Fracture resistance of fiber-reinforced PMMA interim fixed partial dentures

Abstract

Purpose: To compare different fiber reinforcements on fracture toughness of interim polymethyl methacrylate materials and then use the best combination to determine the optimal position for fiber placement in an interim 3-unit fixed partial denture (FPD).

Materials and methods: In the first stage of the study, five groups of notched fracture toughness specimens were fabricated and loaded to failure (Instron): (1) unreinforced (control); (2) reinforced with pre-impregnated silanized E-glass fibers (Fibrestick); (3) cold plasma-treated woven polyethylene fibers (Ribbond triaxial); (4) pre-impregnated silanized plasma-treated woven polyethylene fibers (Construct); and (5) 1.0-mm-diameter stainless steel wire. In the second stage, the optimal position (occlusal, middle, or cervical third of pontic) for reinforcement with glass fibers (regimen 2) was tested by loading a 3-unit FPD to failure. All groups were compared with analysis of variance (alpha < 0.05).

Results: The fracture toughness (in MPam(1/2)) for each reinforced group (Fibrestick 2.74 +/- 0.12, Construct fibers 2.59 +/- 0.28, Ribbond triaxial 2.13 +/- 0.20, and orthodontic wire 1.66 +/- 0.09) was statistically greater (p< 0.05) than for the unreinforced group (control = 1.25 +/- 0.006). Fracture loads for FPDs were greatest when the fiber reinforcements were placed in the cervical third (cervical = 1165 N).

Conclusions: The use of fiber and, to a lesser extent, orthodontic wire is an effective method to reinforce interim restoration resins.