A comparison of different instruments in the gutta-percha-filled canals re-treatment

Objectives: To compare the effectiveness of Hero R-ENDO, Profile and H-files with reciprocal instruments during the removal of root canal fillings. Methods: A total of 36 canals from single-rooted maxillary anterior teeth were divided into three groups. All the canals were accessed and then prepared with K-files and obturated with gutta-percha and iodoform paste in laterally condensation technique. After two weeks of obturation, re-treatment was performed with the following instruments: H-files with reciprocal instruments(groupI); Profile(groupII); R-ENDO(groupIII). Chloroform was used in all groups. The time required to achieve the working length was recorded. The teeth were subsequently split longitudinally, photographs were taken with a digital camera and the remnants within the root canals after re-treatment were assessed. The amount of filling materials pushed out of apex was also recorded. The results were compared by means of ANOVA test and Chi square test among the groups. Results: Group III was significantly faster than other groups (P<0.01)to achieve the working length. All groups left gutta-percha inside the canal, but Group III was clearer than other groups(P<0.01). Group III had significantly little amount of filling material pushed out of apex(P<0.01). Conclusions: Hero R-ENDO removed the filling materials faster and cleaner than other instruments. But it's necessary to clean and shape the root canal subsequently. Profile instruments were inadequate in completely removing the gutta-percha filling material from the root canals.