Dentist-specific effects on the longevity of dental restorations.

Abstract

Numerous studies have been carried out on the longevity of restorations. The focus in these studies has been to explain differences in longevity according to characteristics of the patient and type of restoration. No attempts have been made to estimate dentist-specific effects, that is, how much of the variation in longevity can be explained by dentist variation compared with patient variation. If dentist-specific variation is large, this may indicate a need to reassess the way dentists are taught restorative dentistry, or it may indicate a need for further education of qualified dentists. To estimate dentist-specific variation in the longevity of restorations in the first permanent molars for children aged 6-18 years in Norway. The data set encompassed all children born in 1993 who received one or more restorations in their first permanent molars. This encompassed 72 573 restorations for 64,728 children who were treated by 2473 public dental officers. The data were analysed using two multilevel models--mixed-effects logistic regression and mixed-effects linear regression. The dentist-specific variation was low. The intraclass correlation coefficient varied from 0.03 to 0.09 in different specifications. Public dental officers in Norway show a high degree of homogeneity with regard to longevity of restorations. Further improvements in the longevity of restorations can most likely be achieved by preventing secondary caries and by improving the physical properties of materials.