Chlorine dioxide flushing protocols for microbial reduction in dental chair units

Area of Science:

• Dental hygiene
• Microbiology
• Infectious disease control

Background:

• Dental chair unit (DCU) waterlines are prone to microbial contamination, posing infection risks.
• Regular disinfection is crucial for patient and dental staff safety.

Purpose of the Study:

• To evaluate chlorine dioxide (ClO₂) rinsing protocols for microbial and biofilm reduction in DCUs.
• To determine optimal ClO₂ concentrations and flushing frequencies for effective waterline disinfection.

Main Methods:

• Automated protocols with varying ClO₂ concentrations and flushing frequencies were tested.
• Microbial load was assessed using flow cytometry and agar culturing.
• Biofilm removal efficacy was evaluated.

Main Results:

• Continuous low-dose ClO₂ (1.2 mg/L) achieved sustainable microbial reduction (up to 2.51 log₁₀).
• Single high-dose shock disinfections (22.7 mg/L) provided only transient reductions.
• ClO₂ effectively removed biofilms, but its depletion during stagnation necessitates continuous application.

Conclusions:

• Permanent low-dose ClO₂ application is recommended for sustainable disinfection of DCU waterlines.
• Periodic high-concentrated shock disinfection can be used for biofilm removal, particularly for P. aeruginosa biofilms.