Stress distribution in resin-based CAD-CAM implant-supported crowns

Objective: This study aimed to evaluate the influence of new resin-based CAD-CAM im-plant-supported materials on posterior crown restoration stress and strain concentrations. Methods: A previous 3D implant model was edited to receive a cement-retained posterior crown manufactured with different CAD/CAM materials (Estelite P Block, Estelite Block II or Estelite Layered Block). Each solid model was exported to the computer-aided engineering software and submitted to the finite element analysis of stress and strain. Material prop-erties were assigned to each solid with isotropic and homogeneous behavior according to the manufacturer information. A vertical load of 600 N was applied in the occlusal region of the crown, via a simulated food bolus, and stress was calculated in Von Misses (sigma VM) for the implant, abutment and screw, Maximum (sigma MAX) Principal Stresses for the crown and microstrain for the bone. Results: All simulated materials showed acceptable stresses levels with a similar stress pattern among the models. At the crown intaglio region and cement layer, however, dif-ferences were observed: Estelite P Block showed a lower tensile and shear stresses mag-nitude when compared to other resin-based materials with lower elastic modulus. Significance: The stress effect of different resin-based CAD-CAM implant-supported crowns is predominant in the crown and cement layer, with Estelite P Block showing 7.4 % versus 9.3 % and 9.2 % for Estelite Block II and Estelite Layered Block of crown failure risk. (c) 2022 The Author(s). Published by Elsevier Inc. on behalf of The Academy of Dental Materials. This is an open access article under the CC BY license (http://creative-commons.org/licenses/by/4.0/).