RESUMO
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.
RESUMO
Objective To investigate the differences in stress distribution at the bone-implant interface of dental implants with different length-diameter ratios, so as to provide references for the design of novel dental implants. Methods The three-dimensional finite element model of mandible was established using Geomagic studio, SolidWorks and ANSYS Workbench software. The mandibular molars were applied with different vertical or oblique forces, to compare and analyze stress distributions on dental implants and the surrounding bone tissues. Results Under the same length-diameter ratio, the maximum peak equivalent stress of implant under oblique loading was significantly higher than that under vertical loading. The Von Mises stresses of implants in Group A and Group B occurred in the neck under oblique and vertical loading. Under oblique loading, the implant stress variation in Group A and Group B was 144.74-374.67 MPa and 161.52-475.38 MPa, respectively. Under vertical loading, the implant stress variation in Group A and Group B was 101.28-187.40 MPa and 110.08-210.32 MPa, respectively. The maximum Von Mises stress of Group A was significantly smaller than that of Group B. Conclusions Dentists should focus on a length-diameter ratio of 2.67 to select the standard implants, and the jawbone quality of patients should be taken into full account.