Five-year performance of high-copper content amalgam restorations in a multiclinical trial of a posterior composite

Purpose: This paper reports the 5-year performance of the restorations of the high-copper content dental amalgam alloys included in the worldwide programme of clinical trials of Occlusin, including unique data on wear. Methods: The methods employed are common to those previously reported for the multiclinical evaluation of Occlusin. Analysis of the data is limited to simple statistical procedures. Results: The findings lend support to existing knowledge concerning the favourable performance of restorations of high-copper content dental amalgam alloys, notably in relation to restorations in moderate- to large-sized Class II preparations in permanent molar teeth. Analysis of the data sheds new light on the influences of variables, including type of tooth restored, size and class of restoration and the presence or absence of occlusal contact(s) on performance. Conclusion: Conclusions are drawn regarding ways in which protocols for future evaluations of the type reported should be expanded, and, together with suggestions for further work, it is concluded that this paper is a timely reminder of the value of existing dental amalgam alloys.