Abstract: OBJECTIVE To observe the application of Failure Mode and Effects Analysis (FMEA) based on multidisciplinary teamwork (MDT) in contamination risk control of dental unit waterlines (DUWLs) and evaluate the effect. METHODS From Jul. 2023 to Jun. 2024, a total of 16 dental units were chosen from stomatology department of Zigong Fourth People's Hospital. The MDT-FMEA team employ FMEA to find out the potential failure modes during the process of DUWLs management, the high risk failure modes were determined by quartile method; the causes and possible consequences were analyzed, the intervention measures were taken, and the effects were evaluated. RESULTS The declined rates of the risk priority number (RPN) values of the 10 high risk failure modes reached 39.92% to 63.93%. The compliance rates of rinsing mobile ports, three-in-one syringe tips, waterlines, suction pipelines and cuspidors between the pre-treatment and the treatment were higher after the intervention than before the intervention (P＜ 0.05). The compliance rates of waterline disinfection, remaining water drainage from waterlines and hand hygiene of operators increased from 35.90%, 57.39% and 64.09% to 78.05%, 95.00% and 88.33%, respectively (P＜ 0.001). The total bacterial colony counts at the outlet of high-speed handpieces decreased from 62.00 (14.25, 670.00) CFU/ml to 30.00 (10.00, 60.00) CFU/ml (Z=-2.147, P= 0.032); the total bacterial colony counts at the outlet of three-in-one syringes decreased from 33.50 (20.50, 175.50) CFU/ml to 23.00 (9.50, 57.00) CFU/ml (Z=-2.252, P= 0.024). The qualified rates of water samples from both high-speed handpieces and three-in-one syringes increased to over 90% (P＜ 0.05). No pathogenic bacteria were detected in the high-speed handpieces or three-in-one syringes after the intervention. CONCLUSIONS The FMEA based on multidisciplinary collaboration can be applied in risk management of DUWLs, effectively improve the management of waterlines, and raise the qualified rate of water for oral diagnosis and treatment.