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.
List of papers. The papers are removed from the thesis due to publisher restrictions.
Paper I Vidnes-Kopperud S, Tveit AB, Espelid I. Changes in the treatment concept for approximal caries from 1983 to 2009 in Norway. Caries Res 2011;45:113-20. DOI: 10.1159/000324810
Paper II Vidnes-Kopperud S, Tveit AB, Gaarden T, Sandvik L, Espelid I. Factors influencing dentists' choice of amalgam and tooth-colored restorative materials for Class II preparations in younger patients. Acta Odontol Scand 2009;67:74-9. DOI: 10.1080/00016350802577800
Paper III Kopperud SE, Tveit AB, Gaarden T, Sandvik L, Espelid I. Longevity of posterior dental restorations and reasons for failure. Eur J Oral Sci. 2012;120:539-48. DOI: 10.1111/eos.12004