In the dental industry, contamination by biofilm formed in dental unit waterlines is a serious concern (“Dental Unit Waterlines Problem/DUWP”).
Dr. Nano peels off biofilm by nanobubbles with a small amount of running water and fills waterlines with nanobubble water to create a clean environment where it is difficult for bacteria to grow biofilm.

Background to Develop Dr. Nano for Dental

Waterline in Dental Equipment Are Easily Contaminated by Biofilm

Mechanism of biofilm formation

  • - Tap water used for dental treatments is kept warm to human body temperature. Furthermore, chlorine in tap water loses its efficacy during the night or while the equipment is not in use. They are the ideal condition for bacteria to propagate and form biofilm.
  • - Biofilm is sticky polymer created by bacteria to form colonies. It protects bacteria from germicides (such as chlorine in tap water).
  • - Disinfectant works only to floating bacteria but will not penetrate through biofilm or bacteria beneath the biofilm.
  • - Some biofilms may be removed by flushing water. However, remaining bacteria may rebuild its colony in a short period.
  • - Particularly, the waterlines used in dental equipment are narrow and long, it is difficult to flush out biofilms with low pressure water.
  • - Once biofilm forms and adheres to the waterline, it is difficult to remove it with tap water alone.

Warning for Biofilm Contamination of Dental Equipment

MHLW Scientific Research Report (2017):

“The farther the distance from water main, number of heterotrophic bacteria increases and free chlorine residual concentration decreases.” This indicates that water used for dental treatment is contaminated with bacteria.

* MHLW : Ministry of Health, Labour and Welfare, JAPAN
Fig.1 Typical Dental Treatment Station
Source: MHLW Scientific Research Report, 2017 (Figure 6 on Page 103)

    Fig. 1 indicates:

  1. Even though bacteria may not be detected near the watermain, bacteria count increase is seen closer to the handpiece.
  2. Although there is higher concentration of free chlorine residual at the watermain, by the time water reaches to the handpiece, the potency decreases below 0.1 ppm, which is lower than the Japan Water Authority guideline.
  3. While free chlorine residual sterilizes the waterline near the source, if the amount of bacteria is too high, free chlorine may lose its efficacy, and the potency will decrease by the time it reaches the handpiece.
  4. The above two results suggest that free chlorine sterilizes the waterline near the source; however if the bacteria count is too high, free chlorine residual loses its disinfecting characteristics.

  5. The following risks are alarming:

  6. From the result of Fig.1, bacteria invade from the handpiece side, not from the water supply side. They form a biofilm towards the source of the dental unit waterlines as they grow.
  7. It cannot be denied that "bacteria observed in the dental unit waterlines", which have invaded from the handpiece side, may be the oral bacteria from previous patient. This raises a concern that the risk of infecting other patients exists.
  8. Although, the handpiece is removed from the hose after each patient, replaced, and sterilized, the fact that bacteria are still detected in the unit evidences bacteria have reached the hose through the handpiece. It is inevitable to draw a conclusion that such bacteria have grown in the hose.

Concerns of Using Chemical Disinfectant


  1. It is nearly impossible to disinfect waterline unless high concentration chemical is used or saturate it for a long period of time (Risk of developing resistant bacteria is also a concern.)
  2. If less potent chemical to avoid health hazard is used, it will be impossible to eliminate biofilm completely.
Fig.2 To Sterilize Biofilm with Commonly Used Chemical
Source: Edstrom Japan Website: How to Sterilize Biofilm with Commonly Used Chemical (Fig. 4)

Characteristic of Nano Bubble Water

Effect of Cleaning with Nano Bubble Water

Cleaning power of bubbles is well known. Compared to micro-sized bubbles, nano-sized (1/1000 of micro) bubbles last longer and cleaning efficiency continues longer.

Fig.3 Micro bubbles vs. Nano bubbles
Fig. 3:

*Cavitation is a phenomenon that occurs when pressure in water suddenly drops leaving behind an area of low pressure often as a bubble of gas. 
  • - Needs motor to rotate the screw fast enough in water.
  • - Requires a large device which may create noise and vibration from the motor that may not be suitable for dental use.

Dr. Nano Mini for Dental

Mechanism to Create Nano Bubble Water

The mechanism of generating nanobubble water is cavitation. Generally, a screw is rotated at high speed to create pressure differences.

    Dr. Nano Mini for Dental has adopted advanced technology that generates nanobubbles by forcing water to hit fixed screws. Furthermore, it has been developed for dental units with the following unique features (Patent pending):

  1. 1. Use only water pressure to create nano bubble water. No need for any electricity nor any other source of energy.
  2. 2. Efficiently generate nanobubbles using small amount of water to handpiece (0.1 L / min or less).
  3. 3. On the other hand, ensure the maximum rate of water flow for a dental unit (2.0L / min).
  4. 4. Successfully minimized it to 40mm in length using ultra-precision machining of 6D milling technology.
  5. 5. Manufactured in Japan.
Fig.4 Mechanisim for Dr. Nano to Create Nano Bubble Water

Benefit of Dr. Nano for Dental Use

  1. 1. Physical Sterilization
    - Physically remove biofilm buildup in waterline with nano bubbled water generated by the devise.
    - Biofilm debris from the waterline will be flushed out with minimum water flow. Upon removal of biofilm, floating bacteria are eliminated by chlorine contained in tap water.
    - Dr. Nano continuously supplies nano bubble water to the waterline and prevents re-attachment or rebuild of biofilm in the waterline.
  2. 2. Compact and Easy to Install
    - Simply attach Dr. Nano by setting back the existing pipe to minimum of 40mm.
  3. 3. Maintenance Free
    - No use of electric or mechanical parts necessary to repair.
    - No need for parts replacement nor electricity bill to run.
  4. 4. Environmentally Friendly
    - No chemical is used. Nanobubble water is generated by tap water and air.
    - Simple packaging.

Contact us


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New Environmental Technology Council  (NETC)
Suite#2918, 4-1 Kioicho, Chiyoda-ku, Tokyo 1020094 Japan
Tel : +81-50-3558-7088

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