DH Ha*, GD Slade, AJ Spencer

Caries risk is assessed clinically for all children in the South Australian (SA) school dental service (SDS) where cross-sectional data show age-related reduction in the percentage children classified as high-risk (%HIGH). However, longitudinal patterns of changes in risk status and disease rate have not previously been reported. OBJECTIVE: To examine longitudinal age-related patterns of clinically-assessed caries risk status and observed caries rate among SA children. METHODS: Clinical dental examination data from children aged 6-12 yrs who had two or more examinations during 2002-05 were extracted from the SDS electronic patient record system. Clinician's assessment of child's risk status at each examination was recorded as low, medium or high. Risk status change was assessed. The number of decayed, missing and filled surfaces at each examination was used to compute net caries increment, which was divided by number of surfaces-years at risk to calculate caries incidence density rate (DMFS-ID). RESULTS: 46,471 children had two or more examinations separated by intervals ranging from 6 to 30 months. Cross-sectional analysis confirmed a monotonic reduction in the percentage of children classified as high-risk (%HIGH) from 28% among 6-year-olds to 11% among 12-year-olds (p<0.01). However, in longitudinal analysis, risk status increased between examinations for 8% (%INCRISK) of children. %INCRISK followed a U-shaped distribution among age groups, reducing from 9% among 6-year-olds to 6% among 9-year-olds, and increasing to 10% among 12-year-olds (p<0.01). DMF-ID declined from 1.08 events/100-surface-years among 6-yr-olds to 0.35/100-surface-years among 10-yr-olds and levelled to 0.42/100-surface-years among 12-yr-olds (p<0.001). CONCLUSIONS: In contrast to inferences drawn from cross-sectional data, clinically-assessed caries risk among SA children peaked at the ages of 6 and 12 years. However the peak at 12-years of age did not conform with age-related pattern of DMF-ID. Supported by University of Adelaide, SA Dental Service and Australian Dental Research Foundation.

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