Abstract
The aim of this study was to investigate the causes of the failure of various types of dental restorations and their longevity. Questionnaires were sent to 10 dental clinics in Japan. When a restoration was replaced or a tooth with a restoration was extracted, each dentist recorded the type of restoration and cause of the failure, and asked the patient about the duration of the restoration. A total of 3,120 failed restorations was analyzed. Secondary caries, loss of restoration, and endodontic involvement were the major causes of failure of overall restorations. Amalgam, composite resin, and inlay restorations were most often replaced because of secondary caries. Cast crowns and banded crowns were most frequently treated again due to endodontic involvement. Loss of restorations was the most frequent problem with resin jacket crowns and metal ceramic crowns. The mean duration of composite resins, inlays, cast crowns, and amalgams was 5.2, 5.4, 7.1 and 7.4 years, respectively. The loss of the restorations shortened the longevity of composite resins, inlays, and prostheses except banded crowns.
