[The role of bone level and prosthetic status in hemisections a series of case studies with up to 50 years of follow-up].

Root resections are more successful when there is at least 50% bone remaining, and after splinting the remaining root to adjacent teeth. This study examined the relationship between these two factors. 39 cases from 1 dental practice, with a mean follow-up of 27.8 years were analysed. Cumulative survival after 10 years was 87.2%, 72.9% after 20 years, and 64.7% after 30 years. Bone level, prosthetic status and the ratio of attachment of connected abutments were recorded. Between failed and successful resections there was no difference in bone level at the start of treatment. Connection with other teeth had a significant positive effect. When there was a large difference in attachment between the remaining root and a connected tooth, resection was significantly less successful, provided a dummy span was present. The success of resections with a minimum of 50% remaining bone appears to be due to favourable mechanical loading of connected teeth rather than periodontal stability.