Aim: assessment of dental status and treatment needs for immature first permanent molar (FPM).
Material and method: descriptive retrospective observational clinical study on dental files of 200 children (91 boys) aged between 6-9 years from the Pedodontics Clinic, Carol Davila University, Bucharest. Data about age, sex, FPM dental status at the first visit were selected. Caries prevalence index for FPM (IpFPM) and caries experience indices DMF-T/SFPM were calculated. The distribution and severity of carious lesions and hipomineralisation were assessed, as well as the treatment methods applied. Statistical analysis was performed with SPSS 20.0, using t-test (p<0.05).
Results: a) IpFPM=67.5% (Ipboys=62.63%, Ipgirls=71.55%; p>0.05); DMF-TFPM=1.66±0.80; DMF-SFPM=2.39±1.22; b) FPM status at the first visit (778 FPM examined): 57.20% – caries-free, 35.73% – uncomplicated caries, 4.24% – complicated caries, 1.03% – second caries of a filling, 1.80% correct fillings. Status of FPM with uncomplicated caries – cavitary lesions: 17.98% – superficial; 28.05% – medium; 32.02% – deep; non-cavitary lesions: 21.95%. Status of FPM with complicated caries: 39.39% – pulpitis, 60.61% – necrosis; c) 193 M1p were diagnosed with hipomineralisation (MIH): 147 (76.16%) with mild lesions, 17 (8.81%) – moderate lesions and 29 (15.03%) – severe
lesions. 63 M1p with MIH (32.64%) also had carious lesions: 87.31% uncomplicated caries and 12.69% complicated caries. d) Treatment – uncomplicated caries: 62.5% – modified or classical technique, 37.5% – minimally-invasive technique; complicated caries:76% – endodontic treatment, 24% – extraction.
Conclusions: The increased prevalence of caries on immature FPM, as well as the presence of complicated caries in the age group 6-9 years impose the need for regular dental check-ups so as to detect carious processes at an early stage with the possibility of minimally invasive treatments.
Key-words: first permanent molar, decay, treatment.
First permanent molar (FPM) is important because of the contrast between its major role in maintaining the balance of the dento-maxillary apparatus and its increased caries vulnerability. Because of the early appearance on dental arches, and of having an occlusal surface with numerous pits and fissures, it is quickly exposed to the action of factors with carious potential.
There are numerous studies showing that the prevalence of caries in FPM is increased, even shortly after its eruption [1-5]. Even in developed countries, where caries prevention measures are conscientiously applied, FPM has carious lesions, especially on the occlusal surface. In fact, Pinkham et al. (2005)  showed that 90% of caries in children and adolescents are affecting the occlusal surface.
In addition, FPM can be affected by MIH syndrome, defined by the presence of at least one hypomineralized FPM, frequently associated with hypomineralization of the incisors . It is well known that at the level of structural defects carious lesions graft very easily and have a rapid evolution in depth.
Therefore, regular monitoring of FPM since its eruption is important. However, clinical experience shows that, often, patients are brought
to treatment quite late, the parents considering it as a primary tooth. Therefore, firstly, the vitality of the tooth is endangered and, secondly, its
resistance over time is weakened, requiring multiple and expensive therapeutic maneuvers or even tooth extraction.
In this context, the aim of this study was to assess the dental status and the need for treatment on FPM in a group of children aged 6-9 years treated in a specialized pediatric dentistry clinic.
Material and method
A retrospective descriptive observational cross-sectional clinical study was performed on the dental files of a group of 200 children aged between 6 and 9 years, examined in the Pedodontics Department, University of Medicine and DMFPharmacy “Carol Davila” Bucharest, during 2015-Patients without associated general conditions (non-syndromic), having at least one FPM
erupted on the arch,were included in the study.
Data on the age and sex of the patients, the number of FPM present on the arch, the dental status of FPM at the first clinical visit of the patient, the
presence of carious lesions and / or developmental abnormalities were selected from the files.
Statistical analysis of the data collected was performed with SPSS 20.0. The following were calculated: caries prevalence index of FPM (IpFPM), caries experience indices of FPM (DMF-T/SFPM) calculated for the whole group,
and for age groups and sexes, MIH prevalence index (IpMIH). The distribution and severity of carious lesions, the topography and severity of
developmental defects, as well as the treatment methods applied were also assessed. The statistical significance of the differences between the
mean values was determined by performing a t-test, for a chosen significance level p <0.05.
a) Age and sex distribution of the study group (n = 200 children) is presented in figure 1.
b) Carious lesions affecting the first permanent molar.
Of the 200 children studied, 135 had at least one carious lesion in FPM, the prevalence index being IpFPM = 67.5%. Reported to sex, the FPM caries frequency in boys was 71.55% and 62.63% in girls, differences being statistically significant (p<0.05).
The FPM caries experience indices at the level of the whole group has the following values: DMF-TFPM = 1.66±0.80, DMF-SFPM = 2.39±1.22, the minimum values being registered at 6 years and the maximum values at 9 years (fig.2). Depending on gender, the mean values were: in boys DMF-TFPM = 1.54±0.12, DMF-SFPM = 2.16±0.88; in girls DMF-TFPM=1.76±0.45, DMF-SFPM=2.58±0.56, differences being non statistically significant (p>0.05).
The indices were mainly represented by decay component (D); there were no extracted FPM (DT=1.59, MT=0, FT=0.07; DS=2.32, MS=0, FS=0.07).
c) FPM status
Of the 778 FPM erupted on the arch, more than half were caries-free and over 1/3 had uncomplicated caries (fig. 3).
Analyzing the status of FPM according to age, it is observed that the carious experience doubles from 6 to 9 years (tab. I).
Table I. FPM status by age
A total of 319 FPM with carious lesions were examined, out of which: 278 (87.15%) had uncomplicated caries, 33 (10.35%) had complicated caries and 8 (2.50%) had secondary caries. The distribution of uncomplicated caries according to depth was as follows: 21.95% non-cavitary and 78.05% cavitary (17.98% superficial, 28.05% medium and 32.02% deep). Of the 33 FPM diagnosed with complicated caries, 39.39% had pulpitis, 9.09% uncomplicated pulp necrosis and 51.52% complicated pulp necrosis.
Reported to the topography of the carious lesion, it was found that in 59.87% of cases the occlusal surface was affected, followed by caries affecting 2 surfaces (including occlusal-proximal) – 24.47%, by caries affectiong more than 3 surfaces – 9.08% and by caries localized in the discharge pits – 6.58%. The breakdown by age and topography is shown
in figure 4.
At the upper arch, there were statistically significant more caries-free FPM (63.48%) as compared to the lower arch (51.02%) (p <0.05). Caries lesions were symmetrically distributed on the left and right: 40.37% and 39.59%, respectively (p> 0.05).
d) MIH syndrome
Out of the total of 200 children examined, 49 had FPM with hypomineralisation (MIH sindrom): IpMIH = 24.5%.Regarding the severity of MIH type lesions, out of the 193 FPM with MIH, 147 (76.16%) had mild lesions, 17 (8.81%) moderate lesions and 29 (15.03%) severe lesions. 69.37%
of children with MIH had at least one FPM with carious lesions. Out of the 193 FPM affected by MIH, 63 (32.64%) had carious lesions, out of which 87.31% were uncomplicated and 12.69% were complicated caries, respectively.
e) Treatments performed for FPM
For FPM without MIH lesions, treatments performed were mainly fissure-sealing, preventive resin restorations (PRR)and I or II class restorations (fig. 5).
The treatments performed on FPM with MIH lesions related to the severity of the defects are presented in table II.
Table II. Treatments applied on FPM with MIH depending on severity of the defects
Analyzing the results of the present study it was found that caries prevalence on FPM for our study sample was 67.5%. The percentage is high given that the examination was performed close to the time of FPM eruption on the arch. This increased value could be explained by the fact that FPM have high vulnerability to carious attack, as well as by the fact that parents often confuse it to a primary molar and do not pay attention; the hygiene is also generally poor, especially for developing teeth. Furthermore, dental check-up presence is very low; children usually present in the dental office for an emergency of primary teeth, on which occasion caries lesiosn on FPM are detected. In extreme cases, children’s first visit is related to an emergency of the FPM, due to complicated caries. Caries prevalence index values on FPM is higher than values reported in similar studies conducted in Poland, Estonia, Russia or China, but similar to that obtained in a study from Saudi Arabia (table III).
Table III.Caries prevalence on FPM (IpFPM) – comparative data
Related to gender, boys had more carious lesions on FPM compared to girls. However, several studies claim that girls have a higher frequency of caries on FPM [1, 2, 10]; a possible explanation is that girls have an earlier eruption of FPM, a lower rate of salivary flow, lower salivary IgA concentrations and receive more sweet snacks between meals, than boys . On the other hand, Runnel et al. (2013)  and Rozakova et al. (2020)  found that boys and girls are equally affected.
Mean values of DMF-T/SFPM indices are high for the analyzed age group and show that, on average, a child has at least one immature FPM with caries on 2 surfaces. These results are comparable to those reported in similar studies (table IV).
Table IV. Caries experience indexes on FPM – comparative data
In the present study, lower FPM were more affected than the upper ones (46.69%, and 35.23%, respectively). Similarly, in the study conducted by Gudipaneni et al. (Saudi Arabia, 2020) on a sample of 420 children aged between 7 and 8 years, lower molars were more affected by caries (48.98%) than the upper ones (36.52%) .
Analyzing the status of FPM at the first visit, is found that about 40% of these have uncomplicated or complicated caries and only 3% are already treated. This implies a high treatment need for the studied age group. This idea is reinforced by the fact that both uncomplicated and complicated caries lesions are present from the age of 6 and their prevalence increases with age. Furthermore, even though occlusal caries are predominant, from the age of 6 caries affecting 2 surfaces and from the age of 8, caries affecting on 4-5 surfaces, are present.
Regarding the severity of caries lesions, it was found that uncomplicated caries are predominant, especially medium and deep ones. For complicated
caries, in most cases the clinical form of the disease was gangrene. All these aspects show the late addressability of patients to the dentist, mainly because parents consider that FPM is a primary tooth, showing the increased treatment need. Comparing the severity of caries lesions on FPM with similar studies, is noticed that frequency of FPM with uncomplicated and complicated caries was higher than values obtained in Poland, but lower than those reported in Saudi Arabia (table V).
Table V. FPM status – comparative data
Thus, for our study group fissure sealants could be applied only on 27% of FPM, minimally invasive treatment (PRR) for 23% and restorations using classical or modified classical technique for 42% of cases. About 8% of molars required pulp therapy and 1% even extractions. In a study also conducted in the Bucharest Pedodontics Department between 2008-2011, it was found that fissure sealants could be applied to only 13% of examined FPM, minimally invasive treatment in 24.24% of cases and conventional treatments in 62.76% of cases . A study conducted in Iran in 2007 on a sample of 700 children aged 7-9 years-old showed, that pit and fissure sealing of of the occlusal surfaces was most frequently performed (84.3%), followed by restorations (53.1%). Compared to the present study, endo-dontic treatment (2.4%) and extractions (0.4%) were less frequent and prosthetic treatment was also performed (1.7%) .
The increased number of untreated FPM at the moment of the first dental visit and also the presence of complicated caries in FPM, at an age close to the moment of tooth eruption, show that the situation needs to be improved, by properly educating school children and their parents about oral health.
Thus, regular dental check-ups are required as close as possible to the time of FPM eruption, to allow the pediatric dentist to apply preventive and minimally invasive treatments.
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