Biomechanical Analysis of the Zirconia and Graphene-based CAD-CAM Dental Bridges at Different Pontic Length: A Finite Element Analysis

Abstract

Introduction: During masticatory loading, dental bridges are subjected to various forces that might generate deflections in the bridge framework. For this reason, designing long-span bridges require great care about flexions that happen during the function. This can be compensated by increasing occluso-gingival height, using rigid materials and enhancing resistance to deflection by modifying the abutments’ preparations. The current study hypothesied that the stress, deflection, strain and deformation of the fixed partial dentures are guided by the three-dimensional configurations of the pontic areas, and all other parameters could be mutually changed with different influence on the overall outcome. Aim: The study aimed to evaluate the difference in the amount of stress, deflection, strain and deformation on using different materials and configurations in the pontic and connector area of the dental bridge using the 3D Finite Element Analysis (FEA). Materials and Methods: An invitro virtual biomechanical analysis using 3D FEA method was conducted. 3D models were created from the Cone Beam Computed Tomography (CBCT) of a dentulous patient and two materials were selected for this study, Zirconia and enhanced graphene-based polymer. The study models were assembled into four groups as the following: Group I: 3-unit Zirconia fixed-fixed bridge; Group II: 3-unit Graphene fixed-fixed bridge; Group III: 4-unit Zirconia fixed-fixed bridge; Group IV: 4-unit Graphene fixed-fixed bridge. Using FEA software a 600 N load was applied and the resultant normal stress, deflection, maximum equivalent strain and total deformation data were monitored, collected and interpreted. Results: The findings of the current study showed higher values of normal stress, deflection, equivalent elastic strain and total deformation in Graphene-based bridges (group II and IV) than the Zirconia-based bridges (group I and III). It should also be mentioned that normal stress, deflection, equivalent elastic strain, and total deformation showed higher values in the three-unit bridge (group I and II) than their corresponding 4-unit bridge groups (group III and IV). Conclusion: This biomechanical analysis confirmed that the stress concentration and deflection of the fixed bridge are influenced by material characteristics. However, configuration of the pontic area could influence the studied mechanical parameters regardless the length of the dental bridge.