Finite element analysis of three designs of an implant-supported molar crown.
BACKGROUND
The optimal method of implant support for a single mandibular molar crown is controversial because commonly used, threaded, root-form implants developed by Branemark were not originally designed to support individual crowns.


OBJECTIVE
The purpose of this study was to develop a finite element model of a single mandibular first molar crown supported by (1) a standard 3.75-mm-diameter implant, (2) a 5-mm, wide-diameter implant, and (3) double standard-diameter implants, and to compare the induced displacements as a result of various loading conditions.


METHODS
Three-dimensional finite element models were made to simulate the 3 single-molar implant designs. Each model was analyzed with 2 force magnitudes (35 N and 70 N) and with 2 force directions (vertical and 15 degrees to the vertical axis). Displacements in 3-dimensional space as a result of the simulated loading conditions were evaluated along 3 primary axes, mesiodistal, faciolingual, and superior-inferior.


RESULTS
Mesiodistal and buccolingual displacements for the crown supported by the 5-mm-diameter implant were reduced by approximately 50% compared with the crown supported by the 3.75-mm implant when the crowns were loaded at the distobuccal cusp tip or the distal marginal ridge. The double-implant design recorded the least mesiodistal displacement with off-center loading of the crown.


CONCLUSIONS
When the crown was loaded off-center, the double-implant design produced substantially less displacement when compared with either of the single-implant designs.
Geramy
Allahyar
A
Tehran University of Medical Sciences, Tehran, Iran.
Morgano
Steven M
SM
D001696:Biomechanical Phenomena; D003198:Computer Simulation; D003442:Crowns; D015921:Dental Implants; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008954:Models, Biological; D008963:Molar; D013314:Stress, Mechanical; D013499:Surface Properties
D015921:Dental Implants