Endodontic retreatment of Thermafil versus laterally condensed gutta-percha

The Thermafil device is becoming a popular obturating material. Because endodontic failures inevitably occur with all techniques, questions of retreatment of Thermafil-obturated teeth will also arise. The purpose of this study was to compare retreatment of Thermafil and laterally condensed gutta-percha. Thirty-five mandibular incisors were prepared with a stepback flare technique and divided into two groups. One group (n = 20) was obturated using Thermafil, the other group (n = 15) was obturated with laterally condensed gutta-percha. The teeth were stored in a humidor for 3 months to allow sealer to set. Retreatment of both groups was accomplished using a combination of heat and chloroform solvent. The time for retreatment was recorded. The teeth were split longitudinally and the amount of gutta-percha remaining in the root canal was measured and analyzed statistically. The results showed that in the coronal one-third of the canal, use of the Thermafil device resulted in significantly more remaining gutta-percha than use of laterally condensed gutta-percha. However, in the apical and middle one-third of the canal the difference in remaining gutta-percha between Thermafil and laterally condensed gutta-percha was not significant. The metal carrier was easily removed and the mean time for retreatment was 6.3 min for Thermafil compared with 5.7 min in the lateral condensation group.