Endodontic retreatment: evaluation of gutta-percha and sealer removal and canal reinstrumentation.

To examine the appearance of root canal walls after retreatment, 80 extracted teeth were chemomechanically prepared using a stepback flare technique and obturated with gutta-percha and either Roth's 801 or AH26 sealers. Four techniques were used to remove gutta-percha and sealer: method 1--heat and files; method 2--heat, files, and CaviEndo; method 3--chloroform and files; and method 4--chloroform, files, and Cavi-Endo. The teeth were sectioned longitudinally and the amount of debris remaining was quantitated. The results showed that no technique removed all debris. When AH26 was the sealer, method 4 was significantly less effective. When Roth's 801 was the sealer, method 1 was significantly less effective. Teeth obturated using Roth's 801 sealer were significantly cleaner after reinstrumentation.