Finite Element Analysis of Staggered Placement of Dental Implants

Finite Element Analysis of Staggered Placement of Dental Implants
27 June 2003
Y. SATO1, H. ITOH2, T. SASAKI2, T. OHASHI1, and M. SATO1, 1 Tohoku University Graduate School of Engineering, Sendai, Japan, 2 Tohoku UniversityGraduate School of dentistry, Sendai, Japan
IADR
Objectives: Previous studies have shown, through use of a quasi-three-dimensional photoelastic method, that there are no clear difference in stress distributions between the straight implant configuration and the staggered configuration. The purpose of this study was to compare stresses generated by the two different implant configurations, staggered and straight , in a mandibular posterior edentulous situation through use of a three-dimensional finite element method. Numerical results were then compared with the results from the photoelastic studies. Methods: Two photoelastic models of a human left mandible which were edentulous distal to the canine were used. Three implants with 3.75mm diameters and 8 mm in length were fixed by anchor bridges to the same occlusalscheme, were embedded into the edentulous region of the two models, in a straight configuration and a staggered buccal-lingual configuration. Finite element models were constructed based on the three-dimensional geometries of the photoelastic models measured by X-ray CT and meshed with 10 node tetrahedral elements. Mechanical properties of the models were taken into consideration in the analysis. For the boundary conditions, all nodes at the bottom of mandible bone were constrained in all directions. Static lateral loads were applied to the implants. The stress distributions in the alveolar bone were evaluated. Results: The numerical results showed higher stress concentrations around the middle implant in the staggered configuration than those in the straight configuration. There were no remarkable differences between the two configurations in the other regions. Conclusions: Numerical simulations revealed that there were no clear advantage to a staggered buccal-lingual configuration compared to a straight configuration, which showed agreement with the previous experimental results.