Dental caries in Taranaki adolescents: a cohort study.

OBJECTIVE To document changes in disease experience among Taranaki adolescents in order to enhance understanding of the natural history of dental caries in a key developmental period. METHOD A random sample of 430 adolescents first examined in 2003 at age 13 were re-examined at age 16, when 255 (59.3%) took part. Dental caries status (in the permanent dentition) was recorded at each age by a single calibrated examiner following World Health Organization guidelines. The age-13 and 16 data-sets were merged once clinical data collection was completed. Caries increment was determined by comparing the baseline and follow-up status of each surface. RESULTS Caries prevalence (1+ DMFS) rose from 68% to 79%; mean DMFS rose from 2.9 (SD 4.7) to 3.6 (SD 4.8), and the prevalence of high caries experience (5+ DMFS) rose from 20% to 41%. The 3-year mean net caries increment of 0.5 surfaces (SD 2.6) was dominated by occlusal surfaces and the overall incidence of caries was approximately 46%. Over one-third of the cohort (37%) presented with decayed surfaces at follow-up, and this was significantly higher among Māori and males. CONCLUSION New Zealand adolescents still appear to be experiencing caries at a considerable rate, with social and ethnic inequalities plainly apparent (and appearing to widen).