Effectiveness of the Canal Finder and hand instrumentation in removal of gutta-percha root fillings during root canal retreatment.

The purpose of this study was to quantify the amount of remaining gutta-percha/sealer on the canal walls when the Canal Finder system, hand instrumentation and a combination of both (hybrid technique) were used to remove these materials. The amount of apically-extruded debris and the time required for removal were also recorded. Sixty extracted maxillary anterior teeth were prepared using a stepback technique and obturated with gutta-percha. Reinstrumentation of all groups was done in conjunction with a solvent, chloroform. The teeth were split longitudinally and photographed, and the total area of the root canal and the area of the debris were traced and quantified using a computerized image analysis system. The ratio of remaining obturation material to root canal surface was derived and analysed statistically. Hand instrumentation resulted in less debris remaining than did the other two techniques (P < 0.05). The differences in the amount of apically extruded debris were not significant among the techniques (P > 0.05). The hybrid technique required significantly less time for filling material removal. The Canal Finder system alone was not superior to hand instrumentation.