Sterilizing Effect Of Light-wave On Common Dental Equipment

Oral cavity is a complex ecological environment, There are many microorganisms. Inthe process of oral examination and treatment, the dental equipment contact the tooth,mucosa, saliva and blood inevitablely. It may cause cross infection between patients orbetween patient and medical staff. There are many sterilizing methods used in clinic, butwidely be used and be agreed in clinical is steam sterilization method. Keep to thestipulated time(about30min) when the pressure rise to1029kpa (105kg/cm2) and thetemperature reaches121℃by the method. But time-consuming, energy-consuming andonly suitable for some equipment of high temperature resistance. There are some auxiliarymethods of sterilization such as Dry heat sterilization method, Formaldehyde andGlutaraldehyde disinfection method, Benzalkonium bromide disinfection method, Chlorinedisinfectants disinfection method, Acebtic acid peroxide disinfection method, Ultravioletdisinfection method, and so on. There are so many sterilizing methods, for none of them issuitable for so many different dental equipments. In order to prevent iatrogenic infection,Itis very important to develop suitable sterilizing method for relative equipment.Dental solid metal equipments are the most common tools for dentist, such as theturbine mobile car needle, diamond dental bur, mouth mirror, dental tweezers and probe. So,we want to develop a sterilizing method mainly used for dental solid metal equipments. Inrecent years, the sterilizing methods with light-wave and Microwave were to the attentionby the people gradually.In this study, we want to investigate the temperature efficiency and time efficiency oflight-wave based on the sterilizing effect against different bacterium and virus.ObjectiveTo investigate the temperature efficiency and time efficiency of light-wave on entalsolid metal equipments Methods1. Determination of performance parameter, such as rate of temperature increase andintensity of UV irradiation.2. Using ELISA and Abbott quantitative test to detect HBsAg in different temperatureand time parameter.3. Measure the inactivation of bacteria, fungi and spore with enrichment culture indifferent temperature and time parameter.4. Compare the resistance of light sterilization with enrichment culture in differenttemperature and time parameter between the black variant of Bacillus subtilis (ATCC9372)and oral normal flora.5. All the experiments are operated Strict adherence to Technical Standard Fordisinfection enacted by Ministry of Health of the People’s Republic of China in the year of2009.Results1. The results of temperature increase rate: The longth of time were2min55s、3min3s、3min8s when the temperature went up to120℃、130℃、140℃respectively.2. Results of UV irradiation intensity: The UV irradiation intensity has no obviousrelation with the preset temperature. The UV irradiation intensity went up to1800μW/cm2after1min.And the UV irradiation intensity went up to2000μW/cm2after2min.3. Inactivation of HBsAg by light-wave: the HBsAg antigen was destructed afterbeing disinfected by light-wave at120℃for7min，130℃for5min，140℃for3min4. Sterilizing effect of light-wave against different bacterium: Staphylococcus aureusand Pseudomonas aeruginosa were thoroughly killed after being disinfected by light-waveat120℃for5min，130℃for3min，or140℃for1min; Candida albicans was thoroughlykilled after being disinfected by Light-wave at120℃for7min,130℃for5min,or140℃for3min; The black variant of bacillus subtilis was thoroughly killed after beingdisinfected by Light-wave at120℃for9min,130℃for7min,or140℃for5min.5. Compared with black variant of Bacillus subtilis, the oral normal flora is easier todisinfect. Conclusion1. Compared with black variant of Bacillus subtilis, the oral normal flora is easier todisinfect. So, oral normal flora can be sterilized by light-wave if black variant of Bacillussubtilis was disinfected.2. Light-wave achieves rapid sterilization of the dental solid mental equipments. Inaddition, the higher temperature, the shorter time, and the more efficiency if the equipmentcan withstand the higher temperature. All the pathogens, including spore and virus, can bedisinfected in5min.