a retentive undercut for the female clip. The plastic clip is embedded
in the denture base, if more retention is required the plastic clip can be
transformed into a metal clip this is often necessary because the plastic clip loses
retention rapidly.

Doldar bar : the bar unit consist of a preformed bar that is soldered to coping on
the abutment teeth ,the shape of the bar has parallel sides with a rounded top it fits
a sleeve or clip that is embedded in the acrylic ;retention is due to a frictional fit
only.

Magnetic attachment
Small, strong mini magnets, One of poles cemented in the prepared cavity in
endodontically treated abutment and the other attached to denture base.
Detachable keeper element
Made of stainless steel that is fixed to abutment teeth by Cementing or Screwing
Denture retention element
Has paired, cylindrical Co- Sm magnets axially magnetized and arranged with
their opposite poles adjacent

Types of overdentures
1. Transitional overdentures.
2. Training overdentures.
3. Immediate replacement overdentures.
4. Definitive prostheses.
Transitional overdentures
when the patient is already wearing a partial denture. The transitional overdenture
consists of a modification of this partial denture to replace further lost teeth or to
cover the roots of overdenture abutments once the teeth have been cut down.

Training dentures
Such dentures are commonly employed to replace hopeless posterior teeth once
they have been extracted .They serve as a replacement to allow the patient to
accommodate to the replaced posterior dentition and to palatal coverage in the
case of an upper restoration. This accommodation by the patient includes
swallowing, chewing and speech patterns.

Immediate replacement overdentures

Immediate replacement overdentures are constructed before the last remaining
teeth are extracted and the overdenture abutments prepared A training denture is
often converted to an immediate replacement overdenture that may. with careful
relining, be employed for several months, or years. Even when they are replaced,
such prostheses may serve as spare dentures later on.

Definitive prostheses
These restorations are usually constructed at least 6 months following extraction
of the last teeth and the preparation of the overdenture abutment. By the time such
dentures are made, the edentulous ridges should be matured and the gingival
margins firmly established. Dentures of this type may involve metal bases and
some may be retained by attachments. They should be planned to provide service
for several year .

Sequence of treatment
1. Assessment [clinical examination, study models, radiographs and treatment
plan]
2. Periodontal treatment
3. Preliminary treatment of abutment teeth
4. Preparation of abutment teeth
5. Denture construction.
6. Follow up and maintenance
The causes of failure of overdenture are :
70% periodontal problems of the abutments.
25% caries.
5% endodontic failure.
It is preferable to use separated abutment teeth for better oral hygiene because of
less plaque accumulation.

Impression Technique
As the abutment tooth and the mucosa are of varying compressibility a close
fitting individual tray perforated over the abutment teeth is made ,impression is
taken with low viscocity elastomers ,the denture is fabricated as conventional
denture .

Insertion
The denture has to be passively inserted and removed because applying force on
insertion and removal will effect on the abutment teeth.

Care of Abutments
Following insertion of an overdenture the following are desirable for maintenance
1. Tooth brushing of the abutment with a fluoride-containing tooth paste and
the use of chlorhexidine mouth wash
2. Denture hygiene including removal of prosthesis at night
3. Self-application of topical fluoride to the abutment by the patient
4. Dietary advice regarding reduction of sugar in diet.
5. Frequent recall visits to check status of abutment teeth.
 Dental Implant
Dental Implant : A permucosal device which is biocompatible and biofunctional
and is placed within mucosa or, on or within the bone associated with the oral
cavity to provide support for fixed or removable prosthetics.

Dental implant : a prosthetic device made of alloplastic material(s) implanted into

the oral tissues beneath the mucosa or/and periosteal layer, and on/or within the
bone to provide retention and support for a fixed or removable dental prosthesis.

Alloplastic material : any non-biologic rnaterial suitable for implantation.

Generally metal, ceramic or polymeric materials.

The wish to replace lost teeth in one way or another with implants has occupied
man's spirit for centuries or even millennia. History of dental implants dates back
to early Egypt, implantation at that time was done by transplanting teeth from
sleeves or the poor who would willingly sell their teeth. Teeth from sources such
as goats, dogs, and monkeys were also used for implantation. Metal implant
devices of gold, lead, iridium, tantalum, stainless steel, and cobalt alloy were
developed in the early 20th century.
In the course of the last 50 years, different implantation methods have been
developed and put in practice, though with varying degree of success.

✓ Transdental Fixation (Endodontic Implants).

✓ Submucosal Implants.
✓ Transosteal Implant.
✓ Subperiostal Implants.
✓ Endosteal Implants.

Transdental fixation (endodontic implant) : a smooth and /or threaded pin

implant that extends through the root canal of a tooth into periapical bone and is
used to stabilize a mobile tooth, sometimes called an endodontic stabilizer.
However, they serve another purpose—the stabilization and preservation of
remaining natural teeth, not the replacement of lost teeth.

Submucosal implant : this method involves implanting small button like

retention elements under the mucose memberane, with the purpose of providing
retention for a removable prosthesis this method had not gained wide acceptance.

Transosteal implants : a dental implant composed of a metal plate with retentive

pins to hold it against the inferior border of the mandible and transosteal pins that
penetrate throught the full thickness of the mandible and pass into the mouth in the
parasymphyseal region, called also staple bone implant, mandibular staple
implant, transmandibuler implant.
Subperiostal implants : dental implant that is placed beneath the periosteum
while overlying the bony cortex.

Subperiosteal dental implant abutment : that portion of the implant that

protrudes through the mucosa into the oral cavity for retention or support of a
crown ,fixed or removable prosthesis.

Subperiosteal dental implant substructure : a cast metal framwork that fits on

the residual ridge beanth the periosteum and provides support for the dental
prosthesis by means of posts or other mechanisms protruding through the mucosa,
the implant body.

Subperirrteal dental implant superstructure : the metal framework, usually

within a removable dental prosthesis, that fits onto the dental implant
abutments(s)and provides retention for artificial teeth and the denture material of
the prosthesis.it is a structural component of the fixed or removable dental
prosthesis.

Endosteal dental implant : it is a dental implant that extends into the basal bone
for support, it transects only one cortical plat, it embedded into the bone and fixed
throughout the length of the implant.it can be classified into :

A. Root form implant: it is used where there is adequate amount of bone, it is

available in many forms namely, cylinder or press-fit form, scrow root form, and a
combination root form, its smooth surface is usually coated with hydroxyaptite or
plasma spry, self-tapping forms are usually threaded implants.
B. Blade form endooseous implants: it may be either prefabricated or custom
made, it is indicated when the width of the bone is not adequate for placement of
the root form, it is indicated in full arch edentulous reconstruction.

In the1950s research was being conducted at Cambridge University in England to

study blood flow in vivo. The workers devised a method of constructing a
chamber (hallow) of titanium which was then embedded into the soft tissue of the
ears of the rabbits. In1952 the Swedish orthopaedic surgeon P I Branemark
professor at The Institute for Applied Biotechnology,University of
Goteborg,Sweden,was interested in studting bone healing and regeneration, and
adopted the Cambridge designed 'rabbet ear chamber' for use in the rabbit femur.

Following several months of study he attempted to retrieve these expensive

chambers from the rabbits and found that he was unable to remove them. Per
Brlnemark observed that bone had grown into such close proximity with the
titanium that it effectively adhered to the metal. Branemark carried out many
further studies into this phenomenon, using both animal and human subjects,
which all confirmed this unique property of titanium. He found titanium was the
best material for artificial root replacement.

A two stage threaded titanium root form implant was first presented in North
America by Branemark in 1978 at a conference in Toronto. The Branemark
system has been well received throughout the world. Mechanism of integration of
endosteal implants Osseo-integration ; ls the most significant and important
development in dentistry.

The concept of osseointegration was developed and the term was coined by
Dr.Per-Ingvar Branemark

The word oeseointigratim consists of "Osseo" Latin word for bone and "
integration" the state of being combid into a complete whole.

Osseointrration is defined as :
✓ A direct bone anchorage to an implant body which can provide a foudation
to support a prosthesis; it has the ability to transmit occlussal forces directly
to bone.
✓ The apparent direct attachment or connection of osseous tissue to an inert
alloplastic material without intervening conneclive tissue.

This means that the implant must be made of an inert material to be in direct
contact with bony tissue. without soft tissue interface' and an implant entailing a
continuous transfer and distribution of load from the implant to and within the
bone tissue. such stable bone implants have an interface that consist mainly of
bony tissue which is differs from the one retaining the natural dentition because
the teeth are anchored to their surrounding bone by periodontal ligament which is
highly differentiated connective tissue.

Factors determining the success and failure of osscointegreted

implants :
1. lmplant biocompatibility
2. Implant design
3. lmplant surface.
4. lmplant bed.
5. Surgical technique.
6. Loading conditions.
7. lnfection control.
1- lmplant biocompatibility : can be defined as the compatibilrty of any
(foreign) material with a living organism. Biocompatibile: capable of existing in
harmony with the surrounding biologic enviroment it is clear that there must be
various degree of biocompatibility. Based on the ability of the implant to stimulate
bone formation, implants can be classified into :
1. Bio-tolerant materials.
2. Bioinert materials.
3. Bio-active materials.
4. Bio -inert and structure osteotropic.

l. Bio-tolerent materials : these materials are charact€rized by a low grade tissue

reaction, and often fibrous tissue can be histologically identified between the bone
and the fixture .materials include in this categary are stainless steel, chrom-cobelt
alloy and gold alloy.

2. Bio-inert materials : these materials are characterized by direct contact with the
bone ,with little or no apparent reaction within the host tissue, materials, included
in this group are titaniurn, aluminum oxide and various ceramic materials.

3. Bio-active materials : the characteristic of these materials that they promote

osteogenic activity within the host tissue ,and bond chemically to bone ca-
phosphate apatite, bioceramic and bioglass are includd in this category.

4. Bio-inert and structure osteotropic materials; titanirun with rough srrfaceis an

example of material forming physical and clremical bonds to the bone.

The most commonly used material for oral implants is :

Commercially pure Titanium it oxidize in atmosphere to titanium oxide layer
which adhere firmly to bone it may sprayed with Titanium plasma to increase
surface area for more fixation to bone.

Titanium-6Aluminium-4Vanadium[Ti-6AI-4V] alloy is another material for

implant but there were stronger bone reaction to cp titanium than to Ti-6AI-4V.
commercially pure niobium is well accepted in the body but it is relatively weak
and may lead to implant fracture.

Hydroxyrpotite (HA ) one type of calcium phosphate ceramic material was tried
as a solid material for use as oral implant ,but due to the brittle nature fracture
occur too often .There is rapid bone response to HA so it can be used as a coating
to dental implant to enhance osseointegration also it can be used for
augumentation in bone defect .
The starting point in failure in osseointegration is poor implant biocompatibility
with material that corrode in the body .resulting in leak-out ions that may
secondarily disturb the surrounding bone.

2- Implant design : most common design for oseointegration is cylindricat they

can be either threadcd ,HA coatod or not .unsuitable implant designs may lead to
relative lack of implant stability resulting in micro movements resultant bone
saucerisatim and subsequnt implant loss.

3- Implant surface : a smooth surface implant is less prone for osseointegration

as compard to an implant with mild surface roughness which can produce the best
bone fixation- too smooth implant surface will result in primary faiture in
osseointegration ,also too rough there will be a risk of adverse bone reactions and
secondary loss of integration.

4- Implant bed : a healthy site is required for good osseointegrdion .old age does
not cause poorer implant result, previously irradiated area is contraindicated a l-
year delay after irradiation before inserting implant is recommended expected
success result are about 10% lower than for non irradiated patients. Smoking is
contraindicated for implant placement as it
affect vascular supply to the surgical site due to vasoconstriction so it will impair
soft tissue wound healing also it affect the immune system of the patient and
impair normal cellular function and have negative effect on bone so the implant
failure is about twice the non smoker patient

5- Surgicrl technique : the surgical site should be subjected to minimum possible

trauma ,this objective depends on continuous a ranged careful cooling while
surgical drilling is performed at low rotatory rate using sharp instrument and the
use of graded series of drills.

6- Loading conditions : over loading the reorganized bone tissue prematurely will
cause failure of osseoitegration. A two stage implant insertion is advised ,the
implant is first inserted in the bone and then the soft tissue are sutured back so
that the implant will be incorporated in bone under protectd conditions second
surgery is carried out 3-6 month later when osseoitegration is complete the buried
implant is exposed and connected to the oral cavity by means of a trans epithial
abutment.

7- Inffection control : infection especially from periodontium should be

avoided.All surgical protocols to avoid infection should be followed .
Advanteges of Dentel Implants
l. They preserve the bone : when a tooth is extracted the body senses the loss and
beguns to resorbe the bone that used to support that tooth. In the case of multiple
missing teeth, this can lead to facial collapse, inability to wear even removable
prosthesis. This is in addition to the esthetic problems. The presence of a dental
implant signals to the body that this bone is still needed, the implant stimulates the
bone like a natural tooth and these difficulties are prevented.

2. Improved function : implants can be designed such that the effect of harmful
forces can be minimized .the chewing efficiency is greater than other prosthetic
replacements.

3. Aesthetic : Implants provide a natural I appearance of the tooth as if it is

emerges directly from the soft tissue.

4. Stability and retention : Implants are more stable and retentive due toss-
integration.

5. Comfort : lmpants are more comfortable as the extent of the flanges of the final
prosthesis can be reduced .

Disadvantages of Dental Implants

1. They may be more expensive than other methods of tooth replacement.
2. Cannot be used in medically compromised patients who cannot udergo
surgery.
3. Many patients do not accept longer duration of treatment. There is usually a
healing time required and complicated fabrication procedures.
4. It requires a lot of patients cooperation because of repeated recall visit for
after care is essential.
5. It cannot be universally placed due to the presence of anatomical limitation.
Indications for Dental Implants
1. Completely edentulous patient who is unable to tolerate a conventional
Prosthesis this might results from mechanical problems [poor retention ] or
functional disturbances [nausea or psychological reasons].
2. Single missing tooth with adjacent sound teeth, reduction of adjacent teeth
structure is needed in abutment preparation.
3. Implant treatment may be considered a preferred option in difficult
prosthetic situation.
a. Distal extension saddle
b. Extensive saddles where support for partial denture or bridge is
limited
c. Anterior saddle cases.
4. maxillofacial prosthesis [ears, eyes, obturators].
5. Patient desire [patient who refuses the use of removable type prosthesis]
Contraindications for Dental Implants :
Every patient is suitable for dental implant , the major contraindications are :
1. Patient whose systemic health preclude minor oral surgery procedure
[unregulated diabetic, coagulation problems, periodic use of steroids].
2. Patients with poor oral hygiene..
3. High-dose irradiated patient.
4. Patient with history of psychotic disorder.
5. Pathology of hard or soft tissue.
6. Heavy smoker patient.
7. Young patients under the age of l8 years old because the bone is not
completely formed extreme young age is a relative contraindication to the
insertion of the implants ,the general recommendation is to wait completion
of growth before inserting oral implants in young individuals.

Mechanical structure of the implant

1- Implant body or fixture : is that part of the implant that is placed within the
bone during first stage of surgery it could be threaded or non threaded . The
threaded implant bodies are available in commercially pure titanium or as titanium
alloys, they may be with or without hydroxyapatite coating.

2- Healing screw : during the healing phase the screw is normaily placed in
superior surface of the body .The functions of this component are :
✓ Facilitates the suturing of soft tissue
✓ Prevents the growth of the tissue over the edge of the implant.
3- Healing cap : they are dome shaped screws placed over the healing screw after
the second stage of sugery and before insertion of the prosthesis .They may range
in length from 2 to l0 mm. They project through the soft tissue into the oral cavity
.They function to prevent overgrowth of tissues around the implants during the
healing phase.

4- abutment is the part of the implant which resemble a preparcd tooth and is
designed to be screwed into the implant body .It is the primary component, which
provides retention to the prosthesis.

5- Impression posts : it is a small steam facilitate the transfer of intraoral location

of the implant or abutment to similar position on the cast they are placed over the
implant body during impression making.

6- laboratory analogues : these are machined structures which represent the bod
y of the implant they are placed on the laboratory cast in order to fabricate an
implant supported prosthesis .
After the implant body is inserted into the prepared bone cavity, the impression
post is placed over it .Consecutively the analogue is fixed over the impression post
.An impression is made and the analogue-impression post complex gets attached
to the impression and comes away with it .When the impression is poured the
impression post analogue complex will get embedded to the cast.

7- Prrosthesis retaining screw : it penetrate the fixed restoration and secure it to

the abutment.

Treatment Planning
Planning for implant procedure is extremely important this usually involves a team
work between oral surgon, prosthodntist and the dental technician to develop a
coordinated treatment plan and.

Diagnosis
It is very inportant that the general physical condition of the patient is checked
accrrately, in order to obtain an overall health assessment, initial data gathered on
each patient should include medical history, dental history, radiographic study,
study casts, and photographs, all essential in treatment planning. Basod on the data
and a through clinical exam, a detailed treatment plan can be proposed including
locations and directions for fixture.

Medical history
Patient must be medically fit to undergo surgery and complex prosthodontics
treatment.
The basic idea for evatuding the medical history is to identify potential medical
problems that could prohibit a patient from receiving implant treatment. if a
problem exists. immediate consultalion with the patient's primary care physician
and/or specialist should be done. A through explanation of proposed treatment is
outlined for the physician and final decision for treatment is mad after joint
consultation. The patient’s medical history may reveal a number of conditions that
could complicate or even contra-indicate implant therapy. These include:
1. Bleeding disorders; Paget’s disease; A history of radiation therapy in the
maxilla or mandible region; Uncontrolled diabetes; Epilepsy that presents
with more than one grand mal seizure per month;
2. In addition, there are a host of systemic medical conditions, including
steroid therapy, hyperthyroidism, and adrenal gland dysfunction
3. Substance abuse including tobacco and alcohol.
Dentel History
Dental history includes information gathered during the oral exanination. Evaluate
soft tissue condition for health of periodontium, evaluate remaining teeth
condition for caries, relative positions, mobility, plaque index, and presence of
calculus. Evaluate edentulous area for undercuts, pathology and size and shap of
residual bone. Evaluate present occlusion for interferences, occlussal wear,
prematurities, associated muscle tenderness, limited range of mandibular motion,
and evaluate for temporomandibular disorders. Evaluate parafunictional habits
such as bruxism which can have detrimental long term effects.

Radiographic Examination :
It involves radiographic evaluation of the bone :
1 - Periapieal radiographs : it gives a detailed picture about the amount and
quality, of bone remaining.
2 - occlusal radiographs : They provide information about the facio-lingual width
of the bone.
3 - cephalometric radiograph : It provide information about faciolingual
dimensions plus the lingual aspect of the residual mandibuler bone and the shape
of the maxillary ridge also it is used to determin and evaluate the loss of vertical
dimension. Skeletal inter-arch relationships and crown-implant ratio.
4 - Panoramic radiograph : it is the most frequently used radiograph vertical
height of the bone can be evaluated .it also gives an idea about the location and
extent of limiting anatomical structure .to discover possible pathological findinqs
and to obtain general information on bone qualitvy or density .
5 - Computed tomography : It gives a detailed view of the cross sectional
anatomy of the alveolar ridges they are often needed for maxillary treatment.

Study cast
Study casts, a facebow transfer, and occlussal rcgisteration are essential for
treatment planning. The study casts are important for studying the remaining
dentition and residual bone. and for analyzing the mraxillomandibular
relationship. The mounted study casts can be helpful to the surgeon for fixture
placment.

A diagnostic wax-up can be done on the studv casts- it helps to determine the
esthetic placement of teeth and potential functional speech disturbances.
Diagnostic study cast mounted on a semiadjustable articulator will assist in
planning and designing the final prosthesis , the number and location of potential
fixtures should be identified and anticipated abutment type should be decided
Oral Examinetion
A thorough clinical examination is important and specific attention to the
following:
1. Patient slrould be capable of good oral hygiene.
2. pre-existing periodontal disease and caries should be controlled.
3. The bony implant site must have bone of suffrcient height width and quality
for implant placement.
4. There should be enough inter-ridgespace for implant super structure and
prosthesis[minimum 7 mm].
5. There should be enough space between existing teeth for implant placement
without tooth damege [minimum 7mm].
6. The implant should not impinge on key anatomical feature [mental nerve
foramenl.

Anatomical limits for fixture placcment :

Maxillary anterior region :
The maxillary anterior region has less bone quality and lower bone quantity when
compared to the mandibular anterior region. In many patiens,there are anatornieal
limitations in the maxilla. The nasal cavity and maxillary sinuses usually interfer
with fixture site selection. especiallv in a patient with severe bone resorption.
when the bone resorption is severe, bone availabilitv may be limited to canine
eminelce area, lateral wall of the nasal cavity and medial wall of the sinus.

Maxillary posterior region

Due to the resorption pattern, proximity of sinuses, and quality of bone, fixtures
are rarely placed in the maxillary molar areas. in the premolar areas of the maxilla
the bone usually thick and spongy. 'l'he premolar area usually has adequate bone
height compared to the molar area and may accommodates fixture between lateral
and inferior walls of adjacent sinuses.

Mandibular anterior region

The mandibular anterior region between mental foramina usually has adequate
bone for placement of four to six fixtures. A minimum of 7 millimeters from the
inferior border of the mandible to the crestal ridge is needed in this region for
adequate fixture length. During surgical procedures, carful dissection of the
mental foramina and associated structures is necessary.
Mandibuar posterior region
In the mandibular posterior region, fixture installation can be difficult due to the
presence of the inferior alveolar canal. To insure a margin of safety,there should
be a minmum of one millimeter clearance between the apex and the inferior
alveolar canal.
Examination of existing denture helps the dentist decide whether they are adequate
for temporary use during the post surgical healing phase.

Treatment options for completely edentulous jaws :

successful osseointegration enables the dentist and the edentulous patient to
consider one of two alternatives to traditional complete denture experience .These
alternatives are an implant supported fixed or overdenture prosthesis depending on
the quality and quantity of the bone, and anatomical
limitation(nerves,vessels,antrum).

Implant -Supported Fixed Prothesis

Patient who have been shown to benefit most significantly from this technique are
the maldaptive ones.

Fixed prosthesis with(4-6) implants generate occlusal forces approximitly that of

natural teeth while conventional dentures generate one fourth the force of natural
dentition The decision to treat an edentulous arch with an implant supported fixed
prosthesis is influenced by the following factors
1. The number of the implant abutments ; for clinical successes with implant-
supported fixed prosthesis suggested five implants placed between the
mental foramina to support a 10-12 unit fixed mandibular prosthesis
Five to six implants to support an 8-10 unit fixed maxilrary prosthesis.
2. The location of the implants is more favorable when their configuration is
curved rather than flat because it allows for more occlusal units and an
optional cantilever design .A flat implant arch form is better candidate for
an overdenture design.
3. The quality of the host bone sites; clinical experience suggests that loosely
textured cancellous bone makes for potentially vulnerable osseointegrated
rcsponse .
4. The quantity of the host bone sites or the amount of the residual ridge
reduction that has oocured .This is a frequent in the maxilla where
augumentation technique may be required if fixed prosthesis is planed
alternative surgical approach include sinus lift procedure.
5. Amount of circum oral activity this consideration applies almost to the
maxilla As a role patients with extensive vertical and horizontal anterior
maxillary bone resorption are candidate for implant-supported overdentres
and not for fixed prosthesis.
Implant Supportcd Overdentures
Although tooth and implant abutment attachment mechanisms differ their
prosthetic role is identical.they provide enhanced prosthesis retention and stability
, and their influence on adjacent bone levels appears to be similar the
bone high is maintained in the area where implants were located.

The nrmber of implants placed for overdentrre support differs in the mandible and
in the maxilla and is influenced by residual jaw morphology.

Maxillary overdenture rcquire the placement of a minimrm of three to four

implant usually joined with connecting bar.Implant length should be l0 mm or
longer. sevral implant should be prescribed when reduced host bone site preclude
placement of 10 mm or longer fixture.

For mandibular denture two implant appears to be adequate. Thc inter implant
distance should preferabty exceed l2mm to provide sufficient space to
accommodate retentive component.
As a general role the younger the edentulous patient the greater the benefit from
implant-supported fixed prosthesis to reduce overall long-term

Advantege of overdenture prosthesis over fixed full arch :

1. Fewer fixture.
2. More economical.
3. Iess lab work.
4. Easier oral hygiene maintains.
5. No cap existence between framework and crestal tissue.
6. better esthetic and phonetic result.

Impression Technique for Implant

seven to l0 days after second phase surgery preliminary impression of maxilla and
mandible are made using an alginate impression material in stock edentulous
impression tray and caste in dental stone and trimmed for the preparation of the
custom tray fabrication .

Custom Tray Fabrication

The custom tray is used to make an impression that will provide an accurate
recording of the mandibular or maxillary tissues and their relationship to the
integratd fixtures.The tray is different from a standard edentulous tray is that it has
opening that are designed to allow access to the guide pins and impression coping
.In the tray there will be a window over occlussal portion of the abutment area.
Clinical Impression procedures :
Impressions copings are attached to the abutnents with the proper length pins .
The square impression copings are preferred beacause they resist rotation and
displacernent in the impression material.
The open window custom tray is tried in the mouth for comfort and path of
insertion .Base plate wax is seated over the window and the tray is heated in a
water bath ,and then inserted over the guide pins and impression copings. .the
guide pins should penetrate the wax to allow access for removal of the impression.

The impression material should be medium viscosity After the material is loaded
into the tray and the syringe ,the material is first injected around the impression
copings, and the tray seated using the guide pins and the holes in the wax-window
as a guide for placement. After the material has set ,the guide pins unscrewed with
e scrow driver,the guide pins are left in the same holes in the impression to allow
accurate placement of the abutment replica.

Master cast : the master cast the foundation for farbricating the implant
prosthesis . Brass replica have been precisely machined to be-analogues of the
superior surface of the abutment the replicas are screwed onto the impression
copings with guiding pins. After the placement of the brass replica the final
impression is casted in vacuum mixing die stone for master cast.

Criteria For Success Of Dental Implant

1. The individul unattached implant is inmobile when tested clinically.
2. No evidence of radiolucency is present as asscssed on an undistorted
radiograph.
3. The mean vertical bone loss is less than 0.2m nnually after the first year of
service.
4. No persistent pain, discomfort, or infection is attributed to the implant.
5. The implant design does not preclude placement of a crown or prosthesis
with an appearance is satisfactory to the patient and dentist.

Failures in implants
An implant can be long term prosthesis when placed in ideal situation, but the
possibility of failure does exist.
The causes can be classified as follows :

A- Failure due to systemic factors : if the patient develop systemic diseases

like diabetes mellitus after implant placement which decreas the prognosis
management is by treatment of systemic condition of the patient.

B- failure due to surgical complication : implant surgery is an invasive

procedure and all precaution to maintain asepsis should be followed. Factores
which affect normal wound healing can produce implant failure. Infection of the
surgical site can lead to loss of Osseointegration. Management is by aseptic
procedures, antibiotic cover and good post operative care are essential to ensure
proper healing.

C- failure due to implant prosthetic component failure : the most common

problem includes escrow loosening and framework failure.

Causes :
1. Screw design : conical screws in the implant superstructure tend to loosen.
2. Inadequate torque application : torque is the amount of force required to
tighten the implant . the torque valuefor gold screws is about 10-20 Ncm.
3. Arch form : the arch form should be maintained because it provides cross-
arch splinting and tripod effect,which balance the prosthesis against
masticatory forces. Failure to maintain the arch form can lead to loosening
of the screw attachment and fracture of the super-structure.
4. implant loss : it is a rare complication, which occurs due to sudden of
alveolar bone dueto periimplantitis which is bone loss around an implant,the
loss may be stress induced or bacterial induced or both.
5. implant fracture : in an implant system, the abutment and prosthesis are
connected to the implant with screws.the system is designed such that the
secrws acts as stress breakers there by protecting the implant. Causes for
fracture include lack of inter-maxillary space and excessive implant loading.
6. Cantilever extensions : the greater the cantilever distance the greater is the
chance for implant fracture.
7. Inaccurate frame work abutment interface : there slrould be precisc
junction between the abuhent surface and the posthetic
framework,inaccurate fit can lead to constant tension in the componants
which lead to screw loosening or fracture.
8. Occlusal factors : there should be an equal distribution of the force.
Masticotory force are usually vertical, implant bear vertical forces better
than horizontal forces,occlusal forces should be directed vertically and the
artificial teeth should have shallow cusp and narrow occlusal table and no
premature contact in case of overdentne balanced occlusion to be used-
Fixed prosthesis with(4-6) implants generate occlusal forces approximitly
that of natural teefh while conventional detures generate one forth to one
fifth the force of natural dentition.
9. Framcwork fracture : cornrnon area of fracture include solder joint and
the point just distal to the distal most implant.
D- failure due to poor orel hygiene : in case of natural teeth the bacteria in
gingivitis affects the epithelial attachment t without loss of connective tissue and
the bone is protected ,in implant no connective tissue barrier exist therefore no
protection of bone so rneticulous oral hygiene is a must for the long term success
of the implant , manegement includes patient motivation and regular follow-up.
Precision Attachments
These attachments allowed prostheses to combine the advantages of fixed and of
removable restorations
An attachment is a precision connector made up of two parts:
✓ One part is connected to a root, a tooth or an implant.
✓ The other part to an artificial prosthesis, and is used to provide mechanical
connection between the two.

The precision attachment denture has long been considered the highest form of
partial denture therapy. It combines a fixed and removable prosthodontics in such
a way as to create the most esthetic partial possible. It also has the reputation of
lasting far longer than the conventional partial.
The precision attachment partial denture should differ only in the means of its
retention when compared to the clasp-retained partial denture.The only reason for
utilizing this mechanical device is to replace the visible clasp arm.

✓ Attachments are rigid or resilient connectors that redirect the forces of

occlusion.
✓ They are stress attenuators and absorbers.
✓ Their function is to protect and preserve soft tissue and bone, as well as
provide retention and cosmetic alternatives.

There are number of attachments available now. At the same time, attachments are
being used in all manner of restorative procedures, from partial dentures to
implant-based prostheses.

No single attachment is perfect for every application, it is critical that the

appropriate attachment be utilized for each individual case situation.
By analyzing study models and x-rays, the clinician can make several important
determinations, each of which will influence final attachment selection.

Indication of the attachment are :

1. Fixed bridgework
2. Partial Denture
3. Overdentures
4. Unilateral or bilateral free end denture
5. Implant prostheses.
Diagnostic Procedures
➢ Space will almost always be a major consideration and a problem for
precision attachment selection and use.
➢ Therefore, a diagnostic wax-up and set up is essential for every case,
regardless of what is found in the opposing arch,
➢ This diagnostic positioning of teeth on bases that will allow verification in
the mouth must be done so that tooth position can be evaluated.
➢ The final position of all teeth and the denture base, must be known to ensure
that the space requirements of the attachment system under considerations
can be met.

When insufficient space is available, either the system selected or the oral
environment must change, through surgeries ,orthodontics or tooth modification .
The clinician will need up-to-date comprehensive catalog of attachment systems
that indicates all dimensions of each unit.
In choosing all attachment system, the laboratory must have experience with the
chosen system or be willing to experiment a long with the clinician .

Classification of Precision Attachments :

There are many different types of prefabricated attachments available and they are
usually classified according to the location or shape and form:
1. Extracoronal
2. Intracoronal,
3. Radicular stud
4. Bar.

1- Intracoronal Attachments
An intracoronal attachment is one which is contained within the normal contours
of the crown portion of a natural tooth.
The placement of the attachment requires that the abutment tooth be restored with
a full or partial coverage (3/4) crown.

2- Extrocoronal attachments
are positioned entirely outside the crown contour of the tooth.
The advantages of this type of attachment are that the normal tooth contour can be
maintained, minimal tooth reduction is necessary and the possibility of
devitalizing the tooth is reduced.
Also, the path of insertion is easier for patients with limited dexterity.
It is more difficult to maintain hygiene with extracoronal attach and patients need
to be instructed on the use of hygiene accessories such as brushes etc.
3- Radicular stud and intraradicular stud type
➢ Radicular and intraradicular stud type attachments are connected to a root
reparation.
➢ The female or male is soldered or cast to a root cap coping.
➢ Some stud type attachments are directly cemented to the prepared root
without requiring a cast coping.
➢ Stud type attachments may promote improved or easier oral hygiene and
enhance the crown-root ratio due to the low profile.

Retentive attachments
Function :
1. Securing the prosthesis against forces that tend to lift it.
2. Providing periodontal support for the prosthesis
3. Transferring the forces of the muscles of mastication from the prosthesis to
the Periodontium in as nearly axial direction as possible
4. Distributing shearing forces
5. Stabilizing and/or splinting the abutment tooth.

Retentive mechanism
1. Friction between the male and female components active retention provided
by springs that fit into recesses.
2. magnetic anchor

Magnets
Indication : Some metal alloys possess magnetic properties which can be utilized
in the retention of overdentures or partial dentures
Materials :
Two different alloys are used as magnets in dentistry. These are cobalt-samarium
and iron neodymium-boron. Both of these rare earth magnets have strong
attractive forces.
Advantages :
➢ There is less need for parallel abutments as a rigid line of insertion is not
critical.
➢ Furthermore, the technique is simple, involving minimal time at the
chairside and in the laboratory.
➢ There is less need for parallel abutments as a rigid line of insertion is not
critical.
➢ Furthermore, the technique is simple, involving minimal time at the
chairside and in the laboratory.
Disadvantages :
➢ Magnets are brittle materials with a low corrosion resistance.
➢ Even when encapsuiated in stainless steel, titanium or palladium, the
coating may wear and the magnetic alloy will come into contact with saliva.
➢ The combination of saliva contact and wear has a deleterious effect on the
corrosion resistance of the material procedure
➢ Magnets are brittle materials with a low corrosion resistance.
➢ Even when encapsuiated in stainless steel, titanium or palladium, the
coating may wear and the magnetic alloy will come into contact with saliva.
➢ The combination of saliva contact and wear has a deleterious effect on the
corrosion resistance of the material procedure

The magnets are placed on the replica of the keepers and cured within the denture
base material. The overdenture abutments have a cast magnetic alloy post and
coping which is placed in the root canal. A direct pick up technique can be used at
the chairside where the magnets are directly attached to the denture with
autopolymerising acrylic.

Rigid attachments
Advantages :
➢ Minimum tipping of the abutment teeth when subjected to lateral forces.
➢ Reduction of the load on the edentulous ridge during function and
parafunction.

Disadvantages :
➢ Applied forces and movements of the denture are transmitted almost
entirely to the abutment teeth.
Rigid attachments should be used whenever possible because they place lower
demands on the edentulous ridge during function and parafunction, and require
fewer repairs than do non-rigid attachments .

Non-rigid attachments
Advantages
Reduced effect of tipping force on the abutment teeth (principle of shortening).

Disadvantages
Greater stress on the tissues supporting the denture (ridge resorption)
Bar attachment
Hader Bar
This bar can serve either as a bar joint or a bar unit or as stud.It consist of
preformed plastic bars and clips. The plastic bar is attached to the coping wax-up
and is casted with the coping. The plastic clips can be imbedded in the denture
base to gain retention .
There is no universal or ideal design is available, so if attachments are used, they
should be selected from group with the most suitable characteristics for the task
required.
However, the principle concern is always the distribution of forces to maintain
remaining alveolar ridges and teeth in an optimal state of health and to provide the
patient with improved comfort and function.

Attachment Advantages Short comings

Magnets Easy to use . Questionable retention
Easy to repair Poor lateral stability
No stress relief Corrosive'
Loosen or unthread
Expensive
Ceka, Octa-link Easy to use Expensive
Easy to repair Requires frequent
Good retention maintenance Loosen or
Stress-breaking unthread
ERA Adjustable retention Need frequent
Easy to replace replacement
Modest in cost

Zest, O-rings Inexpensive Abutments must be

Good retention. parallel
Stress-breaking Less rigid than metal
Easy to use (O-rings) to-metal
Wear more quickly
than metal
Hader, Dolder Stress-breaking Expensive
Easy to maintain
Easy to repair and replace
Pinlock, Lew Easy to maintain Expensive
Easy to use
Factors affecting attachment selection
1. Available inter-arch space.
2. Crown root ratio and alignment of the roots.
3. Type of coping.
4. Number of teeth present.
5. Amount of bone support.
6. Location of abutments.
7. Location of the strongest abutments
8. Whether the overdenture is a tooth supported or tooth tissue-supported.
9. The type of the opposing dentition whether it is complete denture,
overdenture, fixed appliance or natural dentition.
10. The maintenance problems and the cost.
11. Clinical experience and personal preference.

Advantages of precision attachment in general

1- Improved esthetic and elevated psychological acceptance.
2- Mechanical advantage :
➢ Direct the forces along the long axis of the tooth.
➢ Force application closer to the fulcrum of the tooth.
➢ Reduce non-axial loading.
➢ Decrease torqueing force.
➢ Rotational movement of the abutment.
3- In distal extension base cases.
➢ Reduce stress to the abutment.
➢ Allow rotational/vertical movement of denture base.

4- Cross arch load transfer and prosthesis stabilization.

5- Compared to conventional clasp retained partial denture

➢ Less liable to fracture.
➢ Less bulky and more esthetics.
➢ Better retention and stability
Disadvantages of precision attachment in general
1- Complexity of design. Procedures for fabrication and clinical treatment.

2- Minimal occlusogingival abutment height (4-6mm).

To incorporate attachment without overcoming.

3- Anatomy of the tooth- limited faciolingual tooth Width(incisor and canine

areas).
4- Expensive
➢ Complexity of laboratory and clinical procedure.
➢ Attachment maintenance.
➢ Repair or periodic replacement

5- Wearing of attachment components.

6- Required high technical expertise – Dentist and Technician.

7- Required aggressive tooth preparation.

8- Cooperation on the part of the patient.
➢ Difficult to insert an remove.
➢ Mentally challenged patient.
9- Increase demand on oral hygiene performance.

Bone graft
Graft : A viable tissue that after removal from a donor site is implanted with in a
recipient tissue is then restored repaired and regenerated.
Grafting : Grafting is a procedure used to replace/ restore missing tissue .
Principles of grafting
1. Host bone regeneration capacity
2. Surgical asepsis
3. Host site preparation
4. Optimization of growth factor
5. Graft immobilization
6. Soft tissue coverage

Biological mechanism
Osteogenesis : bone formation, from cells that survive in the graft and are capable
of produce new bone.
Osteoconduction : Physical effect by which the matrix of the graft forms scaffold
on which cells in the recipient are able to form a new bone.
Osteoinduction : Chemical process which stimulation of osteoprogenitor cells to
differentiate into osteoblasts that then begin new bone formation .The most widely
studied type of osteoinductive cell mediators are (BMP)(bone morphogenetic
protein).

Mechanism of bone formation in a cancellous cellular bone emanate from survival

of the osteoprogenitor cells (osteoblst & marrow cells)

Transplanted osteoprogenitor cells survive within the recipient tissue for first 3-4
days by a nutritional diffusion from the surrounding vascular tissue envelop From
3rd day – capillary buds start proliferation from surrounding tissue. Between 3rd
and 14th day – complete revascularization occur.

Healing principles
revascularization of a cancellous graft may be completed within 2 weeks . In
contrast, revascularization of cortical grafts is much slower , due to lack of
anastomoses. Grafted cortical bone particles may not entirely be replaced with
host bone at the recipient bed, but grafted cancellous bone will be completely
replaced by new host bone within the first year after transplantation.
Types of bone grafts: Autograft, Allograft, Xenograft & alloplast :
Autogenous graft
Bone is transferred from one site to other in the same individual Considered the “
gold standard ” by which other materials are judged Osteoinductive,
osteoconductive, and osteogenic properties & No risk of infection.

✓ Inraoral source : Max. tuberosity – Ramus.

✓ Extraoral source : rib ,Tibia, Iliac crest , Calvarial bone.

Advantag :
1. no immune reaction
2. all three properties present

Disadvantages :
1. Low availability of bone volume
2. Require a second operative site
3. Significant patient morbidity

Allograft
Graft is obtained from an individual other than the patient .

BMP cause differentiation of mesenchymal cells into osteoblasts

Human cadavers source

Advantage :
1. no donor site morbidity
2. large amount can be used

Disadvantages :
1. Risk of disease transmission
2. Possible infections
3. antigenicity risks
Xenograft
Naturally derived hydroxylapatite from bovine, coral
It is Osteoconductiv, Similar structure, chemistry, and porosity of human bone.
Disadvantages : Risk of disease transmission - Remains in the defect for years -
Continuous macrophage activity.

Alloplast
a naturally occurring mineral that is also the main mineral component of bone
1. Hydroxyapetite
2. Polymers
3. Bioactive glass
4. Calcium sulphate

Grafting Application
1- Alveolar socket preservation

2- Onlay grafting Procedure

3- Alveolar bone split osteotomy: Used to increase ridge thickness

4-Maxillary sinus lift

Complication of grafting
1. Soft tissue dehiscence
2. Infection
3. Mobilization of the graft
4. Graft resorption
5. Cyst formation
6. Transmission of diseases

Complete Edentulism Classification

Definition
Complete Edentulism : The physical state of the jaw or jaws following removal of
all erupted teeth and the condition of the supporting structures available for
reconstrictive or replacement therapy.
Edentulism, is total tooth loss, is more prevalent among persons with less than a
high school education, those without dental insurance, non-Hispanic blacks, and
current everyday smokers

Complete Edentulism
1. Bone Height of the mandibular only , Despite the lack of unknown etiology
identification and measurement of the residual bone height is the most easily
quantity calculated as an objective criterion, since loss of denture supporting
structures always occurs for an edentulous mandibular ridge. This represents a
measurement of the chronic debilitation associated with mandibular complete
edentulisim. Continued decrease in bone volume affects: The continued decrease
in bone volume effects :
1. denture- bearing area;
2. Tissue remaining for reconstruction.
 3. Facial muscle support.
4. Total facial height.
5. Ridge morphology.
The importance of various co-factors is unknown.
Residual bone height can be radiographically surveyed, still technique variations
together with the different manufacturer's magnifications of panoramic machines.
To minimize the variability in radiographic technique measurements should be
made at the portion of the mandible with the least vertical height.

Values assigned to one of the following types measured at the least vertical height
of the mandible, to which the patients are classified :
Type I (most favorable): residual bone height of 21mm or greater
Type II - residual bone height of 16-20mm .
Type III - residual bone height of 11-15mm .
Type IV - residual vertical bone height of 10 mm or less measured at the least
vertical height of the mandible.

2. Residual Ridge Morphology

Type A
1. Anterior labial and posterior buccal vestibular depth that resists vertical
and horizontal movement of the denture base
2. Palatal vault morphology that resists vertical and horizontal movement of
the denture base
3. Sufficient tuberosity definition that resists vertical and horizontal
movement of the denture base
4. Hamular notch is well defined to establish the posterior extension of the
denture base
5. Absence of tori or exostoses.
Type B
1. Loss of posterior buccal vestibule.
2. Palatal vault morphology resists vertical and horizontal movement of the
denture base.
3. Tuberosity and hamular notch are poorly defined, compromising
delineation of the posterior extension of the denture base.
4. Maxillary-palatal tori and\or lateral exostoses are rounded and do not
affect the posterior extension of the denture base.
Type C
1. Loss of anterior labial vestibule.
2. Palatal vault morphology offers minimal resistance to vertical and
horizontal movement of the denture base.
3. Maxillary palatal tori and\or lateral exostoses with bony undercuts that do
not affect the posterior extension of the denture base.
4. Hyperplastic, mobile anterior ridge offers minimum support and stability
of the denture base.
5. Reduction of the post molar space by the coronoid process during
mandibular opening and\or excursive movements.

Type D
1. Loss of anterior labial and posterior buccal vestibules
2. Maxillary palatal and/or lateral tori-rounded or undercut- that interferes
with the posterior border of the denture.
3. Hyperplastic, redundant anterior ridge
4. Palatal vault morphology that does not resist vertical or horizontal
movement of the denture base
5. Prominent anterior nasal spine

3. Muscle Attachments to the mandible only,

Type A
Adequately attached mucosal base without undue muscular impingement during
normal function in all regions.
Type B
Attached mucosal base in all regions except labially from canine to canine.
Mentalis muscle attachment near crest of alveolar vestibule ridge.
Type C
Attached mucosal base in all regions except anterior buccal and lingual
vestibules from canine to canine.
Genioglossus and mentalis muscle attachment near crest of the alveolar ridge.

Type D
Adequately attached mucosal base only in the posterior lingual region.
Mucosal base in all other regions are detached.
4. MaxillomandibuIar Relationship
The classification of the maxillomandibular relationship characterizes the position
of the artificial teeth in relation to the residual ridge and\or to opposing dentition .
Examine the patient and assign a class as follows :

Class I : the most favorable

Maxillomandibular relationship allows tooth position that has normal
articulation with the teeth supported by the residual ridge.

Class II
Maxillomandibular relation requires tooth positioning outside the normal ridge
relation to obtain esthetics, phonetics, and articulation. e.g.
✓ antero- posterior tooth position is not supported by the residual ridge.
✓ antero- vertical and\or horizontal overlap exceeds the principles of fully
balanced occluion.
A method for arranging artificial teeth for class II jaw relation:{ Homework}

Class III
Maxillomandibular relationship requires tooth positioning outside the normal
ridge relation in order to obtain esthetics, phonetics, and articulation; i.e.,
crossbite—anterior and/ or posterior, tooth position is not supported by the
residual ridge.

Diagnostic Classification of Complete Edentulism

Integration of diagnostic findings
A classification system for complete edentulism based on diagnostic findings, to
determine appropriate treatments for patients. 4 categories
Class I.... An uncomplicated clinical situation.
Class II
Class III
Class IV patients representing the most complex and higher risk situation.
Class I
✓ This classification level describes the stage of edentulism that is most apt
to be successfully treated by conventional prosthodontic techniques with
complete denture prosthesis.
✓ All four of the diagnostic criteria are residual bone height of 21 mm or
greater measured at the least vertical height of the mandible.
✓ Class I maxillomandibular relationship.

Class II
✓ This classification, level distinguishes itself with the noted continuation of
the physical degradation of the denture supporting structures and in
addition is characterized with the early onset of systemic disease
interactions, localized soft tissue factors and patient management (life
style considerations). Residual bone height of 16-20 mm measured at the
least vertical height of the mandible.
✓ Class I maxillomandibular relationship.
✓ Residual ridge morphology that resists horizontal and vertical movement
of the denture base (Type A, B-Maxilla)

Class III
✓ This classification level is characterized by the need for surgical revision
of denture supporting structures to allow for adequate prosthodontic
function.
✓ Additional factors now play a significant role in treatment outcomes.
✓ Residual bone height of 11-15 mm measured at the least vertical height of
the mandible.
✓ Class I, II and III maxillomandibular relationship.
✓ Residual ridge morphology has minimum influence to resist horizontal or
vertical movement of the denture base-Type C- Maxilla.
✓ Location of muscle attachments with moderate influence on denture base
stability and retention -Type C- Mandible

Class IV
✓ This classification level describes the most debilitated edentulous
condition. Surgical reconstruction is almost always indicated but cannot
always be accomplished due to the patient's health, desires, past dental
history and financial considerations.
✓ When surgical revision is not selected, prosthodontic techniques of a
specialized nature must be used in order to achieve an adequate treatment
outcome.
✓ Residual bone height of least vertical height of the mandible.
✓ Class I, II and III maxillomandibular relationships, residual ridge offers
no resistance to horizontal or vertical movement -Type D—Maxilla.
✓ Location of muscle attachments with significant influence on denture
base stability and retention—Type D and E—Mandible.