Influence of implant connection type on the biomechanical environment of immediately placed implants - CT-based nonlinear, three-dimensional finite element analysis.
OBJECTIVE
The purpose of the present study was to evaluate the biomechanical environment of immediately placed implants, before and after osseointegration, by comparing three different implant-abutment connection types.


METHODS
A computer tomography-based finite element model of an upper central incisor extraction socket was constructed containing implants with either external hex, internal hex, or Morse-taper connection. Frictional contact elements were used in the bone, implant, abutment, and abutment screw interfaces in the immediately placed simulations. In osseointegrated simulations, the repair of bone alveolar defect and a glued bone-to-implant interface were assumed. By analysis of variance, the influence was assessed of connection type, clinical situation, and loading magnitude on the peak equivalent strain in the bone, peak von Mises stress in the abutment screw, bone-to-implant relative displacement, and abutment gap.


RESULTS
The loading magnitudes had a significant contribution, regardless of the assessed variable. However, the critical clinical situation of an immediately placed implant itself was the main factor affecting the peak equivalent strain in the bone and bone-to-implant displacement. The largest influence of the connection type in this protocol was seen on the peak equivalent stress in the abutment screw. On the other hand, a higher influence of the various connection types on bone stress/strain could be noted in osseointegrated simulations.


CONCLUSIONS
The implant-abutment connection design did not significantly influence the biomechanical environment of immediately placed implants. Avoiding implant overloading and ensuring a sufficient initial intraosseous stability are the most relevant parameters for the promotion of a safe biomechanical environment in this protocol.
Department of Diagnostic and Surgery, UNESP - São Paulo State University, Araraquara, Brazil. rspessoa@uol.com.br
Roberto S
RS
Pessoa
Luiza
L
Muraru
Elcio Marcantonio
EM
Júnior
Luis Geraldo
LG
Vaz
Jos Vander
JV
Sloten
Joke
J
Duyck
Siegfried V N
SV
Jaecques
D001696:Biomechanical Phenomena; D003198:Computer Simulation; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous / Q000379:methods*; D019250:Dental Implants, Single-Tooth; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis; D020342:Finite Element Analysis; D006801:Humans; D008437:Maxilla; D016348:Osseointegration; D033081:Shear Strength; D014057:Tomography, X-Ray Computed; D020390:Tooth Socket / Q000601:surgery; D016474:Weight-Bearing