DOI: 10.14457/tu.the.2020.1145
title: Biomechanical performance of short dental implant supported prosthesis with distal cantilever placed in posterior atrophic maxilla: finite element study

description: The present study has designs on evaluating the biomechanical performances of short dental implant-supported prosthesis with distal cantilever placed in posterior atrophic maxilla. This study was divided into 2 major examinations.The first part was to assess the effect of implant diameter and cortical bone thickness on the biomechanical performance of short dental implant-supported prosthesis with distal cantilever placed in posterior atrophic maxilla. The second part was to evaluate the influence of cantilever arm length (CAL) and cortical bone thickness on the biomechanical performance of short implant-supported fixed partial prosthesis with distal cantilever at posterior atrophic maxilla. All of these were assessed by finite element method.Part I: The present study aimed to assess the effect of implant diameter and cortical bone thickness on the biomechanical performance of short dental implant-supported distal cantilever placed in posterior atrophic maxilla by finite element method. There were 6 stimulating models in this study, which consisted of a bone block and short dental implant of 7 mm in length, 3 differences of diameter (5.0, 5.5, and 6.0 mm) and2 variations of cortical bone thickness (thickness of 0.5 and 1.0 mm). All models were applied with 200 N of force with 30° inclination to lingual direction. Von Mises stress and strains were used to evaluate the biomechanical performance of the short dental implant and surrounding bone. Results showed that increasing of implant diameter led to decrease in stress level on neck of dental implants and strains in surroundingcortical bone. However, the implant diameter equal or smaller than 5.0 mm should not be used due to high stress level with could be a cause of implant failure. In addition, clinician should aware of placing implant with inadequate bone stock whichlead to surrounding bone resorption.Part II: The aim of this study was to evaluate the influence of cantilever arm length (CAL) and cortical bone thickness on the biomechanical performance of short implantsupported fixed partial prosthesis with distal cantilever at posterior atrophic maxilla by finite element method. Each model was composed of a bone block presenting with short implant (5.5 x 6.0 mm) placed in first maxillary molar of two different in corticalbone thicknesses (0.5 and 1.0 mm). The variation of mesiodistal crown width-tocantilever arm length ratios (MCW: CAL ratio) were simulated (1:0.75, 1:1, 1:1.25) and the applied load were 200 N in axial direction of all models. The von Mises stress and microstrain were used to evaluate the biomechanical performance of the implant and surrounding bone, respectively. The result showed that the longer CAL caused the higher stress at the neck of implant and strain distribution area at the surrounding cortical bone in all simulated models. The cortical bone thickness reveals the positive effect to biomechanical performance. In the biomechanical point of view, this study suggests that the clinicians should concern when using short dental implant-supported prosthesis with distal cantilever placed in posterior maxilla especially in a thin cortical bone situation.