Analysis of the effectiveness of calcium hydroxide removal with variation of technique and solvent vehicles.

CONTEXT Calcium hydroxide (Ca(OH)2) paste filling is largely used as intra-canal medication and can be combined with different vehicles. Removal of that paste should be preceded by obturation, to avoid the occurrence of apical microleakage. AIMS To evaluate the efficiency of removal of pulp Ca(OH)2, from using different vehicles (water, propylene glycol) and removal techniques (mechanical and ultrasonic). STUDY DESIGN Twenty-four premolars and four human incisors were prepared with step-back technique and divided into six groups according to the removal techniques and vehicles used: Group distilled water/mechanical removal, Group distilled water/ultrasonic removal, Group propylene/mechanical removal, Group propylene/ultrasonic removal, negative control group, and positive control group. The differences between groups were analyzed. MATERIALS AND METHODS The teeth were prepared by step-back technique. The samples were evaluated by stereomicroscopy, using a scoring system for the evaluation of residues in the canal. STATISTICAL ANALYSIS Mann-Whitney test was used to a comparison between groups with the same vehicle. For comparison between groups, regardless of the vehicle, we used the Kruskal-Wallis test, considering P < 0.05 for both tests. RESULTS Groups using distilled water or propylene glycol did not show statistically significant results. When the groups were compared, differences were detected between groups distilled water/propylene and mechanical removal/removal ultrasonic, with the first featuring superior performance. CONCLUSION None of the removal techniques employed in this study was able to completely remove Ca(OH)2 from the root canal. However, the use of distilled water as a vehicle and ultrasonic removal presented the best performance.