Three-dimensional finite element analysis of stress distribution for different implant thread slope and implant angulation / 대한치과보철학회지

PURPOSE: The purpose of this study was to find an inclination slope of the screw thread that is favorable in distributing the stresses to alveolar bone by using three dimensional finite element analysis. MATERIALS AND METHODS: Three types modelling changed implant thread with fixed pitch of 0.8 mm is the single thread implant with 3.8degrees inclination, double thread implant with 7.7degrees inclination and the triple thread implant with 11.5degrees inclination. And three types implant angulation is the 0degrees, 10degrees and 15degrees on alveolar bone. The 9 modelling fabricated for three dimensional finite element analysis that restored prosthesis crown. The crown center applied on 200 N vertical load and 15degrees tilting load. RESULTS: 1. The more tilting of implant angulation, the more Von-Mises stress and Max principal stress is increasing. 2. Von-Mises stress and Max principal stress is increasing when applied 15degrees tilting load than vertical load on the bone. 3. When the number of thread increased, the amount of Von-Mises stress, Max principal stress was reduced since the generated stress was effectively distributed. 4. 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, the triple thread implant had a least amount of stress. This shows that the triple thread implant gave a best result. CONCLUSION: A triple thread implant to increase in the thread slope inclination and number of thread is more effective on the distribution of stress than the single and double thread implants especially, implant angulation is more tilting than 10degrees on alveolar bone. Thus, effective combination of thread number and thread slope inclination can help prolonging the longevity of implant.

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

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.