Effect of continuous irrigation on apical transportation, centering ability and volume of removed dentin in curved root canals: a micro computed tomography study

Aim: To assess the effect of continuous irrigation on apical transportation, centering ability and volume of removed dentin during root canal shaping with different file systems using micro-computed tomography (micro-CT).

Methodology: Twenty mandibular molars with a curvature of 25-35° were included. The teeth were scanned with micro-CT before shaping procedures and randomly divided into 4 groups (5 teeth, 10 canals) as follows: Continuous irrigation and WaveOne Gold (C-WOG), Continuous irrigation and Hyflex EDM (C-HEDM), Traditional irrigation and WaveOne Gold (T-WOG) and Traditional irrigation and Hyflex EDM (T-HEDM). Following root canal shaping procedures, all the teeth were re-scanned with micro-CT. Apical transportation and centering ability were evaluated through axial sections at the level of 1, 2, 3, 5 and 7 mm from the apical foramen. The amount of dentin removed was also analyzed by using micro-CT.

Results: The C-WOG and C-HEDM groups resulted in significantly less apical transportation at 7 mm bucco-lingually compared to the T-WOG group. The C-HEDM group was able to stay bucco-lingually centered at 7 mm significantly more than the T-WOG group. No statistically significant difference was observed among the groups in terms of the volume of removed dentin.

Conclusion: It can be concluded that continuous irrigation caused less apical transportation and better centering ability at 7 mm level in bucco-lingual direction.