|Year : 2014 | Volume
| Issue : 1 | Page : 18-22
Enamel hypoplasia and its correlation with dental caries in 12 and 15 years old school children in Shimla, India
Shailee Fotedar1, GM Sogi2, KR Sharma3
1 Department of Public Health Dentistry, HP Government Dental College, Shimla, Himachal Pradesh, India
2 Department of Public Health Dentistry,KLE Institute of Dental Sciences Belgaum, Karnatka, India
3 Department of Pedodontics, HP Government Dental College, Shimla, Himachal Pradesh, India
|Date of Web Publication||18-Aug-2014|
Department of Public Health Dentistry, HP Government Dental College, Shimla 171 001, Himachal Pradesh
Source of Support: None, Conflict of Interest: None
Aim: The aim was to assess the prevalence of enamel hypoplasia and its correlation with dental caries in 12 and 15 years old school children in Shimla city, Himachal Pradesh, India. Materials and Methods: This was a cross-sectional study conducted on a sample of 1011 school children aged ranging between 12 and 15 years old in Shimla city, Himachal Pradesh, India. A modified developmental defects of enamel index was used to classify the enamel defects. The statistical tests used was Chi-square tests. P < 0.05 was considered to be statistically significant. Results: The prevalence of enamel opacities was 18.2%. At 12 years of age, the prevalence was 17.9%, whereas at 15 years it was 18.6%. The tooth prevalence of enamel opacities of the entire sample was 11.8%. At 12 years tooth prevalence was 10.9% and at 15 years it was 12.7%. There was a significantly higher prevalence of Enamel hypoplasia among males at both the age groups. The diffuse type of enamel opacity was the most commonly seen at both the age groups. A significant association was found between caries and enamel opacities (P < 0.01). The occurrence of enamel opacities was statistically higher in children with the youngest mothers. Conclusions: The prevalence of enamel defects in this study is low when compared to National prevalence (22.3% at 12 years and 23.2% at 15 years). This study revealed a significant association between enamel defects and dental caries.
Keywords: Age groups, dental caries, dental enamel hypoplasia
|How to cite this article:|
Fotedar S, Sogi G M, Sharma K R. Enamel hypoplasia and its correlation with dental caries in 12 and 15 years old school children in Shimla, India. J Indian Assoc Public Health Dent 2014;12:18-22
| Introduction|| |
Enamel is a unique mineralized tissue in its method of development, structure and chemical nature. Mature enamel, containing very little organic matrix, is the most highly mineralized and hardest tissue in the body. Enamel is so stable that it can resist heavy occlusal forces and various noxious chemicals. However, enamel is not without its weaknesses.
Developmental defects of enamel (DDE) (enamel hypoplasia's) present a wide range of features. The defects may affect a circumscribed area of one surface of the enamel or, at the other extreme; they may be widespread, affecting all surfaces of the enamel throughout its full thickness. Enamel Hypoplasia may be due to disruption in the process of enamel matrix formation, which in turn causes defect in quality and thickness of enamel.
A large number of causes have been described for enamel defects, both environmental and genetic. Enamel hypoplasia may be inherited as primary defects of enamel or may be acquired, as a result, of childhood medical problems such as infections, metabolic derangements, premature birth and nutritional disorders. The abnormal discoloration and tooth morphology associated with enamel hypoplasia may compromise esthetics and predispose the affected teeth to dental caries. 
Traditionally, dental health professionals have not regarded this as being of public health importance but they have recognized that the public's concern about esthetics could increase the potential for enamel defects to become a problem. 
At present, the severity and distribution of enamel hypoplasia vary in the different indigenous populations. Recent studies indicate that 3-15% of children shows signs of enamel hypoplasia in their permanent dentition. , As there were no earlier studies regarding the prevalence of enamel hypoplasia in school children in Shimla city, this study was conducted.
- To assess the prevalence and severity of enamel hypoplasia of school children aged 12 and 15 years in Shimla city
- To examine the etiological factors associated with enamel hypoplasia and to assess the correlation of enamel hypoplasia with dental caries.
| Materials and Methods|| |
A cross-sectional epidemiologic study was conducted among the school going children aged 12 years and 15 years in Shimla city. Ethical approval to conduct the study was obtained from the Institutional Review Board. Written consent for the participation of the children in the study was obtained from the Principals of the schools concerned.
A two-stage cluster sampling technique was used for obtaining the required sample for the study. For the purpose of the study, Shimla city was arbitrarily divided into four geographical regions, which correspond to the four varying demographic areas of the city. Schools from each region were randomly selected to obtain the desired sample size, such that there was an equal representation from each of the four zones. The fluoride level in drinking water in all the four geographical regions of Shimla city is <1.5 ppm. 
Under the municipal corporation of Shimla, there were 43 schools (12 senior secondary, 24 secondary and 7 middle), where the children in age group of 12 and 15 were available. Out of the 43 schools there were 26 government and 17 private schools as per the data available from the director of education, Himachal Pradesh in February, 2009. Total number of school children in the age group of 12 and 15 years were 6870.
The sample size was calculated by taking a prevalence of enamel opacities at 17-27% (National Oral Health Survey in Himachal Pradesh)  and computed using the Epi Info (U.S Centers for Disease control Atlanta, Georgia) - version 6 statistical package at 95% confidence interval. The calculated sample size was 985. For obtaining the required sample size, seven government and five private schools were selected randomly with proportionate representation from each zone and a total of 1011 subjects was examined over a period of 3 months April to June 2009.
- School children (male and female) who have completed their 12 and 15 years of age
- Children present on the day of examination.
- Children who refused to participate were excluded.
Data collection was carried out by one of the authors. The author was assisted by an alert and co-operative recording assistant. Data regarding general information was obtained through interview and recorded on a modified WHO proforma.  The subjects were examined by type III  clinical examination in their respective schools on a comfortable chair. A modified DDE index was used to classify the enamel defects.  Enamel hypoplasia was considered present if a tooth surface showed enamel to be either pitted, grooved or missing. Enamel opacity was considered to be a distinct change in translucency of enamel. The extent, type and color of each defect, were recorded. Subsequently, these variables were classified into three groups: Demarcated opacity, diffuse opacity and hypoplasia. Positive cases of enamel hypoplasia were given a questionnaire, to be filled by their parents regarding maternal age at the time of delivery, number of pregnancies, childhood infections and birth weight. Dental caries was diagnosed and classified using WHO criteria. 
Random sample of five students was called for a re-examination at the end of the day to ascertain the intra-examiner reproducibility. Intra-examiner reproducibility determined using the kappa statistic was 0.85. Instruments were sterilized by autoclaving at the end of the day's clinical examination. At the site, chemical sterilization was followed. A referral was forwarded to the parents of the children in need of treatment.
The data collected was analyzed by Statistical Package for Social Sciences (SPSS) package 13. The statistical tests used were Chi-square tests for categorical data and t-test for continuous variables. A P < 0.05 was considered as statistically significant, and P < 0.001 was taken as highly statistically significant.
| Results|| |
Of the total study population, 49.2% were in the 12 years age group and 50.8% were in the 15 years age group. Among the 12 years age group there were 322 (64.8%) males and 175 (35.2%) females, whereas in the 15 years age group, there were 304 (59.2%) males and 210 (40.8%) females [Table 1].
In this study, 18.2% (185) subjects had enamel opacities. At 12 years of age, the prevalence was 17.9% (89 subjects) whereas at 15 years it was 18.6% (96 subjects). In these 185 subjects, out of 1765 teeth examined, 210 (11.8%) had enamel hypoplasia. Out of these 210 hypoplastic teeth 91 teeth (10.9%) were affected at the age of 12 years, and 119 teeth (12.7%) were at the age of 15 years [Table 2]a]. Mean number of enamel defects teeth per child was 0.233 at the age of 12 years and 0.252 at the age of 15 years. There was a significantly higher prevalence of Enamel hypoplasia among males at both the age groups.
The diffuse type of enamel opacity was the most commonly seen defect affecting 7.4% of subjects at 12 years of age and 7.9% of subjects at 15 years of age. This was followed by demarcated type of defect and then enamel hypoplasia at both the age groups [Table 2]b].
|Table 2: Prevalence of enamel opacities according to subjects and teeth and type of defect |
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[Table 3] shows the prevalence of dental caries according to age and gender. Three hundred and seventy-nine (37.4%) of total children had at least one decayed tooth with a mean of 0.84. Dental caries was found in hypoplastic teeth also. In 1011 subjects, 298 (78.7%) had dental caries without enamel hypoplasia and 81 (21.3%) had enamel hypoplasia with dental caries. Out of 26863 teeth without hypoplasia 1054 (3.9%) had at least one decayed tooth with a mean of 2.6. Out of 210 hypoplastic teeth 99 (47.1%) had dental caries. A significant association was found between caries and enamel opacities (P = 0.004) [Table 4].
|Table 4: Association of enamel hypoplasia and dental caries (subjects-wise and teeth-wise) |
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There was no significant difference in the prevalence of enamel opacities by socio-economic status. Subjects were divided into five different categories based on their mothers' ages at the time of their birth. Analysis of enamel opacities by maternal age showed a statistically significant difference among the groups (P = 0.012), with the highest occurrence among the children with the youngest mothers (<20 years) at 30% versus 20% for Group II (20-24 years), 22% for Group III (25-29 years), 11% for Group IV (30-34 years), and 17% for Group V (>35 years). Analysis of enamel opacities by number of previous pregnancies showed statistically higher prevalence in mothers with multiple pregnancies. This study shows 20% prevalence of enamel opacities in low-birth weight children [Table 5].
| Discussion|| |
A cross-sectional study was carried out to assess the prevalence of enamel opacities and to assess its correlation with dental caries among school children in Shimla city, Himachal Pradesh, India. The 12 and 15 age groups were chosen for this study as these are global monitoring ages for dental caries for international comparisons and monitoring of disease trends. The present study sample consisted of school children from both public and private schools in order to have representation of children from all the social, economic and cultural communities.
In this study, 18.2% of subjects had enamel hypoplasia which is higher than 13% as reported by Idiculla et al.  but is lower than reported by Daneshkazemi and Davari  (32.7%), Nik-Hussain  (56%), Dummer et al.  (53%) and Mackay and Thomson  (51.3%). The prevalence of enamel opacities was lower at 12 years of age when compared to 15 years, which may be due to less exposure to some etiological factors than those at 15 years as also observed by Sedano et al. 
There was significantly higher prevalence of enamel hypoplasia among males at both the age groups, which were also reported by Slayton et al.,  and Dummer et al.  but in contrast to Oral Health Survey and Fluoride Mapping 2003  where no difference was reported among gender regarding enamel hypoplasia.
There was significantly higher prevalence of diffuse type of enamel opacity affecting 7. 4% of subjects at 12 years of age and 7.9% of subjects at 15 years of age, which was also reported by Idiculla et al.,  Nik-Hussain  and Kanagaratnam et al.  and Sujak et al. 
In this study, the maxillary central incisors showed the highest prevalence followed by the mandibular first molars. The least number of hypoplastic teeth involved were the maxillary canines. These similar findings were observed by Jackson et al.,  Li et al.  and Golpaygani et al. 
As we could be inferred from [Table 4], the prevalence of caries in hypoplastic teeth is evident. The association between dental caries and enamel opacities was statistically significant which was also observed by Seow,  Golpaygani et al.,  Hong Levy.  This may be because in addition to the lack of maturation the presence of developmental structural defects in enamel may increase the caries risk. Gillepsie  in a study on enamel hypoplasia and dental caries found that, caries superimposed on hypoplastic teeth becomes more extensive as the age advances, which is also seen in this study.
In this study, analysis of enamel opacities by maternal age showed a statistically higher prevalence of enamel opacities among the children with the youngest mothers (<20 years), which was also reported by Slayton et al.  and Idiculla et al.  This is because young mothers are more likely to have babies born prematurely or with low-birth weight and there is clear evidence that shows that low-birth weight babies (<2500 g) are at a greater risk of developing enamel defects. The probable reason could be a deficiency of bone mineral, as a result, of metabolic derangements and inadequate mineral supply as also noted by Seow et al.  Our study shows 20% prevalence of enamel opacities in low-birth weight children.
This study shows a higher prevalence of enamel opacities in mothers with multiple pregnancies which were also reported by Idiculla et al. 
In spite of significant research advances in dental development and enamel formation in the recent years, the pathogenetic mechanisms of developmental enamel defects remain poorly understood. It is likely that advances in cell and molecular biology will rapidly improve our understanding of this complex field in the future.
Finally, well controlled long-term clinical studies of children with systemic and local enamel anomalies are urgently required to identify the clinical complications associated with this common clinical entity.
| Conclusion|| |
The school children aged 12 and 15 years of Shimla city had mild prevalence of hypoplasia. There was a statistically significant co-relation between enamel hypoplasia and dental caries. The prevalence of hypoplastic teeth increased as the age advanced. The most commonly occurring enamel defect was diffuse type at both the age groups. Medical morbidity in the prenatal, peri-natal and infancy may be important etiological factors in the pathogenesis of enamel hypoplasia although the relative importance of these factors is difficult to determine.
| Acknowledgments|| |
The authors would like to thank Mrs. Kusum Chopra, Statistician, without whose valuable input this work would not have been possible.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]
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