In recent years, the hygienic condition of dental unit waterline (DUWL) has gradually received attention in China. At the same time, many local standards have been introduced. For example, Beijing issued "DB11/T 1703- 2019 Technical Specifications for Waterway Disinfection of Oral Comprehensive Treatment Units" on December 25th, 2019, while Zhejiang Province issued "DB33/T 2307-2021 Technical Specifications for Cleaning and Disinfection of Dental Waterway Systems" on January 29, 2021.

In fact, various countries in the world have begun to pay attention to issues related to waterway pollution in dental treatment units much earlier, and have made relevant specifications. This article summarizes the standards of various countries in this regard as follows:

Foreign standards related to the waterway of dental treatment units

In 1996, the American Dental Association (ADA) formulated an ideal standard to address the problem of contamination of dental unit waterline, requiring the bacterial content of dental water used for non-surgical procedures to be below 200cfu/ml; promulgated and implemented the technical specification "Guidelines for Practice Success, Managing the Regulatory Environment: Dental Unit Waterlines" was issued.

The U.S. Centers for Disease Control and Prevention formulated the "Summary of Infection Prevention Practices in Dental Settings (2003)", which systematically summarizes and proposes the problems and intervention measures for waterway infection in comprehensive oral treatment units.

The third edition of the infection control guidelines released by the Australian Dental Association in 2015 recommends that the total number of bacterial colonies in dental non-surgical water should be ≤500 CFU/mL. It also emphasizes that for patients with low immunity, the total number of bacterial colonies in water should be controlled at 200 CFU/mL or less.

Japan has made mandatory regulations on the quality of water output from dental treatment units, requiring it to comply with Japan's drinking water standards, that is, the total number of bacteria is ≤100 CFU/mL, and Escherichia coli must not be detected.

In the guidelines issued by Poland, reference was made to the water quality standards recommended by the United States before 2000, that is, the total number of bacteria ≤ 200 CFU/mL.

In the guidelines issued by the United Kingdom, although there is no numerical limit on the bacterial concentration of effluent, it is emphasized that medical water must meet drinking water standards.

Regarding DUWLs water quality hygiene, the Organization for Safety, Asepsis and Prevention (OSAP) has developed a guidance document "Dental Unit Waterlines: Check Your Dental Unit Water IQ” and “Dental Unit Waterlines: Dental Unit Waterline Fact Sheet”.

Domestic standards related to the waterway of dental treatment units

In 2017, the Jilin Provincial Bureau of Quality and Technical Supervision promulgated the "Management Standards for Oral Diagnosis and Treatment Water" (DB22-T2714-2017), which clearly states that the total number of bacterial colonies in oral diagnosis and treatment water and source water does not exceed 100CFU/mL, and usually the intervention level is the maximum allowable 50% of the level; the water used in the oral comprehensive treatment unit should comply with the requirements of GB 5749.

In 2018, the "Microbiological Standards for Water Used in Comprehensive Oral Treatment Units" (DB12/T 804-2018) issued by the Tianjin Municipal Market and Quality Supervision and Administration Commission clarified that the total number of bacterial colonies in the water supply should be <100 CFU/mL, and Salmonella, Pseudomonas aeruginosa and total coliforms must not be detected; the total number of bacterial colonies in the water from the three-purpose gun and dental handpiece should be <500 CFU/mL, and Salmonella, Pseudomonas aeruginosa, and total coliforms must not be detected; oral cavity Sterile water should be used during surgical procedures, dental implant procedures, or oral treatment in immunocompromised patients.

In 2019, the Beijing Municipal Administration for Market Regulation promulgated the "Technical Specifications for Waterway Disinfection of Oral Comprehensive Treatment Units" (DB11/T 1703-2019), which clearly states: The input water hygiene requirements for oral comprehensive treatment units must at least be drinking water that meets GB 5749. Water should be treated by a water treatment device as the input water. Hygiene requirements for diagnosis and treatment water: the total number of bacterial colonies in diagnosis and treatment water should not exceed 100 CFU/mL.

In 2021, the "Technical Specifications for Cleaning and Disinfection of Dental Chair Waterway Systems" (DB33/T 2307-2021) promulgated by the Zhejiang Provincial Administration for Market Regulation pointed out that the total number of bacterial colonies in oral diagnosis and treatment water and nutrient agar culture should not exceed 100 CFU/ mL, R2A agar medium culture should not exceed 500 CFU/mL.

In addition, the "Hygiene Requirements for Medical Water Systems in Medical Institutions (Draft for Approval)" compiled by the Heilongjiang Provincial Center for Disease Control and Prevention and the "Disinfection and Hygiene Requirements for Water Systems in Dental Comprehensive Treatment Units (Draft for Review)" compiled by the Jiangsu Provincial Center for Disease Control and Prevention may be released in the near future. In these two standards, it is clearly stipulated that the water source of the dental treatment unit should comply with the requirements of GB 5749, softened water should be used, the total number of bacterial colonies in the water should be ≤100 CFU/mL, and Pseudomonas aeruginosa and Salmonella should not be detected. and coliforms; sterile water should be selected as cooling water or flushing water for dental handpieces used in dental operations; sterile water should be selected when patients with immune deficiency receive oral diagnosis and treatment.

Taken together, the national and local governments are constantly improving the water hygiene requirements for comprehensive oral treatment units in order to strictly, standardize the safety of water for oral diagnosis and treatment, and reduce the risk of infection to patients and medical staff during the diagnosis and treatment process as much as possible.