Argon laser initiated resin photopolymerization for the filling of root canals in human teeth.

This work was undertaken to determine if 488 nm light is transmitted through dentin in quantities adequate to polmerize resin located several milimeters from the light source (an optical fiber). The spread of polymerization in a camphorquinone activated resin due to 488 nm light emanating from an opaque plastic canal was compared with light emanating from a canal of the same diameter in tooth dentin. Results indicated that irradiation of a resin-filled chamber via an opaque canal generated a series of ellipsoidal forms, while irradiation via a root canal generated bullet-shaped forms of much larger volume and weight. The base of these bullet-shaped forms was flat against the dentin-resin interface and surrounded the canal. These results indicated that 488 nm argon laser light was transmitted through dentin and could act to polymerize resin at a distance of several millimeters from the canal. Further experiments verified that resin in lateral canals of tooth roots was readily polymerized by 488 nm light applied at low power levels (50 mW). These experiments demonstrate the effectiveness of the argon laser in polymerizing light activated dental resins located within or adjacent to tooth dentin at distances up to several milimeters from the fiberoptic terminus. The flexibility and control that these procedures make possible in the obturation of root canals may lead to substantial improvements in endodontic therapy.