With the development of China's economy and the improvement of people's health awareness, the demand for oral medical services has increased rapidly. In recent years, with the continuous publicity of oral health, the awareness of oral health of domestic residents has gradually increased. The results of the fourth national oral health epidemiological survey showed that the awareness rate of residents' oral health knowledge was 60.1%, and 84.9% of them had a positive attitude towards oral health care.

At present, the dental chair unit (DCU) is a necessary medical equipment in the daily diagnosis and treatment process of the stomatology department. The DCU is a complex integrated system that provides substances (such as gas, water and electricity) and equipment. The dental unit waterline (DUWL) (hereinafter referred to as: DUWL) is an important part of the dental treatment table. Its main function is to provide water, and provide treatment equipment such as mobile phones and three-purpose guns during the treatment process. Provide therapeutic water for cooling and flushing.

In 1963, British dentist Blake first reported on DUWL contamination and found that DUWL contained a large number of bacteria. The study found that after the new oral comprehensive treatment table was connected to the water supply pipeline for a week, the bacterial concentration of the water supply pipeline could reach 2×105CFU/mL, and after long-term use, the bacterial concentration could reach up to 1.0×106CFU/mL.

DUWL, on the other hand, consists of narrow, elongated tubes that are highly susceptible to bacterial contamination and colonization to form biofilms. During the treatment process, the bacteria colonized in DUWL are often washed down by the water flow, and can enter the patient's mouth with the water flow, or can be inhaled into the respiratory tract by the patient or dental staff through the aerosol generated by the ultrasonic scaler and the high-speed turbine handpiece. This leads to infection; therefore, DUWL contamination is considered to be one of the important ways to cause dental cross-infection.

The bacteria isolated from DUWL mainly come from the natural environment, such as Legionella, Pseudomonas, non-tuberculous mycobacteria, etc.; followed by bacteria from the human body, such as Staphylococcus aureus, protozoa, fungi, molds, etc., Although relatively rare, there have also been reports of such pathogens isolated from DUWL, and the production of these bacteria has caused varying degrees of harm to the mouth and body.

Therefore, DUW pollution has attracted more and more people's attention. The most commonly used treatment methods are ozone water and hypochlorous acid water. Which one has the best effect?

In 2017, the Chinese Journal of Disinfection published the article "Research on Intervention Methods for Waterway Water Pollution in Oral Comprehensive Treatment Stations in Medical Institutions" written by Jiang Ning and others from Shanghai CDC. The effects of water and ozone water disinfection of oral treatment table waterways (DUWLs for short) were observed. The main contents and viewpoints of the article are summarized as follows:

1. This study found that hypochlorous acid water with available chlorine of 20 mg/L can significantly reduce the bioburden of DUWLs waterway and improve the water quality of DUWLs.

2. Under the action of hypochlorous acid water, the total number of bacterial colonies showed a slow rise in the first week due to the continuous shedding of the biofilm, and when the biofilm was thoroughly disposed of, the water quality of the entire pipeline showed long-term improvement.

3. Disinfection intervention measures can significantly improve the sanitation quality of oral comprehensive treatment table water, and the disinfection effect of hypochlorous acid water treatment is better than that of ozone water.

Note: The solubility of ozone in water is relatively low, generally 0.1-10mg/L. When the concentration of ozone water is high, ozone easily escapes from the water, resulting in a pungent odor.

In recent years, domestic scholars have also begun to study hypochlorous acid water. Huang Ning et al. used three different concentrations of hypochlorous acid water (10, 20, 40 mg/L) to continuously disinfect DUWLs, and tested the water samples. The average pass rate of DUWLs was 98.33%, 98%, and 99.25% in turn. During this period, the disinfection of DUWLs was stopped for 7 days, and then the microbial biomass of water samples was tested. The disinfection effect of acid water on the waterway of the oral comprehensive treatment table is obvious.

Liu Xiaokang et al. used 10 mg/L hypochlorous acid water to detect DUWLs, and the result showed that the qualified rate of water sanitation in the oral comprehensive treatment table before disinfection was only 8.85%. 15%。 After continuous disinfection with hypochlorous acid water, the hygienic quality pass rate increased to 49.15%. It is suggested that DUWLs are seriously polluted, and the use of hypochlorous acid water to disinfect DUWLs can improve the sanitation quality of waterway water, thereby preventing the occurrence of infection.

It can be seen from the above experiments that the feasibility of pollution control of hypochlorous acid water for disinfection of oral comprehensive treatment table waterway is verified. It is reported that with regard to DUWL pollution, my country has formulated the "GB/T Sanitary Requirements for Water System Disinfection of Dental Units (Draft for Approval)". The great improvement has added a better boost to the oral treatment field.