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Table of Contents
Year : 2018  |  Volume : 8  |  Issue : 2  |  Page : 44-48

The prevalence of molar-incisor hypomineralization in primary schoolchildren aged 7–9 years in Qassim Region of Saudi Arabia

Department of Public Health, Pedodontics and Orthodontics, College of Dentistry Al Rass, Qassim University, Al-Qassim, Kingdom of Saudi Arabia

Date of Web Publication30-May-2018

Correspondence Address:
Hazim Rizk
Department of Public Health, Pedodontics and Orthodontics, College of Dentistry Al Rass, Qassim University, Buraydah, Al-Qassim
Kingdom of Saudi Arabia
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jid.jid_77_17

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Context: Molar-incisor hypomineralization (MIH) is described as hypomineralization of systemic origin affecting one or more first permanent molar and incisors. Aims: This study aims to evaluate the prevalence of MIH in primary schoolchildren from 7 to 9 years in Qassim region. Settings and Design: A cross sectional study included 411 school children aged 7-9 years chosen by stratified random sampling from public schools in 7 different cities of Qassim Region, Saudi Arabia. Subjects and Methods: This cross-sectional study was carried out to determine the MIH prevalence in randomly selected sample of 411 Saudi Arabian schoolchildren aged 7–9 years in Qassim region of Saudi Arabia. All the examinations were performed in the children's schools in good daylight by a single examiner, to eliminate interexaminer variability. The examiner was calibrated with the MIH diagnostic criteria of the European Academy of Pediatric Dentistry. Statistical Analysis Used: Descriptive statistics displayed in the form of frequency and percentage. Comparison between different study groups using Chi-square tests at significance level P < 0.05. Results: The overall prevalence of MIH in our study was 25.1% (n = 103). Of these, 256 teeth (5.2%) displayed only demarcated opacity and 42 teeth (0.9%) had posteruptive enamel breakdown. Conclusions: The prevalence of MIH in Al-Qassim region, Saudi Arabia in 7–9-year-old children is high (25.1%) with no significant difference between upper and lower jaws.

Keywords: Demarcated opacities, molar-incisor hypomineralization, prevalence

How to cite this article:
Rizk H, Al-Mutairi MM, Habibullah MA. The prevalence of molar-incisor hypomineralization in primary schoolchildren aged 7–9 years in Qassim Region of Saudi Arabia. J Interdiscip Dentistry 2018;8:44-8

How to cite this URL:
Rizk H, Al-Mutairi MM, Habibullah MA. The prevalence of molar-incisor hypomineralization in primary schoolchildren aged 7–9 years in Qassim Region of Saudi Arabia. J Interdiscip Dentistry [serial online] 2018 [cited 2023 Jun 2];8:44-8. Available from: https://www.jidonline.com/text.asp?2018/8/2/44/233617

   Clinical Relevance to Interdisciplinary Dentistry Top

  • In molar-incisor hypomineralization cases, rapid caries development and difficulty in achieving profound anesthesia is a challenge in dental practice
  • Knowledge of MIH will help the dentist in early detection and intervention that will enhance the patient compliance and treatment outcome.

   Introduction Top

The term molar-incisor hypomineralization (MIH) is used to define a developmental anomaly in which one to four permanent first molars and possibly incisors appear with demarcated opacities due to enamel hypomineralization. This may lead to posteruptive enamel breakdown.[1] In the literature, such molars are referred to as nonfluoride enamel opacities, internal enamel hypoplasia, nonendemic mottling of enamel, opaque spots, idiopathic enamel opacities, and cheese molars.[2],[3] Clinically, the management of MIH can be challenging for both the dentist and the child. Rapid caries development in the erupting FPM and inability to anesthetize the tooth are major concerns for the dentist.[4] The treatment of teeth with MIH can be painful due to difficulties in achieving profound anesthesia of the affected tooth. As a result, children with hypomineralized first molars may exhibit difficult behavior and manifest with dental fear and anxiety.[5],[6] Early identification of the affected children and appropriate management can make the condition easier to treat and prevent possible negative consequences and associated high health cost.[7]

A wide range of prevalence (4%–40%) has been reported for MIH by various investigators in different countries.[8] The highest prevalence was reported from Finland [4] and Denmark.[6] On the other hand, studies in Sweden,[9] Germany,[10],[11] and England [12] found prevalence rates of 10%–18%.

In Asia, prevalence rates encountered ranged from 2.8% in Hong Kong, 6% in Ukraine,[13] and 40% in Brazil.[14],[15]

The studies on the prevalence of MIH are few in the Middle East more so in Saudi Arabia. There are no studies published on the prevalence of MIH in the Qassim region to the best of our knowledge. Hence, the aim of study is to evaluate the prevalence of MIH in primary schoolchildren aged from 7 to 9 years in Al-Qassim region.

   Subjects and Methods Top

Ethical considerations

The research was approved from Students' Research Facilitation Committee and ethical clearance was obtained from Ethical Committee of our institution.

Sampling method

This research was performed in public primary schools in Qassim region. The Qassim region was divided into 7 strata for different geographical areas, namely Buraydah, Onaizah, Alrass, Albadaia, Albukairyah, Almithnab, and Oyun Aljuwa. Two schools were randomly selected from each stratum. All students in the selected age group were examined. The authorities of the selected schools were contacted to seek their permission. Informed written consent of all participating children was obtained from the parents through a letter sent to them through the schools.

Study design and sample

This cross-sectional study had the following inclusion criteria: children aged from 7 to 9 years were selected, children with fully or partly erupted first permanent molar and incisors, and Saudi children. Cases of dental fluorosis, enamel hypoplasia or amelogenesis imperfecta, and Demarcated opacities in incisor only were excluded.

Diagnostic criteria

For the diagnosis of MIH, the judgement criteria proposed by the European Academy of Paediatric Dentistry (EAPD) was used [Figure 1].[7]
Figure 1: Definitions of the judgment criteria to be used in diagnosing molar-incisor hypomineralization for prevalence

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Calibration of the examiner

The diagnostic criteria and the record chart to be used in the study were discussed. An experienced professional in diagnosis and management of MIH (the first author) and the examiner (second author) went over the criteria for assessing hypomineralization in permanent molars and incisors. Both of them filled a record chart for every one of the 50 clinical photographs prepared in a presentation for the calibration session. Those clinical photographs showed 99 teeth identified for diagnosis, which covered all the degrees of MIH to be assessed and those ones that should not be classed as MIH such as fluorosis, hypoplasia, and amelogenesis. The diagnostic agreement between the examiner and the gold standard was satisfactory for all the diagnostic criteria. The percentage diagnostic agreement exceeded 95%. This process was repeated after 4 weeks, and the same results were obtained.[12]

A total of 411 children were included in the study. The child was seated and examined with a head light using disposable examination kit (mouth mirror, a probe, tweezer). Cotton rolls were used to remove excess plaque. The opacities were recorded according to color shades of white, yellow, and brown. Only demarcated opacities larger than 1.0 mm of diameter were considered in our study.

Regarding the severity of lesions, teeth presented with demarcated opacities with no need of treatment were considered to have mild MIH; moderate MIH included lesions in teeth with rough and broken enamel. Severe defects included the presence of hypomineralized lesions associated with loss of dental structure affecting both enamel and dentin, atypical restorations replacing affected hard tissue and teeth extracted because of severe hypomineralization. Each child individual hypomineralization grade was defined by the most severe defect seen in his/her first permanent molars or permanent incisors.

Statistical analysis

The analysis of data was carried out using Statistical Package for Social Sciences Computer Software (SPSS 21.0, Inc., Chicago, USA). Descriptive statistics was displayed in the form of frequency and percentage. Comparison between different study groups using Chi-square tests at significance level P < 0.05.

   Results Top

The final sample size was 411 children ranged between 7 and 9 years. With a total of 411 children examined and a confidence level of 95% (X = 0.001) for the MIH prevalence found in this reference population of approximately 1,300,000 people. A total of 4932 teeth were examined and 24 teeth could not be examined because of incomplete eruption.

The degree of MIH according to EAPD criteria is shown in [Table 1].
Table 1: The degree of molar-incisor hypomineralization according to European Academy of Pediatric Dentistry criteria

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The prevalence of MIH in Qassim region is shown in [Table 2].
Table 2: Prevalence of molar-incisor hypomineralization in Qassim region

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[Table 3] shows the comparison between upper and lower arch.
Table 3: Comparison between upper and lower arch

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   Discussion Top

This study showed that MIH in Al-Qassim region was high in comparison with data from other countries. The wide range of prevalence rates obtained in the published studies could be related to the different diagnostic criteria employed. The present study used the MIH diagnosis criteria established by EAPD in 2003. Research that has used the same criteria as the present study also showed similar MIH prevalence rates, such as da Souza et al.[16] in Brazil and Ghanim et al.[17] in Iraq, with 19.8% and 18.6%, respectively. EAPD recommends studying prevalence in 7–9-year-old children because at this age, the first molars and incisors have already appeared in the mouth but have only erupted recently, making it easier to detect the defect before it is masked by deterioration or other pathological conditions are superimposed. Authors who have compared samples from different age groups [18],[19],[20],[21] have observed that owing to hypomineralized enamel breakdown, as a result of chewing forces and possible caries development, older children present more severe defects than younger children. Only longitudinal studies of children with MIH would make it possible to measure the clinical changes in defects over time and to detect affected teeth among those that erupt later.

The finding of several affected teeth of the same tooth type may support the hypothesis of a systemic origin for MIH, which will most likely affect all teeth developing during the time period where the systemic insult had occurred. However, the study shows that not all index teeth were affected in each child and not to the same extent. It is possible that groups of ameloblasts are active at different times during the amelogenesis of individual FPMs, which might explain the asymmetry and varying severity of the defect in affected dentitions.

In agreement with previous studies, we found that demarcated opacities were the most frequent type of MIH.[22]

The prevalence of posteruptive breakdown in our study is less than compared to studies from Jeddah [22] and Greek.[23] This may partly be explained by the inclusion of younger children in our study. This explanation is supported by findings of Wogelius et al.[6] who reported an increased prevalence of posteruptive breakdown by increasing age.

The result has shown that there is no difference between upper and lower arches which is different than the study performed in Jeddah.[22]

For the prevalence of MIH, Alrass city has shown the most area which is affected by MIH and Almuznaib city is the least affected area.

According to EAPD [7] criteria, there is no teeth that have atypical restoration or extracted due to MIH because a younger age group that was selected.

In our study there were no teeth extracted or with atypical restoration due to the younger age group selected.

   Conclusions Top

This study shows that MIH is relatively high among schoolchildren (25.1%) population of this region. Retrospective and prospective studies are needed to clarify the etiology of MIH. Adequate care must be taken by the dental health professionals and administrators for the cases of MIH and provide the proper treatment for it. In our opinion, a case can be made for routine screening of children for MIH.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

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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. 2
van Amerongen WE, Kreulen CM. Cheese molars: A pilot study of the etiology of hypocalcifications in first permanent molars. ASDC J Dent Child 1995;62:266-9.  Back to cited text no. 3
Alaluusua S, Lukinmaa PL, Koskimies M, Pirinen S, Hölttä P, Kallio M, et al. Developmental dental defects associated with long breast feeding. Eur J Oral Sci 1996;104:493-7.  Back to cited text no. 4
Jälevik B, Klingberg GA. Dental treatment, dental fear and behaviour management problems in children with severe enamel hypomineralization of their permanent first molars. Int J Paediatr Dent 2002;12:24-32.  Back to cited text no. 5
Wogelius P, Haubek D, Poulsen S. Prevalence and distribution of demarcated opacities in permanent 1st molars and incisors in 6 to 8-year-old Danish children. Acta Odontol Scand 2008;66:58-64.  Back to cited text no. 6
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. 7
Jalevik B. Prevalence and diagnosis of molar- incisor hypomineralization (MIH): A systematic review. Arch Paediatr Dent 2010;11:59-64.  Back to cited text no. 8
Jalevik B, Klingberg G, Barregard L, Noren JG. The prevalence of demarcated opacities in permanent first molars in a group of Swedish children. Eur Arch Paediatr Dent 2001;8:87-94.  Back to cited text no. 9
Preusser SE, Ferring V, Wleklinski C, Wetzel WE. Prevalence and severity of molar incisor hypomineralization in a region of Germany – A brief communication. J Public Health Dent 2007;67:148-50.  Back to cited text no. 10
Dietrich G, Sperling S, Hetzer G. Molar incisor hypomineralisation in a group of children and adolescents living in Dresden (Germany). Eur J Paediatr Dent 2003;4:133-7.  Back to cited text no. 11
Zagdwon AM, Toumba KJ, Curzon ME. The prevalence of developmental enamel defects in permanent molars in a group of English school children. Eur J Paediatr Dent 2002;3:91-6.  Back to cited text no. 12
Cho SY, Ki Y, Chu V. Molar incisor hypomineralization in Hong Kong Chinese children. Int J Paediatr Dent 2008;18:348-52.  Back to cited text no. 13
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. 14
Alaluusua S. Aetiology of molar-incisor hypomineralisation: A systematic review. Eur Arch Paediatr Dent 2010;11:53-8.  Back to cited text no. 15
Souza JF, Costa-Silva CM, Jeremias F, Santos-Pinto L, Zuanon AC, Cordeiro RC, et al. Molar incisor hypomineralisation: Possible aetiological factors in children from urban and rural areas. Eur Arch Paediatr Dent 2012;13:164-70.  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
Mahoney EK, Morrison DG. The prevalence of molar-incisor hypomineralisation (MIH) in wainuiomata children. N Z Dent J 2009;105:121-7.  Back to cited text no. 18
Biondi AM, López Jordi Mdel C, Cortese SG, Alvarez L, Salveraglio I, Ortolani AM, et al. 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. 19
Whatling R, Fearne JM. Molar incisor hypomineralization: A study of aetiological factors in a group of UK children. Int J Paediatr Dent 2008;18:155-62.  Back to cited text no. 20
William V, Messer LB, Burrow MF. Molar incisor hypomineralization: Review and recommendations for clinical management. Pediatr Dent 2006;28:224-32.  Back to cited text no. 21
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Kevrekidou A, Kosma I, Arapostathis K, Kotsanos N. Molar incisor hypomineralization of eight- and 14-year-old children: Prevalence, severity, and defect characteristics. Pediatr Dent 2015;37:455-61.  Back to cited text no. 23


  [Figure 1]

  [Table 1], [Table 2], [Table 3]

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