Treatment decisions on approximal caries and longevity of Class II restorations

Abstract

Placing restorations due to dental caries is still a commonly performed treatment by dental practitioners in Norway. The aim of this thesis was to explore dentists’ treatment decisions on approximal caries and to assess the longevity of approximal restorations in posterior teeth and reasons for their failure. The research employed a questionnaire and included a practice-based study. The questionnaire revealed that, in 2009, 7% of Norwegian dentists would restore approximal lesions confined to enamel, compared with (in similar studies) 18% in 1995 and 66% in 1983. A saucer-shaped preparation technique was most favoured in 2009. As restorative material, resin composite was preferred by 95% of the dentists. In the practice-based study, amalgam (not today permitted) was placed significantly more often in male patients with caries experience (DMFT) and severe caries, and in molars. After an average follow-up period of 4.6 yr, the mean annual failure rate was 2.9% for resin-composite restorations and 1.6% for amalgams. Multilevel Cox-regression analyses identified patient age, caries experience, deep cavity, saucer-shaped preparation technique and one brand of resin-composite as factors predisposing to reduced longevity of resin-composite restorations. Taking all relevant factors into account, dentists could improve the longevity of their restorations.