Dental unit water system harbor bacterial biofilms, studies have shown that output water from Dental Unit Waterlines (DUWLs) are usually heavily contaminated with microorganisms which derive from biofilm on the internal surface of DUWLs. At present it is believed that the majority of infections, particularly chronic with exacerbations, are a result of biofilm formation, particularly in the presence of biomaterials. It should be emphasised that penetration of antibiotics and other antimicrobial agents into deeper layers of a biofilm is poor, causing therapeutic problems and necessitating sometimes removal of the implant or prosthesis. Biofilms play an increasing role in dentistry as a result of more and more broad use in dental practice of plastic and implantable materials. Biofilms are produced on the surfaces of teeth as dental plaque, in the para-nasal sinuses, on prostheses, dental implants, as well as in waterlines of a dental unit, constituting a particular risk for severely immune compromised patients.

As biofilm develop, planktonic cells and by products are released into the water and are subsequently aerosolized by dental instruments including turbine dental hand pieces and ultrasonic scalers. Patients and staff are exposed to fine aerosols containing microorganisms, fragments of biofilm and bacterial endotoxins. When this occurs, the risk of contracting illness such as Legionnaires Disease is increased.
A variety of organisms are found in DUWL including bacteria, fungi and protozoa. Of particular concern to health are the respiratory disease causing bacteria such as

  1. Legionella spp
  2. Atypical mycobacterium spp
  3. Pseudomonas species

What are biofilms?

Biofilms are any group of microorganisms (germs, bacteria, mold etc.) in which cells stick to each other in sort of a conglomerate on the surface of the skin, intestines etc. If you compare the biofilm to a fried egg, the yolk in the center of the egg is the bacterial or the fungal infection and the larger white part that surrounds the yolk is synonymous with the biofilm which protects the bacteria from antibiotics and the human immune system.

The image below sums up the formation of the biofilm and its life cycle. The free-floating bacteria binds to the surface of intestine for example. The bacteria starts to grow and multiply. Intermicrobial communication induces the formation of the protective slime (biofilm). The biofilm offers protection from antibiotics and host defense cells. The mature bacteria leave the biofilm and look for now opportunities for colonization.

In DUWL that are not treated with a biocide such as disinfectant, the contaminating bacteria are able to multiply and form a biofilm on the inner surface the DUWL.

Biofilms form rapidly, and within a week start shedding large numbers of bacteria into the waterline.

A combination of factors promote biofilm formation:

  1. DUWL are made of micro-bore tubing that has large surface area to volume ratio.
  2. Overnight stagnation.
  3. Relatively low levels of water usage.
  4. DUWL are a dead-leg on the plumbing system.

Ozone offers many benefits as a disinfectant. It acts on contact to eliminates 99.999% of all bacteria, viruses, and molds, thereby removing the chance of biofilm and slime from forming in the first place. Its bacterial disinfection mechanism works by oxidizing the bacteria cell wall and membrane, causing cell lysis and impairing cell functionality. Bacteria and microorganisms cannot build a resistance to ozone. Ozone exhibits a short half-life before reverting back to oxygen, its only by-product, and leaves behind no residue.
Taking the benefits of ozone, Biosure PFDS provides a more effective and economical way to offer consistent supply of bacteria free water for dental treatment, reducing postoperative inflammation in patients, and protect medical staff from the bacterial infection form DUWLs. PFDS does not require manual operation, which helps to save cost and improve dental care quality.

Recommend model: PFDS

  • Fast and powerful
  • Eliminates dental unit clogging occurrences
  • Reduce human error
  • No harsh chemicals
  • Safe for patients to ingest
  • Environmentally friendly
  • Enhanced protection for dental team and patients health

Biosure PFDS technology generates ozone direct from tap water. Therefore, no harmful by products like NOx will be generated. After reaction, ozone turns into clean, odorless and colorless oxygen. Only when ozone concentration in detail lines over 0.3ppm. Therefore, it effectively keeps dental water lines clean.

  • Ozone does not damage plumbing fittings or pipes, nor affect the pH of water. Moreover, it leaves no chemical by-products in water, as it breaks down to give oxygen.
  • Ozonated water leaves no biocidal traces so there is no contamination risk in bonding procedures and does not interfere with dental material bond strengths in endodontic.

Test Item0sec5sec15secReduction(%)


Staphylococcus aureus (CFU/ml)5.4×105Not DetectedNot Detected>99.999 %
Escherichia Coli (CFU/ml)2.5×1056.1×10< 10  99.99 %
Salmonella (CFU/ml)1.7×1051.9×10Not Detected  99.9 %
Pseudomonas aeruginosa (CFU/ml)4.5×105Not DetectedNot Detected>99.999 %
Candida albicans (CFU/ml)1.3×105Not DetectedNot Detected>99.999 %
MRSA (CFU/ml)1.3×105Not DetectedNot Detected>99.999