title: The prevalence of Molar-Incisor Hypomineralisation (MIH) in Wainuiomata children.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  Cross-sectional survey of developmental defects of enamel in a random sample of children attending primary school in Wainuiomata, Wellington.
  
  
  METHODS
  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.
authors.affiliation: Dental Research Group, Wellington School of Medicine & Health Sciences, Newtown, Wellington. erinkm@slingshot.co.nz
authors.forename: Erin K
authors.initials: EK
authors.lastname: Mahoney
authors.forename: David G
authors.initials: DG
authors.lastname: Morrison
mesh_terms: D016009:Chi-Square Distribution; D002648:Child; D003430:Cross-Sectional Studies; D004245:DMF Index; D003744:Dental Enamel Hypoplasia / Q000453:epidemiology* / Q000208:ethnology; D005260:Female; D006801:Humans; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D010139:Pacific Islands / Q000453:epidemiology; D015995:Prevalence; D018709:Statistics, Nonparametric