|Year : 2021 | Volume
| Issue : 3 | Page : 246-250
Molar incisor hypomineralization: Prevalence and severity in schoolchildren of Puno, Peru
Denise M Argote Quispe, Guido Perona Miguel de Priego, Roberto A Leon Manco, Camila Palma Portaro
Department of Dentistry for Children and Adolescents, Universidad Peruana Cayetano Heredia, Lima, Peru
|Date of Submission||19-Oct-2020|
|Date of Decision||14-Sep-2021|
|Date of Acceptance||27-Sep-2021|
|Date of Web Publication||22-Nov-2021|
Dr. Denise M Argote Quispe
Av. Honorio Delgado 430, Urbanizacion Ingenieria, San Martin de Porres, Lima 31
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Context: The prevalence of molar incisor hypomineralization (MIH) varies considerably around the world. South America is one of the regions with the highest prevalence. Aim: The aim of the study was to determine the prevalence and severity of MIH in children residing in urban and rural areas of Puno, Peru. Design: This was an observational cross-sectional study that included 404 children, aged 7–10 years old, from urban and rural public schools in Puno, Peru. Subjects and Methods: A previously calibrated examiner established the MIH diagnosis based on the index that integrates the criteria of the European Academy of Paediatric Dentistry and the modified index of developmental defects of enamel (mDDE index), as well as the caries experience based on the DMFT index. Statistical Analysis Used: The information was analyzed using descriptive statistics and bivariate analysis. Results: Eighty children (19.8%) presented MIH, and the prevalence was higher in the urban area. Demarcated opacities were the most prevalent type of lesion (52.1%), followed by atypical caries lesions (36.7%). The more severe the defects, the greater their extent. Similarly, the greater the extent of tooth defects, the greater the number of teeth affected per child. Children with MIH had slightly higher rates of tooth decay experience (DMFT). However, no significant association was found between caries experience and MIH. Conclusions: The population studied showed a high prevalence of MIH, similar to other studies in South American populations. The prevalence varied among residence areas, being more prevalent in the urban area. Mild lesions were more frequent.
Keywords: Child (DeCS), dental caries, dental enamel, dental enamel hypoplasia, prevalence
|How to cite this article:|
Argote Quispe DM, de Priego GP, Leon Manco RA, Portaro CP. Molar incisor hypomineralization: Prevalence and severity in schoolchildren of Puno, Peru. J Indian Soc Pedod Prev Dent 2021;39:246-50
|How to cite this URL:|
Argote Quispe DM, de Priego GP, Leon Manco RA, Portaro CP. Molar incisor hypomineralization: Prevalence and severity in schoolchildren of Puno, Peru. J Indian Soc Pedod Prev Dent [serial online] 2021 [cited 2021 Nov 29];39:246-50. Available from: https://www.jisppd.com/text.asp?2021/39/3/246/330714
| Introduction|| |
Molar incisor hypomineralization (MIH) is a qualitative enamel defect of systemic origin, affecting from one to four first permanent molars and is frequently associated with permanent incisors. It is characterized by demarcated opacities with variable coloration, from white, cream, yellow to brown. The location is usually asymmetrical. The etiology is not yet completely understood, as there is not enough evidence to determine specific causal factors. Affected enamel has greater porosity than healthy enamel, which promotes rapid bacterial penetration into the dentin, resulting in chronic inflammation of the pulp. Hypomineralized enamel lacks the hardness and durability of normal enamel and is prone to fracture once exposed to the oral environment. Consequently, there is a rapid development of carious lesions in the first permanent molars, which are sometimes severely affected. Because of these characteristics, MIH involves a series of problems that significantly affect the quality of life of children.,,,, Currently, MIH is a global problem and the most common type of developmental defect of enamel. The worldwide prevalence is worryingly high (14.2%) and varies considerably from 0.5% in India to 40.2% in Brazil. Similarly, in the analysis by continents, South America shows the highest MIH prevalence. In Peru, there is little information available on the prevalence of MIH, especially in rural areas. Therefore, the objective of this study is to determine the prevalence and the severity of MIH in school-aged children residing in urban and rural areas of Puno, Peru and to find its association with dental caries experience.
| Subjects and Methods|| |
This cross-sectional study was carried out in schoolchildren between the ages of 7 and 10 years from public schools of the urban and rural areas of the city of Puno. The city of Puno is located in the Department of Puno in Southeastern Peru. It has an area of 71,999.00 km2 and a population of 1172,697 inhabitants (2017). To calculate the sample size, the population of children aged 7–10 years in 2018 according to data from the Ministry of Health of Peru (MINSA) was 18,692. The prevalence of MIH in this population had not been previously reported, so a 50% probability was taken as a reference. These data were processed in the EPIDAT 4.0 statistical program; resulting in a minimum sample size of 376 children (95% confidence level and a standard error of 5%).
The protocol for the study was approved by the Ethics Committee of the Universidad Peruana Cayetano Heredia, Lima, Peru (SIDISI Code 102654). In addition, parents and children signed written statements of consent before their participation in the study.
All children were examined by a pediatric dentist (DA) calibrated with MIH diagnosis. The calibration process consisted of four phases: (i) theoretical training, (ii) practical discussion, (iii) calibration, and (iv) final evaluation. The gold standard was represented by a consensus of four researchers with over 10-year experience in the diagnosis of MIH from the Universidade Estadual Paulista, Brazil, and the Universidad CES, Colombia. A high intra-examiner concordance was obtained (k = 0.87), and the inter-examiner accuracy was above 0.89.
The clinical examination was conducted in the school setting (classroom) with the aid of a trained assistant to record findings. Before the examination, the children brushed their teeth under the supervision of the examiner. The teeth were dried with sterile gauze and examined with the help of a portable light source, dental mirror, and when required, a Probe recommended by the World Health Organization (WHO). MIH was recorded based on the diagnostic criterion that integrates the modified index of developmental defects of enamel (mDDE index) and the European Academy of Paediatric Dentistry (EAPD) criterion.
All permanent teeth were examined. First, the degree of eruption was recorded, followed by the clinical appearance of the defect and second, the extent of the defect. Hypomineralized opacities were specified by color and were subclassified in white-cream and yellow-brown. The extent of the defect in a tooth was measured according to the surface area of the enamel affected as follows: less than one-third of a tooth surface, at least 1/3 but <2/3, and at least 2/3 of the tooth surface. Opacities of ≤2 mm in diameter were not recorded. In terms of severity, a tooth affected by MIH was considered “mildly affected” when only demarcated opacities were present, and “severely affected” when posteruptive enamel breakdown, atypical restoration, or atypical caries lesions were present, or when it was lost due to MIH. Finally, the experience of caries was recorded with the DMFT index (decayed, missed, or filled tooth) following the WHO recommendations.
| Results|| |
A total of 404 children were examined for the presence of MIH, of whom 254 were from urban and 150 from rural areas. The sample consisted of 226 girls and 178 boys. The mean age was 8.4 ± 0.9 years. MIH was diagnosed in 80 children (19.8%). The prevalence of MIH was significantly lower in the rural area (Chi-square test, P = 0.012). According to the residence area, the prevalence of MIH in urban and rural area was 23.6% and 13.3%, respectively. There was no significant differences in MIH prevalence according to the gender (Chi-square test, P = 0.950) or age groups (Chi-square test, P = 0.445). The children included in this study had a high average caries experience (average CPOD: 3.1 ± 2.3; dmft 6.8 ± 3.3). Children with MIH had slightly higher averages of DMFT (3.5 ± 2.0) compared to those without MIH (3.0 ± 2.4). Nevertheless, no significant association was found between caries experience and MIH (Mann–Whitney U-test, P = 0.310) [Table 1].
|Table 1: Prevalence of molar incisor hypomineralization in schoolchildren in Puno and its distribution by gender, age, residence area, and caries experience|
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A total of 221 teeth presented hypomineralization defects, of which 52.7% were located in the mandible and 47.3% in the maxilla. Both maxillary and mandibular teeth were equally affected (Rho de Spearman, P = 0.175). Demarcated opacities were the most prevalent type of defect (52.1%), being white-creamy opacities (40.3%) more frequent than yellow/brown opacities (11.8%).
The second most common finding was atypical caries lesions (35.7%), followed by posteruptive breakdowns (6.3%) and atypical restorations (4.5%). In addition, three first permanent molars lost due to MIH were identified (1.4%) and three other could not be categorized due to extensive coronary breakdown. Severe defects were found almost exclusively in first permanent molars, only two incisors with posteruptive fracture and one with atypical restoration were found. Regarding the extent of the MIH defect, 41.2% of cases involved at least 1/3 of the tooth surface. While the percentage of cases involving at least 1/3, but <2/3 and at least 2/3 of the tooth surface was 30% and 25.8%, respectively.
There was a significant association between the severity of the MIH defect in terms of clinical appearance and their extension (Chi-square test, P < 0.001). In mild defects, the extent of the lesion in most cases was at least one-third of the tooth surface. However, in severe defects, the extent of the lesion increased significantly. The most prevalent extent in these defects was at least two-third of the tooth surface [Table 2]. In addition, the severity of MIH gradually increased with the age of the child. The prevalence of severe defects according to the age for 7, 8, 9, and 10 years was 39.3%, 41.7%, 55.1%, and 61.7%, respectively.
|Table 2: Distribution of types of molar incisor hypomineralization lesions (severity) and their relationship to the surface area of the affected tooth (extent)|
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There was a significant increase in the extent of the defect area with the increasing number of affected molars/incisors per child (Chi-square test corrected by Yates, P < 0.001) [Table 3]. For children who had one tooth affected by MIH, we observed that only 5% of the defects affected at least two-thirds of the tooth surface, compared to 63% in cases where children had up to four teeth affected by MIH.
|Table 3: Extension of the tooth surface involved by the molar incisor hypomineralization defect in relation to the number of incisors/molars affected by molar incisor hypomineralization per child|
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| Discussion|| |
Overall, the results of the present study show that MIH is a common clinical finding in a childhood population of the Peruvian highlands. The MIH prevalence results of the present study (19.8%) are comparable to international studies conducted in similar age groups in Iran (20.2%), Iraq (18.6%), and Sweden (18.4%), and those reported in South America such as those developed in Brazil (20.4%, 19.8%, and 18.4%).,, However, this prevalence is high compared to studies developed in Colombia (11.2%) and Argentina-Uruguay (6.5%). Variations in MIH prevalence are probably due to differences in the study design (sample size, calibration, diagnostic criteria, and age groups), environmental, and ethnic factors.
Similar to the study developed by Da Costa-Silva et al., we also observed differences in MIH prevalence by residence area. In this study, the prevalence was clearly higher in the urban area. It can be inferred that possible etiological factors involved with MIH may present themselves differently between rural and urban populations such as prematurity and diseases in early childhood, which have been associated as possible etiological factors of MIH. The results of the Demographic and Family Health Survey in Peru reports a higher prevalence of prematurity in urban areas, and a higher infant and child mortality rate in rural areas, with highly significant differences. These findings reinforce the need for prospective cohort studies in order to evaluate the possible influence of these factors on this development defect of the enamel.
In this study, a recently validated evaluation tool was used to diagnose MIH defects, which integrates the modified index of developmental defects of enamel and the EAPD judgment criterion. Demarcated opacities were the most commonly found defect type (52.1%). In addition, in this population, white/creamy opacities were more prevalent than yellow/brown opacities, similar to what was observed in other studies.,
Of interest, the second most frequently found defect was atypical caries lesion. However, the findings of the present study differ from previous studies, which reported posteruptive breakdown as the second most common finding.,,, The difference in the findings could be attributed in part to the high prevalence of caries in the population studied and to the characteristics of hypomineralized enamel. Among these, a significant reduction in hardness, mineral content, and greater porosity compared to a normal enamel stands out. Therefore, these characteristics probably make enamel affected with MIH even more prone to rapid caries development.
It was found that the greater the severity of the MIH defect, the greater the extent of the defect, in accordance with previous findings., Similarly, the extent of the MIH defect was associated with the number of teeth affected by MIH per child. A total of 75.0% of children with only one tooth affected by MIH had defects involving less tooth surface area. On the other hand, 63.3% of children with four teeth affected by MIH had defects involving a greater surface area of the tooth. This relationship has been previously reported by other study.
The prevalence of dental caries in schoolchildren in Peru is very high, which makes masking MIH defects by caries lesions, atypical restorations, and large occlusal destructions very likely. In this study, the sample consisted of children from 7 to 10 years of age in order to minimize the risk of bias. Some limitations of our study should also be considered. First, the use of a convenience sample which may not be representative of the country. Second, given the cross-sectional nature of the study, our results show a momentary picture of the state and the consequences of MIH defects.
| Conclusion|| |
The prevalence of MIH in schoolchildren in the city of Puno was high (19.8%) and varied widely between areas of residence. Demarcated opacities were the most frequent type of MIH defect observed, followed by atypical caries lesions. Given the high reported prevalence of MIH, health professionals are advised to diagnose these defects promptly, in order to apply appropriate preventive and restorative treatments.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]