This study aims to investigate the effects of variable thread pitch on stress distribution in bones of different bone qualities under two different loading conditions(Vertical,and Horizontal)for a Zirconia dental impl...This study aims to investigate the effects of variable thread pitch on stress distribution in bones of different bone qualities under two different loading conditions(Vertical,and Horizontal)for a Zirconia dental implant.For this purpose,a three dimensional finite element model of the mandibular premolar section and three single threaded implants of 0.8 mm,1.6 mm,2.4 mm pitch was designed.Finite element analysis software was used to develop the model and three different bone qualities(Type II,Type III,and Type IV)were prepared.A vertical load of 200 N,and a horizontal load of 100 N was applied at the abutment surface.The von-Mises stress criterion was used to analyze the results.The crestal bony-region of the mandibular section was subjected to maximum von-Mises stresses for all bone qualities.The outcome of this study indicates that,horizontal loading had more influence on stress distribution than vertical loading,regardless of the bone qualities and pitch values.Varying the dental implant pitch does not cause any decrease in stress distribution in bone,when the bone density decreased.The study concluded that implants with minimum pitch values induced lesser stress values at the implant-bone interface.展开更多
Purpose: The aim of the present study was to use finite elemental analysis (FEA) to evaluate bone stress near an implant placed at the border between the mandible and fibular graft in mandibular reconstruction. Materi...Purpose: The aim of the present study was to use finite elemental analysis (FEA) to evaluate bone stress near an implant placed at the border between the mandible and fibular graft in mandibular reconstruction. Materials and Methods: A fibular model (FM) and transplantation model (TM) were constructed for FEA. In TM, mandible was on the mesial side and the fibular graft was on the distal side. The implant was positioned at the center of both bone models. In TM, it was placed on the border between the mandible and fibular graft. A 10-mm implant was used in the monocortical model and a 15-mm implant was used in the bicortical model. The loading force was set at 100 N, the angle was set at 90°, and the loading position was set as center, mesial, or distal on the upper surface of the prosthesis. Von Mises equivalent stress values of the bone near the implant collar and apex at the middle line between buccal and lingual side were measured. Results: In all models, stress values were significantly lower with center loading than with distal loading and mesial loading. In center loading, the stress values were significantly lower in the bicortical model than in the monocortical model. There were no significant differences in stress values between FM and TM in all conditions. Conclusions: Bone stress was least with the center loading position, which was further decreased by bicortical fixation. There was no increase in mechanical stress associated with placing an implant at the border between the mandible and the fibular graft.展开更多
In order to investigate the influence of abutment material on the stress of implant-supported all-ceramic single crown, a 3D finite element model of implant-supported mandibular first premolar was computed by COSMOS/M...In order to investigate the influence of abutment material on the stress of implant-supported all-ceramic single crown, a 3D finite element model of implant-supported mandibular first premolar was computed by COSMOS/M 2.85 software. Alumina, zirconia, and titanium were used as abutment materials respectively. Vertical 600 N and horizontal 225 N load was applied on the occlusal surface. The results show that the stress distribution of implant-supported single crown was similar for different abutment materials. Maximum stresses within the crown were higher when titanium abutment was used. Maximum stress of titanium abutment was lower than that of ceramic abutment. Within the screw and fixture, maximum stresses had no difference under vertical loading but higher as titanium abutment was used under horizontal loading. There was no difference of maximum stress within the bone when different abutment materials were used. The present findings indicate that the abutment material had no influence on the stress distribution of implant-supported all- ceramic single crown but maximum stress when the titanium abutment was lower than that of ceramic abutment.展开更多
The influence of platform-switched abutment on stress distribution within the surrounding bone,fixture,abutment,and screw under various loading conditions were studied.Two 3-D finite element models representative of a...The influence of platform-switched abutment on stress distribution within the surrounding bone,fixture,abutment,and screw under various loading conditions were studied.Two 3-D finite element models representative of an implant-supported metal crown for the mandibular first molar and its surrounding bone were computed.Model A simulated the implant with non-platform-switched abutment and model B was for platform-switched abutment.A load of 100 N was applied vertically and obliquely at the center fossa,the tip of the buccal cusp and the distal fossa,respectively.The results show that the distribution of Von Mises stress in the two models is similar.When platform-switched abutment is used,the maximum Von Mises stress within the surrounding bone is lower;however,this value is higher within the fixture and screw.展开更多
文摘This study aims to investigate the effects of variable thread pitch on stress distribution in bones of different bone qualities under two different loading conditions(Vertical,and Horizontal)for a Zirconia dental implant.For this purpose,a three dimensional finite element model of the mandibular premolar section and three single threaded implants of 0.8 mm,1.6 mm,2.4 mm pitch was designed.Finite element analysis software was used to develop the model and three different bone qualities(Type II,Type III,and Type IV)were prepared.A vertical load of 200 N,and a horizontal load of 100 N was applied at the abutment surface.The von-Mises stress criterion was used to analyze the results.The crestal bony-region of the mandibular section was subjected to maximum von-Mises stresses for all bone qualities.The outcome of this study indicates that,horizontal loading had more influence on stress distribution than vertical loading,regardless of the bone qualities and pitch values.Varying the dental implant pitch does not cause any decrease in stress distribution in bone,when the bone density decreased.The study concluded that implants with minimum pitch values induced lesser stress values at the implant-bone interface.
文摘Purpose: The aim of the present study was to use finite elemental analysis (FEA) to evaluate bone stress near an implant placed at the border between the mandible and fibular graft in mandibular reconstruction. Materials and Methods: A fibular model (FM) and transplantation model (TM) were constructed for FEA. In TM, mandible was on the mesial side and the fibular graft was on the distal side. The implant was positioned at the center of both bone models. In TM, it was placed on the border between the mandible and fibular graft. A 10-mm implant was used in the monocortical model and a 15-mm implant was used in the bicortical model. The loading force was set at 100 N, the angle was set at 90°, and the loading position was set as center, mesial, or distal on the upper surface of the prosthesis. Von Mises equivalent stress values of the bone near the implant collar and apex at the middle line between buccal and lingual side were measured. Results: In all models, stress values were significantly lower with center loading than with distal loading and mesial loading. In center loading, the stress values were significantly lower in the bicortical model than in the monocortical model. There were no significant differences in stress values between FM and TM in all conditions. Conclusions: Bone stress was least with the center loading position, which was further decreased by bicortical fixation. There was no increase in mechanical stress associated with placing an implant at the border between the mandible and the fibular graft.
基金the National Natural Science Foundation of China (No.30801312)
文摘In order to investigate the influence of abutment material on the stress of implant-supported all-ceramic single crown, a 3D finite element model of implant-supported mandibular first premolar was computed by COSMOS/M 2.85 software. Alumina, zirconia, and titanium were used as abutment materials respectively. Vertical 600 N and horizontal 225 N load was applied on the occlusal surface. The results show that the stress distribution of implant-supported single crown was similar for different abutment materials. Maximum stresses within the crown were higher when titanium abutment was used. Maximum stress of titanium abutment was lower than that of ceramic abutment. Within the screw and fixture, maximum stresses had no difference under vertical loading but higher as titanium abutment was used under horizontal loading. There was no difference of maximum stress within the bone when different abutment materials were used. The present findings indicate that the abutment material had no influence on the stress distribution of implant-supported all- ceramic single crown but maximum stress when the titanium abutment was lower than that of ceramic abutment.
基金Funded by the National Key Technology R&D Program of China during the 11th Five-year Plan (No.2007BAI18B05)
文摘The influence of platform-switched abutment on stress distribution within the surrounding bone,fixture,abutment,and screw under various loading conditions were studied.Two 3-D finite element models representative of an implant-supported metal crown for the mandibular first molar and its surrounding bone were computed.Model A simulated the implant with non-platform-switched abutment and model B was for platform-switched abutment.A load of 100 N was applied vertically and obliquely at the center fossa,the tip of the buccal cusp and the distal fossa,respectively.The results show that the distribution of Von Mises stress in the two models is similar.When platform-switched abutment is used,the maximum Von Mises stress within the surrounding bone is lower;however,this value is higher within the fixture and screw.
