To Evaluate The Potential Risk Of Aerosols And Spatters In Dental Department And Control Measures

OBJECTIVE: High-speed dental handpieces and ultrasonic scalers produce a significant amount of aerosol and spatter during dental procedures. These aerosols and spatters generated from a patient's mouth may contain saliva, nasopharyngeal secretions, plaque, blood and tooth components. When patients harbor viruses, either blood-borne or respiratory, or respiratory bacterial pathogens such as Mycobacterium tuberculosis, the aerosol and spatter generation may prove a significant health hazard to dental personnel and patients.The objective of the project is to measure the concentration, the duration of microbial aerosols and spatters in dental department and to apply this information to evaluate the potential risk. The ozone air disinfector which is effective intervening measure may control the aerosols and spatters in dental department so that we may provide safe clinical environment for dental personnel and patients.Method: The first part study was performed in three different dental departments. Air samples were collected 30min before dentaltreatments (7:30), 2h after the dental treatments (10:30),at the end of dental treatments(11:30) , 1h after the dental treatments ended(12:30) . Air samples were sampled over random 25 days. During the second part of the study forty subjects who had been treated with ultrasonic scaling were divided into two groups by treating order. Group B as experiment was given intervening measure by the ozone air disinfector at the beginning of ultrasonic scaling treatments and group A without the device. The ozone air disinfector works 5 minutes. Air samples were collected at different appointed period and then incubated at 37℃under constant temperature for 48 hours. The laboratory technician performed bacterial colony counting. Data collected were statistically analyzed using the analysis of variance (ANOVA) and Mann-Whitney Test.Result: We learned from the statistical analysis of the first study that there was significant difference between the periodontal departmentⅠand the musosal department , the periodontal departmentⅡand the musosal department 2h after the dental treatments (P < 0.05). At the end of dental treatments, there was significant difference between the periodontal departmentⅠandthe musosal department , the periodontal departmentⅠand the periodontal departmentⅡ(P < 0.05). There was significant difference between the periodontal departmentⅠand the musosal department , the periodontal departmentⅠand the periodontal departmentⅡ1h after the dental treatments ended(P < 0.05).A Mann-Whitney test was conducted to determine significant difference between the ultrasonic scaling treatments with the ozone air disinfector and the ultrasonic scaling treatments without the device at different appointed time(P < 0.05).Conclusion:1.The results of this sampling program have shown that the aerosols and splatters generation are mainly caused by ultrasonic scaling treatments.2.The results monitored have shown that quantities of colony-forming units of microbial aerosols and spatters during the dental treatment sessions were found to be higher, especially during ultrasonic scaling treatments. Two hours after the dental treatments (10:30),the mean quantity of colony-forming units (1140±496.19 cfu/m3) in 5-chair dental periodontal department was 4.8 timesthan that of aerosols and splatters before dental treatments ; the maximum l quantities of colony-forming units of microbial aerosols and spatters was 2138.87 cfu/m3 .The mean quantity of colony-forming units (1238.37±511.61 cfu/m3) in single dental periodontal department was 4.3 times than that of aerosols and splatters before dental treatments , the maximum quantities of colony-forming units of microbial aerosols and spatters was 2149.35 cfu/m3 .Ultrasonic scaling treatments are often carried out at the two dental periodontal departments. The data has shown that the aerosols and splatters generation are mainly caused by ultrasonic scaling treatments.The mean quantities of colony-forming units of the periodontal departmentⅠand the periodontal departmentⅡwere nearly about 2 times than that of musosal department. The data has shown that the mean quantities of colony-forming units generated are different during different dental treatments and ultrasonic scaling treatments may generate a great amount of aerosols and splatters which may cause the higher quantities of colony-forming units in dental department. The higher quantities of colony-forming units far exceedthe National Disinfection Technology Criteria and may cause a significant health hazard to dental personnel and patients.3.At present, the studies in our country are concerned with the quantities of colony-forming units of microbial aerosols and splatters. This study focused on the duration of microbial aerosols and spatters in dental department.At the end of dental treatments, the mean quantities of colony-forming units in different dental department were found to be >500cfu/m3.Because of the less times of dental treatments in the single dental periodontal department, the levels of quantities of colony-forming units decreased by approximately 45% compared with that 2h after the dental treatments ;the quantities of colony-forming units of microbial aerosols and spatters in the multichair dental periodontal department was 4.1 times than that of microbial aerosols and spatters before dental treatments .1h after the dental treatments ended, the mean quantities of colony-forming units in the single dental periodontal department and musosal department were found to be <500cfu/m3;the levels of quantities of colony-forming units in the single dental periodontaldepartment decreased by approximately 39% compared with that at the end of dental treatments;the quantities of colony-forming units of microbial aerosols and spatters in the single dental periodontal department was 1.5 times than that of microbial aerosols and spatters before dental treatments .1h after the dental treatments ended, the mean quantities of colony-forming units in the multichair dental departments was found to be >500cfu/m3;the levels of quantities of colony-forming units in the multichair dental periodontal department decreased by approximately 45% compared with that at the end of dental treatments;the quantities of colony-forming units of microbial aerosols and spatters in the multichair dental periodontal department was 2.3 times than that of microbial aerosols and spatters before dental treatments .As the data demonstrates, the duration of microbial aerosols and spatters in dental department is longer and the levels of quantities of colony-forming units hadn't returned to the normal background level after 1h of the dental treatments ended. 1h after the dental treatments ended, the quantities of colony-forming units of microbial aerosols and spatters in the multichair dental periodontal department was 2.3times than that of microbial aerosols and spatters before dental treatments .The duration of microbial aerosols and spatters in the multichair dental periodontal department was by far longer than that of microbial aerosols and spatters in the single dental periodontal department and musosal department. The dental personnel have been exposed to the aerosols and spatters for a long time.4.The Staphylococcus aureus was isolated and identified during the study. The result has shown that infective aerosols and splatters may generate during normal dental procedures.5.The ozone air disinfector was applied at dynamic state during ultrasonic scaling treatments which may control the quantities of colony-forming units of aerosols and spatters in dental clinic. After dynamic disinfection , the quantities of colony-forming units may conform to the National Disinfection Technology Criteria so that we may provide safe environment for dental personnel and patients. At present, the ozone air disinfector hasn't been applied at dynamic state during ultrasonic scaling treatments in previous studies of our country.