Three-dimentional finite element analysis of stress distribution for different implant thread slope

Seo, Young Hun; Vang, Mong Sook; Yang, Hong So; Park, Sang Won; Park, Ha Ok; Lim, Hyun Pil

Abstract

STATEMENT OF PROBLEM: The screws of dental implant, having various thread types, can be categorized into different classes by their geometrical form, and each type transmits dissimilar amount and form of stress to alveolar bone. PURPOSE: The purpose of this study was to find an inclination angle of the screw thread that is favorable in distributing the stresses to alveolar bone. MATERIAL AND METHODS: In this study, We used three dimensional finite element analysis with modeling having three types of thread inclination angles and fixed pitch-0.8 mm (single thread type with 3.8 degrees inclination, double thread type with 7.7 degrees inclination, triple thread type with 11.5 degrees inclination).
RESULTS
The results obtained from this study were as follows; 1. When the number of thread increased, the amount of Von-Mises stress was reduced since the generated stress was effectively distributed. 2. Since the maximum principal stress affects on the alveolar bone can influence deeply on the longevity of the implants when comparing the magnitude of the maximum principal stress double thread had least amount of stress. This shows that the double thread screw gave best result.
CONCLUSION
In conclusion, double, and triple thread screws were found to be more effective on distribution of the stress than the single thread screws. But, increasing in the thread inclination angle such as triple thread screw relate on the magnitude of the maximum principal stress affecting on the alveolar bone can become problematic. Thus, effective combination of thread number and thread inclination angle can help prolonging the longevity of implant.