Objective: Paediatric restorative dentistry continues being a challenge in everyday clinical practice. Practise-based survival analysis covering entire age cohorts offer an epidemiological approach to this issue in studying survival of restorations in primary teeth. The aim of this study was to compare survival of restorations in primary molars in 1985, 1990, 1995 and 2000 age cohorts associated with some population-related factors.
Material and methods: Data from dental records of the entire cohorts were obtained from the Health Centre of Kemi, Finland covering the period 1989-2009. The longevity of the restorations was illustrated using the Kaplan-Meier survival curves and tested with log-rank test and Cox proportional hazards regression analysis. The retrospective caries risk definition for individuals was based on the early restorations in the first permanent molars.
Results: Total number of the placed restorations was 2755. Survival of the restorations was the shortest in the 1995 cohort and the longest in the 1985 cohort (p < 0.001). The greatest deterioration was between the cohorts in 1990 and 1995. Survival was also shorter for the children at high risk for caries compared with the low risk children (p < 0.001).
Conclusions: Survival of the restorations shortened distinctly towards the younger cohorts and was also shorter for the high risk compared with the low risk children. Due to the variety of materials in paediatric dentistry, handling them carefully according to manufacturers' instructions must be emphasized to avoid failures of restorations due to technical reasons. Also, non-invasive treatment must always be given together with invasive treatment.