Methods: This cross-sectional survey of enamel defects and their associations was initiated by sending questionnaires to the parents of 600 children, this entailed a postal survey being completed and consent obtained to examine the child. The survey sought sociodemographic information of the parental responder and also enquired about the child's previous fluoride exposure.
The Developmental Defects of Enamel (DDE) index was used to assess 10 index teeth for enamel defects, the teeth were examined uncleaned and wet and a digital image of the teeth was also taken. An examination for dental caries was also undertaken at this time and all data was recorded electronically.
Results: With an effective participation rate of 74.5%, four hundred and thirty-six children were examined.The prevalence of enamel defects of any type was 51.6%, with distribution of demarcated opacities being 38.8%, diffuse opacities 24.1% and hypoplastic defects 5.5%. Children who had lived their entire lives in a fluoridated area had over 2 times the odds of having a diffuse opacity affecting less than one third of the labial surface of the index teeth.
Conclusion: This study suggested that children who had lived in fluoridated areas had not experienced an increase in the prevalence of diffuse opacities compared to previous New Zealand studies. The benefits of water fluoridation remain as an important public health measure, with those children living continuously in a fluoridated community having half the caries experience of those who have not.