The purpose of this study was to evaluate the insertion depth of several brands of master gutta percha cones after shaping by various Ni-Ti rotary files in simulated canals.

Fifty resin simulated J-shape canals were instrumented with ProFile, ProTaper and HEROShaper. Simulated canals were prepared with ProFile .04 taper #25 (n = 10), .06 taper #25 (n = 10), ProTaper F2 (n = 10), HEROShaper .04 taper #25 (n = 10) and .06 taper #25 (n = 10). Size #25 gutta percha cones with a .04 & .06 taper from three different brands were used: DiaDent; META; Sure-endo. The gutta percha cones were selected and inserted into the prepared simulated canals. The distance from the apex of the prepared canal to the gutta percha cone tip was measured by image analysis program.

Within limited data of this study, the results were as follows

1. When the simulated root canals were prepared with HEROShaper, gutta-percha cones were closely adapted to the root canal.

2. All brands of gutta percha cones fail to go to the prepared length in canal which was instrumented with ProFile, the cones extend beyond the prepared length in canal which was prepared with ProTaper.

3. In canal which was instrumented with HEROShaper .04 taper #25, Sure-endo .04 taper master gutta percha cone was well fitted (p < 0.05).

4. In canal which was instrumented with HEROShaper .06 taper #25, META .06 taper master gutta percha cone was well fitted (p < 0.05).

As a result, we concluded that the insertion depth of all brands of master gutta percha cone do not match the rotary instrument, even though it was prepared by crown-down technique, as recommended by the manufacturer. Therefore, the master cone should be carefully selected to match the depth of the prepared canal for adequate obturation.