Home | About Us | Editorial Board | Current Issue | Archives | Search | Instructions | Subscription | Feedback | e-Alerts | Login 
Journal of Indian Society of Pedodontics and Preventive Dentistry Official publication of Indian Society of Pedodontics and Preventive Dentistry
 Users Online: 763  
  Print this page Email this page   Small font sizeDefault font sizeIncrease font size

  Table of Contents    
Year : 2021  |  Volume : 39  |  Issue : 3  |  Page : 246-250

Molar incisor hypomineralization: Prevalence and severity in schoolchildren of Puno, Peru

Department of Dentistry for Children and Adolescents, Universidad Peruana Cayetano Heredia, Lima, Peru

Date of Submission19-Oct-2020
Date of Decision14-Sep-2021
Date of Acceptance27-Sep-2021
Date of Web Publication22-Nov-2021

Correspondence Address:
Dr. Denise M Argote Quispe
Av. Honorio Delgado 430, Urbanizacion Ingenieria, San Martin de Porres, Lima 31
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jisppd.jisppd_460_20

Rights and Permissions



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 2022 Aug 18];39:246-50. Available from: http://www.jisppd.com/text.asp?2021/39/3/246/330714

   Introduction Top

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.[1] The etiology is not yet completely understood, as there is not enough evidence to determine specific causal factors.[2] Affected enamel has greater porosity than healthy enamel,[3] which promotes rapid bacterial penetration into the dentin, resulting in chronic inflammation of the pulp.[4] Hypomineralized enamel lacks the hardness and durability of normal enamel and is prone to fracture once exposed to the oral environment.[3] Consequently, there is a rapid development of carious lesions in the first permanent molars, which are sometimes severely affected.[1] Because of these characteristics, MIH involves a series of problems that significantly affect the quality of life of children.[3],[4],[5],[6],[7] Currently, MIH is a global problem and the most common type of developmental defect of enamel.[8] The worldwide prevalence is worryingly high (14.2%)[9] and varies considerably from 0.5% in India[10] to 40.2% in Brazil.[11] Similarly, in the analysis by continents, South America shows the highest MIH prevalence.[9] 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 Top

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)[12] 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.[13]

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.[14] Finally, the experience of caries was recorded with the DMFT index (decayed, missed, or filled tooth) following the WHO recommendations.[15]

   Results Top

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

Click here to view

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)

Click here to view

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

Click here to view

   Discussion Top

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%),[16] Iraq (18.6%),[17] and Sweden (18.4%),[18] and those reported in South America such as those developed in Brazil (20.4%, 19.8%, and 18.4%).[19],[20],[21] However, this prevalence is high compared to studies developed in Colombia (11.2%)[22] and Argentina-Uruguay (6.5%).[23] 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.,[20] 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.[2] The results of the Demographic and Family Health Survey in Peru reports a higher prevalence of prematurity in urban areas,[24] and a higher infant and child mortality rate in rural areas,[25] 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,[26] which integrates the modified index of developmental defects of enamel and the EAPD judgment criterion.[13] 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.[22],[27]

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.[11],[16],[28],[29] The difference in the findings could be attributed in part to the high prevalence of caries in the population studied[30] 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.[3] 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.[16],[17] 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.[17]

The prevalence of dental caries in schoolchildren in Peru is very high,[30] 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 Top

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.

   References Top

Weerheijm KL, Jälevik B, Alaluusua S. Molar-incisor hypomineralisation. Caries Res 2001;35:390-1.  Back to cited text no. 1
Silva MJ, Scurrah KJ, Craig JM, Manton DJ, Kilpatrick N. Etiology of molar incisor hypomineralization – A systematic review. Community Dent Oral Epidemiol 2016;44:342-53.  Back to cited text no. 2
Elhennawy K, Manton DJ, Crombie F, Zaslansky P, Radlanski RJ, Jost-Brinkmann PG, et al. Structural, mechanical and chemical evaluation of molar-incisor hypomineralization-affected enamel: A systematic review. Arch Oral Biol 2017;83:272-81.  Back to cited text no. 3
Fagrell TG, Lingström P, Olsson S, Steiniger F, Norén JG. Bacterial invasion of dentinal tubules beneath apparently intact but hypomineralized enamel in molar teeth with molar incisor hypomineralization. Int J Paediatr Dent 2008;18:333-40.  Back to cited text no. 4
Weerheijm KL, Duggal M, Mejàre I, Papagiannoulis L, Koch G, Martens LC, et al. Judgement criteria for molar incisor hypomineralisation (MIH) in epidemiologic studies: A summary of the European meeting on MIH held in Athens, 2003. Eur J Paediatr Dent 2003;4:110-3.  Back to cited text no. 5
Americano GC, Jacobsen PE, Soviero VM, Haubek D. A systematic review on the association between molar incisor hypomineralization and dental caries. Int J Paediatr Dent 2017;27:11-21.  Back to cited text no. 6
Kotsanos N, Kaklamanos EG, Arapostathis K. Treatment management of first permanent molars in children with Molar-Incisor Hypomineralisation. Eur J Paediatr Dent 2005;6:179-84.  Back to cited text no. 7
Hubbard MJ, Mangum JE, Perez VA, Nervo GJ, Hall RK. Molar hypomineralisation: A call to arms for enamel researchers. Front Physiol 2017;8:546.  Back to cited text no. 8
Zhao D, Dong B, Yu D, Ren Q, Sun Y. The prevalence of molar incisor hypomineralization: Evidence from 70 studies. Int J Paediatr Dent 2018;28:170-9.  Back to cited text no. 9
Subramaniam P, Gupta T, Sharma A. Prevalence of molar incisor hypomineralization in 7-9-year-old children of Bengaluru City, India. Contemp Clin Dent 2016;7:11-5.  Back to cited text no. 10
[PUBMED]  [Full text]  
Soviero V, Haubek D, Trindade C, Da Matta T, Poulsen S. Prevalence and distribution of demarcated opacities and their sequelae in permanent 1st molars and incisors in 7 to 13-year-old Brazilian children. Acta Odontol Scand 2009;67:170-5.  Back to cited text no. 11
MINSA. Ministerio de Salud. Estadísticas (2016). Available from: http://www.minsa.gob.pe/estadisticas/estadisticas/Poblacion/Poblacion Marcos.asp?21. [Last accessed on 2018 Jun 07].  Back to cited text no. 12
Ghanim A, Elfrink M, Weerheijm K, Mariño R, Manton D. A practical method for use in epidemiological studies on enamel hypomineralisation. Eur Arch Paediatr Dent 2015;16:235-46.  Back to cited text no. 13
Ghanim A, Silva MJ, Elfrink ME, Lygidakis NA, Mariño RJ, Weerheijm KL, et al. Molar incisor hypomineralisation (MIH) training manual for clinical field surveys and practice. Eur Arch Paediatr Dent 2017;18:225-42.  Back to cited text no. 14
World Health Organization. Oral Health Surveys: Basic Methods. 4th ed. Geneva: Word Health Organization. 1997.  Back to cited text no. 15
Ghanim A, Bagheri R, Golkari A, Manton D. Molar-incisor hypomineralisation: A prevalence study amongst primary schoolchildren of Shiraz, Iran. Eur Arch Paediatr Dent 2014;15:75-82.  Back to cited text no. 16
Ghanim A, Morgan M, Mariño R, Bailey D, Manton D. Molar-incisor hypomineralisation: Prevalence and defect characteristics in Iraqi children. Int J Paediatr Dent 2011;21:413-21.  Back to cited text no. 17
Jälevik B, Klingberg G, Barregård L, Norén JG. The prevalence of demarcated opacities in permanent first molars in a group of Swedish children. Acta Odontol Scand 2001;59:255-60.  Back to cited text no. 18
Tourino LF, Corrêa-Faria P, Ferreira RC, Bendo CB, Zarzar PM, Vale MP. Association between molar incisor hypomineralization in schoolchildren and both prenatal and postnatal factors: A population-based study. PLoS One 2016;11:e0156332.  Back to cited text no. 19
da Costa-Silva CM, Jeremias F, de Souza JF, Cordeiro Rde C, Santos-Pinto L, Zuanon AC. Molar incisor hypomineralization: Prevalence, severity and clinical consequences in Brazilian children. Int J Paediatr Dent 2010;20:426-34.  Back to cited text no. 20
de Lima Mde D, Andrade MJ, Dantas-Neta NB, Andrade NS, Teixeira RJ, de Moura MS, et al. Epidemiologic study of Molar-incisor hypomineralization in schoolchildren in North-Eastern Brazil. Pediatr Dent 2015;37:513-9.  Back to cited text no. 21
Mejía JD, Restrepo M, González S, Álvarez LG, Santos-Pinto L, Escobar A. Molar incisor hypomineralization in Colombia: Prevalence, severity and associated risk factors. J Clin Pediatr Dent 2019;43:185-9.  Back to cited text no. 22
Biondi AM, López Jordi Mdel C, Cortese SG, Alvarez L, Salveraglio I, Ortolani AM. Prevalence of molar-incisor hypomineralization (MIH) in children seeking dental care at the schools of dentistry of the University of Buenos Aires (Argentina) and University of la Republica (Uruguay). Acta Odontol Latinoam 2012;25:224-30.  Back to cited text no. 23
National Institute of Statistics and Informatics. Peru: Results indicators of the Budgetary Programs. First Semester; 2019. Available from: https://proyectos.inei.gob.pe/endes/2019/ppr/Indicadores_de_Resultados_de_los_Programas_Presupuestales_ENDES_Primer_Semestre_2019.pdf. [Last accessed on 2019 Mar 11].  Back to cited text no. 24
National Institute of Statistics and Informatics. Statistics: Health-Deaths. Available from: https://www.inei.gob.pe/estadisticas/indice-tematico/sociales/. [Last accessed on 2019 May 21].  Back to cited text no. 25
Ghanim A, Mariño R, Manton DJ. Validity and reproducibility testing of the Molar Incisor Hypomineralisation (MIH) Index. Int J Paediatr Dent 2019;29:6-13.  Back to cited text no. 26
Gambetta-Tessini K, Mariño R, Ghanim A, Calache H, Manton DJ. Carious lesion severity and demarcated hypomineralized lesions of tooth enamel in schoolchildren from Melbourne, Australia. Aust Dent J 2018;63:365-73.  Back to cited text no. 27
Jeremias F, de Souza JF, Silva CM, Cordeiro Rde C, Zuanon AC, Santos-Pinto L. Dental caries experience and Molar-Incisor Hypomineralization. Acta Odontol Scand 2013;71:870-6.  Back to cited text no. 28
Petrou MA, Giraki M, Bissar AR, Basner R, Wempe C, Altarabulsi MB, et al. Prevalence of molar-incisor-hypomineralisation among school children in four German cities. Int J Paediatr Dent 2014;24:434-40.  Back to cited text no. 29
Castillo JL, Palma C, Cabrera-Matta A. Early childhood caries in peru. Front Public Health 2019;7:337.  Back to cited text no. 30


  [Table 1], [Table 2], [Table 3]


Print this article  Email this article


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Article in PDF (439 KB)
    Citation Manager
    Access Statistics
    Reader Comments
    Email Alert *
    Add to My List *
* Registration required (free)  

   Subjects and Methods
    Article Tables

 Article Access Statistics
    PDF Downloaded173    
    Comments [Add]    

Recommend this journal

Contact us | Sitemap | Advertise | What's New | Copyright and Disclaimer | Privacy Notice
  2005 - Journal of Indian Society of Pedodontics and Preventive Dentistry | Published by Wolters Kluwer - Medknow 
Online since 1st May '05