Survival of Restorations in Patients of Different Risk of Caries

Objectives: No real reasons for the replacement of restorations were observed to have accurately recorded in normal dental records. This motivated a comparison of the renewal rate of restorations between caries active and caries resistant subjects. The null hypothesis was that survival of restorations is shorter in caries active patients.

Methods: Dental records from 1557 patients in a net work of health centers in Finland were analysed using the age cohorts born in 1960, 1970, or 1980. More than 19000 restorations (amalgams and composites) were placed during 1965 – 1995 in patients examined and treated annually from the age of 5 years. The age groups were subdivided into high risk subjects who required a restoration due to dental caries in any of their first molars during the same year the tooth was registered having emerged. Non-risk subjects were those with healthy dentition at age 10. Survival curves for each of the restoration materials were drawn separately for each tooth/surface.

Results: High caries risk subjects had shorter survival times for amalgam restorations than low risk subjects. No difference was seen in composite restorations between risk groups. The survival time for risk subjects was shorter in the 1980 cohort than in the 1970 cohort. Amalgam restorations were superior to composite restorations both for high risk and low risk subjects on occlusal surfaces.

Conclusions: The shortest survival of any material in the youngest age cohort was thought to be due to the fact that any restoration was replaced by composite restorations because of the demands of the patients. Thus patient-related factors shortened the survival times of all materials. This practice based study gives a hint that public demand rather than findings by evidence based dentistry is the reason for the shortened survival of amalgam restorations in the youngest age cohort.