sterilisation in Dentistry /certified fixed orthodontic courses by Indian dental academy


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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

  • Why ethanol 70 - 75% are usually used for sterilization and not 90 - 100% concentration?
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  • Personal contact: Diseases spread from one person to other by direct contact.Carrier contact: Any person who harbours a pathogenic microorganism without getting the disease himself is considered as carrier.Droplet: It occurs when the person breathes, talks, sneezes or coughs.Indirect transmission:Occurs through dirty hands, soiled laundry articles, contaminated instruments or anything touched during the dental procedures.
  • Which can reduce the risk of exposure of the DHCW’s skin or the mucosal membrane to potentially infective materials. In 1996, CDC has expanded uni prec to other aspects of disease transmission and renamed it as “standard precautions. “
  • [essential for both patient and dentist.]
  • sterilisation in Dentistry /certified fixed orthodontic courses by Indian dental academy

    1. 1. STERELISATION IN DENTISTRY INDIAN DENTAL ACADEMY Leader in continuing dental education
    2. 2. INTRODUCTION Micro organisms are ubiquitous. Since they cause contamination, infection and decay , it becomes necessary to remove or destroy them from materials or from areas. Micro organisms that are most commonly seen are bacteria and microscopic fungi. They may be pathogenic or non pathogenic, present on both animate and inanimate surfaces. They are divided into a) Vegetative bacteria b) Sporulating bacteria
    3. 3. DEFINITIONS Sterilizing:- Refers to killing of all microbial life. Sterilization:- Is defined as the process by which an article, surface or medium is freed of all living microorganisms either in the vegetative or in the spore form. Disinfection: is defined as the destruction or removal of all pathogenic organisms or the organisms capable of giving rise to infection Sepsis:- Refers to presence of infection, infectious material or agent.
    4. 4. ASEPSIS:- It is the prevention of contact with pathogens. Antisepsis:- Is used to indicate the prevention of infection, usually by inhibiting the growth of bacteria in wounds or tissues. Bactericidal:- These are agents which are able to kill bacteria. Bacteriostatic:- These agents prevent the multiplication of bacteria.
    5. 5. METHODS OF STERILIZATION PHYSICAL         Sunlight Drying Dry heat Flaming Incineration Hot air oven Filtration Radiation      Moist heat Pasteurization boiling steam under normal and high pressure Ultrasonic and Sonic vibrations
    6. 6. CHEMICALS Alcohols  Aldehydes  Halogens  Phenols  Surface-active agents  Metallic salts  Gases  The purpose for which the sterilization is carried out depends on → Materials which has to be sterilized → Nature of microorganism that are to be removed or destroyed
    7. 7. SUN LIGHT  Sunlight has high bactericidal activity due to presence of U.V. and heat rays. It’s sterilizing power varies according to the circumstances.  Bacteria suspended in water are readily destroyed by exposure  of sunlight Spontaneous sterilization under natural conditions.  Limited clinical utility.  DRYING      Moisture is essential for bacteria Drying therefore has a deleterious effect on most bacteria. Viruses are more resistant Highly unreliable Spores are unaffected
    8. 8. HEAT          Most reliable method for sterilization The factors affecting sterilization by heat are → Nature of the heat moist heat is more effective than dry heat Time and temperature – the time required for sterilization is inversely proportional to The temperature of exposure. this can be expressed as thermal death time Kills by protein denaturation, oxidative damage and the toxic effect of elevated levels of electrolytes
    9. 9. Dry heat steriliz ation flaming incineration Hot air oven
    10. 10. Flamming:     Most primitive of all methods Used for sterilization of Innoculating loops or wires, points of forceps and searing spatulas. The instruments are held in a bunsen flame till they become red hot Burs dipped in alcohol & flammed 2 or 3 times
    11. 11. INCINERATION • • This is an excellent method for safely destroying materials such as contaminated cloth, animal carcasses and pathological materials Plastic like PVC and polythene can also be incinerated
    12. 12. HOT AIR OVEN       Widely used method of sterilization by dry heat. Temperature:160 c- 170 c (320 – 340 F) Time period: 1hr Used to sterilize glassware, forceps, scissors, scalpel , glass syringes, swabs, liquid paraffin, dusting powder etc. Hot air is a bad conductor of heat and its penetrating power is low. Bacterial spores require a temperature of 140 c for 3 hours to get killed
    13. 13. INSTRUCTIONS FOR HOT AIR OVEN  The oven is usually heated by electricity.  It must be fitted with fan to ensure even distribution of air & elimination of air pockets.  It should not be overloaded  Glassware should be dry before placing into the oven.  The oven must be allowed to cool slowly for about 2 hours before the door is open since the glassware may crack by sudden uneven cooling.  Rubber materials except silicone rubber will not withstand high temperature
    14. 14. ADVANTAGES DISADVANTAGES 1. Preserves the sharpness of metallic instruments 2.Does not cause rust, leaves the instruments dry & can be used with packing 3.Reliable & economical 4.Does not dull cutting edges. 1.Longer processing time ( 1-2 hrs) 2.Does not conduct heat efficiently 3.High temperatures pose a hazard to operators and may damage more heat sensitive items such as rubber or plastic. 4.Has poor penetration. 5.May discolor and char fabric. 6.Destroys heat labile items. 7.Cannot sterilize liquids. 8.Unsuitable for hand pieces. 9.Cooling of the oven takes a long time.
    15. 15. COX STERILIZER  Rapid heat transfer sterilizer  Operates at 370-375 F (190 C).  Sterilization time 6 minutes for unwrapped ,and 12 minutes for wrapped instruments. Advantages   No corrosion of carbon steel instruments and burs. Cutting edges are not dulled.
    16. 16. GLASS BEAD / SALT STERILIZER  Temperature between 425 F(218 C) and 475 F(246 C)  Broaches, files, silver cones and reamers sterilized in 5s Absorbent points & cotton pellets in 10s o Not suited for hollow instruments
    17. 17. Temperature below 100 c Temperature at 100 c Steam under pressure Steam at atmospheric pressure
    18. 18. TEMPERATURE BELOW 100C Pasteurization     Holder method : 63 c – 30 mins Flash method : 72 c – 15 – 20 seconds followed by cooling quickly to 13 c or lower All non sporing bacteria's – mycobacterium, brucella, salmonella are destroyed. Vaccines of non sporing bacteria in special bath for 60 c – 1 hr
    19. 19. TEMPERATURE AT 100°C BOILING       veg. bacteria – 90 – 100 c spores – prolonged periods of boiling INSTRUCTIONS: Add 2% sodium bicarbonate to water ( increases the efficiency) Hard water should not be used Not recommended for surgical instruments Materials should be immersed in water & lid should not be opened for 10 – 30 min.
    20. 20. STEAM AT ATMOSPHERIC PRESSURE  It is used to sterilize culture media  Sterilization is done for 90 min , but for media containing sugars or gelatin an exposure of 100 c for 20 min on 3 successive days is used. This is known as TYNDALLISATION or INTERMITTENT STERILISATION. TYNDALLISATION:  Ist exposure – kills bacteria in vegetative form & in next 24 hrs spores germinate into veg. form.  IInd exposure – remaining veg. forms are destroyed.  IIIrd exposure - as a precaution (to kill if any veg. forms or spores remaining)
    21. 21. STEAM UNDER PRESSURE AUTOCLAVE This is the most effective method of sterilization   Autoclave is a chamber which can withstand pressure of greater than 2 atmosphere. Moist heat (steam)of 121 c under a pressure of 15psi for 15 min is used.
    22. 22. PRINCIPLE:  Saturated steam has penetrating power & when it comes in contact with cooler surface it condenses & gives latent heat to that surface.  This ensures moist conditions for killing the microbes.  Temperature : 108 c – 147 c Operates at 121 C at 15 lbs for 15 to 20 min. Flash sterilizaion : 134 C at 20 to 30 lbs for 3 to7min
    23. 23.        There are three major factors required for effective autoclaving: pressure, temperature and time. Pressure: It is expressed in terms of psi (pound per square inch) or kpa (kilo Pascal's: kpa = 0.145psi). Temperature: To achieve required pressure, the temp must be reached and maintained at 121 degree C (250 F) with the increase in temperature and pressure, super heated steam is formed. The exposure to this super heated steam brings about the sterilization. Time: Higher temperature and greater pressure, shorter the time required for sterilization. At 15 psi pressure, the temperature of steam can reach 121 degree c . The time required to kill all living organisms at this temp is 15 mins, at 126 degree for 10 mins, and at 134 degree c for 3 mins sterilization can be complete.
    24. 24. Presently, two types of autoclaves are available. 1. Porous load autoclaves: To achieve complete sterilization, 121 degree at 20 psi are maintained for 20 mins, the articles which can be sterilized by this method include: towels for draping. suture materials. cotton rolls, rubber gloves etc. 2. Small portable bench model type autoclaves: 
    25. 25. To avoid or minimize corrosive action of steam on metals, the use of following agents have been reported.  Crawford and Oldenburg (1967) recommended addition of ammonia to the autoclaves.  Accepted dental therapeutics (1977) recommends use of dicylohexylammonium nitrate or cyclohexylamine and decylamine.  Bertocoltti and hurst (1978) recommend 2% sodium nitrate.
    26. 26. WRAPPING INSTRUMENTS FOR AUTOCLAVING:     Instruments must be cleaned, but not necessarily dry. Closed ( non perforated ) container ( closed metal trays, copper glass vials ) and aluminium foils cannot be used, because they prevent the steam from reaching the inner sections of the packs. Cassettes, drums, trays with opening on all sides may be used. Packaging used for autoclaving must be porous, to permit steam to penetrate through; and reach the instruments. The materials used for packaging could be fabric or sealed biofilm/paper pouches, nylon tubing, sterilization wraps and paper wrapped cassettes.
    30. 30. PROCEDURE  Articles are placed in cabinet & doors are bolted.  Vacuum of about 20 inches is applied.  Steam is introduced at pressure of 15 lbs/sq.inch & when temperature is reached to 121 c time is noted & sterilization is continued for 20 mins.  Materials like surgical gauze, dressings etc, should be dry before removing.  Steam is removed & dry heat is introduced from outside into the cabinet for 15 mins.
    31. 31. Advantages: 1. Short efficient cycle time. 2. Good penetration. 3. Ability to process a wide range of materials. 4. Reliable Disadvantages: 1.Corrosion of unprotected carbon steel. 2.Dulling of unprotected cutting edges. 3.Possibility that packages may remain wet at end of cycle. 4.Possible deposits from use of hard water. 5.Possible destruction of heat sensitive materials. 6.Heat & moisture may act overtime to dull & rust instruments, weaken certain plastics & rubber items
    32. 32. FAILURES OF AUTOCLAVE  If dressing or theatre garments are tightly packed then steam cannot circulate freely.  Failure due to subsequent re-contamination.  Defect in steam- air mixed.  Defect in design of apparatus.
    33. 33. TESTS FOR EFFICIENCY OF HEAT STERILIZATION: 1. Thermocouple: This is a thermometric testing and a reliable gauge of efficiency. One recording is taken from a thermocouple placed inside a test pack of towels and a second one from the chamber drain. comparison between the two recordings gives a good guide regarding the speed at which the steam penetrates the load. 2. Brown’s test : These are ampoules that contain a chemical indicator; which changes its color; from red through amber to green at a specific temperature.. 3. Autoclave tapes: This is a tape printed with sensitive ink that undergoes a color change at a specific temperature. This test forms the basis of the Bowie- Dick test for high vacuum autoclaves. With the application of temperature of 134 degree c for 3.5 mins, there is a uniform development of bars throughout the length of the strips. This shows that the steam has passed freely and rapidly to the center of the load.
    34. 34. CHEMICLAVE  A combination of formaldehyde, alcohol, ketone, acetone and steam at 20psi serves as an effective sterilizing agent.  Temperature used is 134 c for 20 mins. Advantages  Minimal corrosion.  Dry instruments are available after cycle. DISADVANTAGES  Long aeration period required.  Adequate ventilation required.  Chemical hazards possible.
    35. 35. Filtration Filtration helps to remove bacteria from heat labile liquids such as sera and solutions of sugars or antibiotics used for preparation of culture media. Following types of filters are usedCandle filters     Used for purification of water for industrial and drinking purposes. They are 2 types: Unglazed ceramic filters - Chamberland & Doulton Diatomaceous earth filters - Berkfeld & Mandler
    36. 36. Asbestos filters          Are disposable. Single use discs. They have high adsorbing capacity and tend to alkalinize filtered liquids. Sintered glass filters Prepared by heat fusing finely powdered glass particles of graded sizes. They have low absorptive property Can be cleaned easily Brittle and expensive. Membrane filters Routinely used in water purification and analysis, sterilization and sterility testing The preparation of solutions for parenteral use.
    37. 37. RADIATON Two types of radiation are used for sterilization purpose  Nonionizing radiation – U.V.Rays, Infrared rays  Ionizing radiation - X-Rays , Gamma Rays, Cosmic Rays NON-IONIZING RADIATION • Electromagnetic rays with longer wavelengths are used. • Infra red radiation is considered as a form of hot air sterilization. • Infra red radiation is used for rapid mass sterilization of pre packed items such as syringes and catheters. • UV radiation is used for disinfecting enclosed areas such as entryways, operation theatres and laboratories
    38. 38. IONIZING RAYS  ex : X-rays, gamma rays, cosmic rays  Lethal to DNA & other vital cells constituents.  High penetrating power  No increase in temperature ( cold sterilization)  Gamma rays are used for sterilizing plastic syringes, swabs, culture plates, catheter, animal feeds, various types of rubber, cardboard, oils, greases, fabrics, dental implants & metal foils.
    39. 39. ULTRASONIC AND SONIC VIBRATIONS  Ultrasonic and sonic waves have bactericidal property.  survivors are found even after treatment.  Hence it has no practical value in sterilization and disinfection.  Safest way to clean sharp instruments.  Effective up to 9 times more than hand cleaning
    40. 40. CHEMICAL STERILIZATION Ideal requirements for antiseptic/disinfectant:  Wide spectrum of activity & effective against all micro-organisms. Eg: bacteria, spores, viruses, protozoa & fungi  Effective in acid/alkaline media & speedy action  High penetrating power & stable  Compatible with other antiseptic & disinfectants  Should not corrode metals  Not cause local irritation/sensitization  Not interfere in healing  Economical , easily available, safe & easy to use
    41. 41. ALCOHOL   E.g.: methyl alcohol, ethyl alcohol, isopropyl alcohol Methyl alcohol is effective against fungal spores Uses:   To treat cabinets & incubators affected by fungus Cabinets & chambers are wiped with methanol Method:   A pad moistened with methanol & dish of water ( to ensure high humidity) are kept inside & the incubator is left in working temperature for several hours. Disadvantages  Methanol vapors are toxic & inflammable
    42. 42. ETHYL AND ISOPROPYL ALCOHOL  Ethyl & isopropyl are widely used  Alcohol acts by denaturing the proteins  No action on spores  Concentration: 60 – 70 % in water  Isopropyl is preferred over ethyl because  It is better fat solvent,  More bactericidal & less volatile.  Uses : sterilization of clinical thermometers.
    43. 43. ALDEHYDES FORMALDEHYDE  Active against amino group in protein molecule  Bactericidal & sporocidal, lethal against viruses Uses:  To preserve anatomical specimens  Destroys anthrax spores in hair & wool  10 % formalin + 1/2 % sodium tetra borate used to sterilize clean metal instruments  Formalin gas is used to sterilize instruments & heat sensitive catheters, to fumigate wards, sick room & labs,Clothing, bedding, furniture & books Disadvantages:  Gas is irritant & toxic when inhaled
    44. 44. GLUTERALDEHYDE  Similar to formaldehyde  Tubercle bacilli, fungi & viruses  Less toxic & irritant to eyes & skin  No deleterious effect on lenses – cytoscopes & bronchoscopes  Used safely to treat corrugated rubber anesthetic tubes & face masks. Plastic endotracheal tubes , metal instruments & polythene tubing
    45. 45. DYES   I. ANILINE II. ACRILINE Used as skin & wound antiseptics Bacteriostatic on high dilution but low bactericidal ANILINE DYES:    Eg: brilliant green, malachite green & crystal violet More active against Gram +ve than Gram –ve No action against tubercle bacilli MODE OF ACTION: React with the acid in the cell Used in microbiology labs as selective agents in culture media  ACRILINE DYES:  Active against Gram +ve than Gram –ve  ex: proflavine, acriflavine, euflavine & aminarine MODE OF ACTION:  Impair the DNA complex of organism & destroys the reproductive capacity of cell.
    46. 46. HALOGENS  ex: Iodine and chlorine  Iodine is bactericidal with moderate action against spores  Active against tubercle bacilli and viruses  Chlorine & its compounds have been used as disinfectants in  Water supplies, swimming baths, food & dairy industries. QUATERNARY AMMONIUM COMPOUNDS  Benzalkonium chloride is widely used as both antiseptic & disinfectant.  Antibacterial spectrum is similar to alcohols.  Limited to Gm+ve & some Gm-ve organisms.  Not effective against spores, viruses, mycobacterium tuberculosis
    47. 47. PHENOLS   Obtained by distillation of coal tar between temperatures of 170 - 270 c Lethal effect of phenol is due to their capacity to cause cell membrane damage & lysis of cell  Low concentration – precipitates proteins.  Phenol ( carbonic acid) powerful microbicidal substance  Lysol & cresol – active against wide range of organisms & toxic to humans  Active against Gram + ve & fairly against Gram–ve  Aqueous solution used in treatment of wounds.
    48. 48. GASES ETHYLENE OXIDE  Time required for sterilization – 10 - 16 hrs.  Highly permeable & colorless liquid with a boiling point of 10.7 c  But at normal temperature & pressure is a highly penetrating gas.  Highly inflammable & in concentration in air greater that 3 % is highly explosive. If mixed with carbon dioxide and nitrogen explosive tendency is eliminated MODE OF ACTION:  Acts by alkylating the amino, carboxyl, hydroxyl and sulfhydryl groups in protein molecules and also reacts with DNA & RNA
    49. 49. Uses: Tubing, handpeices, & prosthetic appliances   Unsuitable for fumigating rooms due to explosive property Successful in sterilizing – glass, metal, paper surfaces, clothing, plastics, soil, food stuff, & tobacco. FORMALDEHYDE  Widely used for fumigating operation theatres & other sick rooms.  Low temperature steam & formaldehyde (LTSF)  Designed primarily to sterilize cytoscopes & other heat sensitive materials.  Applicable to wide variety of equipment that withstands temperatures of 70 75 c
    50. 50. BETAPROPIOLACTONE (BPL)  Condensed product of ketone & formaldehyde with boiling point of 163 c  Low penetrating power but more efficient for fumigating purpose than formaldehyde  Rapid bactericidal action but carcinogenic  0.2% BPL is used for sterilizing biological products  Kills all micro-organisms and viruses
    51. 51. SURFACE ACTIVE AGENTS  These are the substances which alter energy relationships at interfaces producing a reduction of surface(or)interfacial tension.  They are widely used as wetting agents ,detergents and emulsifiers  These are broadly classified as → Anionic → Cationic → Nonionic → Amphoteric
    52. 52. METALLIC SALTS  Germicidal action depending upon concentration  Salts of silver, cu, Hg, are used as disinfectants  They are protein coagulants & have the capacity to combine with free sulphydryl group of cell enzymes  Mercuric chloride used in medicine but highly toxic  Organic compounds like thiomersal, phenyl mercury nitrate, & mercurochrome are used as mild antiseptics.  Cu. Salts are used as fungicides.
    53. 53. LIQUID CHEMICAL STERILISATION  This is the method used only with heat sensitive materials  Items should be immersed in the solution for – 10 hrs  Effectiveness cannot be verified by biological monitored, so has little value.  Used only as secondary method for items that cannot be sterilized by any other method
    54. 54. ARTICLES AND METHOD OF STERILIZATION ARTICLE  Disposable syringes  Non disposable syringes METHOD OF STERILIZATION  Gamma radiation  Ethylene oxide  Autoclaving  Hot air oven  Infrared radiation  Boiling at 100 c
    55. 55. Suture materials except catgut Autoclaving Catgut Ionizing radiation Bone and tissue grafts, adhesive dressings, Implants Ionizing radiation Dressings, Aprons, Gloves, Catheters. Autoclaving Sharp instruments 5%Cresol Water Chlorine as hypo chlorites Skin Tincture iodine, savlon, spirit (70%ethanol)
    56. 56.      PROCEDURES BEFORE STERILIZATION Pre sterilization cleaning Tips on wrapping and packaging Make sure the instruments don’t protrude from package. More than two layers of wrap. Place biologic or chemical indication along with packages. PROCEDURES AFTER STERILIZATION     Drying and cooling Distribution. Storage: After sterilization the instruments are stored in a central sterilizing area Sterilization area should be well separated to avoid probable contamination
    57. 57. CAUSES OF STERILIZATION FAILURE           Improper cleaning of instruments Improper packing Improper temperature in sterilizer Improper loading of sterilizer Improper timing of sterilization cycle STEPS TO BE TAKEN AFTER STERILIZATION FAILURE Take the sterilizer out of service Procedures to identify problems Retest and observe the cycle Determine the fate of sterilizer Test the repaired or new sterilizer
    58. 58. MONITORING OF STERILIZATION  Sterilization must be tested weekly with biological spore tests using heat resistant spores and tested daily with process indicators.  Sterilizing monitoring has four components: 1) Sterilization indicator on the bag and date of sterility 2) Daily process indicator strips 3) Weekly biological spore tests 4) Documentation note book
    59. 59. SPORE TESTING Once per week  After training of new sterilization personnel  Whenever a new type of Packaging material is used  During initial uses of a new sterilizer  First run after repair of sterilizer  With every implantable device and bold device until results of test are known  After any other change in sterilization procedure 
    60. 60. ASEPSIS Surface asepsis of dental instruments can be achieved by two methods:  By cleaning and disinfecting contaminated surfaces.  Preventing the surface from becoming contaminated by use of surface cover. 
    61. 61. CLASSIFICATION OF DISINFECTANTS 1. Phenol derivatives: Phenol Cresol Resorcinol Hexyl resorcinol Hexachlorophene 3. Halogens Iodine Iodophores Chlorine Chloroform Chloroxylenol 2. Oxidizing agents 4. Bisguanides Potassium permanganate Hydrogen peroxide Benzoyl peroxide Chlorhexidiene
    62. 62. DISINFECTANTS Commonly used disinfectants • Sodium hypochlorite (0.1- 0.5%) • Cidex(2% glutaraldehyde) • Chloramine 2% • Ethyl alcohol [70% to 90%] • Formaldehyde 8% and Formalin 20% • Bisguanides. • Povidine –iodine (2.5%) • Phenols
    63. 63. INFECTION CONTROL    INFECTION CONTROL:- It is defined as the selection and use of procedures and products to prevent spread off infectious diseases. Infection control involves 2 basic factors Prevention of spread of microorganisms from their hosts Killing and removal of microorganisms from objects and surfaces. Infection through any of the routes requires the following 1)Susceptible host 2)Pathogen with sufficient infectivity and numbers to cause infection 3)Portal through which the pathogen enters the host
    64. 64. AN INFECTION TO OCCUR REQUIRES ALL THE FOLLOWING CONDITIONS TO BE PRESENT A susceptible host A pathogen with sufficient infectivity and numbers to cause infection. A portal through which the pathogen may enter the host. A reservoir or source that allows the pathogen to survive and multiply e.g. blood
    65. 65. WHY IS INFECTION CONTROL IMPORTANT IN DENTISTRY?  Both patients and dental health care personnel (DHCP) can be exposed to pathogens  Contact with blood, oral and respiratory secretions, and contaminated equipment occurs  Proper procedures can prevent transmission of infections among patients and DHCP
    66. 66. OBJECTIVES OF INFECTION CONTROL  Reducing the no. of pathogens  Breaking the cycle of infection  Eliminating cross contamination
    67. 67. INFECTIONS IN DENTAL OPERATORY Autogenous infections    Are those caused by microbes that the patient carries on or in his or her own body. The microbes usually are harmless within the oral cavity, but may cause disease if they enter the tissues. Eg: infective endocarditis, oral abscesses. Cross infections    Are caused by infectious agents that are transmitted among dental personnel, patient and the environment. The transfer of disease may be from dentist to patient or vice versa. Eg: hepatitis B is an occupational hazard for dental personnel , on the other hand there are evidences of dentists transmitting hepatitis B.
    68. 68. PATHWAYS OF CROSS INFECTION  Patient to practitioner  Practitioner to patient  Patient to patient  Clinic to community  Clinic to practitioners family  Community to patient.
    69. 69. 1. Source of infection 4. Susceptible host Factors affecting transmission of infection 3.Route of transmission 2. Means of transmission
    70. 70. 1.Source of infection: -a patient ,member of dental team. 2.Means of transmission: -microorganisms in the blood, present -contact with blood or saliva mixed with blood may transmit pathogenic microorganisms from one person to another.
    71. 71. 3.Route of transmission: A. Inoculation: -direct contact, -accidental injury with a contaminated needle Ex: hepatitis, herpes simplex, clostridium tetani, staphylococcus. B. Inhalation: -aerosols and splatter. Ex: CMV, varicella zoster, mycobacterium tb, streptococcus pyogenes, candida, rubella.
    72. 72. Modes of disease transmission: 1.Personal contact 2.Carrier contact 3.Droplet transmission 4.Indirect transmission
    73. 73. PERSONAL CONTACT  Diseases spread from one person to other by direct contact  Eg: veneral diseases such as AIDS, herpes, syphilis. Contact with contaminated blood, saliva and mucous may spread them. Carrier contact  Person who harbours a pathogenic microorganism without getting the disease himself is considered as carrier.  The carrier often exhibits no symptoms. Eg: serum hepatitis, AIDS Droplet transmission  It occurs when the person breathes, talks, sneezes or coughs.  Eg: common cold, flu.
    74. 74. INDIRECT TRANSMISSION Face  Clothing  Cabinets  Restorative material packs  Light handles  X-rays  Patient charts  Pumice pan  Patient towels  Cotton roll             Hair Handles of drawers Medicament bottles Cement jars Anesthetic supplies Light switch X-ray tube head Prosthesis Exposed instruments Patient bibs Disposable items
    75. 75.
    76. 76. 1. Medical history 2. Universal precautions/ standard precautions 3. Personnel health elements
    77. 77. 4. Sterilization and disinfection of patient care items 5. Dental unit waterline (DUWL) contamination 6. Environmental infection control
    78. 78. UNIVERSAL PRECAUTIONS  Identification of the infected patients by medical history, physical examination or lab tests for each and every individual  Are a set of precautions designed to prevent transmission of HIV, HEP B and other blood borne pathogens when providing 1st aid or healing care.  All the patients are considered potentially infectious  Involve the use of protective barriers such as gloves, gowns, aprons, masks, protective eye wear  It is also recommended to prevent injuries caused by needles, scalpels and other sharps.
    79. 79. PERSONNEL HEALTH ELEMENTS OF AN INFECTION CONTROL PROGRAM  Education and training  Immunizations  Exposure prevention and post exposure management  Medical condition management and work-related illnesses and restrictions  Health record maintenance
    80. 80.  The Advisory Committee of Immunization Practices (ACIP): 1. Tetanus and diphtheria – 3 doses: 1 every 10 yrs. 2. Influenza – 1 dose annually 3. Pneumococcal – 1 dose 4. Hepatitis B – 3 doses(0, 1-2, 4-6 months) 5. MMR – 1 dose 6. Varicella – 2 doses 7. Meningococcal – 1 dose 8. Annual tuberculin tests 9. Frequent throat cultures
    81. 81. HAND HYGIENE  Hands are the most common mode of pathogen transmission  Reduce spread of antimicrobial resistance  Prevent health care-associated infections SEMMELWEIS introduced the concept of hand washing with lime.
    82. 82. HAND HYGIENE DEFINITIONS  Handwashing  Washing hands with plain soap and water  Antiseptic handwash  Washing hands with water and soap or other detergents containing an antiseptic agent  Alcohol-based handrub  Rubbing hands with an alcohol-containing preparation  Surgical antisepsis  Handwashing with an antiseptic soap or an alcoholbased handrub before operations by surgical personnel
    83. 83. SPECIAL HAND HYGIENE CONSIDERATIONS  Use hand lotions to prevent skin dryness  Consider compatibility of hand care product  4% chlorhexidiene gluconate and 3% PCMX are efficient scrubbers s with gloves (e.g., mineral oils and petroleum bases may cause early glove failure)  Keep fingernails short  Avoid artificial nails  Avoid hand jewelry that may tear gloves
    85. 85. Frequently missed areas of the hands during washing Most Frequently missed Less Frequently missed Not missed
    86. 86. GLOVES:  Gloves should be worn when contact with blood.  When contacting any contaminated surfaces, & objects.  Gloves are single-use items and should be replaced as soon as contaminated or immediately if torn, punctured, or when their integrity is compromised  Single-use gloves should not be washed for reuse.  Washing gloves causes "wicking," (invasion of liquids through undetected holes in the latex gloves).  Rinsing to remove excess powder or cornstarch is permissible.  Deterioration of gloves may be caused by disinfectants, oils, oilbased emollients, and improper storage, such as exposure to heat.
    87. 87. Sterile surgical gloves. Non sterile latex gloves. Vinyl examination gloves. Utility gloves.
    88. 88. GLOVE PLACEMENT  Always glove and deglove infront of pt  Place gloves over cuff of long sleeved clinic wear  Keep gloved hands away from face, hair, clothing, telephones, pt records, clinicians stool etc  Immediately remove torn gloves, wash hands thoroughly and wear new gloves  Wash hands promptly after glove removal
    89. 89.
    90. 90.
    91. 91.
    92. 92. LATEX HYPERSENSITIVITY  Patients or clinicians may develop a sensitivity to rubber latex  Symptoms range from dermatitis to a life threatening anaphylactic shock  Only available treatment is avoiding all contact  Latex sensitivity is due to protein allergens
    94. 94. GENERAL RECOMMENDATIONS CONTACT DERMATITIS AND LATEX ALLERGY  Educate DHCP about reactions associated with frequent hand hygiene and glove use  Get a medical diagnosis  Screen patients for latex allergy  Ensure a latex-safe environment  Have latex-free kits available (dental and emergency)
    95. 95. MASKS OR FACE SHIELDS      Masks along with eyewear & face shields protect against aerosols. Change the masks every hour or change for every patient. Masks covering mouth and nose minimize inhalation of aerosol & protects the mucosal contamination. Types: cone, ear loop & surgical 95% of filtration efficiency in presence of 3-5 micrometer particles. EAR LOOP MASKS
    96. 96. CHARACTERISTICS OF IDEAL MASK        No contact with the wearers lips and nostrils Has a high bacterial filtration efficiency rate Fit snugly No fogging of eye wear Convenient Made of material that does not irritate Does not collapse during wear or when wet
    97. 97.
    98. 98. materials: Plastic foam, fiber glass, synthetic fiber mat, paper. Mask removal: -grip side elastic or tie strings to remove. -never handle the outside of a contaminated mask with gloved or bare hands. Never place the mask under the chin.
    99. 99.  Use of eyewear protective -to avoid eye infections. -contamination can be introduced from saliva, biofilm, carious material, pieces restorative materials of old during cavity preparations, bacteria laden calculus during scaling and any other microorganisms contained splatter. in aerosols or
    100. 100. Features: -wide coverage, with wide shields, to protect around the eye. -shatterproof: made of strong, sturdy plastic -lightweight -flexible and with round smooth edges to prevent discomfort if pressed against the nose or ears. -Easily disinfected.
    101. 101. Types: -goggles -eyewear with side shields -eyewear with curved frames -post mydriatic spectacles used by ophthalmologists. -Child sized.  Care: -clean with detergent and rinse thoroughly. 
    102. 102. GOWNS  NEUBERS -- discovered cap and gown  Gowns, aprons, lab coats, clinic jackets, should be worn when occupational exposure is reasonably anticipated.  Long sleeve, high neck, cotton/polyester garments are considered satisfactory barriers.  Sleeves should be long enough so that gloves fit securely over cuffs or end of sleeves.
    103. 103. ENVIRONMENTAL SURFACES  May become contaminated  Not directly involved in infectious disease transmission  Do not require as stringent decontamination procedures  Clinical contact surfaces High potential for direct contamination from spray or spatter or by contact gloved hand  Housekeeping surfaces Do not come into contact with patients or devices Limited risk of disease transmission
    104. 104. Housekeeping Surfaces
    105. 105.  Cleaning Clinical Contact Surfaces  Use barrier precautions (e.g., heavy-duty utility gloves, masks, protective eyewear) when cleaning and disinfecting environmental surfaces  Physical removal of microorganisms by cleaning is as important as the disinfection process  Do not use sterilant/high-level disinfectants on environmental surfaces  Cleaning Housekeeping Surfaces    Routinely clean with soap and water Clean mops and cloths and allow to dry thoroughly before re-using Prepare fresh cleaning and disinfecting solutions daily and per manufacturer recommendations
    106. 106. SHARP ITEMS  Anesthetic needles, scalpel blades, wires, endodontic files are considered potentially infectious & handled with caution to prevent injury.  Needles must not be bent, recapped, or removed .  Contaminated needles should be placed in leak proof, puncture resistant containers with color coded biohazard symbol.
    107. 107. PREVENTION OF NEEDLE STICK INJURIES  Ensuring that the needles and surgical blades are sheeted, covered, when not in use.  Keeping full contact and retain full concentration while handling such instruments  Adequate retraction of tissues  Over gloving or using double gloves whenever indicated
    108. 108. IMMEDIATE TREATMENT OF NEEDLE STICK INJURY     The wound should be encouraged to bleed as copiously as possible. If the patient has not received hepatitis B vaccination this should be commenced immediately. In some cases if hepatitis B positive then hyper immune gamma globulin is given. Many authorities recommend the propylactic use of azothymidine for needle stick injuries. but its value in the prevention of HIV has not been proved. HAIR    Hair should be kept out of field. Hair can trap heavy contamination Person must protect hair with a surgical cap when encountering heavy spatter.
    109. 109.  WASTE  WHO classified waste as follows 1.General non hazardous 2.Sharps 3.Chemical and pharmaceutical 4.Infectious and 5.Other hazardous medical waste
    110. 110. DISPOSAL  House hold non infective waste: collected in thick polythene bags and discarded  Sharps: collected separately in puncture resistant plastic containers and should be sealed securely  Infected hospital waste: collected in metallic containers, decontaminated by autoclaving and disposed off at garbage disposal sites. It is done by following methods also:  Incineration – sophisticated method of burning the waste.  Deeply buried with bleaching powder and lime
    111. 111.  Color coding 1. Red: -bags, buckets, containers -dressings, gloves, other contaminated material 2. yellow: -bags, buckets, containers -anatomical parts and lab waste -biotechnological, microbiological waste, blood, bloody fluids, bandages, soiled linen.
    112. 112. -bags in cardboard carton -plastics, tubing, catheters, iv sets, syringes without needles.  - WHITE - bags in cardboard carton, containers -glass bottles and vials -
    113. 113. 5.Red can: -puncture proof, sharps container, cans, thick cardboard boxes. -needles, scalpels, surgical instruments. 
    114. 114. STERILIZATION AND DISINFECTION REGARDING MAJOR DENTAL PROCEDURES       Theatre washing and fumigation Soap and water may be used Then with 3% Lysol. Fumigation is done with formaldehyde, and the formaldehyde vapors are neutralized with ammonium hydroxide. Theatre sterility test After fumigation procedures, swabs are taken from potential areas harboring clostridium tetani swabs are incubated for a minimum of 10 days and then tested for growth of clostridium tetani. A negative report should be obtained. Three such consecutive negative repots should be obtained to start a new operation theatre.
    115. 115. OPERATING ROOM PROCEDURES The ceiling,walls, and floors are regularly disinfected,especially following a contaminated case.  The operating rooms should have two sets of doors.  The operating theatre should provide a safe, efficient and a user friendly environment; being at the same time, free from bacterial contamination, as far as possible.  The access to operation theatre and the recovery area is restricted to operation theatre personnel, who are required to don special scrub dress before entering the operation room area. 
    116. 116.     • The scrub suit comprises of a pair of pants/skirt/pyjama and a shirt/blouse. • A surgical cap is used to cover the hair completely. • A mask is then placed and tied over the nose and mouth. • Theatre shoes or shoe cover may be used.
    117. 117. Once the patient is prepared and draped, only those personnel, who have scrubbed, gowned and gloved, may work at the surgical site. • The backs of those who are gowned are considered non-sterile, and also the areas below the waist; unless the gowns are long and back gowns are worn. • Hence, one must be careful to keep the arms above the waist, when not operating. • The masks and surgical cap are not sterile, hence should not be touched. •
    118. 118. FUMIGATION OF OPERATION THEATRES: The operation theatres are disinfected by fumigation. The fumigation can be achieved by the use of fumigators as well as potassium permanganate reaction technique. Fumigation is initiated after setting up of the instrument(STERI TRAX) in place. The chemical used in 40% formaline. Fumigator is set for 30 mins.
    119. 119. Relative humidity(RH): higher the humidity, better is the disinfection. A minimum of 70% humidity is essential. Temperature: Evaporation of gaseous fumigant is more at the higher temperature. Formaldehyde levels in the air in the operation theatre: The dose of formalin is usually decided by the size of the room. As a general rule, about 180 ml is used for a room of the size 1000 cubic feet (= 10 x 10 x 10 feet).
    120. 120. Masks: •disposable masks made of synthetic fibers are better; and contain filters made of polyester or polypropylene. •Surgical antifog masks with flexible nosebands are available which follow facial contours and retain a high efficiency of filtration. •Masks provide protective function for wearer against blood-borne viruses, as part of a policy of universal precautions.
    121. 121. Hand Scrub Techniques • Hand scrub is the first step towards aseptic surgical technique. • Wise et al (1959) have shown that 20 – 30 % of surgeon’s gloves get punctured by the end of operation. • Cole and Bernard (1964) have documented the out pouring of bacteria from the surgeon’s hands, through the punctured gloves into the wound. • It is therefore imperative to have clean hands inside the gloves. • The purpose of hand scrub is two-folds; • The first is to remove the superficial contaminants and loose epithelium. This is achieved from mechanical action of the brush. • The second purpose is to reduce bacterial count on the skin. Ellis (1972) reported that use of the iodophor scrubbing solution, results in the effectiveness of the scrub in reducing the surface bacterial count.
    122. 122. HAND SCRUBING (CONT.)         All jewelers be removed before washing. The nails should be checked for cleanliness. All gross sub nail contaminated should be removed. The scrubbing begins at the tip of one finger of one hand. The scrubbing is continued along the skin surfaces of fingers and the interfinger webbing. The scrubbing is continued until all the surfaces of the hand are completed. Then the hands are cleaned along the forearms and the scrubbing is progressed towards the elbow, extending 2’’ above the elbow In the similar manner the other hand is scrubbed beginning at the fingertips and scrubbing towards the elbow.
    123. 123. • A scrubbed area should not be touched again because of the possibility of contamination from an unscrubbed are. • Dunphey and Way (1973) recommend that scrubbing procedure may be done for approximately 10 mins. After the scrubbing of both the arms the brush is discarded and the arms are rinsed of excess soap. • The rinse should be done with arms elevated above the elbow progressing down the arms and elbows. The arms are not rubbed during the rinse. • The surgeon approaches the scrub nurse for the sterile drying towel. The technique of drying begins at the fingertips of one hand progresses down the arm. Then with the opposite side of the towel, the other arm is dried in a similar manner.
    124. 124. Hand disinfections. • There are some proprietary preparations available for preoperatively washing of hands of surgeons and assistant which have a bactericidal effect and which do not cause excessive drying of skin. • Hibiscrub and phisomed contains 4 percent chlorhexidine gluconate. • Betadine - contain 7.5 percent providone-iodine. • 3% PCMX (Para chloro meta xylenol) • Soap containing disinfectants, like hexachlorophene. • 70% hibisol(2.5% chlorhexidine in 70% alcohol) lotion may be applied. • Washing may be continued for 5 minutes in running water. This is followed by drying of hands and forearms.
    125. 125. PREPARATION OF THE SURGICAL SITE: • Hair in the area of surgery is removed, preferably, just prior to scrubbing the skin. • Shaving the area the night before produces small abrasions on the skin and resident bacteria multiply as a result of injury. • This problem can be overcome by decreasing the time interval between the shave and the skin preparation. • A lubricating ointment should be applied to patient’s eyes, and they are covered. • The external auditory meatus is plugged and blocked, if bleeding in the vicinity is anticipated. • The scrubbing should begin in the centre of the site to be prepared, and move outward concentrically, away from the site of operation. • This avoids contamination of already scrubbed site of surgery.
    126. 126. DRAPING THE PATIENT: The purpose of draping a patient is to isolate the field of surgery from other parts of body that have not been prepared for surgery, and also from non sterile equipment and sterile equipment.
    127. 127. ADDITIONAL PRECAUTIONS TO BE TAKEN INCASE OF H.I.V. PATIENTS  If possible schedule surgery at the end of list  The team should be limited to essential members of staff and procedures to be performed by experienced, fully trained staff.  Operator should wear - 2 pairs of gloves - plastic gown - head cap - mask - protective eye wear  Procedures should be performed in a way, which minimizes the formation of droplets, spatter and aerosols - utilizing high volume aspirators - rubber dams - all surfaces inside the operatory and equipment should be thoroughly cleaned
    128. 128. ADDITIONAL PRECAUTIONS TO BE TAKEN INCASE OF HBV PATIENTS          HBV is a stable DNA hydrophilic virus that can withstand drying for more than 7 days I milliliter of infected blood contains 1 billion virus particles PRECAUTIONS Proper medical history 2 pairs of gloves Protective eye wear with solid side shield Masks or face shields for heavy spatter Disposable plastic gown PEVENTION HBV can be effectively prevented by vaccination. The vaccines commonly used are Engerix – B , Recombivax - B One dose followed by 2nd dose 1 month later and a 3rd dose 6 months later
    129. 129. ADVANCES IN DISINFECTION AND STERILIZATION Ortho-phthalaldehyde       It contains 0.55% 1,2-benzenedicarboxaldehyde. Fast-acting high-level disinfectant No activation required Odor not significant Claim of excellent compatibility with materials Claim of not coagulating blood or fixing tissues to surfaces Disadvantages      Limited clinical use More expensive than glutaraldehyde Eye irritation with contact Slow sporicidal activity Repeated exposure may result in hypersensitivity in some patients with bladder cancer
    130. 130. Hydrogen peroxide gas plasmas •They are generated in an enclosed chamber in a deep vacuum, by using radio frequency or microwave energy to excite the gas molecules and produce charged particles, many of which are in the form of free radicals. • This process has the ability to inactivate a broad spectrum of microorganisms, including resistant bacterial spores. Disadvantages •Cellulose (paper), linens, and liquids cannot be processed •Sterilization chamber is small (∼3.5–7.3 ft3) •Requires synthetic packaging (polypropylene wraps or polyolefin pouches) or special container tray •Hydrogen peroxide may be toxic at levels 11 ppm Superoxidized water The FDA recently cleared this liquid high-level disinfectant that contains 650–675 ppm free chlorine
    131. 131. Ozone enriched water Ozone affects microbial membranes and denatures metabolic enzymes. is an effective biocide against: • Bio - Film • Bacteria • Viruses • Fungi ( yeast, mold and their spores ) • Protozoa ( including cysts ) Antimicrobial Action • Causes irreversible damage to the fatty acids in the cell membrane (e.g. phosphatidylethanolamine) and cellular macromolecules, e.g. DNA. • Biphasic death curve: an initial rapid inactivation stage followed by a slower inactivation stage. • 3000 times faster than chlorine • Bactericidal effect on Salmonellae, Staphylococcus, E. coli, etc. • Rapid and effective sporicide (Bacillus and Clostridium spores)
    132. 132. CONCLUSION “Prevention is better than cure”. A proverb so well suited to sterilization and asepsis. A thorough understanding and application of the principles of sterilization will help ensure safety from the invisible but deadly world of microbial pathosis and assist the practitioner in delivering holistic care with maximal efficiency ensuring happy and healthy patients, personnel and physicians themselves.
    133. 133. REFERENCES        Text book of microbiology--AnanthNarayan. cedric, mim, hazel, m.docrell -medical microbiology Text book of oral and maxillofacial surgery-laskin vol 1 Text book of surgery----Sabiston’s Text book of oral and maxillofacial surgery---- Gustav. O . Kruger. Oral and maxillofacial infections-----Topazian, Goldberg, Hupp Internet
    134. 134.