Durability of tunnel restorations in general practice: a three-year multicenter study

Twelve dentists, clinically experienced and familiar with the tunnel techni que, placed 374 tunnel restorations in permanent teeth. Mean age of the pat ients was 19.1 years (range 10-74). The filling material used was a glass c ermet cement, Ketac Silver. After 1, 2 and 3 years the teeth were controlle d by the dentists. The bitewing radiographs from baseline, 1, 2 and 3 years were also analyzed by 2 of the authors, independently. The baseline radiog raphs showed technical defects in 6% and indicated remaining dentin caries in 8% of the restorations. After 3 years, 305 restorations were accessible for examination. The cumulative replacement rate was 20%. The main reasons for replacement were marginal ridge fracture (14%) and dentin caries (3%). The number of restorations showing untreated progressive caries increased d uring the study. After 3 years, untreated dentin caries was seen in 28 case s (11%) and almost half of the left enamel lesions showed progression.