Micro-CT evaluation of a nanodiamond irrigant for hard-tissue debris removal during sonic agitation

To investigate the efficacy of nanodiamond irrigation solution with sonic agitation for removing of hard-tissue debris (HTD) within the isthmus-containing mesial roots of human mandibular molars using micro-CT analysis.

Forty mesial roots of extracted human mandibular molars were selected based on micro-computed tomography scans (9-μm resolution). The mesial canals were mechanically prepared using ProTaper® Gold nickel-titanium rotary instruments and divided into four groups (n = 10 each) according to the final irrigation protocol: sonic agitation with nanodiamond irrigation solution for three 20-s cycles, sonic agitation with 17% EDTA for three 20-s cycles, sonic agitation with 3% NaOCl for three 20-s cycles and manual syringe irrigation with NaOCl using a 30-G needle syringe for 60 s. The samples were scanned again after canal preparation and the use of the final irrigation protocols. Data were collected to evaluate the percentage of HTD removed. Statistical comparisons were made using the anova post hoc Tukey test (p < .05).

None of the irrigation protocols was able to completely eliminate HTD from the isthmus-containing mesial canals of mandibular molars. However, sonic agitation with the nanodiamond irrigant and sonic agitation with 17% EDTA irrigation solutions showed higher mean reductions of HTD (68.0% and 68.9%, respectively) compared to sonic agitation with 3% NaOCl and manual syringe irrigation with 3% NaOCl (43.4% and 13.7%, respectively) (p < .05).

The effectiveness of sonic agitation in removing HTD from the entire root canal was superior to that of manual syringe irrigation. When employing sonic agitation, the addition of nanodiamonds to NaOCl demonstrated enhanced HTD removal capabilities compared to using NaOCl alone and was comparable to that of EDTA. These results suggest that sonic agitation with a nanodiamond irrigation solution may serve as an effective alternative approach for HTD removal in root canal treatment.