Comparative study of 12 thread shapes of dental implant designs: a three-dimensional finite element analysis

The purpose of this study was to determine the optimal thread shape for an experimental cylinder implant. Twelve three-dimensional finite element models with an implant of different thread shape were created: 1mm, 2mm, and 3mm square designs (S-1, S-2, and S-3); 90, 60, and 30 V-shaped designs (V-1, V-2, and V-3); 45, 30, and 15 buttress designs (B-1, B-2, and B-3); 45, 30, and 15 reverse buttress designs (R-1, R-2, andR-3). The stress distributions and the maximum Von Mises stresses in cortical and cancellous bone of all models were compared under axial and buccolingual loads. It was found that model S-2 in square design, model V-3 in V-shaped design, and model B-3 in buttress design showed the best stress distribution respectively. And the stress distribution in models R-1, R-2, and R-3 were as good as those in models S-2, V-3, and B-3.The results imply that S-2, V-3, B-3, R-1, R-2, and R-3 thread shapes all appear to be suitable for use in a cylinder implant. And the wide top angle thread should be avoided in a cylinder implant.