Comparison of different cleaning techniques for the removal of root canal sealer from dentine surfaces: An SEM-EDX analysis

To evaluate and compare the effectiveness of different cleaning protocols for removing AH Plus root canal sealer remnants from coronal dentine surfaces before adhesive restorative procedures using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Forty-nine dentine specimens prepared from extracted human molars were randomly allocated to seven groups according to the cleaning protocol: negative control, positive control, dry cotton pellet, ethanol with cotton pellet, ethanol followed by 37% phosphoric acid, ethanol followed by air abrasion (53 μm Al₂O₃), and ethanol followed by air abrasion and 37% phosphoric acid. Residual sealer contamination was quantified by measuring zirconium (Zr) weight percentages using EDX, while dentine surface morphology was evaluated by SEM. Data were analyzed using one-way ANOVA and Tukey's post hoc test (p < 0.05). Significant differences were observed among the cleaning protocols (p < 0.001). The positive control group exhibited the highest zirconium content, whereas no zirconium was detected in the negative control group. Ethanol cleaning significantly reduced residual sealer compared with dry cotton pellet cleaning. Protocols incorporating phosphoric acid and/or air abrasion resulted in significantly lower zirconium levels than ethanol alone; however, no statistically significant differences were observed among these advanced cleaning protocols. The combined ethanol, air-abrasion, and phosphoric acid protocol yielded the numerically lowest residual zirconium content (2.64 ± 0.10 wt%), corresponding to a descriptive reduction of 86.4% relative to the positive control group. Ethanol alone was insufficient for the complete removal of AH Plus sealer remnants. Phosphoric acid and/or air abrasion following ethanol cleaning resulted in significantly lower residual zirconium levels than ethanol cleaning alone, although no statistically significant differences were observed among the advanced cleaning protocols. Further studies are needed to determine whether these improvements in surface cleanliness enhance adhesive performance and clinical outcomes.