A Comparative Evaluation of Depth of Penetration of Sodium Hypochlorite with Various Surfactants in the Dentinal Tubules: An In Vitro Study.

Abstract

The present study aimed to evaluate and compare the depth of penetration of sodium hypochlorite (NaOCl) solution combined with various surfactants—cetrimide and benzalkonium chloride—into dentinal tubules using a confocal laser scanning microscope (CLSM).

Introduction: Effective irrigation is critical for successful endodontic therapy. Sodium hypochlorite (NaOCl) remains the most widely used irrigant due to its antimicrobial and tissue-dissolving properties. However, its high surface tension restricts its penetration into dentinal tubules. Incorporating surfactants like cetrimide and benzalkonium chloride may enhance its wettability and effectiveness.
Aim: To evaluate and compare the depth of penetration of 2.5% sodium hypochlorite alone and in combination with 0.2% cetrimide and 0.1% benzalkonium chloride into dentinal tubules using confocal laser scanning microscopy (CLSM)

Materials and Methods: Thirty extracted single-rooted human premolars were decoronated and instrumented with ProTaper Gold rotary files. The specimens were divided into three groups (n=10): Group A - 2.5% NaOCl; Group B - 2.5% NaOCl + 0.1% Benzalkonium chloride; Group C - 2.5% NaOCl+ 0.2% Cetrimide. Rhodamine B dye was added for visualization under CLSM. Data were analyzed using one-way ANOVA and Tukey’s post hoc test (p < 0.05).
Results: Group B (NaOCl + Benzalkonium Chloride) demonstrated the highest mean depth of penetration in the coronal,middle and apical third, while Group A (NaOCl alone) showed the lowest depth of penetration. Inter-group comparisons revealed statistically significant differences between NaOCl alone and surfactant-modified NaOCl in all thirds.

Conclusion: Addition of benzalkonium chloride to NaOCl improved dentinal tubule penetration compared to NaOCl alone or NaOCl with cetrimide. However, apical penetration remained the lowest in all the groups.