Influences on the bulk fracture incidence of amalgam restorations: a 7-year controlled clinical trial

Abstract In a clinical study 360 posterior amalgam restorations were made in 57 adult patients. Each patient received 6 restorations of 6 different commercial alloys (5 conventional and 1 high copper alloy system). The restorations were equally distributed over mandibular and maxillary premolars and molars. Most of the restorations were of the Class 2 type. From annually taken black and white photographs of the occlusal surface of the restorations over a period of 7 years the incidence of occlusal and approximal bulk fractures was evaluated. The tooth and jaw type and the amalgam alloy each have a significant influence on the incidence of both types of bulk fractures.