J Adv Prosthodont.  2021 Feb;13(1):12-23. 10.4047/jap.2021.13.1.12.

Three-dimensional finite element analysis of buccally cantilevered implant-supported prostheses in a severely resorbed mandible

• Alom G
• Kwon HB
• Lim YJ
• Kim MJ

• KMID: 2513163
• DOI: http://doi.org/10.4047/jap.2021.13.1.12

Abstract

Purpose
The aim of the study was to compare the lingualized implant placement creating a buccal cantilever with prosthetic-driven implant placement exhibiting excessive crown-to-implant ratio.
Materials and Methods
Based on patient’s CT scan data, two finite element models were created. Both models were composed of the severely resorbed posterior mandible with first premolar and second molar and missing second premolar and first molar, a twounit prosthesis supported by two implants. The differences were in implants position and crown-to-implant ratio; lingualized implants creating lingually overcontoured prosthesis (Model CP2) and prosthetic-driven implants creating an excessive crown-to-implant ratio (Model PD2). A screw preload of 466.4 N and a buccal occlusal load of 262 N were applied. The contacts between the implant components were set to a frictional contact with a friction coefficient of 0.3. The maximum von Mises stress and strain and maximum equivalent plastic strain were analyzed and compared, as well as volumes of the materials under specified stress and strain ranges.
Results
The results revealed that the highest maximum von Mises stress in each model was 1091 MPa for CP2 and 1085 MPa for PD2. In the cortical bone, CP2 showed a lower peak stress and a similar peak strain. Besides, volume calculation confirmed that CP2 presented lower volumes undergoing stress and strain. The stresses in implant components were slightly lower in value in PD2. However, CP2 exhibited a noticeably higher plastic strain.
CONCLUSION
Prosthetic-driven implant placement might biomechanically be more advantageous than bone quantity-based implant placement that creates a buccal cantilever

Keyword

Dental prosthesis; Implant-supported; Bone resorption; Dental stress analysis; Finite element analysis