Microstrain Around Dental Implants Supporting Fixed Partial Prostheses

Objective: The present study used strain gauge analysis to perform an in vitro evaluation of the effect of axial and non-axial loading of implant-supported fixed partial prostheses, varying implant placement configurations and the loading points.

Method: Three internal hexagon implants were embedded in the center of each polyurethane block in straight and off-set placement. Microunit abutments were connected to the implants applying a torque of 20Ncm, and plastic prosthetic cylinders were screwed onto the abutments, which received standard patterns cast in Co-Cr alloy (n=10). Four strain gauges (SG) were bonded onto the surface of the block tangentially to the implants, SG 01 mesially to implant 1, SG 02 and SG 03 mesially and distally to implant 2, respectively, and SG 04 distally to implant 3. Each metallic structure was screwed onto the abutments with a 10Ncm torque and axial and non-axial load of 30kg was applied at five predetermined points (A, B, C, D, E). The data obtained from the strain gauge analysis were analyzed statistically by RM ANOVA and Tukey’s test, with a conventional level of significance of p<0.05.

Result: The results showed a statistically significant difference for the loading point (p=0.0001), with point E (non-axial) generating the highest microdeformation (327.67µε) and point A (axial) the smallest (208.93µε). No statistically significant difference was found for implant placement configuration (p=0.856).

Conclusion: It was concluded that offset implant placement did not reduce the magnitude of microstrain around implants under axial and non axial loading conditions and loading location influenced this magnitude.