Objective: The aim of this epidemiological, data-based survival study was to study the longevity of restorations in permanent molars of adolescents in the 1990 and 1995 birth cohorts during the period of 1992-2005 in the City of Vantaa, Finland.
Materials and methods: The dental records of 2975 (1990 cohort) and 3147 (the 1995 cohort) adolescents were analyzed. The longevity of restorations from their placement until replacement was illustrated using the Kaplan-Meier survival curves. The influence of the cohort, gender and caries risk on the survival rate was assessed using the Cox proportional hazards regression analysis.
Results: A majority of the restorations were tooth-colored. The proportion of amalgam restorations was almost non-existent in both cohorts. The survival of tooth-colored restorations on the occlusal surfaces of molars was lower in the 1995 cohort compared to the 1990 cohort. The need of replacement of glass-ionomer restorations was twice that of composite restorations' hazard ratio 2.27 (1.62-3.16).
Conclusions: Composites are the most frequently used dental materials and have the longest survival times among adolescents. The survival of restorations per se is poorer in the more recent than in the earlier birth cohort.
Keywords: amalgam; interproximal; occlusal; survival; tooth-colored.