Evaluatıon of calcium hydroxide removal efficiency of two different irrigation activation techniques from artificial internal resorption cavities prepared at different root levels

The aim of this study is to evaluate the calcium hydroxide removal efficiency of two different irrigation activation techniques from artificial internal resorption cavities prepared at different root levels with three different methods. The root canals of 102 single-rooted human maxillary incisors teeth were prepared up to working length using the Reciproc system to size R50. The roots were split longitudinally into two equal parts. Samples were divided into two equal number of groups, coronal and apical (n = 51). Standardized simulated internal root resorption cavities in the apical or coronal part was prepared in the two root halves. Then, the root halves were reassembled, and calcium hydroxide was placed into the root canals, with the exception of six samples that separated from the coronal and apical group for the negative control group. Another six teeth (the positive control group) were not subjected to the calcium hydroxide removal procedures. Forty-five samples from each of the coronal and apical group were randomly divided into three experimental groups (n=15), according to the removal techniques: conventional syringe irrigation (CSI), sonic irrigation (SI) and passive ultrasonic irrigation (PUI). Five millilitres of 2,5% NaOCl and 17% EDTA were used in all experimental groups during the calcium hydroxide removal procedures. The amount of remaining calcium hydroxide was evaluated with three different methods (photographic, radiographic and weight). The data were statistically compared using the one-way analysis of variance and post hoc Tukey test, correlation analysis of examination methods were made with Spearman Rank method (p≤0,05). None of the irrigation techniques could completely clean the calcium hydroxide from the standardized simulated internal root resorption cavities of the root canals. In the photographic method, PUI was superior to the other groups (p<0,05). In the radiographic and weight method, PUI and SI removed significantly more calcium hydroxide than CSI, with no significant differences between them (p>0.05). In the photographic and radiographic method, the amount of remaining calcium hydroxide was much more in the coronal cavities; in the weight method (p<0.05), the difference between coronal and apical cavities was not significant (p>0.05). More calcium hydroxide was removed in all samples with the PUI technique compared to the other two techniques. The amount of remaining calcium hydroxide was much more in the coronal cavities compared to the apical. Different correlations were found between the examination methods.