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Study Identifies 3 Key Factors in Keeping Dental Handpieces Free of Contamination

Without proper care and maintenance, the line used to deliver output water to a dental handpiece is susceptible to bacteria contamination. Because water line contamination creates the risk of bacterial exposure to patients, dental practitioners must take measures to keep these output lines as clean as possible.

A review published in the International Dental Journal in 2018 identifies three key factors that influence the risk of bacterial contamination of handpiece water lines. Accounting for data collected for six years between 2012 and 2017, this study provides guidance as to the proper care and repairing for dental handpiece parts.

These factors are:

  1. Frequency of disinfection of dental handpiece water lines;
  2. Water supply source; and
  3. Proper functioning of the handpiece’s anti-retraction valve (also known as check valves).

To arrive at these conclusions, researchers collected data from 318 dental chair units from 64 hospitals located in Tianjin, China. The researchers collected bacteria samples from the handpiece output water lines and measured the concentration of bacteria in colony forming units per millilitre of water.

First, the study found that daily or weekly disinfection of the water lines significantly impacted the concentration of foreign bacteria in the lines. Most of these units (78.93%) did not have a process in place for regular water line disinfection.

Second, the researchers identified differences in bacteria concentration based on the origin of the water output to the handpiece. When the water supply source is hospital purified (either hospital self-purified water or purchased purified water), the bacteria concentration is lower. This finding suggests that bacteria that comes in with the water is a contributor to the contamination.

Third, contamination is reduced if the if the handpiece’s anti-retraction valve is properly functioning. The anti-retraction valve is designed to prevent contaminated fluids from being drawn into the handpiece. Previous studies have demonstrated that dental water units with automatic sterilization cycles are more effective in preventing contamination than mechanical flushing of water lines.

This final finding emphasizes the importance that dental practitioners pay mind to this component while repairing for dental handpiece parts. Check valves must be cleaned routinely and repaired or replaced periodically as they accumulate build-up of bacteria on the surface of the valve, which can lead to valve failure.

R-tech Dental recommends checking anti-retraction valves at least every six months to ensure they are properly functioning. If not, they must be repaired or replaced.