Comparing stress in implant supported monolithic zirconia fixed partial denture between canine guidance and group function occlusal patterns: a finite element analysis.

Monolithic zirconia is an emerging material for crowns and bridges. Possibility of full digital design has made it an attractive alternative material for implant supported prostheses. A proper design is vital in the success of such prosthesis like any other. This study, in the shortage of scientific evidence, has tried to assess the stress distribution of occlusal forces inside the implant-prosthesis system of a 3-unit bridge made of monolithic zirconia. A 3-unit monolithic zirconia bridge supported by two implant fixtures placed on the teeth number 13 and 15 was digitalized. It was converted to a mesh of 59000 nodes and 34000 elements. Five types of occlusal forces (one as vertical centric, two on 15 and 30 degrees assuming canine pattern of lateral movement, and two on 15 and 30 degrees assuming group function pattern) were applied. The stress distribution among all components of the implant-bridge system was assessed using Ansys Workbench 14 software and finite element analysis. the maximum stress was between 286 and 546 MPa which were found in either the fixture-abutment screw area or in the upper part of the pontic connector between canine and first premolar. The amount of maximum pressure was increased by increase in the angle of occlusal force. Notable higher stress was recorded in the group function occlusal pattern. Monolithic zirconia can be promising in designing bridges in the canine-premolar area. However, proper design is necessary with more attention to be paid to the connectors and types of occlusal forces.