Comparison of the in vitro fatigue resistance of an acrylic resin removable partial denture reinforced with continuous glass fibers or metal wires.

PURPOSE

The fatigue resistance of heat-polymerized acrylic resin test specimens reinforced with continuous glass fibers or metal wire was investigated.

MATERIALS AND METHODS

Test specimens in the shape of maxillary removable partial dentures were reinforced with one of the following: (1) circular steel wire (cross-sectional diameter, 1.0 mm); (2) semicircular steel wire (cross-sectional diameter, 1.0 x 2.0 mm); or (3) continuous unidirectional E-glass fibers. Ten specimens were fabricated for each test group. The specimens were tested by a constant force flexural fatigue test at a force of 180 N while immersed in 37 degrees C water. The number of loading cycles required to generate a fatigue fracture and the position of the fracture were measured.

RESULTS

Results showed that the test specimens, which were either unreinforced or reinforced with metal wires, fractured after 13,197 to 39,237 loading cycles. For the glass fiber-reinforced test specimens, the fracture did not coincide with the region of the strengthener but with the opposite side of the test specimen after 1,239,298 loading cycles. The position of the fracture showed a statistically significant variation between the test groups (P < .001).

CONCLUSIONS

This study suggests that the fatigue resistance of acrylic resin removable partial dentures reinforced with glass fibers are superior to those removable partial dentures reinforced with conventional metal wire.