Patterns of indirect fracture in intact and restored human premolar teeth

Abstract

Abstract Fracture patterns of contralateral pairs of intact and restored premolar teeth were determined after dynamic loads of equal energy were applied to the medial aspects of the buccal cusps. The predominant fracture path for intact teeth ran obliquely from the occlusal fissure to the buccal cervical region, followed by fractures from the point of impact. Most teeth restored with MOD amalgams fractured from the base of the cavity, whereas those with amalgam overlays suffered less severe fractures, sited higher in the cusps. When teeth restored with MOD gold overlays and full gold crowns fractured, the site was frequently in the root. The value of cuspal protection by means of overlay techniques was confirmed by this study.