Analysis of the ups and downs of caries experience among Norwegian children aged five years between 1997 and 2003.

Objective: To study caries trends and investigate the possible reasons for changes among 5-year-old Norwegian children in the period 1997-2003. In this cross-sectional analytical time trend study at district, county, and national levels, aggregated data from the Public Dental Services (PDS) and official statistics were used, i.e. number of children and percentage receiving treatment, sale of fluoride tablets, socio-economic background, caries prevalence, and d3mft scores.

Results: Caries prevalence increased from 30% in 1997 to just over 40% in 2001, but by 2003 it had dropped to 36%. The corresponding mean number of d3mft were 1.1, 1.6, and 1.4 at national level. Caries prevalence and experience varied considerably between counties and between dental districts throughout the observation period. Multivariate analyses at county level indicated a significant negative association (p < 0.05) between caries prevalence, the sale of fluoride tablets, and net mobility. The impacts of the predictor variables education, income, infant mortality, proportion of immigrants, and the percentage of children treated varied but were rarely significant.

Conclusions: The increasing trend in the prevalence of caries among 5-year-old Norwegian children in the period 1997 to 2001 has reversed. The deterioration in dental health of 5-year-olds after 1997 was associated with a reduction in the sale of fluoride tablets, whereas increased sales of fluoride tablets after 1998 reflect improved caries prevention among preschool children and may explain the improved caries status of these children in 2003.