Estimation of the retainer height biomechanical contribution in posterior resin-bonded fixed partial dentures: a structural-thermal coupled finite element analysis

This study determines the RBFPD (resin-bonded fixed partial dentures) biomechanical aspects to retainer height using structural-thermal coupled finite element (FE) analysis under normal (37A degrees C) and high (51A degrees C) oral temperatures. Three RBFPD FE models with different retainer heights (100, 75, and 50% of the distance from 2 mm above the CE (cementum-enamel) junction to the occlusal surface) were created using image processing, contour stacking, and mapping mesh procedures. After FE model validation, the maximum first principal and von Mises stresses in the remaining tooth (sigma(T)) and prosthesis (sigma(P)), were recorded for all models under structural-thermal coupled analyses. The simulation results showed that the sigma(T) and sigma(p) values decreased with greater retainer height as a result of the increasing prosthesis stiffness and maximizing bonding area between the enamel and retainer at normal oral temperature (37A degrees C). However, no significant stress differences were found according to the retainer height varying dimensions at high (51A degrees C) temperatures. The RBFPD retainer height biomechanical response is dominated by the structural analysis result (at 37A degrees C) and it is recommended that the prosthesis retainer have as great a height as possible to decrease the stress values.