OBJECTIVES: The aim was to examine the caries incidence in adolescents using the Public Dental Service (PDS) during a 5-year period in relation to their caries experience at baseline and risk classification.

METHODS: A five-year retrospective cohort study based of the dental records from 17 PDS clinics in southeastern Sweden was conducted; 159 individuals born in 1997 were included, and their caries risk was classified at 12 and 17 years of age. Caries prevalence and documented risk groups were assessed at baseline and after five years.

RESULTS: The increment of caries (both initial and manifest caries) was higher, to a statistically significant degree, after five years in adolescents who were recorded as caries-free at baseline compared to individuals with caries at baseline (p<0.001). In individuals with caries at baseline, the greatest increment of caries was found at approximal sites (p<0.001). At baseline, individuals were classified as low (94%), medium (6%) and high risk (0%). After five years, the figures were 74%, 20% and 6%, respectively. Although classified in a low-caries-risk group, 9% had ≥ 6 decayed or filled surfaces at baseline, and 23% did after five years. Approximately 62% of individuals were registered as caries-free at baseline, and 45% were after five years.

CONCLUSIONS: There was an increase in caries over five years, especially among adolescents without caries experience at baseline. The majority of adolescents had the same risk classification after five years. Further research with a larger sample size is needed to evaluate risk assessment for caries.