Published on

Published in: Health & Medicine, Business
  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide


  1. 1. 1 Sterilization and disinfection Presented By : Dr. Vartika Srivastava P.G. Ist year
  2. 2. Contents Introduction Definitions Objectives Instrument cleaning step Packaging step Method of sterilization Test for sterilization Care of sterile Instruments 2
  3. 3.  Disinfectants  Preparation of treatment room  Unit water lines  Patient preparation  Occupational Accidental Exposure Management  Conclusion  References 3
  4. 4. • Micro organisms are ubiquitous. Since they cause contamination, infection and decay , it becomes necessary to remove or destroy them from materials or from areas. • Sterilization procedures used in dentistry should be simple but effective and of relatively short duration. 4
  5. 5. LOUIS PASTEUR of France was among the first to use sterilization techniques, he developed the steam sterilization, hot air oven and the autoclave. Pasteurization was a method developed by him to rid of tubercle bacilli from milk. JOSEPH LISTERJOSEPH LISTER,, applied Pasteur's work and introduced antiseptic technique in surgery (1867). He is the father of antiseptic surgery. 5
  6. 6. 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 : It is the destruction or removal of all pathogenic organisms to a level which seems to be no longer harmful to health. 6
  7. 7. SEPSIS : Refers to presence of infection, infectious material or agent ASEPSIS :  freedom from infection,  prevention of contact with pathogens 7
  8. 8. INFECTION : Invasion of the body tissues by the pathogenic bacteria INFECTION CONTROL : Prevention of spread of micro-organisms from their hosts Killing or removal of micro-organisms from objects and surfaces 8
  9. 9. CONTAMINATION : Contamination is the presence of a minor and unwanted constituent in a material, in a physical body, in the natural environment, at a workplace, etc. .. Decontamination: It is the process of removal of contaminating pathogenic microorganisms from the articles by a process of sterilization or disinfection 9
  10. 10. ANTISEPTIC : Refers to a chemical agent that is used on or in living tissues to kill or prevent the growth of microbes. AEROSOL: Invisible airborne particles dispersed into the surrounding environment by dental equipment (e.g., handpieces, electronic instruments). 10
  11. 11. OBJECTIVES 11
  13. 13. DENTAL CHAIR •Controls all foot operated •If manually operated needs disposable cover for buttons •Surface should be made up of plastic material that withstand chemical disinfection without damage or discoloration . 13
  14. 14. 14
  15. 15. LIGHT Foot operated switches Removable handle for sterilization or disposable barrier control 15
  16. 16. CLINICIAN STOOL Smooth , plastic material that is easily disinfected and has a minimum of seams and creases Foot operated controls 16
  17. 17. FLOOR •Carpeting should be avoided •Floor covering should be smooth , easily cleaned and non absorbent. 17
  18. 18. SINK •Smooth material (stainless steal) •Wide and deep for effective hand washing without splashing •Water faucets and soap dispensers with electric knee or foot controlled 18
  19. 19. WASTE •Heavy duty plastic bags linear to be sealed tightly for disposal. 19
  20. 20. 20
  22. 22. MANUAL CLEANING PROCESSING cleaning of instrument should be done before sterilization 22
  23. 23. PROCEDURE Wear heavy duty gloves and mask Dismantle instruments Use detergent and scrub Brush with strokes away from the body Rinse thoroughly Dry on paper towel 23
  24. 24. ULTRASONIC PROCESSING STEP Ultrasonic cleaning prior to sterilization is safer than manual cleaning 24
  25. 25. ADVANTAGES Increased efficiency Reduced danger to clinician from direct contact Penetration into areas of instruments where the bristle of a brush may be unable to contact Removal of tarnish 25
  26. 26. Procedure Instrument must be completely immersed Dismantle instruments with detachable parts Time accurately by manufacturer’s guide Drain , rinse and air dry 26
  27. 27.  Often instruments are packed for sterilization to be stored and handled without being contaminated.  Packing depend on the intended shelf life after sterilization.  The available packing options are:  Textile has shelf life of 1 month  Paper has shelf life of 1 – 6 months  Nylon, glass, and metal have shelf life of 1 year if tightly closed 27
  28. 28. Tips on wrapping and packaging 28 Make sure the instruments don’t protrude from package. more than two layers of wrap. Place biologic or chemical indication along with packages.
  29. 29. 29
  30. 30.  Physical agents 1. sunlight 2. drying 3. dry heat - red heat - flaming - incineration - hot air oven - glass bead sterilization - ethylene oxide Gas Sterilization 30
  31. 31. 4. moist heat - pasteurization - boiling - steam under normal pressure - steam under pressure 5. filtration - candles - asbestos pad - membranes 6. radiation 7. ultrasonic and sonic vibrations 31
  32. 32.  Chemical agents 1. alcohols - ethyl alcohol - isopropyl alcohol - trichloro butanol 2. aldehydes - formaldehyde - glutaraldehyde 3. dyes 4. halogens 5. surface active agents 6. metallic salts 7. gases 32
  33. 33. • Sunlight possess appreciable bacterial activity and plays an important role in the spontaneous sterilization that occurs under normal conditions • The action is mainly due to UV rays • Direct sunlight has germicidal activity. 33
  34. 34. • Moisture is essential for growth of bacteria. • Drying in air has therefore a deleterious effect. • This is unreliable, spores are unaffected. 34
  35. 35. The factors influencing sterilization by heat are 1.Nature of heat. 2.Temperature and time 3.Number of microorganisms 4.Characteristics of organisms 5.Type of material from which organisms have to be eradicated. 35
  36. 36. Red Heat sterilized by holding them in Bunsen flame till they become red hot. USE : bacteriological loops straight wires tips of forceps and searing spatulas 36
  37. 37. • This is a method of passing the article over a Bunsen flame, but not heating it to redness, USE :  Scalpels  mouth of test tubes,  Flasks  glass slides  cover slips 37
  38. 38. • This is a method of destroying contaminated material by burning them in incinerator. USE :  soiled dressings  animal carcasses  pathological material  bedding etc 38
  39. 39. This is the most widely used method of sterilization by dry heat. 39 TEMPRATURE TIME (minutes) 160 °c 120 170° c 60 150° c 150 140° c 180
  40. 40. Advantages:- 1.Is effective and safe for sterilization of metal instruments and mirrors. 2. Does not dull cutting edges. 3. Does not rust or corrode. 40
  41. 41. Disadvantages:- 1.Requires long cycle for sterilization except for forced air. 2.Has poor penetration. 3.May discolor and char fabric. 4.Destroys heat labile items. 5.Cannot sterilize liquids. 6.Unsuitable for hand pieces. 7.Cooling of the oven takes a long time. 41
  42. 42. Uses: Forceps Scissors Scalpels Swabs glass ware petri-dishes Pipettes Flasks all glass syringes. Pharmaceuticals products like Liquid paraffin, dusting powder, fats and grease 42
  43. 43. Glass bead sterilization Used to sterilize endodontic instruments 210°c – 230°c for 10-30 sec. 43
  44. 44.  Ethylene oxide, a gas at temperatures above 108°C, is a highly penetrative, non corrosive agent with a cidal action against bacteria, spores and viruses.  It destroys microorganisms by alkylation; and causes denaturation of nucleic acids 44
  45. 45. 45
  46. 46. Uses:  Plastic goods  polythene tube  artery and bone grafts  vaccines  culture media 46
  47. 47. Pasteurization • Used to kill bacteria in raw milk. • Holder Method – 63 °c for 30 mins • Flash Method -72°c for 15 -20 sec followed by quickly to 13°c or lower 47
  48. 48. 48
  49. 49. Hot Water Bath To inactivate non sporing bacteria for the preparation of vaccines - Special vaccine bath at 60o Cfor one hour is used Serum or body fluids containing coagulable proteins can be sterilized by heating for 1 hr at 56o C in a water bath for several successive days. 49
  50. 50. 50
  51. 51. Inspissator Sterilizes by heating at 80-85o C for half an hour for 3 successive days Used to sterilize media such as Lowenstein- Jensen & Loefller’s serum 51
  52. 52. 52
  53. 53. TEMPERATURE AT 100O C Boiling: Kills vegetative forms of bacterial pathogens. Hepatitis virus: Can survive up to 30 minutes of boiling. Endospores: Can survive up to 20 hours or more of boiling 53
  54. 54. Disadvantage Time consuming Does not destroy spores Cutting instruments should not be sterilized by boiling as they loose their sharpness. 54
  55. 55. 55
  56. 56. A single exposure of 90 min usually ensures sterilization but for media containing sugars or gelatin an exposure of 100c for 20 min on 3 successive days is used. This is known as TYNDALLISATION or INTERMITTENT STERILISATION. 56
  57. 57. Invented by Charles Chamberland in 1879 Autoclaves -2 types. 1.Porous load autoclave 2.Small bench top automatic autoclave Temperature -136°c; Pressure-32pounds; Cycle time-5min flash sterilization. 57
  58. 58. • Denaturation and coagulation of microbial proteins occur during exposure to the high temperature of the steam. Temperature: 121c Pressure : 15psi Cycle time :15-20 min. Packing material must allow steam to penetrate 58
  59. 59. 59
  60. 60. Advantages: 1. Short efficient cycle time. 2. Good penetration. 3. Ability to process a wide range of materials. . 60
  61. 61. 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. 61
  62. 62.  This method uses a combination of dry saturated steam and formaldehyde to kill bacteria, spores and most viruses.  Formaldehyde acts by alkylation of the nucleic acids  The required combinations of temperature and pressure are 127 to 132°C at 20 to 40 psi for 30 minutes. 62
  63. 63. 63
  64. 64. For sterilization of : Endoscopes Cardiac catheters  Respiratory equipment 64
  65. 65. 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. 65
  66. 66. Following types of filters are used- 1.Candle filters- purification of water for industrial and drinking purposes. 2.Asbestos filters- • Disposable, single use discs. • They have high adsorbing capacity • Alkalinize filtered liquids. 66
  67. 67. 67
  68. 68. 3.Sintered glass filters- • Are prepared by heat fusing finely powdered glass particles of graded sizes. •low absorptive property •brittle and expensive. 4.Membrane filters- •Routinely used in water purification and analysis, •sterilization and sterility testing •preparation of solutions for parenteral use. 68
  69. 69. Radiation Two types of radiation are used for sterilization. 1. Non ionizing and 2. Ionizing. Non ionizing - Infra red and UV rays. Ionizing - Gamma rays and high energy electrons. 69
  70. 70. Non Ionizing Radiation • Electromagnetic rays with longer wavelengths are used. • Infra red radiation is considered as a form of hot air sterilization. 70
  71. 71. USE • Rapid mass sterilization of pre packed items such as syringes and catheters. •Disinfecting enclosed areas such as entryways, operation theatres and laboratories. 71
  72. 72. Ionizing radiation- Also referred as cold sterilization  X- rays, gamma rays and cosmic rays are highly lethal to DNA and other vital constituents.  They have high penetrating power, since there is no appreciable increase in temperature. 72
  73. 73. USE •Commercial plants use gamma radiation for sterilizing items like plastics, syringes, swabs, catheters, animal feeds, oils, greases, fabrics etc. 73
  74. 74.  Ultrasonic and sonic waves are credited with bactericidal powers but the results have been variable.  Microorganisms vary in sensitivity to them, survivors are found even after treatment.  Hence it has no practical value in sterilization and disinfection. 74
  75. 75. 75
  76. 76. To be continued …… 76
  77. 77. 77 Sterilization and disinfection Sterilization and disinfection
  78. 78. CONTENT Chemical agents Classification of instrument to be sterilized Test for sterilization Disinfectants Infection in dental operatory Universal precaution Patient preparation Unit water line Occupational accidental exposure management Waste Osha regulation 78
  79. 79. Chemical Agents 79
  80. 80. 80
  81. 81.  Wide spectrum of activity  Active in the presence of organic matter  Effective in acid as well as alkaline media  Speedy action  High penetrating power  Stable  Compatible with other antiseptics and Disinfectants  Not corrode metals 81 IDEAL CHEMICAL DISINFECTANT
  82. 82.  Not cause local irritation or sensitization  Not interfere with healing  Not be toxic if absorbed into circulation  Cheap and easily available  Safe and easy to use 82
  83. 83. 83
  84. 84. Alcohols : Ethanol /Isopropyl alcohol are frequently used No action on spores Concentration recommended 60-90% in water Uses Disinfection of clinical thermometer. Disinfection of the skin 84 Spectrum: Effective against fungi, vegetative bacteria, Mycobacterium species and some lipid-containing viruses
  85. 85. Limitation: Not effective against spores. Concentration: Most effective at 70% in water. Caution: Do not use near flames due to flammability. May swell rubber or harden plastics. 85
  86. 86. Aldehydes FORMALDEHYDE To preserve anatomical specimens Destroying Anthrax spores in hair and wool 10% Formalin+0.5% Sodium tetra borate is used to sterilise metal instruments 86
  87. 87. Formaldehyde gas ItIt is used for sterilizing instruments and heat sensitive catheters, for fumigating wards, sick rooms and labs. . 87  Caution: Formaldehyde can react with free chlorine to produce toxic gas.  Irritant vapours are released hence Neutralise with ammonia following decontamination
  88. 88. 88 FUMIGATION
  89. 89. 89 Concentration: Glutaraldehyde is commercially available as 2% w/v aqueous solution which must be made alkaline to "activate" A 2% glutaraldehyde solution, for at least 10 hours, can be used to sterilize heat labile items. A 2% glutaraldehyde solution, for at least 10 hours, can be used to sterilize heat labile items. Spectrum: Active against vegetative bacteria, spores, fungi and many viruses. Spectrum: Active against vegetative bacteria, spores, fungi and many viruses.
  90. 90. 90 Use: for instruments such as, bronchoscopes, corrugated rubber anesthetic tubes, face masks, endotracheal tubes, metal instruments, polythene tubing. Use: for instruments such as, bronchoscopes, corrugated rubber anesthetic tubes, face masks, endotracheal tubes, metal instruments, polythene tubing.
  91. 91. Caution:  Glutaraldehyde is known to cause dermatitis and asthma. It should not be used in an area with little or no ventilation. Eye protection, a plastic apron, and gloves must be worn Should be stored away from heat sources and in containers with close-fitting lids. The length of time that glutaraldehyde solutions can be used varies but they are usually good for up to 14 days. 91
  92. 92. 92 Dyes
  94. 94. Phenols These are obtained by distillation of coal tar between temperatures of 170c and 270c Powerful microbicidal  Phenolic derivatives have been widely used as disinfectants for various purposes in hospitals Eg: Lysol, cresol , 94
  95. 95. use : To clean wards Various combinations are used in the control of pyogenic cocci in surgical & neonatal units in hospitals. Aqueous solutions are used in treatment of wounds 95
  96. 96. Metallic salts  Salts of silver, copper and mercury are used as disinfectants.  Act by coagulating proteins  Marked bacteriostatic, weak bactericidal and limited fungicidal activity 96
  98. 98. 98 critical Semi critical Non critical
  99. 99.  Improper cleaning of instruments  Improper packing  Improper temperature in sterilizer  Improper loading of sterilizer  Improper timing of sterilization cycle 99
  100. 100.  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 100
  101. 101. Test for sterilization Different micro-organism and chemical indicators are used for test . Micro – organism used : Steam autoclave – Bacillus stearothermophilus vails , ampules or strips. Dry heat oven – Bacillus subtilis strips. Chemical vapour – Bacillus stearothermophilus strips. Ethylene oxide – Bacillus subtilis strips 101
  102. 102. Commonly used disinfectants • Sodium hypochlorite (0.1- 0.5%) • Cidex(2% glutaraldehyde) • Chloramine 2% • Ethylalcohol [70% to 90%] • Formaldehyde 8% and Formalin 20% • Bisguanides. • Povidine –iodine (2.5%) • Phenols 102
  103. 103.  Broad spectrum of action  Fast acting.  Not affected by physical factors  Non toxic  Surface compatability  Should not have residual effect on treated surfaces.  Easy to use.  Odourless  Economical 103
  104. 104. 104
  105. 105.  As a stop gap measure, to use only until the sterilizable instruments can be obtained.  For use in surgical hand washing preparations  For disinfection of environmental surfaces contacted during an appointment.  For disinfection of dental appliances prior to insertion into a patients mouth. 105
  106. 106.  Autogenous infections  Cross infections. 106
  107. 107.  Are those caused by microbes that the patient carries on or in his or her own body.  Many of the procedures in dentistry are invasive and open the tissues to infections by micro organisms. These microbes usually are harmless within the oral cavity, but may cause disease if they enter the tissues. Eg: infective endocarditis, oral abscesses. 107
  108. 108.  Many autogenous infections can be prevented by preoperative prophylactic therapy. Eg: endocarditis is prevented by the use of antibiotics. 108
  109. 109.  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. 109
  110. 110.  Patient to practitioner  Practitioner to patient  Patient to patient  Clinic to community  Clinic to practitioners family  Community to patient. 110
  111. 111.  Blood and certain body fluids of all patients are considered potentially infectious  Universal precautions include use of gloves, gowns, aprons, masks, protective eye wear  Precautions to prevent injuries caused by needles, scalpels and sharps 111
  112. 112.  Clinical attire  Use of face mask  Gloves  Protective eye wear 112
  113. 113.  Wearing apparel is vulnerable to contamination from spatter, splash, aerosols and patient contact  Gowns should be clean and maintained free from contamination  High necked, long sleeved, knee length  Should be changed when visibly soiled  Disposable head caps should be worn to prevent hair from contamination  Plastic or disposable apron 113
  114. 114.  Surgical masks or chin length face shields must be worn to protect face, oral mucosa and nasal mucosa.  Masks should have 95% filtration efficiency of 3 to 5µm in diameter  Should be changed for each patient  Chin length face shield may be worn 114
  115. 115. 115
  116. 116.  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 116
  117. 117.  Is necessary to prevent physical injuries and infections of the eyes.  Contamination can be introduced from saliva, biofilm, carious material, pieces of old restorative materials during cavity prep, bacteria- laden calculus during scaling and micro-organism in aerosols or spatter.  Trans conjunctival transmission of hepatitis B reported – but rare. 117
  118. 118. 118
  119. 119.  Hands serve as a means of transmission of blood, saliva, dental biofilm  Finger nails serve as a reservoir for micro- organisms  Skin breaks serve as a port of entry. 119
  120. 120.  Maintain clean, smoothly trimmed, short finger nails  Remove hand and wrist jewelry  Never expose open skin lesions or abrasions to patients oral fluids or tissues  After glove removal, wash hands thoroughly 120
  121. 121. 121
  122. 122.  Wearing gloves is the standard practice to protect both the patient and clinician from cross contamination  Properly fitting gloves protect from exposure through cuts and abrasions often found on hands. 122
  123. 123. 123
  124. 124.  Always glove and DE glove in front of patient  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 don new gloves  Wash hands promptly after glove removal 124
  125. 125. Full mouth disinfection should be done. It was introduced by Leuven et al in 1990. should be completed in 2 appointments in 24 hrs Scaling and root planing Tongue is brushed with chlorhexidiene gel (1%) for 1 minute The mouth is rinsed with chlorhexidiene solution(0.2%) for 2 minutes Periodontal pockets irrigated with chlorhexidiene solution(1%) 125
  126. 126. 126
  127. 127. Procedures for clinical use : Flush all water lines at least 2 min at the beginning of each day. Run water through water syringes for 30 seconds before and after 30 seconds after each patient appointment. 127
  128. 128. 128
  129. 129. Significant exposure Premucosal stick or wound with needle or sharp instrument. Contamination of any obviously open wound with blood or saliva. Exposure of patient’s body fluid to unbroken skin. 129
  130. 130. Procedure following Exposure Immediately wash the wound. 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 prophylactic use of azothymidine for needle stick injuries. 130
  131. 131. WHO classified waste as : 1.General non hazardous 2.Sharp 3.Chemical and pharmaceutical 4.Infectious 5.Other hazardous medical waste 131
  132. 132. 132 Colour Types of waste Red Dressings, gloves & other contaminatedDressings, gloves & other contaminated materialmaterial Yellow Anatomical parts & lab waste,Anatomical parts & lab waste, biotechnology, microbiological waste,biotechnology, microbiological waste, blood , body fluids , bandages, soiled linenblood , body fluids , bandages, soiled linen Blue Plastics, turbings, catheters, iv sets, syringesPlastics, turbings, catheters, iv sets, syringes without needleswithout needles white Glass bottles and vialsGlass bottles and vials Red can Needles , scalpels, surgical instrumentsNeedles , scalpels, surgical instruments
  133. 133. 133
  134. 134. Osha Regulation 1.Employers must provide HB immunization to employees without charge within 10 days of employment. 2. Employers must require that universal precautions be observed 3. Employers must implement engineering skills to reduce production of contaminated spatter, aerosols 4.Employers must implement work practice control precaution to minimise splashing spatter or contact of bare hands with contaminated surfaces 5. Employers must provide facilities and instruments for washing hands, removing gloves and washing other skin surfaces as soon as possible after contact with blood 134
  135. 135. 6. Employers must prescribe safe handling of needles and other sharps 7.Employers must prescribe disposal of single use needles, vials and carpules 8.Contaminated reusables must not be stored or processed in a manner that requires employees to reach hands into containers to retrieve them 9.Employers must prohibit eating, drinking in the operatory or clean up area. 10.Place blood and contaminated specimen into suitable containers 135
  136. 136. 11. At no cost to employees, employers must provide personal protective equipment 12.Contaminated equipment that requires service must first be decontaminated 13. Contaminated sharps and regulated wastes should be discarded in hard walled containers 14.Employers must provide laundering of protective garments 136
  137. 137.  Text book of microbiology – Ananthnarayana & Paniker – 7th edition  Medical microbiology – greenwood  Clinical practices of dental hygenist – Wilkins – 9th edition  Contemporary oral and maxillofacial surgery – Peterson – 2nd edition  Text book of oral and maxillofacial surgery – Gustav O. Kruger -6th edition 137