Implant-bone interface stress distribution in immediately loaded implants of different diameters: a three-dimensional finite element analysis.
OBJECTIVE
To establish a 3D finite element model of a mandible with dental implants for immediate loading and to analyze stress distribution in bone around implants of different diameters.


METHODS
Three mandible models, embedded with thread implants (ITI, Straumann, Switzerland) with diameters of 3.3, 4.1, and 4.8 mm, respectively, were developed using CT scanning and self-developed Universal Surgical Integration System software. The von Mises stress and strain of the implant-bone interface were calculated with the ANSYS software when implants were loaded with 150 N vertical or buccolingual forces.


RESULTS
When the implants were loaded with vertical force, the von Mises stress concentrated on the mesial and distal surfaces of cortical bone around the neck of implants, with peak values of 25.0, 17.6 and 11.6 MPa for 3.3, 4.1, and 4.8 mm diameters, respectively, while the maximum strains (5854, 4903, 4344 muepsilon) were located on the buccal cancellous bone around the implant bottom and threads of implants. The stress and strain were significantly lower (p < 0.05) with the increased diameter of implant. When the implants were loaded with buccolingual force, the peak von Mises stress values occurred on the buccal surface of cortical bone around the implant neck, with values of 131.1, 78.7, and 68.1 MPa for 3.3, 4.1, and 4.8 mm diameters, respectively, while the maximum strains occurred on the buccal surface of cancellous bone adjacent to the implant neck, with peak values of 14,218, 12,706, and 11,504 microm, respectively. The stress of the 4.1-mm diameter implants was significantly lower (p < 0.05) than those of 3.3-mm diameter implants, but not statistically different from that of the 4.8 mm implant.


CONCLUSIONS
With an increase of implant diameter, stress and strain on the implant-bone interfaces significantly decreased, especially when the diameter increased from 3.3 to 4.1 mm. It appears that dental implants of 10 mm in length for immediate loading should be at least 4.1 mm in diameter, and uniaxial loading to dental implants should be avoided or minimized.
Department of Stomatology, The First Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang Province, China. dingxi@hosp1.ac.cn
Xi
X
Ding
Xing-Hao
XH
Zhu
Sheng-Hui
SH
Liao
Xiu-Hua
XH
Zhang
Hong
H
Chen
D000539:Alveolar Process; D001696:Biomechanical Phenomena; D003758:Dental Implantation, Endosseous / Q000379:methods* / Q000706:statistics & numerical data; D015921:Dental Implants / Q000706:statistics & numerical data*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008334:Mandible; D008953:Models, Anatomic; D003765:Models, Dental; D013314:Stress, Mechanical; D016474:Weight-Bearing
D015921:Dental Implants