Failure of removable partial denture castings during service.

The fracture of removable partial denture castings does not occur in a random manner but rather at characteristic sites that are determined by the designs of the castings. These sites will be located where elastic stresses resulting either from handling or from normal function are likely to be concentrated. Regions of abrupt change in cross-sectional areas and internal voids also have been shown to cause stress concentration. In many instances the regions of stress concentration that are present may act as sites for crack initiation, with fatigue as the ultimate mode of failure.