Compositional and weave pattern analyses of glass fibers in dental polymer fiber composites.

PURPOSE: This study compared weave patterns and glass compositions of five glass fiber materials found in commercial fiber-reinforced dental composites.
MATERIALS AND METHODS: A scanning electron microscope (SEM) was used to investigate the woven structure of five glass fiber products, and an energy-dispersive x-ray spectrometer (SEM/EDS) was used to determine the elemental composition of these glass fibers in the bulk and at the surface of the fiber. Five fibers of each product were analyzed.
RESULTS: The fiber products were either unidirectional rovings or bidirectional weaves. More precisely, the woven structures were linen weave, twill weave, or twill weave ribbon. SEM/EDS analysis revealed that the composition of the glass fibers was typical for E (electrical)-glass fibers with one exception. One product intended for use in fixed prosthodontics included unidirectional fibers with a composition consistent with a modified high-tensile-strength R-glass. Boron oxide found on the surface of glass fibers would likely contribute to an increased potential for corrosion of fiber-reinforced composite.
CONCLUSIONS: The predominant fiber composition in these products is E-glass. Because the degree of hydrolytic stability of polymer-fiber composites over time may lead to material failure in permanent restorations, this property should be investigated further.