When people think about dental safety, they often think about gloves, masks, sterilization, and surface disinfection. But two of the most important safety systems in a dental practice are often less visible: indoor air and dental unit waterlines (DUWLs).

When both are managed well, they help protect patients and the dental team every day.

Indoor Air: Start With the System

Better indoor air starts with the HVAC system. An evaluation of the heating, ventilation, and air conditioning system—including filtration—should be the first step in improving air quality.

From there, focus on the layers that matter:

• optimize outside air, airflow, filtration, and exhaust
• use the highest compatible MERV-rated filters and replace them according to MIFUs
• manage airflow from cleaner to less-clean areas and away from occupants
• use portable HEPA filtration, source capture, HVE, isolation devices, and UVGI as supplemental controls where appropriate
• monitor and maintain the system over time

Indoor air safety is not a one-time fix. It depends on how the whole system works together.

DUWLs: Safe Water Takes a Written Plan

Dental unit waterlines are especially vulnerable to biofilm because they contain narrow tubing and often have slow or intermittent water flow. If they are not maintained, microbial contamination can rise to unsafe levels.

For dental treatment water, the standard is clear: ≤500 CFU/mL.

A written DUWL policy should make that expectation explicit:

“The facility will never use water that fails to meet potable water standards or has >500 CFU/mL of detected bacteria.”

That policy should also explain how the practice will:

• follow MIFUs for equipment and DUWL products
• train staff on both the why and the how
• ensure access to treat the lines
• use appropriate source water
• maintain continuous DUWL treatment
• use shock treatment when indicated
• use sterile water or saline through a separate sterile system for surgery
• flush lines for 20–30 seconds between patients
• test DUWLs at least quarterly
• document maintenance, testing, and corrective actions
• assign responsibilities and backups
• remove units from use after failed results until testing confirms safe microbial levels

The Bottom Line

Some of the most important infection prevention work in dentistry happens behind the scenes.

For air: ventilation, filtration, airflow, source capture, supplemental controls, and maintenance matter.

For water: continuous DUWL treatment, shock treatment when needed, sterile water for surgery, testing, and documentation matter.

Done consistently, these fundamentals help support safer care for patients and a safer workplace for the dental team.

Help maintain a culture of safety in your practice and strengthen your team’s knowledge. Complete the August 2026 ICIP online course to earn 1 CE credit – free for ADS Members, or available for just $20 for non-members.

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Stay tuned for the next ICIP issue – coming in October 2026!