牙科综合治疗台水路污染及其对策

Contamination of dental unit waterlines and its control measures

牙科综合治疗台水路(dental unit waterline,DUWL)的主要功能是在治疗过程中为手机和三用枪等设备提供治疗用水,起冲洗和冷却作用。DUWL由狭窄、细长的管道组成,易被污染导致生物膜形成。定植于DUWL中的病原菌可随水流进入患者口腔,或通过由超声洁牙机、高速涡轮手机产生的气溶胶被患者或医务人员吸入呼吸道,从而增加牙科治疗感染的危险性。因此,DUWL污染被认为是导致牙科交叉感染的重要途径之一,并引起广泛关注。近年来,关于DUWL污染及对策已有大量研究,本文就其污染的影响因素、污染病原菌种类以及DUWL污染的对策作一综述。

Dental unit waterline （DUWL） is a complex network of interconnected plastic tubes supplying water to the dental unit for the purpose of cooling instruments,irrigating tooth surfaces during dental procedures,rinsing the oral cavity,and washing out the spittoon.DUWL is consisted of several meters of long narrow-bore tubes and can easily become contaminated,leading to formation of biofilms.The narrow bore of the DUWL tubes,water stagnation in the tubes,anti-retraction valve failure,heating of the output water,contamination of the input water or reservoir bottles are all contributing factors of DUWL contamination.Frequently isolated microorganisms from DUWL include Legionella species,Pseudomonas aeruginosa,and Staphylococcus aureus.Occasionally,fungi and protozoa are also detected from DUWL.Contaminated DUWL output water has been associated with increased risks of infection for dental patients.Aerosolized contaminated DUWL water also poses an occupational hazard to dental health care workers.Measures to control DUWL contamination include nonchemical methods and chemical disinfectants.Flushing of DUWL with fresh water,use of anti-retraction valves,use of microbial filters are proven useful nonchemical methods in reducing DUWL contamination.Chemical agents such as hydrogen peroxide,hydrogen peroxide combined with silver ions,electrochemically activated solutions,activated chlorine dioxide are shown to be effective in minimizing DUWL contamination and reducing biofilm formation.Comprehensive measures are suggested to effectively control DUWL contamination,biofilm formation and hence to decrease the risk of microbial exposure of both patients and dental health care workers.