Sterilization and Disinfection I PDF

Do you know who is carrying Dental patients and professionals are exposed to variety of bacterial / Viral / infections? disease-causing microorganisms (bacteria, viruses, fun...

Do you know who is carrying Dental patients and professionals are exposed to variety of bacterial / Viral / infections? disease-causing microorganisms (bacteria, viruses, fungi) Mode of transmission in dental setting CLINICAL CONTACT (source/reservoir) l Direct contact with blood, oral fluids, or other patient materials; SURFACES Person who looks healthy may Body fluids: Blood, oral fluids (saliva), secretions, excretions l Indirect contact with contaminated objects e.g: be a carrier of serious infection Mucous membranes (e.g. oral) contaminated dental instruments, equipment,  have a high potential for amnion Broken skin direct contamination contaminated clinical surfaces from patient materials rt Respiratory tract  by direct spray or spatter generated during dental l Contact of conjunctival, nasal, or oral mucosa with droplets (cough/sneeze) l Inhalation of airborne microorganisms suspended in the air procedures  or by contact with me I DHCP's gloved hand. These surfaces can later contaminate other instruments, devices, hands, or gloves. Environmental surfaces are contaminated The potential routes of transmission of micro-organisms in Breaking the chain of infection !! transmission to clinical contact surfaces Hands can transmit infections the dental surgery Reservoir : equipments, surfaces, skin… dental instruments, equipment, contaminated directly Sterilization / Disinfection brea transfer from patient oral fluids by gloved hands / or/ aerosals to clinical surfaces clinical surfaces become contaminated (source of infection to next patient…) WHY ? Decontamination WHY ? a is the process by which microorganisms Decontamination ‫األخذ باألسباب واجب شرعي بعد التوكل على هللا عز وجل قال‬ Failure to properly disinfect or sterilize equipment are removed or destroyed in order to render an object safe. Cleaning )‫النبي صلى هللا عليه وسلم (اعقلها وتوكل‬ carries risk for person-to-person transmission of microbes causing infections that may lead to major Cleaning is a process, usually involving diseases/ chronic or untreatable infections (e.g., levels of Decontamination: detergent or enzymatic presoak that hepatitis B/C viruses , HIV “blood born viruses” Cleaning removes visible foreign materials (e.g. which then, spread… sexually to wife/husband and dirt or blood) from an object. vertically from mother to foetus. medical devices contact or penetrate with a patient’s Disinfection - Antiseptic sterile tissue or mucous membranes Cleaning is the first and essential step in Disinfection and sterilization are essential for reprocessing dental instruments and ensuring that medical and surgical instruments do Sterilization equipment. not transmit infectious pathogens to patients. Disinfectionsrem.vereduseharmfalpathogenic cleanine nwithbat 8 f ntia  2 disposabletowers iiiii int sina.ae eu Chemical Disinfectants have Cleaning Soaps Disinfection Methods of Disinfection different Mechanisms of action Instruments must be rinsed after cleaning with Disruption of lipid containing / cell membranes main purified water, dried by disposable paper towels Is the removal of harmful pathogenic Moist heat Examples, alcohol 70% wide spectrum of bacterial, fungi, and many viral activities but NOT spores of Quaternary Ammonium Compounds (QAC) one then inspected to ensure that all debris has been microbes, or reducing their number to be washing and rinsing in water at 70°C-90°C will kill most non-sporing micro-organisms Heat at a temperature below 100°C: e.g., Pasteurization disinfection chlorhexidine removed very low Heat at a temperature at l00°C: Boiling Modification of proteins Cleaning machines are available for large scale NOT usually including bacterial spores Examples, chlorine: hypochlorite (Clorox) iodine Wear heavy-duty utility gloves, mask, eyewear, and protective Chemical disinfection (common) clothing should only be used if heat treatment is impractical or if it may cause damage to the equipment. Modification of nucleic acids / DNA 0 Examples, crystal violet inhibit fungi ultraviolet radiation rarely used in dental practice. NB. Depends on concentration of both microorganisms and disinfectant and contact time. And presence of organic matter such as blood/tissue. ma fi imandmicrorasnisn Noninvasive we Intermediate-level disinfectants Chemical Disinfectants High-level disinfectants (HLD) are used for semi-critical items involved with Intermediate-level disinfectants Clean then disinfect clinical contact surfaces that are not DISINFECTING LABORATORY ITEMS Non-invasive procedures that contact intact mucous barrier-protected ((after each patient)) Disinfectants are categorized according to their spectrum of activity into:  On removal from the mouth, impressions or appliances should be rinsed membranes without penetration , and cannot withstand heat (e.g., alcohols, iodophor compounds, phenolic compounds) under running water to remove saliva, blood and debris, immersed in a – high level disinfectants sterilization (e.g., certain types of Digital Sensors or endoscopes with plastic or are used to clean and disinfect surfaces if contamination with bacterial spores and other highly resilient organisms is unlikely. im suitable disinfectant, rinsed and sent to the laboratory – intermediate level disinfectants other components that cannot be heat sterilized). a www.usadwoi – low level disinfectants gief There are three methods of High-level disinfectants (HLD):  boiling  Moist heat at 70-100°C  Chemical (Glutaraldehyde) S are a i NOTE: Clean the surface to remove any organic matter before disinfection. Common chemical disinfectants qgy in dental practice. Antiseptics Sterilization It is important to differentiate between disinfectants and antiseptics: is the killing of ALL living forms antiseptics are biocompatible antimicrobial of microbes including their spores agents (e.g. 70% alcohol) that can be applied safely to the skin of the body or to exposed living tissues For items of invasive procedures Why not 100% alcohol? a sc matiblecwww  Sterilization Sterilization Methods Different methods of sterilization I- STERILIZATION BY HEAT suit different equipment & instruments Required for Critical Items: can be achieved by: objects that enter sterile tissue or the vascular Dry heat sterilization Dry heat. system must be sterile because any microbial (Hot air oven) used for glassware Moist heat above 100°C i.e. autoclaving. contamination could transmit disease. NB. Heat kills by denaturing proteins / membrane damage / enzymatic cleavage Ethylene oxide. (chemical sterilization) E.g, extraction forceps, hospital dressing, gauze, syringes and handpieces. Plasma gas sterilizers. Critical items confer a high risk for infection if they Ionizing radiation. are contaminated with any microorganism. Filtration. devices must be Cleaned first! Autoclave sterilization Advantages and disadvantages of The autoclave Steam is the preferred method for sterilizing steam sterilization Steam sterilization at a temperature higher above 100°C with pressure Advantages: dental devices. Steam sterilization requires Highly effective. direct contact (in the absence of air) between dry saturated steam and all surfaces of the Rapid heating and rapid penetration of instruments. instrument at a temperature of 134°C at 2.25 Nontoxic. bar for a minimum of 3 minutes. Inexpensive. This is usually performed in a benchtop Can be used to sterilize liquids. steam sterilizer Disadvantages: Items must be heat and moisture resistant,e.g. (metals, gauze) Will NOT sterilize powders, ointments or oils. Use mechanical, chemical, and biological monitors to ensure the effectiveness of the sterilization. Needs good maintenance. am 2 Ill- RADIATION Ionizing radiation: II- GASEOUS CHEMICAL IV- FILTRATION Gamma rays: emitted from radioactive cobalt 60. STERILIZATION ß-rays produced by electron accelerators have a Membrane (millipore) filters are the most high penetrating power. commonly used nowadays. Ethylene oxide (EO) gas sterilizers Ultraviolet (UV): UV rays present in sun rays or artificially produced by mercury lamps Vacuum filtration Plasma Gas sterilizers: Hydrogen Syringe filters peroxide (6 hours exposure) Can be used For disposable thermolabile items. Air filters: Large volumes of air may be rapidly e.g. syringes, surgical gloves freed from microorganisms by passage through For reprocessing of thermolabile (heat a a HEPA filters (High Efficiency Particle Arresters). For heat sensitive liquids e.g. I.V. drugs/vitamins sensitive) medical equipment f Dental devices classification : Infection control room The CDC states, “Studies have shown that handpieces can become contaminated internally with patient materials and the next patient may be exposed to potentially infectious materials.” The CDC goes on to state handpieces “should always be heat sterilized after each patient now Look at CDC website Read the lecture from textbook cleaning T.is iInititim sterilization mo.it tdilot Maggs Dryheat 1 chemical nuclec membrane DNA filltara highTinterhediatton 1 Alcohole boling adophov moist chemical phenolic 70 18 Glutraldhyte