The biomechanical analysis of simulating implants in function under osteoporotic jawbone by comparing cylindrical, apical tapered, neck tapered, and expandable type implants: a 3-dimensional finite element analysis.

ABSTRACT

PURPOSE: This study compared the biomechanical behaviors of 4 implants in osteoporosis by 3-dimensional finite element analyses. MATERIALS AND METHODS: Finite element models (FEM) of posterior mandible segments with a cylindrical threaded implant, an apical tapered implant, a neck tapered implant (NTI), and an apical expandable implant were created. Bone segments with normal and osteoporotic biomechanical properties were used. Forces of 100 and 30 N were applied along the implant in axial and buccolingual (BL) directions, respectively. Maximum equivalent stresses in the jaw bone and maximum displacement in the implant-abutment complex were evaluated. RESULTS: In osteoporosis, compared with the cylindrical threaded implant, maximum equivalent stress in cortical bones with the apical tapered implant decreased by 10.1% and 6.57% under axial and BL loads, respectively. With the NTI, those values decreased by 10.72% and 7.87%. With the apical expandable implant, those values decreased by 11.3% and 9.60%. In cancellous bones, the maximum equivalent stress with the NTI decreased by 3.56% under a BL load. Maximum displacement in the implant-abutment complex decreased by 17.1% and 9.41% with an apical tapered implant under axial and BL loads, respectively. With the NTI, those decreased by 21.8% and 17.4%. Values in normal bone indicated better stress distributions and less displacement than those in osteoporotic bone. CONCLUSION: Stress distribution in the jaw bone and implant stability in osteoporotic bone were more sensitive to implant designs than those in normal bone. In osteoporotic bone, the expandable implant and the NTI showed better stress distribution, and tapered implants showed better stabilities.