ABSTRACT
Objective To establish the implant-mandible model with different design parameters, observe stress distributions on the implant and surrounding bone, and analyze the influence of different design parameters on dental implant of the mandible. Methods Eight implant models were designed based on structural characteristic parameters (implant diameter, thread depth, height of abutment through gingiva, thread shape), and assembly of the mandibular model was performed respectively. The models were applied with static 150 N vertical and oblique 45° loads, so as to analyze peak von Mises stress of the implant and bone tissues and explore the structural parameter variables of implant most sensitive to peak von Mises stress. Results The peak stress of the mandible was larger under inclined load than that under vertical load. Implant diameter was the key factor affecting the peak von Mises stress of cortical bone, while thread depth was the key factor affecting the peak von Mises stress of cancellous bone. The peak von Mises stress was also affected by the height of abutment through gingiva, but the effect was not as significant as thread depth and implant diameter. Thread shape had little effect on the peak von Mises stress of the mandible. Conclusions Different implant design parameters can affect the peak stress of different tissues of the mandible, so it is necessary to carefully consider the selection of implant parameters for personalized implants. This study can provide theoretical guidance for structural parameter design of oral implants and provide references for accurate prediction of oral implants.
ABSTRACT
Objective To analyze stress distributions of alveolar bone around implants with different types of implant thread shapes and thread depths during dental immediate implantation, so as to provide references for the design and selection of implants. Methods The simplified model of mandible bone block, implants and mandibular molar were established by Geomagic Studio, SolidWorks and ANSYS Workbench, and vertical and oblique loads were applied on this model, respectively. Stress distributions on implants with different thread shape and thread depth as well as alveolar bone around implants were calculated. Results Under vertical loading, the peak stresses of implants, cortical bone and cancellous bone were in the range of 120.51-129.63 MPa, 9.94-13.25 MPa and 3.92-8.01 MPa, respectively. And the stress of cortical bone around V-shaped, rectangular, buttress or reverse buttress implant remained stable in the range of 0.40-0.45 mm thread depth. Under oblique loading, the peak stresses of implants, cortical bone and cancellous bone were in the range of 220.23-286.51 MPa, 33.39-45.08 MPa, 4.96-12.5 MPa, respectively. Among the models, V-shaped, buttress, reverse buttress implant with 0.45 mm thread depth showed the minimum stress. Conclusions The V-shaped, buttress or reverse buttress implant with a thread depth of 0.45 mm, or the rectangular implant with a thread depth of 0.40 mm had better biomechanical properties.