Stress and Strain Analysis of the Bone-Implant Interface: A Comparison of Fiber-Reinforced Composite and Titanium Implants Utilizing 3-Dimensional Finite Element Study
This study analyzed stress and strain mediated by 2 different implant materials, titanium (Ti) and experimental fiber-reinforced composite (FRC), on the implant and on the bone tissue surrounding the implant. Three-dimensional finite element models constructed from a mandibular bone and an implant were subjected to a load of 50 N in vertical and horizontal directions. Postprocessing files allowed the calculation of stress and strain within the implant materials and stresses at the bone-to-implant interface (stress path). Maximum stress concentrations were located around the implant on the rim of the cortical bone in both implant materials; Ti and overall stresses decreased toward the Ti implant apex. In the FRC implant, a stress value of 0.6 to 2.0 MPa was detected not only on the screw threads but also on the implant surface between the threads. Clear differences were observed in the strain distribution between the materials. Based on the results, the vertical load stress range of the FRC implant was close to the stress level for optimal bone growth. Furthermore, the stress at the bone around the FRC implant was more evenly distributed than that with Ti implant.

Figure 1. Boundary conditions of 3-dimensional finite element model on implant and bone. Arrows represent forces of 50 N in the vertical and horizontal direction, respectively, acting on the upper abutment surface at a distance of 5 mm from upper margin of bone. Figure 2. Path plot image of interface stress between bone and implant.

Figure 3. Stress distribution and path under vertical load of 50 N around fiber-reinforced composite and titanium implant. Figure 4. Strain distribution under a vertical load of 50 N around fiber-reinforced composite and titanium implant. Figure 5. Stress distribution and path under horizontal load of 50 N from the buccal direction around fiber-reinforced composite and titanium implant. Figure 6. Strain distribution under horizontal load of 50 N from the buccal direction around fiber-reinforced composite and titanium implant.
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