Light-transmitting fiber optic posts: An in vitro evaluation.

Statement of problem. The clinical challenge of adhering cement to intracanal dentin is transmitting light to the most apical parts of root canals to allow more efficient polymerization of the cement. Purpose. The purpose of this in vitro study was to compare the cement-polymerizing ability, microstructure, and radiopacity of a new fiber optic post (iLumi fiber optic Post) with a clinically successful fiber post (DT Light Post). Material and methods. Polymerizing ability was compared using a modified depth-of polymerization protocol. A split aluminum mold with a 12-mm cylindrical hole (diameter=4.7 mm) was filled with light-polymerized resin cement (Variolink Esthetic LC). Each fiber post (n=12) was positioned and light-polymerized on the coronal end for 60 seconds with a light-emitting diode polymerization light. Unpolymerized resin was dissolved with an organic solvent, and the weight and length of the polymerized resin cement were measured. Scanning electron microscopy was used to examine vertical and horizontal cross-sections. The radiopacity values of both the posts and 5 additional reference posts were evaluated using an aluminum step wedge. Results. The weight and length of the polymerized resin cement were significantly greater (P<.05) with the fiber optic post, which scanning electron microscopy showed to have a higher density of parallel fibers. The iLumi post demonstrated greater radiopacity among the tested fiber posts and a titanium alloy post. Conclusions. The iLumi fiber optic posts have a unique structural fiber composition and excellent radiopacity and light-transmitting ability that produce more complete polymerization of the resin cement than the DT Light posts.