The prevalence of Molar-Incisor Hypomineralisation (MIH) in Wainuiomata children

N Z Dent J. 2009 Dec;105(4):121-7.


Objectives: The aim of this study was to determine the prevalence of Molar-Incisor Hypomineralisation (MIH) in Wainuiomata children and describe differences in prevalence among Māori, Pacific Island and New Zealand European ethnic groups.

Design: Cross-sectional survey of developmental defects of enamel in a random sample of children attending primary school in Wainuiomata, Wellington.

Method: Study information and consent forms were sent to 850 7-to-10-year-old schoolchildren. Using the modified Developmental Defects of Enamel index, a single paediatric dentist examined students in the classroom. Dental caries experience was recorded as decayed, missing or filled primary and permanent teeth.

Results: Examinations were conducted on 522 children (participation rate 61.4%). The mean age of the children was 8.2 years (range 7 to 10 years). MIH prevalence was 14.9%. The prevalence ofhypomineralisation ofany tooth was 15.3%, and that for hypoplasia was 4.0%. There was no statistically significant ethnic difference in MIH prevalence. The mean DMFT was 0.16 (SD, 0.54) in those without a developmental defect, 0.54 (SD, 1.12) in those with hypomineralisation and 1.85 (SD, 1.85) in those with hypoplasia (p < 0.01).

Conclusions: Approximately one in seven Wainuiomata children have MIH. Ethnicity is not a modifying factor in the occurrence of developmental defects of enamel. The presence of hypomineralisation and/or hypoplasia was associated with significantly greater caries experience in the permanent dentition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chi-Square Distribution
  • Child
  • Cross-Sectional Studies
  • DMF Index
  • Dental Enamel Hypoplasia / epidemiology*
  • Dental Enamel Hypoplasia / ethnology
  • Female
  • Humans
  • Male
  • Native Hawaiian or Other Pacific Islander / statistics & numerical data*
  • New Zealand / epidemiology
  • Pacific Islands / epidemiology
  • Prevalence
  • Statistics, Nonparametric