(PR166) Efficacy of Three Techniques for Removal of Calcium Hydroxide from the Mesial Canals of Curved Mandibular Molars: A Micro-CT Study

Objective: The purpose of this study was to evaluate the efficacy of three irrigation techniques: standard syringe irrigation (SI), ProUltra PiezoFlow (CUI) and EdgeEndo Er,Cr:YSGG (LAI) laser in removing calcium hydroxide from the mesial canals of moderately to severely curved mandibular molars using micro-CT analysis.

Methods: Mesial canals of 30 extracted human mandibular molar teeth were prepared with to size 30/.04 taper or 35/.04 taper rotary instruments. Teeth were randomly assigned to the three experimental groups (n=10) with evenly distributed degrees of curvature. All teeth were scanned with micro-CT following rotary instrumentation. Calcium hydroxide was placed into prepared canals and sealed for 14 days. A micro-CT scan was taken to determine calcium hydroxide paste volume in each tooth. Canals were irrigated utilizing 3 techniques and re-scanned. Volume and percent change of calcium hydroxide before and after irrigation calculated and analyzed.

Results: Calcium hydroxide paste remained in all groups after irrigation. The SI group removed -0.09% in the apical segment (0-3 mm) and 14.1% in the middle segment (3-6 mm). LAI removed 48.8% in the apical segment and 72.1% in the middle segment. CUI removed 14.9% in the apical segment and 50.1% in the middle segment.

Conclusion: Irrigation with LAI removed significantly more calcium hydroxide in the middle and apical segments when compared to CUI and SI (p < 0.05). CUI removed significantly more calcium hydroxide in the middle and apical segments compared to SI (p < 0.05).