A Practice-Based Analysis of the Survival of Restoration Materals

Objectives: Evidence based dentistry has shown that different restoration materials have different survival times. This holds true in real life conditions, too. Our null-hypothesis is that a practice-based dentistry approach analysed scientifically sound way from normal dental records should reveal this.

Methods: Dental records from 1557 patients in a network of health centres in Finland were analysed. The age cohorts were born in 1960, 1970, or 1980. Over 19000 restorations were placed during 1965- 1995 in patients, whose follow-up with annual examinations started at 5 yrs of age. Survival curves (Kaplan-Meier) for each of the restoration materials were drawn separately for each tooth/surface at that age-cohort or age-cohorts bombined. Results: More than 60% of the silicate cement restorations were replaced within five years, and more than 50% of the glass ionomers in seven years. Mean and median survival times for amalgam and resin-based composites were over fifteen years on smooth surfaces, but that of amalgam on only cocclusal surfaces. The longevity of all restoration materials was horter in the younger age-cohorts than in the older. Conclusions: The longevity of silicate cement restorations was so short that their withdrawal from the markets early in the 1970xs was reasonable. The survival times of amalgams and composites were about the same but that of glass-ionomers much shorter. The survival of amalgam restorations was superior on the occlusal surfaces.