Short-term storage stability of NaOCl solutions when combined with Dual Rinse HEDP

Area of Science:

• Dental materials science
• Chemical stability of disinfectants

Background:

• Sodium hypochlorite (NaOCl) is a widely used disinfectant in dentistry.
• Dual Rinse HEDP, containing etidronate, is a novel product for clinical applications.
• Assessing the stability of combined disinfectant solutions is crucial for clinical efficacy.

Purpose of the Study:

• To evaluate the short-term stability of sodium hypochlorite (NaOCl) solutions when mixed with Dual Rinse HEDP.
• To determine the impact of varying NaOCl concentrations and storage temperatures on solution stability.

Main Methods:

• NaOCl solutions (5.0%, 2.5%, 1.0%) were combined with 9.0% Dual Rinse HEDP.
• Stability was assessed over 8 hours at 23°C in glass bottles and polypropylene syringes.
• Effects of heating (60°C) and refrigeration (5°C) on NaOCl concentration (free available chlorine) were measured via iodometric titration.

Main Results:

• At 23°C, NaOCl/Dual Rinse HEDP solutions showed decreased available chlorine over time, with faster degradation at higher initial NaOCl concentrations.
• Heating the mixtures to 60°C resulted in complete loss of available chlorine within 1 hour.
• Refrigeration at 5°C maintained high available chlorine levels for up to 7 hours.

Conclusions:

• Both initial sodium hypochlorite concentration and storage temperature significantly affect the short-term stability of solutions containing Dual Rinse HEDP.
• Refrigeration is recommended for maintaining the efficacy of NaOCl/Dual Rinse HEDP mixtures.