Effect of implant position, angulation, and attachment height on peri-implant bone stress associated with mandibular two-implant overdentures: a finite element analysis.
OBJECTIVE
The aim of this study was to analyze and compare the level and distribution of peri-implant bone stresses associated with mandibular two-implant overdentures with different implant positions.


METHODS
Mathematical models of mandibles and overdentures were designed using finite element analysis software. Two intraosseous implants and ball attachment systems were placed in the interforaminal region. The overdenture, which was supported by the two implants, was designed to withstand bilateral and unilateral vertical masticatory loads (total 100 N). In all, eight types of models, which differed according to assigned implant positions, height of attachments, and angulation, were tested: MI (model with implants positioned in the lateral incisor sites), MC (implants in canine sites), MP (implants in premolar sites), MI-Hi (greater height of attachments), MC-M (canine implants placed with mesial inclination), MC-D (canine implants placed with distal inclination), MC-B (canine implants placed with buccal inclination), and MC-L (canine implants placed with lingual inclination).


RESULTS
Peri-implant bone stress levels associated with overdentures retained by lateral incisor implants resulted in the lowest stress levels and the highest efficiency in distributing peri-implant stress. MI-Hi showed increased stress levels and decreased efficiency in stress distribution. As the implants were inclined, stress levels increased and the efficiency of stress distribution decreased. Among the inclined models, MC-B showed the lowest stress level and best efficiency in stress distribution.


CONCLUSIONS
The lowest stress and the best stability of implants in mandibular two-implant overdentures were obtained when implants were inserted in lateral incisor areas with shorter attachments and were placed parallel to the long axes of the teeth.
Department of Prosthontics, School of Dentistry, Kyung Hee University, Seoul, Korea.
Hae Ryong
HR
Hong
Ahran
A
Pae
Yooseok
Y
Kim
Janghyun
J
Paek
Hyeong-Seob
HS
Kim
Kung-Rock
KR
Kwon
D001641:Bicuspid; D001732:Bite Force; D003481:Cuspid; D003758:Dental Implantation, Endosseous / Q000379:methods; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis / Q000379:methods*; D003828:Denture, Overlay; D020342:Finite Element Analysis; D006801:Humans; D007180:Incisor; D008334:Mandible / Q000502:physiology*; D003765:Models, Dental