Removal of Calcium Hydroxide Pastes Containing N-Methyl-2-pyrrolidone, Local Anaesthesia, Glycerine, and Methylcellulose from Artificial Radicular Grooves: An In-vitro Study

OBJECTIVE: To compare the removal of calcium hydroxide (CaOH) pastes containing N-Methyl-2-pyrrolidone (NMP), lidocaine, glycerine, methylcellulose, or water from artificially created grooves. METHODS: In this study, 115 human single-rooted maxillary incisors with single and straight root canals were prepared using a rotary file up to size 40/.04 and split longitudinally. A longitudinal groove was created from 2 to 5 mm from the apex and filled with CaOH combined with different vehicles. The specimens were divided among 5 experimental groups according to the vehicle as follows: distilled water, lidocaine, glycerine, methylcellulose, and NMP. The two halves were re-attached, and the canals were flushed with 10 ml of 17% EDTA for 60 seconds. The residual amount of CaOH was scored using a stereomicroscope at 8× magnification. Statistical significance was set at P<0.05. RESULTS: The NMP-based group exhibited significantly less residual medicament compared to the distilled water (P<0.05), while there were no statistically significant differences among the methylcellulose-, lidocaine-, and glycerine-based groups and distilled water (P>0.05). CONCLUSION: The vehicle is an important factor in the successful removal of CaOH medicament from the root canals. Within the limitations of the present study, the NMP-based CaOH medicament exhibited better removal efficacy than the distilled water. However, the cleaning success of the methylcellulose-, lidocaine-, and glycerine-based groups was similar to that of distilled water.