INTRODUCTION The unique nature of dental procedures, instrumentation and patient care settings require specific strategies directed to the prevention of transmission of diseases among dental health care workers and their patients.Dental practices should develop a written infection-control program to prevent or reduce the risk of disease transmission. The program should outline the policies, procedures, practices, technologies, and products used to prevent occupational injuries and illnesses among dental team members as well as healthcare-associated infections among patients.The practice setting should establish a working relationship with a qualified healthcare professional/facility to provide dental team members with appropriate occupational health services like vaccinations (hepatitis B, influenza, measles, mumps, rubella, tetanus, and varicellazoster) and postexposure evaluation and management.As a matter of fact, the dentist, dental assistant, dental hygienist and dental technician are at risk of exposure to disease agents through contact with blood or other potentially infectious materials. So by studying and by carefully following the infection control and safety guidelines, all the team work can minimize the risks of disease transmission to himself and to the patients in the dental office.Diseases Transmission in Dental Office;The dental office should have an infection control program to prevent the transmission of disease from the following :Patient to dental team Dental team to patient:Patient to patient:Dental office to community ( include dental team’s family ):Community to dental office to patient To prevent such infections, following is a list of all those procedures and precautions that together constitute infection control. These guidelines should be followed each time treatment is performed because we are never certain of the patient's status, either because they themselves do not know or because they have chosen not to inform their healthcare providers of their condition. Following these guidelines for every patient is called "Standard Precautions".StandardPrecautions1. IMMUNIZATION 2. PATIENT SCREENING 3. HAND WASHING 4. BARRIER TECHNIQUES - • Personal Protective Equipment (PPE)• Rubber dam, Pre-procedural rinsing5. NEEDLE & SHARP INSTRUMENT SAFETY • Occupational Exposure To Blood/Body Fluids7. SURFACE DISINFECTION8. radiographic asepsis 9. laboratory asepsis10. infectious dental waste management &disposalModes of Diseases Transmission :Direct contact with blood or body fluids:Indirect contact with a contaminated instrument or surface:Contact of mucosa of the eyes, nose, or mouth with droplets or spatter:Inhalation of airborne microorganisms Prepare personnel involved in patient care.An essential pretreatment procedure is the preparation of all personnel involved in patient care. This includes the utilization of personal protective equipment (gown, eyewear, mask and gloves) and hand hygienePersonal protective equipment ( PPE ) OSHA requires the employer to provide employees with appropriate personal protective equipment . Examples of PPE 1- Protective clothing2- Surgical masks3- Face shields4- Protective eyewear5- Disposable patient treatment gloves , and 6- Heavy-duty utility glovesHandwashing and hand care :According to the U.S. Centers for Disease Control (CDC) , hand washing is the single most important procedure for preventing the spread of infection. So , you must wash your hands each time before you put on gloves and immediately after you remove gloves . Handwashing is also required if you touch contaminated instruments or surfaces during working .We should always use liquid soap during handwashing . Bar soap should never be used because it may transmit contamination.Guidelines for the use of protective clothing 1) It should not be worn out of the office for any reason .2) Change these work clothes at least daily, or more often if soiled, especially if they become visiblycontaminated with blood.3) It must not be worn during eating or in resting rooms .4) It should be washed and laundered separately . Protective clothing requirements : 1) Should be made of fluid-resistant material ( cotton , cotton/polyester, ordisposable jackets or gowns .2) Clothing should have long sleeves and a high neckline to minimize the amount of uncovered skin .3) Must cover dental personnel at least to the knees when seated.Protective masks :Purpose :the mask worn over the nose and mouth to protect the person from inhaling infectious organisms spread by the aerosol spray of the handpiece or air-water syringe . Types : the two most common types of masks are the dome-shaped and flat types,dome shape and flat shapeGuidelines for the use of protective masks :• Masks should be changed for every patient or more often, particularly if heavy spatter is generated during the treatment or if the mask becomes damp.• Masks should be handled by touching only the side edges to avoid contact with the more heavily contaminated body of the mask.• Masks should conform to the shape of the face .• Masks should not contact the mouth when being worn because the moisture generated will decrease the mask filtration efficiency .Requirements : masks should be at least with 95% filtration efficiency to remove particles 3 – 5 microns in diameter .Protective eyewear :Purpose eyewear is worn to protect the eyes against damage from : • Aerosolized pathogens .• Flying sharp debris such as scrap amalgam and tooth fragments .• Splattered solutions• Caustic chemicalsGuidelines for the use of protective eyewear :1) OSHA requires the use of eyewear with both front and side protection ( solid side shields ) .2) Members who wear correction glasses or contact lenses must wear protective eyewear with a side shields or a face shield . 3) It must be cleaned and decontaminated after each treatment or patient visitaccording to the manufacture’s instructions .Types :Two types of protective eyewear used during patient care :1) Glasses with protective side shield , and2) Clear face shields .Face shields : a chin-length plastic face shield that protects your eyes, nose, and mouth from spatter may be worn and replace the protective eyewear .However , a shield cannot replace the mask because it does not protect against inhalation of contaminated aerosolGloves : Purpose : Glovesmust be worn by the dentist , dental assistant , and dental hygienist during all dental treatment to avoid contact with the patient’s blood , saliva , or mucous membranes or with contaminated items or surfaces .Types : The type of gloves used in dental practice should be determined by the various procedures that are performed in the practice as follow :1) Examination gloves usually are latex or vinyl . These are the gloves most frequently worn by the dental team duringpatient care .2) Overgloves are made of lightweight , inexpensive , clear plastic . Overgloves may be worn over contaminated treatment gloves ( overgloving ) to prevent contamination of clean objects ( telephone , pen ,opening drawers and cabinets ) that may be handled during treatment . Overgloves are discarded after a single use .3) Sterile surgical gloves are used during surgical procedures such as oral surgery or periodontal treatment . Sterile surgical gloves are supplied in specific sizes and prepackaged unites to maintain sterility before use4) Utility gloves are made from a puncture-resistant , heavy material which are not used for direct patient care . Utility gloves may be washed , disinfected , or sterilized and reused and must be discarded when they become old .Managing contaminated sharps :Contaminated needles and other disposable sharps , such as scalpel blades , orthodontic wires , and broken glass must be placed into a sharps container .OSHA , CDC and the EPA classify sharps as infectious waste . According to OSHA regulations , disposable sharps must be placed in a puncture resistant , closable , and color-coded or labeled with the biohazard symbol container immediately after use .Proper processing of contaminated dental instruments in a six-steps process as : 1) Transport : transport contaminated instruments to the processing area .2) Cleaning : clean instruments with a hand-free , mechanical process such as an ultrasonic cleaner or instrumentwasher.3) Packing : warp/package instruments in appropriate materials containing an external process indicator .4) Sterilization : place the packages in a single layers or in racks to increase circulation of the sterilizing agentaround the instruments . Operate the sterilizer according to the manufacture’s instructions . Allow packages to cool before removing them from the sterilizer .5) Storage: Store instruments in a clean , dry environment in a manner that maintains the integrity of the package.Rotate packages so that those with the oldest sterilization date will be used first .6) Delivery : deliver packages to point of use in a manner that maintains sterility of the instruments until they are used . Inspect each package for damage .Impressions and appliances should be rinsed thoroughly to remove all visible blood and debris. Gloves should be worn when handling impressions and pouring models. Certain types of impression material (silicone, polysulphur) can be disinfected by total immersion in glutaraldehyde (2%) or sodium hypochlorite (0.1%). Other materials (alginate, polyether) may be disinfected by submerging for several seconds in sodium hypochlorite (0.1%), which should then be wrapped in a hypochlorite saturated paper towel and kept in a closed container for the recommended disinfectant time.Packaging instruments: Before sterilization the instruments must be packaged to protect them from becoming contaminated after sterilization .They can be contaminated by aerosols in the air , dust , or contact with nonsterile surfaces . An additional advantage to packaging instruments is that they can be grouped into special setups .Sterilization in the dental office : The three most common forms of heat sterilization in the dental office are : :Steam sterilization,:Chemical vapor sterilization, and :Dry heat sterilizationSterilization of hand pieces is recommended whenever possible : Hand pieces that are designed for steam sterilization between uses are preferred. When a hand piece cannot be heat or steam sterilized, chemical disinfection can be used as an alternativeMicroorganisms in WaterlinesThe primary source of microorganisms in dental waterlines is the public water supply It is possible that saliva may be retracted back into the waterlines during the treatment . This process is called suck back''Anti-retraction valves on dental units and thorough flushing of the dental lines between patients minimize the chance of this occurring. Entering public water source has a colony forming units (CFU) count of less than 500; once that water enters the dental waterlines and colonizes within the bio-film, the CFU count skyrockets. There are two “communities” of bacteria in dental unit waterlines: One bacterial community exists in the water itself and is referred to as planktonic (free floating). The other exists in the bio-film attached to the walls of the waterlinesMethods to Reduce ContaminationSelf-contained water reservoirsChemical treatment regimens Micro-filtration Daily Draining and drying of linesSurface disinfectionSurfaces that are likely to become contaminated may be de-contaminated after treatment or protected with disposable coverings before they become contaminated. Effective cross-infection control is aided by a strict system of zoning and the use of sterilizable trays. Procedures should be adopted which limit the areas touched and contaminated each time a patient is treated.Between clinical sessions, work surfaces should be thoroughly cleaned and decontaminated with ethyl alcohol (70%). If there is visible blood or pus, the surface should be cleaned and disinfected with sodium hypochorite (0.5%), followed by water rinse. Protective gloves should be worn and care taken to minimise direct skin, mucosal or eye contact with these disinfectants.