Prevalence of enamel defects and dental caries among 9-year-old Auckland children.

OBJECTIVES

To report the prevalence and severity of enamel defects and dental caries in a probability-based sample of 9-year-old children in the Auckland region, both overall and by residence in fluoridated and non-fluoridated areas.

DESIGN

A two-stage clustered design with stratification. Strata were defined by fluoridated and non-fluoridated regions, school size, and school decile status.

SETTING

Invitations, consent forms and questionnaires were distributed to eligible participants at school for completion at home. Participants were examined at school-based clinics or in a mobile clinic. PARTICIPANTS/MATERIALS AND

METHODS

The source population was 9-year-old children attending schools in the Auckland region and enrolled with the Auckland Regional School Dental Service. Participants returned a completed consent form and questionnaire by post and then had a dental examination. Regression analyses accommodating probability sampling weights, stratification and clustering were employed.

MAIN OUTCOME MEASURES: The modified Developmental Defects of Enamel index was used to classify enamel defects in permanent teeth. Diagnosis of dental caries on deciduous and permanent teeth was visually-based.

RESULTS

Overall, 612 children participated, 310 in fluoridated and 302 in non-fluoridated areas. Diffuse opacities are prevalent inAuckland, with 28.0 per 100 children affected. Significant regional differences by fluoridation status were apparent, with diffuse opacity rates of 29.1 per 100 and 14.7 per 100 children in fluoridated and in non-fluoridated areas respectively (P<0.001). Conversely, the prevalence of deciduous teeth dental caries was significantly lower in fluoridated areas (54.9 per 100) than in non-fluoridated areas (62.0 per 100), P=0.05.

CONCLUSIONS

Diffuse opacities were the predominant tooth defect found in this study, but their prevalence appears largely unchanged from estimates reported within New Zealand over the last 25 years.