This study was conducted to evaluate the insertion depth of Buchanan plugger after shaping by various Ni-Ti rotary files. It was conducted to determine which size of plugger are appropriate, when root canals are shaped with Ni-Ti rotary files and obturated by Continuous wave of condensation technique.

Two type of eighty simulated resin blocks were used : J-shaped and straight shaped canal. The simulated canals were instrumented by ProTaper and ProFile. Buchanan pluggers were inserted into the canal, and then the image was recorded to scanner. The distance from the apex of the canal to the plugger tip was measured by image analysis program. Data were analyzed by one-way ANOVA followed by Scheffe's test.

The results were as follows

1. In straight canal finished up to ProTaper F2 and F3 file, F and FM pluggers were inserted more than 5 mm short of working length.

2. In J-shaped canal finished up to ProTaper F2 file, F pluggers were inserted more than 5 mm short of working length. Finished up to ProTaper F3 file, F and FM pluggers were inserted more than 5 mm short of working length.

3. In straight and J-shaped canal finished up to ProFile .06/#20 and .06/#25, any of Buchanan plugger could not be inserted more than 5 mm short of working length.

These results suggest that canals shaped by ProTaper could be obturated by Continuous wave of condensation technique with F and FM size Buchanan plugger.