Prevalence of Loss of Permanent First Molars in a Group of Romanian

Children and Adolescents

Anca Maria Rãducanu1, Victor Feraru2, Claudiu Herteliu3, Mihai Andrei Rãducanu4

1 Ph.D, D.D.S. Associate Professor, Department of Paediatric Dentistry, Medical Faculty, Carol Davila University,
Bucharest, Romania. 2 D.D.S. Teaching Assistant, Department of Paediatric Dentistry, Medical Faculty, Carol Davila
University, Bucharest, Romania. 3 Ph.D. Associate Professor, Department of Statistics and Econometrics, University
of Economics, Bucharest, Romania. 4 D.D.S. Previously Undergraduate Student, Department of Paediatric Dentistry,
Medical Faculty, Carol Davila University, Bucharest, Romania

Abstract
Aim: The aim of this retrospective study was to evaluate the prevalence of loss of permanent first molars in a sample of
Romanian children and adolescents. Method: The study was performed using the records of all patients who had visit-
ed one of the authors at the Paediatric Dentistry Department of the Faculty of Dental Medicine, UMF Carol Davila,
Bucharest, between 2001 and 2007. The study sample was drawn from an initial sample of 849 patients, 44 of whom
had lost permanent first molars. These 44 children and adolescents, age range 8 to 17 years (median age: 13 years and
10 months) had lost 57 permanent first molars as a result of extractions. The data collected from the patients’ records
were statistically tested using descriptive methods as well as using multivariate techniques. Results: The percentage of
children and adolescents with extracted permanent first molars was 5.2%. The number of patients with extraction of
these teeth increased with age and the most frequently extracted molars were lower left and right first molars. The per-
manent first molars were mainly lost after the age of 11 years and the resulting post-extraction space rarely underwent
spontaneous space closure. Conclusions: Just over 5% of the children and adolescents included in this study had lost
permanent first molars. In the children and adolescents studied, the vast majority of permanent first molar extractions
took place after the age of 11 years, too late for spontaneous space closure. The loss of permanent first molars can be
avoided if good preventive measures are instigated before these teeth erupt and are continued after they have erupted.

Key Words: Permanent First Molars Loss, Children and Adolescents, Romania

Introduction range from restoring the tooth to maintain its pulpal

Permanent first molar teeth usually erupt when a vitality to devitalisation and endodontic treatment,
child is six years of age. They are considered to be possibly followed by the provision of a crown, and
the most important permanent teeth because of to early extraction [1,2,4,7].
their numerous roles in the development and main- The negative consequences of early extraction
tenance of the occlusion [1,2]. can be prevented or reduced by establishing the
The important role of these teeth in the correct optimum moment for extraction and by early ortho-
development of the adult dentition can be compro- dontic and/or prosthetic treatment of the edentulous
mised by their vulnerability to dental caries and space [2,4,7].
developmental structural defects which, without A number of previous studies have reported
treatment, can lead to their progressive destruction the prevalence of tooth loss in children. Al-Emran
[1,2,3,4,5,6,7]. (1990) reported that the overall prevalence of miss-
A number of factors have to be considered ing teeth in Saudi Arabian children aged from 13.6
when planning treatment for carious first molars. to 14.6 years, including extractions and trauma,
They include the degree of destruction of the was 13.6% [8]. Tooth extraction was the most com-
crown, the extent to which the pulp has matured, mon cause of tooth loss (8.6%), followed by
the presence/absence and nature of pulpal damage, hypodontia (4%) and trauma (1%). The mandibular
the attitude and wishes of the patient and his/her first molar was the most frequently extracted tooth
parents; all have to be considered. Treatment may [8].

Corresponding author: Dr. Victor I. Feraru, Str. Ionel Perlea Nr. 12, Bucharest, Romania;
e-mail: victor.feraru@gmail.com

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A Mexican study [11] into tooth loss in a group Clinical examinations were performed using a
of children aged from 7-13 years found that it was dental mirror and a dental probe. Data from the
at least 7.5% and that the prevalence of lost first clinical examination were supplemented with a his-
permanent molars was 2.1%. Loss of permanent tory of any extractions. These histories were
first molars was more common (70% of all first obtained by asking the patients concerned for their
molars lost) in the mandibular arch [9]. memories of the extraction(s) and from existing
A recent study in the North of England report- narratives in the patient records. The following data
ed that 8% of the 17-year-olds who were examined
were also extracted from the patient records:
had had permanent first molars extracted [10].
patient’s first and second names, address, age, sex,
Previous Romanian studies have reported that
dental status (caries, fillings, missing teeth, crowns,
in 13-14-year-old children who had not received
systematic (regular) dental care, the frequency of bridges, and removable prostheses), if applicable,
extracted or scheduled-to-be-extracted permanent the date and causes of loss of permanent first
first molars was between 30 and 40% [11,12]. molar(s) and the post-extraction consequences
(continued eruption of the opposing tooth, horizon-
Aims tal drift of the neighbouring teeth, maintenance of
The aims of the present study were to evaluate: the post-extraction space, its reduction or complete
1. The prevalence of the permanent first molar closure by tipping or other movement of the neigh-
loss and its aetiology in a group of Romanian chil- bouring teeth).
dren and adolescents. An adapted version of the International Caries
2. Post-extraction movement of adjacent and Detection and Assessment System (ICDAS) [13]
opposing teeth, taking into account the sex, age, was used to assess the permanent first molars as:
and the time elapsed from the moment of the
0 = Sound.
extraction.
1 = Enamel caries without cavitation (instead
3. The status of remaining permanent first
molars in children who had had at least one perma- of first visual change in enamel and distinct visual
nent first molar extracted, compared to children change in enamel).
with no extraction of permanent first molars. 2 = Caries with cavitation (instead of localised
enamel breakdown, underlying dark shadow from
Methods dentine, distinct cavity with visible dentine, exten-
A cross-sectional retrospective study was carried sive distinct cavity with visible dentine), where
out in the Paediatric Dentistry Department of the direct restorations are possible.
Dental Medicine Faculty of the UMF Carol Davila, 3 = Coronal destruction by decay, where indi-
Bucharest, Romania, using a convenience sample rect restorations are required.
of all children and adolescents who had consulted 4 = Where conservative treatment is no longer
and been treated by one of the authors (AMR) possible.
between 2001 and 2007. 5 = Restoration in need of re-intervention
The inclusion criteria were all healthy commu- (instead of lost or broken restoration and temporary
nicative children (older than five years and younger restoration).
than 18 years) with at least one fully erupted per- 6 = Correct restoration (instead of tooth-
manent first molar.
coloured restoration and amalgam restoration;
The exclusion criteria were healthy but uncom-
sealant restoration).
municative patients, patients with various mental
7 = Extracted (instead of tooth missing because
disabilities, patients younger than the age of five
of caries and tooth missing for reasons other than
years, patients with no erupted permanent first
molar(s). caries).
Intra-examiner and inter-examiner reliability 8 = Prosthetic treatment (instead of stainless
tests were performed. The best intra-examiner reli- steel crown, porcelain or gold or porcelain-fused-
ability was obtained by the senior examiner to-metal crown or veneer).
(AMR), who achieved a kappa score of 0.97. It was The post-extraction space was evaluated by
therefore decided that she would perform all the visual inspection and with the use of a graduated
examinations, minimising the degree of variability dental probe. Apparent vertical and horizontal post-
associated with different examiners. extraction movements were measured.

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 OHDMBSC - Vol. VIII - No. 3 - September, 2009

The children/adolescents or their parents were ed permanent first molars, and 13 because they had
asked how long ago the extraction(s) had taken place. mental disabilities. Thus the final sample was 849
The dependent variables in the study were the patients, 422 (49.7%) girls and 427 (50.3%) boys.
time since the permanent first molar(s) had been They were between five years and five months and
extracted and the consequences of the extraction(s) 17 years and six months old (median age 13 years
on the position of adjacent teeth. 10 months).
Post-extraction tooth movement was assessed A total of 44 children (5.2%) from the sample
in terms of two variables, which were horizontal had missing permanent first molars and a total of 57
and vertical migration. permanent first molars were missing, representing
Horizontal migration was assessed as: 1.71% of the total number of permanent first
- Maintained space (1). molars in the overall sample. Thus 32.7% of all per-
- Space diminished by horizontal tooth move- manent first molars had been extracted in the 44
ment (2). children and adolescents who made up the sample
- Space diminished by tilting (3). The mean age of the children and adolescents
- Space closed (4). with missing first molars was 11.3 years (SD=3.51
Vertical migration was assessed as either years) and the median age was 10.6 years (range
extruded (over-eruption of the opposite tooth) (1) 5.2–17.9 years). The age distribution of the chil-
or not extruded (0). dren with extracted permanent first molars can be
Independent variables used in the analyses seen at Figure 1.
were: gender, age, time elapsed since the extrac- Eleven children presented with more than one
tion, location of permanent first molar extracted permanent first molar, of whom six were
(upper/lower, left/right—16, 26, 36, 46) and the girls (five with two extracted molars and one with
tooth’s status (nominal discrete variable, as three) and five boys (four with four extracted
described previously). molars and one with three) (Table 1).
The “reason for extraction” was measured on a Fifty (87.7%) of permanent first molars were
nominal scale and limited to two possibilities: lost due to dental caries and seven (12.35) were lost
caries and molar–incisor hypomineralisation due to MIH.
(MIH), constituting a dichotomised variable. Forty (more than 70%) of the extracted perma-
Data were analysed using statistical software nent first molars were from the mandible, of which
(SPSS version 15; SPSS Inc, Chicago, USA). The 20 (35.1%) were lower left and 20 (35.1%) were
chi-square test was used to assess associations. lower right permanent first molars. In the maxilla,
nearly twice as many upper-left permanent first
Results molars (11-19.3%) had been extracted as upper-
From the initial sample of 1016 patients, 167 right permanent first molars (6-10.5%) (Figure 2).
were excluded: 77 because they were younger than A chi-square test indicated that the higher inci-
five years of age, 52 because although healthy they dence of extractions for mandibular molars was sta-
were uncooperative, 25 because they had no erupt- tistically highly significant (P<0.0001).

Table 1. Distribution of Children With Missing Permanent First Molars

Number of permanent % of total examined
first molars extracted
Total affected 44 5.2
% of affected cases
One tooth missing 33 75.0
Two teeth missing 9 20.5
Three teeth missing 2 4.5
Mean number missing per child 1.3
% of total number of missing teeth
Missing from mandible 40 70.2
Missing from maxilla 17 29.8

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Figure 1. The age distribution of the children with extracted permanent first molars.

Figure 2. Distribution of
loss of permanent first
molars by quadrant.

Table 2. Carious Experience of Permanent First Molars Using the Modified ICDAS Codes
ICDAS Code Molars in patients with missing Molars in patients without
permanent first molars missing permanent first molars
0 3.4% (n=6) 27.7%
1 6.8% (n=12) 19.3%
2 33% (n=58) 40.9%
3 1.7% (n=3) 0.9%
4 7.4% (n=13) 2.5%
5 9.1% (n=16) 3.2%
6 6.3% (n=11) 5.5%
7 32.3% (n=57) 0%
8 - -

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Table 3. Modification of the Post-Extraction Space Related to the Age of the Patient When
the Permanent First Molar was Lost
Maxilla Mandible
Favourable* Unfavourable** Favourable* Unfavourable**
9-10 years 7 1
10-11 years 1
11-12 years 1 1
12-13 years 1
13-14 years 1 5
14-15 years 3 1
15-16 years 1 9
16-17 years 1
17-18 years 1
*Horizontal corporeal migration; complete space closure
**Tilting, extrusion of the antagonist tooth

The carious experience of permanent first tions. The percentage of healthy (caries-free) per-
molars still present in the mouths of patients who manent first molars in patients who had had perma-
had had other first molars extracted was higher than nent first molar extractions (3.4%) was lower than
in patients with no permanent first molar loss. in patients without permanent first molar extrac-
The results of the evaluation of caries experi- tions (27.7%) (Figure 3).
ence in permanent first molars as assessed with the Post-extraction migration occurred as follows:
modified ICDAS codes are presented in Table 2. z Over-eruption of opposing teeth: 12 occur-
Caries was present in 58 (33%) permanent first rences (21.1%).
molars in the 44 patients who had had previous per- z Horizontal migration of the neighbouring
manent first molar extractions, whereas it was pres- teeth: 22 occurrences (38.6%).
ent in 40.9% of the permanent first molars of the z Space reduced by tipping: 12 occurrences
805 patients without previous first molar extrac- (21.1%).

Figure 3. Percentages of all molar teeth in the different modified ICDAS Codes in children with and with-
out loss of permanent first molars.

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Figure 4. The frequency of permanent first molar loss by age groups (%).

z Space reduced by translation: 7 occurrences tical influence (P=0.11) on the occurrence of hori-
(12.3%). zontal migration, neither did gender (P=0.65).
z Space completely closed: 3 occurrences Similarly, vertical drifting (over-eruption) was
(5.3%). seen to occur more frequently in patients from
z Dual drift (horizontal and vertical): 2 occur- older age groups: in six (50%) from the 15-16 years
rences (3.5%). group and in six (50%) of the 17 years and older
Very slightly more girls (22 of 422; 5.2%) than group. In total, vertical drifting (over-eruption)
boys (22 of 427; 5.1%) had lost permanent first occurred in 12 patients and horizontal drifting
molars. This was no statistically significant differ- (migration) in 22 patients.
ence when the chi-square test was applied. Continuous tooth eruption was encountered
The frequency of permanent first molar loss by more frequently when the extraction was per-
age in the groups (under 13; 13-14; 15-16; and 17 formed in the mandible (P=0.02). The appearance
and over years) is presented in Figure 4. of spontaneous vertical migration was not influ-
Unsurprisingly, it increased with age. enced by the patient’s gender (P=0.58).
Post-extraction space appeared to be more fre- Spontaneous vertical migration of the tooth oppos-
ing an extracted permanent first molar appeared at
quently maintained in the mandible than in the
least one year after the extraction.
maxilla. Nevertheless, because of the relatively low
The age at which a permanent first molar
numbers of maxillary permanent first molar extrac-
extraction occurred had a significant influence on
tions, proportionally there was no difference. Space
post-extraction tooth positioning in both maxillary
was maintained after three (50%) upper-right first
(P=0.02) and mandibular (P<0.001) arches. Data
molar extractions and after ten (50%) lower-left concerning the modifications of the post-extraction
permanent first molar extractions and after eight space are presented in Table 3.
(75%) upper-left permanent first molar extractions Most of the favourable modifications (n=7)
and after 14 (75%) lower-right permanent first following a permanent first molar extraction in the
molar extractions. There was no statistically signif- mandible occurred before the age of 10 years. The
icant difference (P=0.57). only patients with the complete closure of the post-
Post-extraction horizontal migration (drifting) extraction space in the mandible were younger than
occurred after 31 of the 57 extractions (54.6%). Its 10 years at the time of the extraction.
occurrence increased with the age of the patient and In the maxilla, although data are insufficient to
unsurprisingly was commonest in those aged 17 obtain a statistically valid conclusion, it seemed
years. The location of the permanent first molar that favourable evolutions of the post-extraction
extractions (maxillary or mandibular) had no statis- space extend until the age of 12 years.

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Discussion mandible confirmed the findings of other studies

Although the initial sample of over 1000 patients [8,9]. Possible reasons for this may be the earlier
was large, the number with missing permanent first eruption of the mandibular molar and its higher
molar teeth was relatively small and even smaller caries-risk due the complex occlusal fissure system
when they were subdivided by age and gender. that predisposes to bacterial plaque accumulation.
There may also be doubts about whether or not the Previous studies have indicated that in order to
sample children were representative of all children minimise negative consequences following perma-
in Bucharest and Romania. The results obtained in nent first molar extraction and to obtain space clo-
this study must be viewed in the light of these con- sure by subsequent drifting of the teeth, it is neces-
siderations. sary to perform the extraction(s) at an optimal time.
The percentage of children who had experi- This has been suggested by one study to be 8.5-10
enced the extraction of permanent first molars and years in the mandible and as late as 10-11.5 years
the frequency of the loss of these teeth was slightly in the maxilla [15] and to be less than 10 years of
lower in the current study than in previous ones age by another study [6]. Although the present
[8,9,10,11,12]. However, valid comparison cannot study did not assess the ideal moment of extraction,
be made as the age groups are not comparable. In its results confirm that the only patients who pre-
the current study, patients had a wide age range. sented with complete closure of the post-extraction
One strength of the study is that the examina- space in the mandible were younger than 10 years
tion of all the patients was performed by a single when their permanent first molars were extracted.
calibrated examiner, who obtained the best rating This result supports the findings of Jälevik and
of the intra- and inter-examiner reliability tests, and Möller (2007), who assessed favourable sponta-
thus we minimised the degree of variability associ- neous space reduction and development of the per-
ated with different examiners. manent dentition and found that it can be expected
Another feature of the study was the opportu- without any intervention in the majority of cases
nity to assess the prevalence of extractions and extracted prior to the eruption of the second perma-
sequelae over a number of years. nent molar [17].
A weakness of the study was the possibility of Although relatively few patients who had lost
errors in the assessment of the post-extraction spa- permanent first molar teeth were assessed in the
tial dimension as this was by clinical methods only, present study, the finding of a greater prevalence of
without any radiological evaluation or from dental post-extraction horizontal rather than vertical
casts. This was because the study was retrospective migration was in conflict with that of at least one
and it would have been unethical to take radi- previous study, which found that over-eruption of
ographs years after the extraction of the permanent the opposing tooth was the main consequence of
first molars just to assess space loss. Further stud- the loss of the permanent first molar [18].
ies are planned which will be longitudinal and per- However, in the present study the patients con-
formed on a representative sample of patients. cerned came from a far wider age range.
Another potential weakness may be the relia-
bility of the information obtained regarding the Conclusions
date of the extractions, because it often depended Just over 5% of the children and adolescents
on the answers given by patient/parents, which may included in this study had lost permanent first
have been imprecise. This situation is inherent to molars. This was probably due to the fact that these
this type of study and could have been avoided only teeth erupt earlier than any other permanent teeth,
if all the extractions had been performed in our other than lower incisors, and are therefore exposed
clinic. to the rigours of the oral environment for a longer
An association between gender and prevalence period of time. In the children and adolescents stud-
of loss of permanent first molars could not be sta- ied, the vast majority of permanent first molar
tistically established. However, as expected, this extractions took place after the age of 11 years, too
prevalence increased with the age of the patients. late for spontaneous space closure. The loss of per-
The finding that there had been a higher proportion manent first molars can be avoided if good preven-
of permanent first molar extractions in the tive measures are instigated.

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