Is there a rise of prevalence for Molar Incisor Hypomineralization? A meta-analysis of published data

Abstract

Since Molar Incisor Hypomineralization was first described as a pathologic entity, public perception often suggests a considerable rise in prevalence of the respective disease. Since there are still considerable doubts regarding the etiology and-accordingly-prevention of MIH and respective therapeutic approaches are difficult this question is of considerable clinical and public interest. Accordingly, a systematic literature search in accordance with the PRISMA guidelines for systematic reviews on Medline, Cochrane Database, EMBASE, LILACS, Web of Science, Google scholar, Scopus was performed to retrieve original articles reporting the prevalence of MIH as defined by the European Academy of Pediatric Dentistry (EAPD). From initially 2360 retrieved titles, 344 full texts were assessed for possible inclusion and finally 167 articles of mainly moderate to high quality and based on data of 46'613 individuals were included in the meta-analysis. All studies published before 2001 had to be excluded since it was not possible to align the findings with the EAPD classification. Studies varied considerably regarding cohort size (25 to 23'320, mean 1'235)) and age (5.6-19 y, mean 9.8 y). Over all studies, the weighted mean for the prevalence for MIH was 12.8% (95% CI 11.5%-14.1%) and no significant changes with respect to either publication year or birthyear were found. A sub-analysis of eleven studies reporting on the prevalence in different age groups, however, revealed strong evidence for an increasing prevalence between the years 1992 (3%) and 2013 (13%).Therefore, based on data from cross-sectional studies a possible rise in prevalence of MIH remains unclear. Future prospective large-scale studies under standardized examination conditions with an emphasis on examiner calibration are needed to gain better understanding in the evolution of the prevalence of MIH.

Keywords: Molar incisor hypomineralisation; Pedodontics; Prevalence.

Fig. 1

PRISMA flow diagram for the literature search

Fig. 2

a and b Prevalences of MIH in the included studies. A Reported prevalences of MIH related to year of publication and B) related to birthyear of the respective cohort. Each black dot indicates the prevalence reported in an individual study. The blue line shows the loess-smoothed prevalence of all studies related to publication year or birth year, while the grey area indicates 95% confidence interval

Fig. 3

a Prevalences of MIH in studies reporting on populations with a mean birth year before 1997 The column on the left indicates first author and year of publication. The position of the boxes indicate the mean value for the prevalence of MIH while the size of the boxes indicates their weight in the meta-analysis. Whiskers depict the confidence interval (CI). Means and CI are given in the column on the right. The rhombus indicates the mean (position) and the CI (horizontal extention) of the overall summary estimate. RE indicates a random effects model for meta-analysis. The heterogeneity variance τ² was estimated to be 0.56, I² was estimated to be 97.7%. b Prevalences of MIH in studies reporting on populations with a mean birthyear from 1997 to 2003. The column on the left indicates first author and year of publication. The position of the boxes indicate the mean value for the prevalence of MIH while the size of the boxes indicates their weight in the meta-analysis. Whiskers depict the confidence interval (CI). Means and CI are given in the column on the right. The rhombus indicates the mean (position) and the CI (horizontal extention) of the overall summary estimate. RE indicates a random effects model for meta-analysis. The heterogeneity variance τ² was estimated to be 0.25, I² was estimated to be 96.8%. c Prevalences of MIH in studies reporting on populations with a mean birthyear after 2003. The column on the left indicates first author and year of publication. The position of the boxes indicate the mean value for the prevalence of MIH while the size of the boxes indicates their weight in the meta-analysis. Whiskers depict the confidence interval (CI). Means and CI are given in the column on the right. The rhombus indicates the mean (position) and the CI (horizontal extention) of the overall summary estimate. RE indicates a random effects model for meta-analysis. The heterogeneity variance τ² was estimated to be 0.79, I² was estimated to be 98.8%

Fig. 4

Prevalences of MIH in studies reporting separately on the prevalence of MIH for different ages. Each black dot indicates the prevalence of an individual study. Grey lines connect data from the same study population. The continuous black line shows the loess-smoothed prevalence across all study cohorts, the dashed lines indicate 95% confidence limits [–, –37, 143]