The Effect Of Low Concentration Chlorinated Disinfectant Assisted By Multi-enzymes Detergent On Elimination And Prevention To Biofilm In Dental Unit Waterlines

Objectives1.Investigation on the pollution of current DUWL:Through cross-sectional investigation on various departments of the dental hospital,the output water of dental chairs used during the treatment and the biofilm pollution of the inner surface in DUWL was known.The current situation of the pollution in DUWL was acquired,the composition,formation and consititution of the biofilm in the inner surface of the DUWL and the plantonic bacteria of the output water were discussed2.Pollution control methods:The effect of multi-enzymes assisted low concentration of chlorine disinfectants to the removal process of biofilm was observed through cellular level.By regular monitoring of water samples and biological membrane morphology change,looking for effective methods of removal biofilm and control water pollution.In order to reduce the pollution of the DUWL,provided basis for reducing stomatological hospital infection effectively.3.Daily management:Based on the experimental groups which the biofilm of DUWL had been removed,multi-enzymes assisted low concentration of chlorine disinfectants daily washing management in low frequency to regular monitoring of water samples.Inspect methods applied to routine preventive maintenance of the effectiveness of DUWL,provided basis for oral nurses clinical disinfection work in output water.Methods1.Stratified sampling method was used to select 27 dental chairs from 8 departments of stomatological specialized hospital as the investigation objects of pollution status.Plankton in output water of handpieces,three-way air/water syringes and the mouth rinsing cups,the biofilm in the tubes of water connection with for handpieces and three-way air/water syringes for treatment was detected.The pollution data was statistically analyzed.2.Comparative experimental study:Four dental chairs with no statistical difference in biofilm growth were selected as control subjects.The experimental group of dental chairs used multi-enzymes+low concentration chlorine disinfectants to wash the handpieces connection tubes,and the control group of dental chairs used purified water+low concentration chlorine disinfectants to wash the handpieces connection tubes.The processing frequency is once a day for 4 weeks.The number of planktonic bacteria and the fluorescence of biofilm in the terminal water of the high-speed handpieces were detected once a week.3.Daily management of the experimental group:After all biofilm removal,use the experimental objects of pollution prevention and regeneration experiment.The management method was still multi-enzymes assisted low concentration chlorine disinfectants,but the frequency was reduced from once a day to twice a week.Results1.DUWL output water was seriously polluted with a total bacterial count of 2-45700 cfu/ml.The median number of planktonic bacteria colonies in output water for high-speed handpieces,three-way air/water syringes and the mouth rinsing cups were 450,1095 and 89 cfu/ml,respectively.And the qualification rates(<100c fu/ml)of output water for three places were 26.0%,0%and 55.6%,respectively.2.The biofilm of DUWL was contaminated by a large number of coccus,bacillus and spirilla.The bacteria were covered by extracellular polymer(EPS)and mixed with organic matrix.3.DUWL was contaminated by a large number of opportunistic pathogens,including 12 families,18 species and 97 strains.Most opportunistic pathogenic bacteria in output water were Gram-negative bacteria.The pathogenic bacteria in biofilm consisted of coagulase-negative Staphylococcus spp.,Enterobacter spp.,Methylobacterium spp.,Ralstonia pickettii,Micrococcus luteus and Bacillus cereus.4.There was no significant difference in fluorescence density between the initial two groups in the comparison between multi-enzymes assisted low concentration chlorine disinfectants and chlorine disinfectants alone.At the first week of treatment,the biofilm in both groups decreased,but the fluorescence density between groups were still higher than 0.05.At the second week of treatment,the biofilm reduction in the experimental group was significantly better than that in the control group,and the fluorescence density value was compared,P<0.05.There was no biofilm in the experimental group at the third week of treatment,but biofilm still existed in the third and fourth weeks of control group with gradually decreased.5.The daily management of low concentration chlorine disinfectants assisted by multi-enzymes was within the standard range(100 cfu/ml)for detecting the number of planktonic bacteria in high-speed handpieces output water every 4 weeks within 32 weeks.After the experiment,the pathogenic bacteria in high-speed mobile phone treatment water were identified as only Pseudomonas and Bacillus.Conclusions1.The number of planktonic bacteria in DUWL output water indicated that DUWL was seriously polluted,especially in three-way air/water syringes.2.The biofilm of DUWL was contaminated by a large number of coccus,bacillus and spirilla.The bacteria were covered by extracellular polymer(EPS)and mixed with organic matrix,forming tight structures on the inner surface of DUWL.3.A large number of opportunistic pathogens existed in DUWL output water,forming a potential source of pathogenic pollution.Patients with immune deficiency have the risk of causing disease and medical personnel have the risk of infection.4.Compared with treatment with chlorine containing disinfectants alone,multi-enzymes assisted low concentration chlorine disinfectants can effectively remove biofilm in three weeks.5.Multi-enzymes assisted daily management of low concentration chlorine disinfectants had played a continuous and effective role in preventing contamination in output water by DUWL which had removed biofilm already.The study providing treatment enlightenment for improving the workload of clinical oral nurses.