Sterilization is the process of removing all microorganisms including bacteria, viruses, and fungi. Disinfection destroys or removes organisms that cause infection but not their spores. The most reliable sterilization methods are heat sterilization methods like moist heat using autoclaves and dry heat using hot air ovens. Chemical agents like alcohol, aldehydes, and halogens are also used for sterilization and disinfection. Proper waste disposal methods sort biohazardous and non-biohazardous medical waste into appropriate categories and containers for safe treatment and disposal.

1. STERILIZATION AND DISINFECTION

2. STERILIZATION Process by which an article , surface or medium is freed of all micro-organisms including viruses ,bacteria ,their spores and fungi , both pathogenic and non-pathogenic DISINFCTION Process of destruction or removal of organisms capable of giving rise to infection . spores are not destroyed . ANTISEPSIS Destruction or inhibition of micro – organisms in living tissues thereby limiting the harmful effects of infection .

3. Medical asepsis Attempt to keep health care staff , patients , and objects as free as possible of agents that cause infection. Surgical asepsis Attempt to prevent microbes from gaining access to traumatic surgically created wounds.

4. AGENTS OF STERILIZATION PHYSICAL AGENTS Sunlight Drying Heat Filtration Radiation CHEMICAL AGENTS Phenols and cresols Aldehydes Vapour phase disinfectants Halogens Alcohols Metallic salts Surface active disinfectants

5. Sterilization by Heat MOST RELIABLE , CERTAIN AND RAPID TYPES DRY HEAT MOIST HEAT

6. STERILIZATION BY DRY HEAT RED HEAT FLAMING INCINERATION HOT AIR OVEN

7. FLAMING Auxiliary method of sterilization. Can be sterilized : POINTS OF FORCEPS CEMENT SPATULAS COTTON PLIERS SILVER CONES Uses Bunsen burner flame . Used only during the of course of procedure.

8. INCINERATION Rapidly destroys contaminated materials such as patient’s dressings and pathological materials.

9. HOT AIR OVEN PRINCIPLE : Hot air causes oxidation of microbial contents leading to cell death .

10. TEMPERATURE ( c ) TIME(min) 160 120 170 60 150 150 140 180

11. HOT AIR OVEN Can be sterilized : Laboratory glassware, glass syringes , instruments . Cannot be sterilized : Grease oil , powders Fabrics and rubber items .

12. . ONLY ADVANTAGE – MAINTENANCE OF SHARP EDGES OF CUTTING INSTRUMENTS such as chisels.

13. Things to note Instruments must be clean and dry prior to wrapping. Wrapping material must be heat resistant. Aluminum foil, metal , glass container may be used . Instruments must be loosely wrapped . It should not be over – loaded .

14. Working Consists of metal cup in which salt is dispensed. To sterilize an instrument properly , immerse it a quarter a inch below salt surface and in peripheral area of sterilizer. Reason – temperature is hottest along its outer rim and lowest in the centre of surface layer of salt.

15. Application Used widely in endodontics for sterilization of broaches , reamers, files : 5 secs Absorbent points , cotton pellets : 10 secs Burs .

16. DRY BEAD STERILIZATION Micro tools , autoclavable instrument trays can be sterilized. Temperature – 320F for 2 hrs , 340F for 1 hr

17. STERILIZATION BY MOIST HEAT BELOW 100 c * Pasteurization * Low temperature steam Formaldehyde sterilization

18. PASTURIZATION Done for milk and milk products Procedure holder method 63 c for 30 mins flash method 72 c for 20 secs Followed by rapid cooling to 13 c or lower

19. Low temperature steam Formaldehyde sterilization Combination of dry saturated steam and formaldehyde. Requires 127 c to 132 c at 20 to 40 psi for 30 mins . Heat sensitive instruments can be sterilized .

20. ADVANTAGES Lack of corrosion Shorter duration Low temperature DISADVANTAGES Requires provision for ventilation to expel vapours

21. MOIST HEAT AT 100 c Boiling at 100 c Free steam at 100c Figure shows a boiler

23. MOIST HEAT ABOVE 100 C AUTOCLAVE * most practical and efficient means of sterilization * uses steam under pressure for sterilization

24. PRINCIPLE Saturated steam is more efficient sterilizing agent than hot air HIGH Penetration RAPID effect GREATER lethal action

27. PARTS PRESSURE GAUGE TEMPERATURE METER

28. AUTO STOP MECHANISM

30. PARAMETERS PRESSURE TEMPERATURE TIME 109 C AT 5 psi 115 c AT 10 psi 121c AT 15 psi 126 c AT 20 psi

31. APPLICATIONS STAINLESS STEEL INSTRUMENTS RESTORATIVE BURS HANDPIECE RUBBER ITEMS

33. FILTRATION DEVICES

34. IRRADIATION IONIZING RADIATION NON – IONIZING RADIATION

35. IONIZING RADIATION Disposable items – needles , syringes , swabs , culture plates , catheters in bulk , suture material , cannulas , pharmaceuticals sensitive to heat . Co – 60 used .

36. NON – IONIZING RADIATION UV , Infra red Rays purification of air in operating rooms .

37. LASERS Can sterilize infected endo instruments in 3 secs. Micro –organisms including spores are destroyed.

38. CHEMICAL AGENTS

39. ALCOHALS Solutions of 70 percent Ethanol and iso – propyl alcohol used as antiseptics . Used for sterilization of dapen dishes , glass slab , gutta percha cones thermometers .

40. AVOID Instruments containing carbon steel should not be soaked in alcohol as corrosive to alcohol . Rubber items absorbs alcohol – can cause tissue reaction . Alcohols dissolve cements holding instruments together and plastics may harden in its presence .

41. ALDEHYDE COMPOUNDS Formaldehyde – not used much . Glutaraldehyde

42. Glutaraldehyde Metal instruments , plastics , rubber , porcelain . Effective against M. TUBERCULOSIS Hepatitis viruses HIV viruses . 2% glutaraldehyde ( cidex ) for 20 mins

43. ETHYLENE OXIDE GAS STERILIZATION Heat sensitive items electric equipment flexible – fiber endoscopes photographic equipment contaminated objects organic compounds – bone morphogenetic proteins extracts * .

44. ADVANTAGES Highly penetrative – even through plastics . Used at low temperatures. Leaves no residue . Heat sensitive articles can be sterilized .

45. DISADVANTAGES High cost Toxicity of gas , need for venting it . Explosive and inflammable . Long period of aeration

46. IODOPHORS MOST EFFECTIVE ANTISEPTICS ACTIVITY dependent on release of FREE IODINE 1% IODINE SOLUTION – BETADIENE , ISODINE

47. ADVANTAGES * LOW TOXICITY * PROLONGED RESIDUAL effect * INEXPENSIVE * ODOURLESS

48. Sodium hypochlorite Gutta percha cones 2.5 % aq for 10 secs followed by rinsing with hydrogen peroxide Complete dentures 2.5 % for 5 min prevents denture stomatitis

49. List of disinfectants Ethanol – 70% Glutaraldehyde – 2% activated cidex , procide , omnicide , glutarex Sodium hypochlorite -1% Hydrogen peroxide – 3% Iodophors – 1% iodine betadine , isodine Others preparations – lysol, savlon, dettol

50. Waste disposal Waste material can be biohazardous material non – biohazardous materials

51. Biohazardous material Waste for infectious disease Waste for poisonous material Human tissue Teeth Blood soaked material

54. Non – biohazardous materials Matrix band Masks Head caps Impression material X – rays packets

55. WASTES FROM DENTAL MATERIALS MERCURY – AMALGAM SILVER THIOSULPHATE – X- RAY FIXER LEAD FOILS

56. Sources Of material Remaining amalgam after its use Scrap amalgam Extracted teeth containing amalgam filling Removal of old amalgam fiiling

57. Mercury containment kit Designed kit to collect any spillage of mercury It contains face mask protection for eyes scotch tape 10 cc syringe covered plastic container with water

58. STEPS Clear the area around spill Wear all protective gears Contain the spread of mercury Use regular syringe to suction out all mercury Pour the contents of syringe into plastic container with 5-10 ml of water Put scotch tape Put the used syringe in a separate container Mercury thus collected can be reused

59. CATEGORIES OF BIO – MEDICAL WASTES Category – 1 Human tissues , organs, body parts Category – 2 Body fluids , blood . Category – 3 Lab cultures , live or attenuated vaccines .

60. Category – 4 Needles , syringes , scalpels , blades , glass Category – 5 Discarded medicines , cytotoxic drugs . Category – 6 Items contaminated with blood or fluids ,cotton , dressing , soiled plaster cast , linen .

61. Category – 7 Disposable items such as tubings , catheters , intravenous sets . Category – 8 Liquid waste – waste from cleaning , disinfection activities .

62. Category – 9 Incerination ash Category – 10 Chemical waste – biologicals , chemicals used in disinfection

63. Bags for disposal YELLOW bags BLACK bags BLUE bags RED bags

67. Type of bag Waste material Treatment option Yellow bag Glooves masks head caps suction tips disposable glooves Incerenation deep burial Red bag Body tissues extracted tooth Autoclaving chemical treatment microwaving Blue bag Needles syringes scalpels blades glass endodontic files Autoclaving chemical treatment microwaving Black bag Discarded medicines incineration ash chemicals used in disinfection Disposed in secure land fill

68. RESOURCES IN INDIA Occupational Safety And Health Adminstration – OSHA http://www.osha.gov/SLTC/dentistry/index.html Centers of disease control and prevention – CDC http://www.cdc.gov.co.in

69. CONCLUSION Sterilization is very essential for both patient protection and ethical reasons. Hence should be strictly followed.

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