Efficacy of different devices in removing calcium hydroxide from the root canal

Objectives: The aim of this in vitro study was to compare the removal efficiency of calcium hydroxide (CH) medicament from the root canal walls with various devices. Materials and Methods: The root canals of 85 extracted human maxillary incisors were prepared with ProTaper NiTi rotary files and randomly divided into five experimental groups (n = 15), whilst the remaining teeth (n = 10) served as positive and negative controls. In each experimental group, CH was placed into the canals by using a lentulo spiral. The negative control did not receive CH placement, and the positive control received the CH, but no subsequent removal. After 7 days, the CH was removed using five different techniques: Group (G) I, Master apical file (MAF) + manual needle irrigation (MNI); GII, CanalBrush (CB) +MNI; GIII, RinsEndo (RE); GIV, Self-adjusting file (SAF) + Vatea; GV, CB+MNI, followed by SAF+Vatea. Irrigants, total irrigant volumes and total irrigation time were kept constant throughout the study for all the experimental groups. The roots were grooved longitudinally and split into halves. Images of each half of the canal were acquired by a digital camera. A scoring system of 1 to 4 was used to assess the amount of residue on the cervical, middle and apical third of the canal. Randomly selected three specimens from each group also evaluated with SEM. The data were subjected to statistical analysis using Kruskal-Wallis and Mann-Whitney tests, with Bonferroni correction, at 95% confidence level (P < 0.05). Results: Remnants of CH were found in all experimental teeth regardless of the device used. When examining the root canal as a whole, there was no significant difference between the groups. When examining the efficacy of CH removal from the apical, middle and cervical third of the canal separately between groups there was a statistically significant difference between the middle (p=0.003) and cervical (p=0.006) thirds. Conclusion: None of the techniques removed the CH medicament completely; the use of the RE and SAF facilitated removal of CH especially from the cervical third.