Fracture force of cantilevered zirconia frameworks: An in vitro study

Statement of problem Little evidence is available showing the effect of connector dimension and cantilever length on the ultimate fracture force of computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia implant frameworks. Purpose The purpose of the study was to determine the impact of variations in the cross-sectional dimension of connector sites and variations in the effective cantilever length (load point) on zirconia implant frameworks. This would allow verification of the fracture force with 2 proposed mathematical models. Material and methods Forty zirconia implant-supported frameworks with 12-mm distal cantilevers were divided into 4 equal test groups (n=10). Connector dimensions (3×5 mm, 3×4 mm) and cantilever loading distance (7 mm, 10 mm) were tested for ultimate fracture force. A 2-way analysis of variance (ANOVA) was used to examine the ultimate fracture force and examine the relationship between connector dimension and ultimate fracture force. The data obtained from all 4 groups were compared and verified with calculations from 2 theoretical mathematical models. Results Two-way ANOVA revealed significant effects for cross-sectional area connector dimension on fracture force ( P