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 Table of Contents  
ORIGINAL ARTICLE
Year : 2019  |  Volume : 7  |  Issue : 2  |  Page : 40-44

Molar incisor hypomineralization in North Malabar: An epidemiological study


1 Department of Pediatric and Preventive Dentistry, Kannur Dental College, Kannur, India
2 Department of Public Health Dentistry, Century International Institute of Dental Sciences, Kasargod, India, Department of Public Health Dentistry, Qassim University, Buraydah, KSA
3 Department of Conservative Dentistry and Endodontics, Govt. Dental College, Kottayam, Kerala, India

Date of Submission16-Apr-2019
Date of Decision03-Sep-2019
Date of Acceptance03-Sep-2019
Date of Web Publication22-Oct-2019

Correspondence Address:
Faizal C Peedikayil
Department of Pedodontics and Preventive Dentistry, Kannur Dental College, Kannur, Kerala
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/dmr.dmr_10_19

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  Abstract 


Background and Objectives: Molar incisor hypomineralization (MIH) is an acquired developmental defect of unknown etiology. The acquired factors include perinatal events, exposure to fluoride, infantile exposure to biphenols and dioxins, childhood illness, specific chronic disease. A study was conducted in two districts, namely Kannur and Kasaragod district of Kerala to know the prevalence of molar incisal hypomineralization. Materials and Methods: A cross-sectional epidemiological study was conducted on a random sample of 2000 normal – healthy school children aged between 6 and 10 years of Kannur and Kasaragod district of Kerala. A full mouth inspection of wet teeth was performed for all the examined children using the 10-point scoring system which is in accordance with the European Academy of Paediatric Dentistry evaluation criteria. Data were collected, recorded, tabulated, and evaluated using the Statistical Package for the Social Sciences 17.0 for Windows. Percentage arithmetic mean value, standard deviation, independent sample t-test, Chi-square test, and Pearson correlations were used while a P< 0.05 was considered statistically significant. Results: The study result showed the prevalence of MIH as 19.8% in children of age group 6–10 years in northern Kerala. The prevalence in Kannur and Kasaragod districts were 16% and 23.6%, respectively. Interpretation and Conclusion: Prevalence of Molar Incisor Hypominerilization is more in Kasaragod district. Therefore, more studies should be done to confirm the effect of environmental factors in those areas.

Keywords: Enamal hypoplasia, hypomineralization, molar incisor hypomineralization


How to cite this article:
Peedikayil FC, Tomy NC, Chandru T P, Muthedath M, Jose J. Molar incisor hypomineralization in North Malabar: An epidemiological study. Dent Med Res 2019;7:40-4

How to cite this URL:
Peedikayil FC, Tomy NC, Chandru T P, Muthedath M, Jose J. Molar incisor hypomineralization in North Malabar: An epidemiological study. Dent Med Res [serial online] 2019 [cited 2019 Nov 12];7:40-4. Available from: http://www.dmrjournal.org/text.asp?2019/7/2/40/269672




  Introduction Top


Developmental defects of enamel are a frequent finding in the deciduous as well as in the permanent dentition. Any dysfunction of ameloblast can result in change in appearance of enamel resulting in developmental defects of enamel ranging from tooth color to the absence of enamel.[1]

Molar incisor hypomineralization (MIH) is described as hypomineralization of 1 to 4 first permanent molars and is frequently associated with similarly affected permanent incisors. Clinical presentation of the defect varies on a continuous spectrum ranging from demarcated yellow or creamy white opacities to brownish defects with or without loss of enamel. It is very common for the affected tooth structure to break down soon after eruption called posteruptive breakdown (PEB). In general, more than one 1st permanent molars were affected, and often incisors were affected but to a lesser degree.[2] MIH is an acquired developmental defect of unknown etiology.[3] The acquired factors include perinatal events, exposure to fluoride, infantile exposure to biphenols and dioxins, childhood illness, and specific chronic disease.[4] MIH may have a multifactor etiology acting additionally or even synergistically, with a genetic predisposition associated with one or more of a range of systemic insults occurring at a susceptible stage in the development of specific teeth.[5]

Initial epidemiological studies have been conducted in Sweden in 1970s to analyze the prevalence, extension, and severity in Swedish children.[6] Most of the prevalence study related to MIH were carried out in Northern Europe with the results ranging from 3.6% to 25%.[7] Some of the Indian studies showed a prevalence in northern Indian region ranging from 6.3% to 9.2%.[8] Studies done in southern Indian showed a prevalence of 8.9%,[9] 0.48%,[10] and 9.7%,[11] respectively.

Considering the severity of the situation, only very few studies have been done on the prevalence of MIH in India. No study was reported citing the prevalence of MIH in south Indian states like Kerala. Hence, this study was conducted to evaluate the prevalence and clinical characteristics of MIH in children residing in two different districts in Kerala state.


  Materials and Methods Top


A cross-sectional epidemiological study was conducted on a random sample of 2000 normal– healthy school children aged between 6 and 10 years of Kannur and Kasaragod districts of Kerala. The study population was equally divided into 1000 children each, respectively, from Kannur and Kasaragod districts. The study was conducted in various private and government schools by the Department of Pedodontics and Preventive Dentistry, Kannur Dental College, Anjarakandy in association with the Department of community dentistry, Century International Institute of Dental Sciences Kasaragod. The inclusion criteria were children aged 6–10 years, born and brought up in Kannur and Kasaragod districts in Kerala and having at least one first permanent molar erupted. Children having amelogenesis imperfecta, dentinogenesis imperfecta, tetracycline staining, diffuse hypoplastic lesions on index teeth were excluded from this study. Furthermore, absenteeism on the day of examination and failure to obtain written informed consent from parents resulted in exclusion from the study.

Sampling method

The study sample comprised 2000 subjects which were equally divided equally into two groups (n = 2000).

  • Group I: Kasargod district (n 1 = 1000)
  • Group II: Kannur district (n 2 = 1000).


Selection of 2000 students aged from 6 to 10 was done using multistage sampling technique. A list of all schools in Kannur and Kasaragod were obtained from the District Educational Office. Each district was divided into five different zones as follows: north, South, West, East, and Central. Randomly two schools were selected from both the private and government sectors, comprising 10 schools in each district.

Dental examinations were done under natural daylight by a well-trained examiner. A full mouth inspection of wet teeth was performed for all the examined children using the 10-point scoring system which is in accordance with the European Academy of Paediatric Dentistry (EAPD) evaluation criteria (Ghanim et al. 2011) [Table 1]. The examination was performed using a dental mirror and a blunt-ended probe. Teeth were cleaned of loose debris by rinsing with plain water and any remaining debris were removed gently by scraping with the probe. Buccal, lingual/palatal, and occlusal surfaces of the first permanent molars and the labial, lingual/palatal surfaces of upper and lower permanent incisors were examined.
Table 1: Criteria for scoring molar incisor hypomineralization according to the European Academy of Paediatric Dentistry recommendations

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The data for each patient were entered on pre-printed pro formas which had the subject's demographic characteristics, the status of eruption of index teeth, scores assigned as per the EAPD criteria and posteruptive breakdown (PEB). Data were collected, recorded, tabulated, and evaluated using the Statistical Package for Social Sciences (SPSS) Statistics for Windows, Version 17.0, SPSS, Inc. Chicago, IL, USA. Percentage arithmetic mean value, standard deviation, independent sample t-test, Chi-square test, and Pearson correlations were used while a P < 0.05 was considered statistically significant.


  Results Top


Of the examined 2000 individuals, 1000 each from Kannur and Kasaragod, 160 (16%) were affected from Kannur and 236 (23.6%) from Kasaragod comprising 396 (19.6%) children [Table 2]. Of the 396 affected individuals, 136 had incisor hypomineralization, 204 had molar hypomineralization and 56 had incisor + molar hypomineralization. [Table 3]. Regarding the 260 individuals with molars affected by MIH, 88 (22.2%) were from Kannur and 172 (43.4%) from Kasargod. Of those individuals, 134 had 1 molar being affected, 90 had 2 molars affected, 10 had 3 molars affected, and 26 had 4 molars affected [Table 4]. The number of children with MIH affected on incisors was 192 of which 100 children 1 incisor being affected, 71 children 2 incisors being affected, 10 children 3 incisors being affected, 8 children 4 incisors being affected, 2 children 5 incisors, and 1 child 7 incisors being affected [Table 5]. Of about 260 children with molars affected by MIH 29 had buccal surface being affected, 18 had palatal, 174 had occlusal, 5 had buccal + palatal, 17 had buccal + occlusal, 2 had palatal + occlusal, 15 had palatal + buccal + occlusal surface being affected [Figure 1]. Of 396 children affected by MIH, 357 had lesion score 1, 14 had lesion score 2, 22 had lesion score 1 and 2, 14 had lesion score 2, and 3, 2 tooth had lesion score 1 and 3 [Figure 2]. Among the 396 children affected by MIH, 303 were under EAPD criteria E1, 14 under EAPD criteria E1a, 63 were under EAPD criteria E2, 15 under EAPD criteria E2a, 1 teeth under EAPD criteria E5. Considering 303 children affected by the EAPD criteria E1 125 children were from Kannur District and 178 from Kasaragod district [Figure 3].
Table 2: Demographic data of the total subjects

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Table 3: Number of children affected with molar incisor hypomineralization

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Table 4: Frequency and district-wise comparison of affected molars with molar incisor hypomineralization

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Table 5: Frequency and district-wise comparison of affected incisors with molar incisor hypomineralization

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Figure 1: District-wise comparison of affected surface in molars with molar incisor hypomineralization

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Figure 2: District-wise comparison of lesion score in relation to molar incisor hypomineralization

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Figure 3: District-wise comparison of extend of defect with respect to European Academy of Paediatric Dentistry criteria

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  Discussion Top


MIH has become a topic of clinical interest since the affected teeth pose esthetic concern and undergo PEB soon after eruption[12] compromising overall oral health of children. In this study, age group of the children selected for the study was 6–10 years. This specific age group was chosen according to the eruption time of incisors and molars to avoid masking effect from advanced carious lesions and extractions, which can minimize the chance of proper diagnosis.[13]

The varied prevalence rate of MIH is observed in India as well as in worldwide studies. The worldwide prevalence of MIH ranged from 2.8%[14] to 40.2%.[15] The present study showed the prevalence of MIH as 19.8% in northern Kerala. This variation in the prevalence of MIH in children in Kerala and other parts of South India could be attributed to the reason in variation in the age group and ethnicity of the children selected.[14]

The present study showed intergroup variation in prevalence in Kannur and Kasaragod district. The reason behind the high prevalence of MIH in Kasaragod than Kannur district may be due to the presence of environmental pollutants like endosulfan which was used extensively as an insecticide about a decade back for cash crops in certain areas of Kasarkod district, even though it is not used nowadays.[16] Endosulfan is a chlorinated hydrocarbon insecticide of cyclodiene subgroup which acts as a contact poison in a wide variety of insects and mites.

Exposure to environmental contaminants such as polychlorinated biphenyls (PCBs) and polychlorinated dibenzop – dioxins/dibenzofurans (dioxins) were considered as a risk factor for MIH. Exposure to PCBs and dioxins has been reported as a potential cause of enamel defects with breast milk postulated as a source.[17] Thus, children in certain areas of Kasargod areas may have got exposed to endosulfan contaminated food during tooth formation period may be the reason behind the increased prevalence in Kasaragod than in Kannur.

In our study, molars were more commonly affected than incisors with 51.5%. Incisors were affected with 34.3%, and molars + incisors were affected with 14%. This study is in correlation with Calderara et al.[18] This can be explained by the fact that 1st molars are the 1st teeth to get mineralized and also the first molar is the tooth which is most exposed to environmental changes.[9] This was in contrast to another study done by Mittal et al. where the results showed that the percentage of molars and incisors affected were almost the same.[15]

The occlusal surface was commonly affected surface in molars and labial surface in case of incisors which is in accordance with a study by Mittal and Sharma.[12] In most of the MIH involved children the commonly affected lesion defect was of mild type extending up to 1/3rd of the tooth, which is similar to the study conducted by Mittal et al.[15] Another study by Mittal and Sharma also showed a higher percentage of mild defects compared to moderate and severe[12] showing similar results to our study. The reason behind mild defects may be the factors causing MIH acting for short period during amelogenesis, which tend to produce less affected teeth with mild defects.[19]

With respect to the type of lesion the present study recorded a major type of lesion with white/creamy demarcated opacities with no PEB with 76.5%. Almost all the prevalence studies show that the white/creamy demarcated opacities with no PEB with a higher percentage. A study by Mittal et al. showed 84.9% for white/creamy demarcated opacities with no PEB which is similar to our study.[15] Various other prevalence studies by Mittaland Sharma[12] Wogelius et al.[20] and Calderara et al.[18] showed similar results.

Another most common lesion type found in our study was yellow/brown demarcated opacities with no PEB. Often such teeth develop caries due to the potential to allow plaque and debris accumulation.[15] Once the caries lesion is initiated in such teeth, its progression is very rapid due to poorly mineralized enamel in the affected teeth.[21] Thus, a preventive intervention such as remineralization therapy at an early stage can minimize the proportion of PEB. Early diagnosis and timely follow-up with the provision of preventive intervention can minimize the consequences of MIH.[12]

All the above facts emphasize on the importance of diagnosing the MIH affected tooth at an early stage and treating it with various treatment modalities so that the lesion would not progress to a severe extend leading to the loss of vitality of the tooth.


  Conclusion Top


The study was an attempt to determine the prevalence of MIH in northern part of Kerala. In our study the prevalence of MIH is high in Kasargod district. However, further more studies should be done to find the involvement of environmental pollutants like endosulphan. So far no study from India has explored the possible association of MIH with putative risk factors such as genetic, systemic, and socio-economical. There is a clear need for still more MIH studies focused on etiological factors responsible for its development to adopt preventive measures and improve understanding of development of the condition.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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Koch G, Hallonsten AL, Ludvigsson N, Hansson BO, Holst A, Ullbro C, et al. Epidemiologic study of idiopathic enamel hypomineralization in permanent teeth of Swedish children. Community Dent Oral Epidemiol 1987;15:279-85.  Back to cited text no. 6
    
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Parikh DR, Ganesh M, Bhaskar V. Prevalence and characteristics of molar incisor hypomineralisation (MIH) in the child population residing in Gandhinagar, Gujarat, India. Eur Arch Paediatr Dent 2012;13:21-6.  Back to cited text no. 8
    
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Kirthiga M, Poornima P, Praveen R, Gayathri P, Manju M, Priya M, et al. Prevalence and severity of molar incisor hypomineralization in children aged 11-16 years of a city in Karnataka, Davangere. J Indian Soc Pedod Prev Dent 2015;33:213-7.  Back to cited text no. 9
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Mittal N, Sharma BB. Molar incisor hypomineralization: Prevalence and defect characteristics in Indian school children. J Cranio Maxillary Dis 2015;4:49-56.  Back to cited text no. 12
    
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Balmer R, Toumba J, Godson J, Duggal M. The prevalence of molar incisor hypomineralisation in Northern England and its relationship to socioeconomic status and water fluoridation. Int J Paediatr Dent 2012;22:250-7.  Back to cited text no. 13
    
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