Effect of combinations of irrigating solutions on dentine wettability

Introduction: The aim of this study was to evaluate the dentine wettability of different endodontic irrigation solutions by measuring the contact angle. Methods: Fifteen roots of recently extracted mandibular premolars were used, and cementum was eliminated. Root canals were instrumented according to the step-back technique using distilled water as an irrigant. The apical and coronal thirds of the roots were eliminated and the middle thirds were transversally sectioned. The 30 segments were embedded in acrylic resin and ground smooth and polished using 400-1200 grit papers. The dentine segments were randomly divided into six groups according to the irrigating solution they were put into contact with at 37°C for 5 mins: distilled water, 1% sodium hypochlorite, 1% citric acid, 17% EDTA, 1% citric acid + 1% sodium hypochlorite, 17% EDTA + 1% sodium hypochlorite. Then a 3 µl drop of distilled water was laid on each dentine surface with a micro-syringe and images were immediately captured with a super steady shot camera and digitalised. The contact angles were measured using ruler software. Results were analysed using one-way ANOVA and Tukey's test. Results: The contact angles were significantly reduced after pre-treatment of the dentine samples with 17% EDTA or 1% citric acid (P 0.05), either alone or in combination with 1% sodium hypochlorite. The latter showed no significant difference compared to the control (P > 0.05). Conclusion: It was discovered that 1% citric acid and 17% EDTA, alone or in combination, increased the surface free energy of dentine. Keywords: citric acid, contact angle, EDTA, sodium hypochlorite, wettability