US Patent 7883335 Reinforced gingival retraction cord

Gingival retraction cords are constructed from two or more strands that are interlocked to form a knitted, braided, woven, or twisted retraction cord. At least one strand is made from an absorbent material and another strand is made from a degradation-resistant material, such as nylon, polyester, fiberglass, or metal. The absorbent strands are impregnated with an active agent. The degradation-resistant strands resist degradation by the active agent. Alternatively, one or more strands are used to make the knit, weave, or braid and each strand is made from two or more different fibers. For example, one or more absorbent fibers and one or more synthetic fibers can be twisted to make a blended strand. The blended strands can be used to knit, braid, or weave a retraction cord. Because the degradation-resistant strands are part of the strand pattern, the retraction cords can be made sturdier without adversely affecting the cord's inherent deformation properties.