Fotona Case Studies

Reaction Rate of NaOCl in Contact with Bovine Dentine: Effect of Activation, Exposure Time, Concentration, and pH

Written by National Dental Innovations | Jun 10, 2025 7:12:38 PM

Unlocking the Secrets of Sodium Hypochlorite's Efficacy in Endodontic Treatment.

Authors: R.G. Macedo, P.R. Wesselink, F. Zaccheo, D. Fanali, L.W.M. Van Der Sluis
Journal: International Endodontic Journal (2010)

Objective

To investigate how activation methods (ultrasound vs. laser), sodium hypochlorite (NaOCl) concentration, pH, and exposure time influence the reaction rate (RR) of NaOCl when interacting with dentinal walls.

Materials and Methods

  • : Standardized root canals in bovine incisors.

  • :

    • NaOCl concentrations: 2% vs. 10%.

    • pH levels: 5 (acidic) vs. 12 (alkaline).

    • Exposure times: 1 vs. 4 minutes.

  • :

    • Passive ultrasonic irrigation (PUI).

    • Laser-activated irrigation (LAI).

    • Control (no activation).

  • : 1-minute activation followed by 3-minute rest interval.

  • : Iodine/thiosulfate titration measured iodine concentration to calculate RR.

Key Results

  • :

    • Longer exposure (4 min) and higher NaOCl concentration (10%) increased RR.

    • Activation (especially LAI) enhanced RR more than passive irrigation.

  • : pH had no effect on RR for 2% NaOCl.

  • : Chlorine consumption rose during the 3-minute rest interval, particularly after LAI activation.

Conclusions

Activation methods (notably laser) strongly modulate NaOCl’s reaction rate, improving its efficacy. Extended exposure and higher concentrations further boost RR, while pH does not influence outcomes for 2% NaOCl. These findings highlight the importance of activation in optimizing irrigant activity during endodontic treatment.

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