The use of continuous fiber reinforcement in dentistry

Fiber-reinforced composite (FRC) formulations were developed to serve as structural components for various dental appliances such as prosthodontic frameworks, retainers and splints. Poly(ethylene terephthalate glycol) and poly(1,4-cyclohexylene dimethylene terephthalate glycol) reinforced with continuous S-2 glass fibers were pultruded into continuous lengths with small rectangular cross sections. The microstructure was evaluated with SEM and optical microscopy. Fiber content and flexure properties were measured and compared to previous results by other authors. The present FRC contained 43-45 volume % fiber, which compared favorably with the 5-15 volume % fiber reported by all earlier investigators of dental FRC. The present materials achieved 65% of the theoretically expected modulus, in contrast to the typical value of 40% calculated in the earlier reports. The flexural strength and modulus of the experimental FRC were approximately 565 MPa and 20 GPa, respectively. The present FRC can be formed into individualized devices, and free fibers need not be manipulated by the operator. The improved properties and handling justify further study of these FRC as structural dental materials.