Objectives: This cross-sectional study aimed to investigate the prevalence and distribution of MIH among children in non-fluoridated urban area of Khon Kaen, Thailand.
Methods: Subjects were 7-8 year-old children randomly selected from five schools. MIH defects were examined by one calibrated dentist using the European Academy of Pediatric Dentistry criteria. Decayed, missing and filled tooth (DMFT) and surface (DMFS) indexes were assessed by other two calibrated dentists. Results: Of 424 children (48.8% males, 51.2% females) examined, the prevalence of MIH was 27.6%, with no differences between boys (28.0%) and girls (27.2%, chi-square, p < 0.001). Among children with MIH, the average number of affected teeth was 2.12±1.11 in FPMs and 0.22±0.54 in incisors. In 20 cases of the affected children (17.1%), defects were also detected in the incisors. The distribution of MIH was similar among the four FPMs (distribution ratio 1.04:1.25:1:1.12 for teeth 16:26:36:46). Dental caries in permanent teeth appeared to be higher in children with MIH (DMFT = 1.43, DMFS = 2.09) than in unaffected children (DMFT = 1.13, DMFS = 1.49, Mann-Whitney U test, p < 0.01 each).
Conclusions: Prevalence of MIH in this group of Thai children is higher than that previously reported in Asia. Data from this study help raising the awareness of MIH in children among the dental professionals. Supported by the Thailand Research Fund (RSA-5280025).