Permanent First Molars Clinical Status among School Children Aged 8-12 Years in Kathmandu

Introduction: Common oral diseases affecting school children are dental caries, gingivitis and malocclusion. Teeth mostly affected by dental caries in permanent dentition of children are the permanent first molars. Permanent first molars are key factors in occlusion and are most susceptible to dental caries. They maintain arch perimeter and provide best anchorage. Loss of these teeth leads to various problems like space management, tooth migration, problem in mastication and malocclusion. Objective: To assess the clinical status of first permanent molars among 8-12 year school children of Kathmandu. Methods: A cross-sectional study was done among 220 schoolchildren of age 8-12 years randomly selected from 2 private and 2 public schools of Kathmandu. Dental caries, gingival and oral hygiene status were measured by Decayed Missing Filled teeth (DMFT) index, Gingival index and Oral hygiene index-Simplified (OHI-S) respectively. Data was entered in Epidata 3.1 and analyzed in SPSS version 20. Results: The prevalence of dental caries in first permanent molars for study population was 54.5%. Mean DMFT score of first permanent molars was 0.96+1.2. Out of 867 molars examined, 197 (22.7%) were decayed. 98.5% of molars were erupted. Among the total study population, 184 (83.6%) had fair oral hygiene and 203 (83%) had gingivitis. Conclusions: This study shows the need to improve oral health status of first permanent molars of school children through promotion of dental health awareness and curative public health measures at school level.


INTRODUCTION
teeth to erupt in the oral cavity followed by permanent maxillary first molars. They erupt distal to primary second molars and have no predecessor. The presence of deep pits and fissures also makes it difficult for these teeth to be kept plaque free. 5 Being the first permanent teeth to erupt, they have the most susceptibility to caries attack. 6 Permanent first molars are important as they bear maximum occlusal load, maintain arch perimeter, and provide the best anchorage. They serve as a key factor in occlusion and as growth centers and their presence influences vertical height of upper and lower jaws and other esthetic properties. 7 Extraction or removal of these teeth leads to various problems in space management, tooth migration, mastication and proper occlusion. 8 In the age group of 8-12 years old, first permanent molars will have already been erupted and exposed to oral environment for 2-6 years. So, these teeth may have been affected by various oral health problems like dental caries, gingivitis and poor oral hygiene in absence of preventive measures. Thus, this study attempts to assess the clinical status of permanent first molars among school children aged 8-12 years old of Kathmandu.

METHODS
A cross sectional descriptive study was conducted among 8-12 years old school children of Kathmandu district. Data collection was done from November 1st -30th, 2017.
Sample size was calculated using the following formula: Taking the prevalence rate of dental caries as 85% from a study in Nepal, 9 the calculated sample size was 204 (approx. 220). Four schools (2 public and 2 private) were selected by convenient sampling method and the school children of particular age group (8-12 years) were randomly selected and included in the study. The children who were medically compromised, absent on the day of examination and who refused to give consent to participate in the study were excluded from the study.
Ethical approval was taken from Institutional Review Committee (IRC) of Kantipur Dental College and Hospital prior to the study. Written permission for conducting the study was taken from the Principals of each of the schools and verbal consent was taken from each participant.
Data were collected and recorded in a pre-designed proforma comprising two parts: first part included demographic details and personal history while the second part included clinical examinations with selected standard indices. Dental caries, gingival and oral hygiene status were measured by Decayed Missing Filled Teeth (DMFT) index, Gingival index and Oral hygiene index-Simplified (OHI-S) respectively. Intra-examiner reliability was tested by Kappa Coefficient among 22 (10% of the sample) who were not included in the main study. Kappa value for DMFT, Gingival indices and OHI-S were, 0.80, 0.70 and 0.89 respectively. Only fully erupted permanent first molars were included in the study.
Examination was done using mouth mirror, probe and explorer under natural light. Aseptic measures were followed during the examination for infection control.Data was entered in Epidata version 3.1 and analyzed using statistical package for social sciences (SPSS version 20).

RESULTS
Out of the total 220 school children examined, 109 (49.5%) were boys and 111 (50.5%) were girls. Total number of students in private and public schools were taken as 110 in each group. The prevalence of dental caries in first permanent molars among the school children was 50%, wherein caries prevalence among boys was 45.9% and among girls it was 54.1%. Among this prevalence the private school children showed caries prevalence of 57.3% and it was 42.7% among the public school children. Of the total 880 permanent first molars examined, 13 (1.5%) were partially erupted. Out of fully erupted 867 permanent first molars, 197 (22.7%) were decayed. Mean DMFT score of the study population was 0.96. There was no statistically significant difference in mean DMFT score according to gender-wise (p-value = 0.24) and school type (p-value = 0.17) ( Table 1)   OHI-S score of the study population was 1.9 and there was no statistically significant difference in mean OHI-S score according to gender (p-value = 0.07). The public school children had greater OHI-S score than the private school children and this difference was found to be statistically significant (p-value < 0.005) ( Table 2).

DISCUSSION
The present study was conducted to assess the clinical status by dental caries, oral hygiene and gingival status of permanent first molars among 8-12 years old school children of Kathmandu. Only the permanent first molars were examined as they play a key role in predicting the dental health of an individual.
In this study, the dental caries prevalence was found to be 50%. In studies conducted by Devaki et al. 5  The absence of severe gingivitis among the study participants is in accordance with the finding that majority had fair oral hygiene. However, majority having gingivitis, though in mild form, reflects irregular brushing methods.
There was statistically significant difference in the mean gingival scores between private and public school children among which the public school children had a higher gingival score. This indicated better gingival health among private school children, attributing the study of having a lower oral hygiene score i.e. better oral hygiene among private school children. However, there was no significant difference in mean gingival score among male and female students.

CONCLUSIONS
This study presents the clinical status of permanent first molars among the school children and the need to improve the oral health status of first permanent molars of school children. This could be done through promotion of