A method of canal preparation to control apical extrusion of low-temperature thermoplasticized gutta-percha

Abstract

This study evaluated an adaptation of an accepted method of root canal preparation for its ability to contain the flow of injection-molded low-temperature thermoplasticized gutta-percha. Twenty-two extracted teeth with a total of 26 canals were mounted in stone. They were radiographed with a #15 file in place to determine working length. Canals were enlarged at the working length three file sizes beyond the initial file that bound. The body of the canal was further prepared to allow placement of a 22-gauge needle within 6 mm of the working length. Integrity of the apical barrier was assessed by probing with a smaller file, and teeth with an unsatisfactory barrier were discarded. Satisfactory canals were obturated using the Hygenic Ultrafil injection system. Teeth were radiographed postoperatively, then removed from stone blocks for examination under ×25 magnification. Gutta-percha was extruded in 1 of 23 canals, as the result of a lateral canal. This method of canal preparation seems to be effective in limiting the flow of injection-molded low-temperature thermoplasticized gutta-percha.