REMOVAL OF THERMAFIL ROOT-CANAL FILLING MATERIAL

The aim of this study was to evaluate if removal of Thermafil plastic carriers and reestablishment of working length were possible in single rooted teeth filled with the Thermafil system. Twenty freshly extract ed maxillary central incisors were prepared and filled with #30 Therma fil plastic obturators according to manufacturer's recommendations. Te eth were divided in two groups: Group I: 10 teeth were retreated using dimethylformamide as a solvent Group II: 10 teeth were retreated usin g chloroform as a solvent Removal of filling material was performed ma nually using K files and H files alternately between carrier and denti nal walls. The average time needed to remove the plastic carrier was 7 min for group I and approximately 61/2 min for group II. No deformati on of the plastic carrier was observed after removal from the canal. R emoval of plastic carriers and measurement of the proper working lengt h were easily performed using manual endodontic instruments. Chlorofor m greatly enhanced this procedure.