The Study On Biofilms Removal Efficiency Of Rapid Multi-enzyme Cleaning Agent Of Different Concentration On The Saliva Ejector

Objective: Research shows that microbial contamination is present in saliva ejector of dental chair units which contributes to the formation of biofilms.In the course of oral treatment,there may exists backflow in saliva ejector while applying saliva ejector in the mouth to get substances such as saliva,blood and bits.Bacteria in saliva ejector can be drawn into the patient's mouth by backflow and pose a potential risk to patients.The research object of this experiment is saliva ejector.The objective of the study is to observe the growth of biofilms which contain bacteria in the saliva ejector.In most hospitals,saliva ejector is flushed only by water.In this study,we used the rapid multi-enzyme cleaning agent to remove biofilms in the saliva ejector of dental chair units and compared biofilms removal efficiency of rapid multi-enzyme cleaning agent of different concentration and got the optimal concentration and verified the best time to clear biofilms,which may provide guidance for reducing the backflow pollution and risk of cross infection among different patients effectively.It may also improve the awareness of preventing cross infection among medical staff and to provide guidance for the prevention of cross infection.Methods: During the time from July to December in 2016,we selected the saliva ejector of dental care units of a department of Jilin University Stomatology Hospital as study objects.We sampled the saliva ejector being used from 1 to 7 days.Among them,the saliva ejector in the working state from 1st to 5th days,the saliva ejector in the non-working state from 6th to 7th days.The saliva ejector is 120 cm long.The remaining 96 cm long pipeline was cut into 64 pieces with each piece 1.5cm long.The 64 pieces of saliva ejector were divided into 4 groups according to the random principle with 16 pieces in each group.Group A?blank control group?:sterile distilled water immersion method,capacity of 500 ml,temperature of 40 ?,soaking time of 5min.Group B₁?experimental group?: soaking in rapid multi-enzyme cleaning agent of concentration 1:100,capacity of 500 ml,temperature of 40?,soaking time of 5min.Group B₂?experimental group?: soaking in rapid multi-enzyme cleaning agent of concentration 1:150,capacity of 500 ml,temperature of 40?,soaking time of 5min.Group B₃?experimental group?: soaking in rapid multi-enzyme cleaning agent of concentration 1:200,capacity of 500 ml,temperature of 40?,soaking time of 5min.Evaluation index: number of bacterial colonies,biofilms clearance rate,observing morphology of biofilms by scanning electron microscopy,observing bacterial morphology by microscope.Results: 1.The number of bacterial colonies?CFU/cm2?in the biofilms in the saliva ejector on the 1⁷th day of Group A?blank control group?were 30.00 ± 10.214,63.47 ± 19.057,179.72 ± 59.196,608.13 ± 236.141,1471.41 ± 634.854,7318.75 ± 2287.038,9480.47 ± 2909.568,respectively.The number of bacterial colonies in the biofilms increased slowly on the first 3 days,and increased relatively quickly on the 4⁵th days.The number of bacterial colonies increased rapidly on the 6-7th days.2.The number of bacterial colonies?CFU/cm2?in the biofilms of the saliva ejector between the 5th?6th?7th days of Group A?blank control group?had significant statistical difference?P<0.05?.3.The number of bacterial colonies?CFU/cm2?between the group B₁,B₂ and B₃ on the 1⁷th days and the number of bacterial colonies of group A had significant statistical difference?P<0.05?.4.The number of bacterial colonies?CFU/cm2?between the group B₁,B₂ and B₃ on the 1³rd days had no significant statistical difference?P>0.05?.5.The number of bacterial colonies?CFU/cm2?between the group B₁,B₂ and B₃ on the 4⁵th days had significant statistical difference?P<0.05?,but between group B₁ and B₂ had no significant statistical difference?P>0.05?.The number of bacterial colonies?CFU/cm2?between the group B₁ and B₃ and the group B₂ and B₃ had significant statistical difference?P<0.05?.6.The number of bacterial colonies?CFU/cm2?between the group B₁,B₂ and B₃ had significant statistical difference?P<0.05?on the 6⁷th days and the number of bacterial colonies?CFU/cm2?between the group B₁ and B₂ and the group B₁ and B₃ had significant statistical difference?P<0.05?,but between group B₂ and B₃ had no significant statistical difference?P>0.05?.7.On the1⁷th days,the clearance rate?%?of group B₁ was 86.23,85.73,84.84,80.79,76.16,63.21 and 51.08,respectively.The clearance rate?%?of group B₂ was 85.30,84.10,84.11,78.69,73.32,50.61,36.51,respectively.The clearance rate?%?of group B₃ was 85.00,83.80,82.56,74.77,69.24,46.98 and 30.85,respectively.8.Observation by scanning electron microscope of the new saliva ejector,the used saliva ejector for 7 days and saliva ejector soaked in rapid multi-enzyme cleaning agent of concentration 1:100 showed that intraluminal surface of the new saliva ejector was smooth,biofilm structure can be observed in intraluminal surface of the used saliva ejector,and decomposed biofilm structure can be observed in the intraluminal surface of saliva ejector soaked in rapid multi-enzyme cleaning agent of concentration 1:100.Bacilli and cocci?streptococcus?were detected after Gram stain on typical colonies selected from nutrient agar culture dish cultured for 48 hours.Conclusions: 1.The intraluminal surface of saliva ejector exist biofilm pollution and bacterial colonies in the biofilm will continue to increase over time in 1⁷ days.2.Rapid multi-enzyme cleaning agent can effectively decompose the biofilm in the intraluminal surface of saliva ejector,which can reduce the risk of cross infection among different patients.3.The bacteria in the saliva ejector will adhere,grow and reproduce with the passage of time and eventually form relatively mature biofilm structure.Their resistance will increase gradually with the development of biofilms and result in reduction in clearance rate.4.Using rapid multi-enzyme cleaning agent of concentration 1:200 can remove biofilms in the saliva ejector effectively in their early formation stage.However,after the formation of relatively mature biofilm structure,even if using rapid multi-enzyme cleaning agent of concentration 1:100 can not achieve the desired cleaning effect.Therefore,to balance cleaning effect and economy,it is recommended to clean biofilms using rapid multi-enzyme cleaning agent of concentration 1:200 on a daily basis.5.In the 1⁵th days,increasing of the number of bacterial colonies in the biofilms is relatively slow when treating patients with saliva ejector;in the 6⁷th days,the number of bacterial colonies in the biofilms will increase rapidly after stopping using saliva ejector because of weekends.Therefore,if the intraluminal surface of saliva ejector is not cleaned every day,it is recommended to clean the saliva ejector on each Friday afternoon and keep the pipeline dry to prevent biofilms coming into their mature stage which may result in an increased difficulty in cleaning.