Photoelastic stress analysis of mandibular fixed prostheses supported by 3 dental implants.

Abstract

To observe the photoelastic stress patterns generated around implants in relation to variations in the diameter and total number of implants supporting fixed complete-arch mandibular frameworks. Three different implant configurations were analyzed (n = 3): 5 standard implants with diameters of 3.75 mm (C), 3 standard implants with diameters of 3.75 mm (3S), and 3 wide implants with diameters of 5.0 mm (3W). The samples were subjected to a vertical compressive load (1.33 kgf) applied at the end of the distal cantilever of the framework. The shear stresses were calculated around the implants, and the data were analyzed using one-way analysis of variance. The implants nearest to the loading showed higher stress values regardless of the group. The C group showed lower shear stress when compared with the other groups (P = 0.001). No significant difference was observed between the 3W and 3S groups (P = 0.785). A reduction in the number of implants, regardless of the implant diameter, showed higher stress concentration around the implants. Five-implant configuration showed lower stress concentration and seems to be more biomechanically predictable.