Extra Positive Air Pressure to Prevent Microbial Contamination in Dental Handpieces: An Experimental Study

Area of Science:

• Biomedical Engineering
• Infection Control
• Dental Technology

Background:

• Dental handpieces (HPs) can facilitate bacterial contamination through suck-back.
• Understanding air pressure (AP) dynamics is crucial for preventing microbial ingress.

Purpose of the Study:

• To evaluate the efficacy of extra positive air pressure (AP) in dental handpieces (HPs) for preventing external bacterial penetration.
• To assess the relationship between AP variations and suck-back phenomenon during HP operation.

Main Methods:

• Investigated suck-back phenomenon by correlating AP variations with occurrence under controlled conditions.
• Measured AP changes using water displacement via glass tube or manometer.
• Utilized an extra AP supplier (EAPS) connected to HP exhaust airlines.
• Conducted bioburden tests by immersing HPs in bacterial cultures during operation to assess contamination risk.

Main Results:

• A maximum negative AP of -2.11 kPa was observed immediately after HP operation without EAPS.
• No negative AP occurred when the EAPS was activated post-operation.
• Bacterial contamination was detected on internal HP components when extra positive AP was insufficient.

Conclusions:

• Inadequate extra positive AP after HP operation increases the risk of bacterial penetration and contamination.
• Applying a minimum of 0.1 MPa extra positive AP to the exhaust airflow for at least 5 seconds effectively prevents microbial contamination.