Efficacy of EDTA, glycolic acid and ethanol in the removal of calcium hydroxide from the apical third: A SEM study

Aim:This thesis aims to evaluate the efficacy of 17% EDTA (Ethylene Diamine Tetraacetic Acid), 10% Glycolic acid (GA), and 70% Ethanol as final irrigation solutions for the removal of Calcium Hydroxide (Ca(OH)2) used as a medicament in root canals. Material and Method:In our study, 76 single-rooted human mandibular premolars extracted due to periodontal or orthodontic problems were used. The teeth were kept in 0.9% saline after tooth extraction until the study period. For standardization, each tooth length was deconstructed to 15 mm. 15 K-type hand files (VDW, Munich, Germany) were used to determine the working length. The root canals were then prepared with an R40 (Reciproc, VDW, Munich, Germany) rotary instrument file with a reciprocal system using an endodontic motor (Eighteeth E Connect S). The root canals were irrigated with 10 ml of 2.5% NaOCl and 2 ml of 17% EDTA during the preparation procedure. The calcium hydroxide medicament used between sessions was placed in the canal and kept in an oven at 37 ˚C and 100% humidity for seven days. The samples were then randomly divided into three experimental groups (n:22) and 2 control groups (n:5) for final irrigation. Group 1: 6 ml 70% ethanol + Sonic activation (SA), Group 2: 6 ml 17% EDTA + SA, Group 3: 6 ml 10% Glycolic acid + SA, Negative control group: 5 ml distilled water, Positive control group: 5ml distilled water. Samples from all experimental groups were subjected to a final irrigaton with 5 ml of distilled water to ensure neutralization. The application and activation times of the solutions were determined as 60 s. Bucco-lingually bisected teeth were examined under SEM at x2000 magnification from the apical triad region and the effectiveness of calcium hydroxide removal was evaluated using Salgado's 5-grade scoring system. Results:The distributions of observers scores for calcium hydroxide removal from canals were examined using Pearson's chi-square test and multiple comparisons were performed with Bonferroni correction, according to the groups. The analysis results were presented as frequency (percentage). The significance level was taken as p< 0.05.Kappa test results showed that there was no statistically significant difference between the observers who performed the assessment (kappa value= 0.749, 0,737, 0,835). For scores 1, 4, and 5, there was no significant difference between EDTA and Glycolic Acid groups (p>0.05), while the Ethanol group removed significantly less Ca(OH)2 than EDTA and GA for these scores (p<0.001). No significant difference was found between the groups for score 2 (p>0.05). For score 3, no significant difference was found between the Glycolic Acid and Ethanol groups (p>0.05). Conclusion:EDTA and GA used as final irrigation agents within the limits of this study gave better results in Ca(OH)2 removal from root canals. Ethanol was insufficient in terms of Ca(OH)2 removal efficiency. None of the irrigation solutions used could completely remove Ca(OH)2 from the root canals.