The influence of CAD/CAM ceramic and heat processed composite inlays on the fracture resistance of premolars (An in-vitro study)


Background: The aim of this in-vitro study was to identify the influence of intracoronal indirect adhesive techniques(heat processed composite (SR Adoro) andcomputer-aided design / computer-assisted manufacturing (CAD/CAM)ceramic (e Max CAD) inlays)on the fracture resistance of maxillary first premolars and to identify the modes offracture of all experimental groups.Materials and Methods: Forty sound freshly extracted upper first premolar teeth were selected then mounted inacrylic blocks, the teeth were divided into four groupsas follow:Group (A): tenintact teeth (control group).Group (B):ten teeth prepared with standardized MOD inlay cavity but not restored. Group(C): ten teeth prepared withstandardized MOD inlay cavity and restored with indirect heat processed composite (SR Adoro).Group (D): ten teethprepared with standardized MOD inlay cavity and restored with CAD /CAM ceramic material (e max CAD).Fracturestrength of the experimented teeth was measured by using universal testing machine (an axial compressiontest).Data were analyzed statistically by ANOVA and least significant difference tests.Results:Group (D) restored with CAD/CAM ceramic inlays showed more resistance to fracture than teeth restoredwith SR Adoro composite inlays group (C), but the values are statistically not significant, using One way ANOVA test ahighly significant differences (P < 0.01) were found among all groups.Conclusions:All CAD/CAM ceramic inlays and 80% of heat processed compositeinlays survived maximum biting forcefor posterior single tooth, so these two types of inlays provide good reinforcement in an extensive MOD cavities inpremolars,The fracture Mode of SR Adoro composite inlays seems to be 80% restorable while CAD/CAM ceramicinlays 90% of it are restorable type of fracture