A Comparative Evaluation of Stress, Strain, and Mechanical Micromotion around Crestally Osseointegrated and Basally Osseointegrated Implants in D2 Type of Bone Using Finite Element Analysis

Background: A basal implant utilizes cortical anchorage, and they are often advocated for patients with insufficient alveolar bone height, which will avoid the need for grafting. Although basal implants are used clinically, questions remain regarding how their load transmission patterns differ from those of conventional crestal implants. Finite element analysis (FEA) serves as a noninvasive tool to evaluate and compare the internal stress patterns and stability of these systems to predict long-term biomechanical success. Aims: The aim of this study was to evaluate and compare stress, strain, and mechanical micromotion around crestally osseointegrated and basally osseointegrated implants in D2-type bone using three-dimensional FEA. Settings and Design: A comparative in vitro study was conducted using three-dimensional FEA. Two distinct mathematical models were made to represent a mandibular posterior segment with D2 type bone density: one simulating a crestally osseointegrated two-piece implant system, and the other one was a basally osseointegrated single-piece implant system. Subjects and Methods: A three-dimensional model of the posterior mandible with D2 bone was constructed using SolidWorks and analyzed in ANSYS software. Two implant systems, a crestally placed endosseous implant and a basally compressive type osseointegrated implant, were virtually placed in identical bone conditions. Simulated masticatory load of (180N) was applied in the vertical direction. Stress (von Mises), strain, and micromotion were recorded in the bone and implant components. Statistical Analysis Used: Statistical analysis was conducted using SPSS version 26.0 (SPSS Inc., Chicago, IL, USA). Descriptive statistics were calculated for all variables. Intergroup comparisons between the crestal and basal implant models were performed using the independent t -test. A P < 0.05 was considered statistically significant. Results: Crestal implants showed lower von Mises stress values (implant body: 6.80 MPa; cancellous bone: 0.24 MPa) than the basal implants (implant body: 29.42 MPa; cancellous bone: 0.26 MPa). Strain values around crestal implants remained within the physiological limits of permissible strain. Micromotion was also significantly lower in the crestal model (0.00169 mm vs. 0.00371 mm in the basal model). Conclusions: The stress distribution and load transfer patterns observed around crestal implants were more uniform, indicating better adaptation to functional loading. This suggests that crestally osseointegrated implants may have superior load-bearing capacity and biomechanical stability in the D2 type of bone quality, making them a more predictable implant option under such loading conditions. The limitations of the present FEA study, crestally osseointegrated implants showed more favorable biomechanical behavior in the D2 bone when compared to basal implants.