Nanodiamond Irrigation With Sonic Agitation Enhances Bioceramic Sealer Penetration

Objectives: This study examined the effectiveness of a nanodiamond irrigation solution with sonic agitation on the penetration of a bioceramic sealer into dentinal tubules.
Methods: Twenty-four extracted single-rooted teeth were instrumented to size F2 (#25) with nickel-titanium rotary files and randomly assigned to four irrigation protocols: 3% sodium hypochlorite with manual irrigation (NaOCl-MI), 3% sodium hypochlorite with sonic agitation (NaOCl-SA), 3% sodium hypochlorite and 17% EDTA with sonic agitation (EDTA-SA), and 3% sodium hypochlorite with 500 nm nanodiamonds at 10 mg/ml with sonic agitation (ND-SA). After obturation with a bioceramic sealer using hydraulic condensation, the teeth were sectioned at 1.5 mm intervals from apex to crown and examined under confocal laser scanning microscopy at 4x magnification. ImageJ measured sealer penetration depth and coverage on canal walls. Statistical analysis used the Kruskal-Wallis test (p<0.05) to evaluate the effects of irrigation protocols on sealer penetration.
Results: For sealer coverage, the NaOCl-SA showed higher coverage in the apical third versus coronal/middle thirds (p<0.05). NaOCl-MI, EDTA-SA, and ND-SA showed no differences among thirds. The ND-SA demonstrated higher coverage in all thirds compared to NaOCl-MI and NaOCl-SA, but was similar to EDTA-SA. For sealer penetration depth, NaOCl-MI, NaOCl-SA, and EDTA-SA showed greater penetration in coronal/middle thirds versus apical third (p<0.05). The ND-SA showed decreasing penetration from coronal to middle to apical thirds. ND-SA demonstrated significantly greater penetration depths in all thirds compared to other groups (p<0.05).
Conclusions: Previous research from our lab showed that sonically-agitated nanodiamond irrigants effectively remove smear layers, debris, and biofilm. Current study demonstrates that they enhance bioceramic sealer tubular penetration, comparable to EDTA-SA, and outperform NaOCl-MI and NaOCl-SA. Nanodiamond irrigants may be a viable alternative to EDTA, improving sealer penetration and reducing microleakage in endodontics. Further studies will assess their impact on sealer penetration after biofilm removal and evaluate retention, leakage, and reinfection risk.