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Journal of Long-Term Effects of Medical Implants
SJR: 0.332 SNIP: 0.491 CiteScore™: 0.89

ISSN Print: 1050-6934
ISSN Online: 1940-4379

Journal of Long-Term Effects of Medical Implants

DOI: 10.1615/JLongTermEffMedImplants.2014003066
pages 109-119

Comparison of the Effects of Different Implant Apical Designs on the Magnitude and Distribution of Stress and Strain in Bone: A Finite Element Analysis Study

Mahdi Kadkhodazadeh
Dental Research Center, Research Institute of Dental Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Ardeshir Lafzi
Periodontics Department, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Saeed Raoofi
Department of Periodontics, Dental Faculty, Shiraz University of Medical Sciences, Shiraz, Iran
Maryam Khademi
Department of Periodontics, Dental Faculty, Ahwaz University of Medical Sciences, Ahwaz, Iran
Reza Amid
Dental Research Center, Research Institute of Dental Sciences, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Mohammad Reza Movahhedy
Manufacturing, Sharif University of Technology, Tehran, Iran
Hasti Torabi
Department of Periodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran

ABSTRACT

Objectives: The aim of this study was to investigate the effects of implant design on the apex area and on stress and stress patterns within surrounding bone. Methods: Three commercially available implants with the same diameter (3.5 mm), same length (10−11 mm), and same complement abutment were selected for modeling as follows: (1) flat apical design with light tapering degree, (2) dome-shaped apical design with light tapering, and (3) flat apical design with intense tapering in one-third of the apical area. According to human conebeam computed tomography (CBCT), the bone was modeled using a cortical thickness of 2 mm and cancellous bone. Forces of 100 N and 300 N in the vertical and 15° angle directions were applied to the entire abutment surface, and the equivalent stress and strain were calculated using finite element analysis (FEA) methods. Results: In all models, stress was concentrated on the cortical bone around the implant neck; in non-axial loads, stress was concentrated on the buccal side. The maximum strain recorded was a microstrain of 7200 μm μm−1 around the apex of sample C, which also showed the highest level of stress detected in cancellous bone (4.4 MPa). We observed the pathologic overload in the apical area of sample B (with a dome-shaped apex); however, the strain value was less than that of sample C. Conclusion: FEA revealed that great sudden changes in diameter along the fixture increases stress and strain in peri-implant bone. Therefore, uniform tapering should be considered as a standard feature for most clinical situations, and a flat apical design, which creates a better stress and strain distribution in surrounding bone than dome-shaped bone, should also be used.