STRILIZATION AND DISINFECTION IN A DENTAL CLINIC Dr. Shahzadi Tayyaba Hashmi shahzadi@inaya.edu.sa

STERILIZATION: The complete removal or destruction of all forms of microbial life including bacterial spores The use of physical or chemical procedures to destroy all microbial life, including large number of highly resistant bacterial spores Uses: Reduce chances of contamination by instruments

DISINFECTION: The procedure intended to reduce microorganisms as far as possible ( but not bacterial spores) by physical or chemical means The use of physical or chemical procedures to eliminate pathogenic organisms on inanimate objects

CATEGORIES OF DENTAL INSTRUMENTS Critical: (Penetrates soft tissues, contact bones, or enters into the bloodstream. E.g surgical instruments, periodontal scalars and endodontic files) Should be sterilized Semi critical: (Contacts mucous membrane but do not penetrate into soft tissues or enter into blood stream. E.g Dental mirror, amalgam condenser and dental hand pieces) Non critical: Contacts intact skin and need to be disinfected only

INSTRUMENTS PREPARATION BEFORE STERILIZATION Cleaning Instruments manual washing Packing or wrapping in plastic bags and sealed

TYPES OF STERILIZATION: Steam sterilization ( autoclave) Chemical vapor pressure sterilization (Chemiclave) Dry heat sterilization Glass bead sterilization for Endodontic instruments (reamers, files) Others Exposure to ethylene oxide gas Ionizing radiations Boiling water

1. STEAM STERILIZATION (AUTOCLAVE): It is a process in which steam is applied to kill the pathogens Usually 15 psi pressure is applied which increases the boiling point to 121 degree centigrade Steam at this temperature may destroy all the known pathogens and their spores within 15 minutes Most effective method of sterilization Surgical instruments can also be sterilized

2. CHEMICAL VAPOR PRESSURE STERILIZATION Sterilization by chemical vapor such as formaldehyde under pressure 131 degree centigrade at 20 psi pressure cycle for 20-30 minutes Corrosion sensitive burs can be sterilized

3. DRY HEAT STERILIZATION Effective and safe for metal instruments because this process does not dull instruments edges or cause corrosion Disadvantage: Less reliable than autoclave

DISINFECTION: Everything which is touched by the operator and assistant and which is in close proximity to the operative field, which cannot be sterilized must be disinfected by scrubbing Instrument tray, handles of light and operating buttons must be disinfected Disinfection can be achieved by boiling water, formaldehyde, sodium hypochlorite and alkaline glutar aldehyde