Comparative Evaluation of Polymeric and Metal Ultrasonic Tips for the Removal of Calcium Hydroxide From Root Canals

BACKGROUND Calcium hydroxide (Ca(OH)₂) is commonly used in endodontics for its antimicrobial and biological qualities. However, completely removing it from the apical third of root canals is challenging in clinical practice. Residual material can compromise sealer adherence and treatment success. This study evaluated the effectiveness of conventional needle irrigation (CNI) and passive ultrasonic irrigation using different tip designs to remove Ca(OH)₂ from the apical third of root canals. MATERIAL AND METHODS Sixty human premolars were sectioned to create standardized grooves filled with Ca(OH)₂ and were divided into CNI, metal ultrasonic activation (MUA), and polymer ultrasonic activation (PUA) groups (n=20/group). Following irrigation with sodium hypochlorite, EDTA, and distilled water, the canals were dried. Residual Ca(OH)₂ area (mm²) was measured via ImageJ. Grooves were evaluated using visual scoring (0-3). ANOVA and Bonferroni tests analyzed quantitative area data. Chi-square and z-tests were used for ordinal scoring (P<0.05). RESULTS Statistically significant differences were observed among the irrigation groups regarding amount of residual Ca(OH)₂ (P<0.001). CNI group exhibited more residual material than the MUA and PUA groups (P<0.001). The MUA and PUA groups did not differ (P=0.999). At the 2-mm and 4-mm levels, CNI resulted in significantly higher observational scores than did the ultrasonic activation groups (P<0.01). CONCLUSIONS Complete removal of Ca(OH)₂ remains difficult. Ultrasonic activation was more effective than conventional irrigation, and metal and polymer tips performed similarly. The flexibility of polymer tips may offer an advantage in curved canals, which should be explored further.