Sodium hypochlorite solution penetration into human dentine: a histochemical evaluation.

Area of Science:

• Endodontics
• Dental Materials Science

Background:

• Sodium hypochlorite (NaOCl) is a crucial irrigant in endodontic therapy.
• Enhancing NaOCl penetration into dentinal tubules may improve disinfection.
• Surfactants are additives that can alter the surface tension of solutions.

Purpose of the Study:

• To evaluate the ex vivo penetration depth of sodium hypochlorite solutions with and without surfactants into human dentine.
• To assess the bleaching ability of sodium hypochlorite solutions in dentinal tubules.

Main Methods:

• Human incisor teeth were used, and root canals were shaped.
• Dentinal tubules were stained using copper sulphate and rubeanic acid.
• Specimens were irrigated with 5.25% NaOCl solutions, with or without surfactants, for 2 minutes.
• Microscopic examination assessed irrigant penetration by measuring bleached circumference, area, and depth.

Main Results:

• Significant staining was limited to the middle and coronal thirds of the root canals.
• In these regions, 80-99% of the root canal circumference was bleached.
• Average penetration depth ranged from 39-62 μm, with maximum penetration up to 131 μm.
• No statistically significant differences in penetration were found between NaOCl solutions with and without surfactants (P=1).

Conclusions:

• The addition of surfactants to sodium hypochlorite solutions did not improve irrigant penetration into dentinal tubules in the middle and coronal thirds of incisor teeth.
• Further research may be needed to explore other methods for enhancing NaOCl penetration in endodontics.