A clinical study of an intracoronal fixed partial denture attachment system.

An alternative tooth replacement system, based on pin retention, was clinically evaluated for up to 4 years in a prospective study. Thirty-two Universal Dental Anchorage anchors, supporting 28 fixed partial prostheses in 25 patients, were placed. Most of these prostheses had a cast complete crown on one abutment; on the other abutment, the UDA anchor functioned as a support for the extension pontine. After a mean observation period of 2 years, nine anchors failed. Around five of the failed anchors, caries was present; this occurred after 2 years or more of function of the prostheses. Early failure (4/9) were registered in the first year of function and were caused by loss of retention (three) or anchor fracture (one). The periodontal condition of the UDA anchor abutment teeth was not significantly different from that of the contralateral side. The number of failures, especially the number caused by recurrent caries, is cause for concern.