infection control in dentistry


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infection control in dentistry

  1. 1. Dr. Akash Ardeshana 1st year MDS (Department of paedodontics and preventive dentistry) 1
  2. 2. content Introduction Objective Infection and infection control Infectious disease in concern in dental practice Cross Infection Transmission of infection in dental clinic 2
  3. 3. General principle of infection control Needle stick injury and management Conclusion Bibliography 3
  4. 4. introduction The concept of asepsis and it role in the prevention of infection control was put forward nearly two century ago. 1850- general principle laid down by lgnaz semmelweiss in europe and oliver holmes in USA. Principle were accepted after Joseph lister’s studies on prevention of wound infection from 1865 to 1891. 4
  5. 5. Infection control procedure, although well recognized in general medicine and surgery, were late in coming to dentistry. Several factors changed the perception of infection control in dental profession, first was that blood and saliva could be vectors for viral infection. Second was AIDS pandemic. 5
  6. 6. Objective Elimination or reduction in spread of infection from all types of microorganisms. Breaking the cycle of infection and eliminating cross contamination. The clinician has a professional responsibility for implementing effective infection control to protect other patients, and a responsibility for safe practice for all members of the dental team. Ensuring and showing to patients that they are well protected from risks of infectious disease. 6
  7. 7. Infection Infection is deposition of organisms in the tissues and their growth resulting in host reaction. The number of organisms required to cause an infection is termed as the infective dose: Depend on: virulence of the organism susceptibility of host age, pre existing dose and drug 7
  8. 8. Infection control Prevention of spread of microorganisms from their hosts Kills or removal of microorganisms from obejcts and surface. 8
  9. 9. Infectious disease in concern in dental practice Viral infection Bacterial infection Fungal infection Parasitic infection 9
  10. 10. Microorganism Major transmission route N. Gonorrhoeae Inhalation T. Pallidum Inhalation M. Tuberculosis Inhalation/inoculation Strep. pyogenes Inhalation Bacteria 10
  11. 11. microorganism Major transmission root CMV Inhalation Hepatitis virus Inoculation HSV 1 and 2 Inoculation HIV Inoculation Measles virus Inhalation Mumps virus Inhalation Influenza virus Inhalation Rubella virus Inhalation adenovirus Inhalation viruses 11
  12. 12. Fungal infection: candidiasis Parasitic infection: pneumocystis carinii infection 12
  13. 13. Tuberculosis Transmitted by inhalation, ingestion and inoculation. Two main infection: tuberculous cervical lymphadenenitis pulmonary infection Prevention: Immunization with BCG vaccine, Gloves and mask should be worn, The inhalation, sedation and anaesthesia equipment must always be treated with high-level disinfectants . 13
  14. 14. Herpes simplex virus This is most common herpese virus transmitted to dental clinic staff. Transmission of infection to dental staff can result in primary herpetic stomatitis or herpetic whitlow Transmission occur by direct contact of abraded skin or intact mucosa with infected lesion or secretion . 14
  15. 15. Hepatitis B virus DNA virus. Incubation period 45 to 180 days. HbsAg main indicator for active infection. the mode of transmission: direct contact with infected blood. Prevention: all members of dental team should be vaccinated against hepatitis and maintained this vaccination schedule. 15
  16. 16. Hepatitis C virus It is a RNA virus. Blood born transmission. The acute phase of HCV infection is usually asymptomatic and only approximately 10% individuals have overt hepatitis. 16
  17. 17. HIV Inability to survive outside host organism. Acts similar to STDs’ Looses its infectivity once desiccated. Transmission: Direct contact between infected host and mucosal surface or epithelial wound. Small amount of virus present in saliva. Person cannot get infected by saliva alone 17
  18. 18. 18
  19. 19. Cross Infection Cross-infection is defined as the transmission of infectious agents among patients and staff within a clinical environment. patient practitionar patient 19
  20. 20. Transmission of infection in dental clinic Factors affecting infection transmission Source of infection Means of infection Route of transmission Susceptible host 20
  21. 21. Modes of disease transmission Personal contact Carrier contact Droplet transmission Indirect transmission 21
  22. 22. Risk of transmission during dental treatment Risk of transmission of through saliva Transmission from dental personal to patient Infection control in dental practice s revised edition 2006 s.Anil, Georges kryier 22
  23. 23. Categories of task in relation to risk Category I: Tasks that involved exposure to blood, body fluid or tissues. Category II: Tasks that do not involve routine exposure to blood, body fluids or tissues. Category III: Tasks that involve no exposure to blood, body fluids or tissues. 23
  24. 24. So The American Dental Association (ADA) and Occupational Safety and Health Act (OSHA) guidelines advise that all dental office staff in category I and II and dentists be trained in infection control to protect themselves and their patient. Essential of preventive and community dentistry 4th edition soben peter 24
  25. 25. OSHA rules on blood borne pathogens 1. Establish an exposure control plan 2. Employers must update the plan annually 3. Implement the use of universal precautions 4. Identify and use engineering controls 5. Identify and ensure the use of work practice controls 25
  26. 26. 7. Provide personal protective equipment (PPE), such as gloves, gowns, eye protection, and 8. Make available hepatitis B vaccinations to all workers with occupational exposure 9. Make available post-exposure evaluation and follow- up to any occupationally exposed worker. 10. Use labels and signs to communicate hazards 11. Maintain worker medical and training records Occupational safety and health administration: blood born pathogen 26
  27. 27. GENERAL PRINCIPLE OF INFECTION CONTROL Identifying high risk patients and source of infection. Universal protection Prevent environmental contamination Use of sharp instruments and needles Handling biopsy specimen Prosthodontic consideration Infection control during radiography Biomedical waste others 27
  28. 28. Identifying high risk patients and source of infection Understaning the disease and their root of transmission that has high susceptibility. Using the CDC recommended question for taking a medical history. Screening every new patient by taking proper medical history and oral examination. Continuing to update patients’s medical history. 28
  29. 29. Universal protection: All infected patient cannot identified on the basis of medical history, physical examination and laboratory examination. Hence, the philosophy is that to consider all patients to be infected with pathogenic organisms. Hence it recommended that certain basis infection control procedure must be followed routinely for all patients, referred to as Universal Protection 29
  30. 30. Universal protections for dental team, include: Routine hand washing Protective barrier technique Immunization 30
  31. 31. Hand washing is the key to Control of Infection 31
  32. 32. Hitsorical background 32
  33. 33. Ignaz Philipp Semmelweis (1818-65) Hungarian obstetrician educated at the universities of Pest and Vienna, introduced antiseptic prophylaxis into medicine. In the 1840s, puerperal or childbirth fever, a bacterial infection of the female genital tract after childbirth, was taking the lives of up to 30% of women who gave birth in hospitals. Women who gave birth at home remained relatively unaffected. 33
  34. 34. Semmelweis observed that women examined by student doctors who had not washed their hands after leaving the autopsy room had very high death rates. He also noted that the lesions of his friend’s wound were similar to those found at post-mortem on those who had died of puerperal fever. Semmelweis concluded that puerperal fever was septic and contagious. 34
  35. 35. He ordered students to wash their hands with chlorinated lime before examining patients; as a result, the maternal death rate was reduced from 12% to 1% in 2 years. Nevertheless, Semmelweis encountered strong opposition from hospital officials and left Vienna in 1850 form the University of Pest. EID Journel Volume 7, Number 2—April 2001 Author affiliation: Centers for Disease Control and Prevention, Atlanta GA, USA 35
  36. 36. Routine hand washing Proper handwashing, hand antisepsis, or surgical hand antisepsis are simple acts that help reduce the risk of disease transmission. Transient microorganisms can come to rest on the hands following direct contact with patients or contaminated environmental surfaces. 36
  37. 37. These microorganisms, which colonize the top layers of the skin, are most frequently associated with healthcare-acquired infections. Fortunately they generally can be removed with routine handwashing. 37
  38. 38. Indications for hand hygiene include: when hands are visibly soiled. after barehanded touching of inanimate. objects likely to be contaminated by blood, saliva, or respiratory secretions. before and after treating each patient. before donning gloves and immediately after removing gloves. 38
  39. 39. Before Decontaminating Hands Cuts and Abrasions must be covered with a waterproof dressing Remove all jewellery and watches. Fingernails should be kept short and clean. Nail art and nail varnish should not be worn. Roll up your sleeves 39
  40. 40. What to Wash your Hands with.  Hands which are visibly soiled or potentially grossly contaminated.  Liquid soap and water  Dried thoroughly with a good quality paper towel.  Hands which are contaminated.  Alcohol hand gel. Guidelines for Infection Control in Dental Health Care Settings Sharon K. Dickinson, CDA, CDPMA, RDA; Richard D. Bebermeyer, DDS, MBA 40
  41. 41. Alcohol Hand rubs  Quick, easy and convenient method to rapidly disinfect physically clean hands.  Decontaminate hands where hand-washing facilities do not exist or are inappropriate.  The disinfectant used is alcohol also include a moisturiser. 41
  42. 42. Hand Hygiene HANDWASHING IS THE SINGLE MOST IMPORTANT MEASURE FOR PREVENTING INFECTION. Less frequently missed Least frequently missed Most frequently missed 42
  43. 43. 43
  44. 44. Sequence for Donning PPE gown mask Goggles or face shield glove s 44
  45. 45. Protective Clothing- gown Protective garments are worn over street clothes to protect them from contamination. Wear protective clothing that covers persona wear long sleeved gown Gowns are to be changed between every patient. 45
  46. 46. Protective clothing can include: reusable or disposable gown, laboratory coat, or uniform. Material may be natural or man made. Clean or starile. 46
  47. 47. How to put a Gown? first select the appropriate type for the task and the right size for you. . The opening of the gown should be in the back. secure the gown at the neck and waist 47
  48. 48. Mask: The provide protection to nose and mouth from likely splashes and sprays of blood or body fluids. Splashes and spray can be generated from a client’s behavior (e.g. coughing or sneezing) or during procedures (e.g. suctioning, irrigation or cleaning equipment). 48
  49. 49. Place over nose , mouth and chin . Fit flexible nose piece over nose bridge Secure on head with ties or elastic Adjust to fit. 49
  50. 50. Gloves: For protection of personnel and patients in dental care setting , medical gloves always must be worn by dental health care workers when there is potential for contacting blood, blood contaminated saliva, or mucous membrane. 50
  51. 51. Gloves Purpose – patient care, environmental services, other Glove material – vinyl, latex, nitrile, other Sterile or non-sterile One or two pair Single use or reusable 51
  52. 52. The American Dental Association has condemned the reuse of gloves, because this practice results in defect in the glove material, which will diminished its value as an effective barrier, and adequate removal of previous patient pathogen cannot be uniformly guaranteed. 52
  53. 53. Do’s and Don’ts of Glove Use Wear patient-care gloves when a potential exists for contacting blood, saliva, other potentially infectious materials, or mucous membranes. Wear a new pair of patient-care gloves for each patient. Ensure that appropriate gloves in the correct sizes are readily accessible 53
  54. 54. Do’s and Don’ts of Glove Use (cont’d) Change gloves During use if torn and when heavily soiled (even during use on the same patient) After use on each patient Discard in appropriate receptacle Never wash or reuse disposable glove. 54
  55. 55. 55
  56. 56. Protective eyewear In dentistry two type of product generally available goggles or eye shields and face shields 56
  57. 57. How to Don Eye and Face Protection Position goggles over eyes and secure to the head using the ear pieces or headband. Position of face shield over the face and secure on brow with handle band adjust to fit comfortably 57
  58. 58. Sequence for removing PPE gown mask Goggles or face shield gloves 58
  59. 59. How to Remove Gloves (1) Using one gloved hand, grasp the outside of the opposite glove near the wrist. Pull and peel the glove away from the hand. 59
  60. 60. How to Remove Gloves (2)Slide one or two fingers of the ungloved hand under the wrist of the remaining glove. Peel glove off from the inside, creating a bag for both gloves. Discard in waste container. 60
  61. 61. Remove Goggles or Face Shield Using ungloved hands, grasp the “clean” ear or head pieces and lift away from face. If reusable, place them in a designated receptacle for subsequent reprocessing. Otherwise, discard. 61
  62. 62. Removing Isolation Gown Unfasten ties. Peel gown away from neck and shoulder. Turn contaminated outside toward the inside. Fold or roll into a bundle. Discard. 62
  63. 63. Removing a Mask Untie the bottom, then top, tie Remove from face Discard PPE Use in Healthcare Settings 63
  64. 64. Immunization procedure The dental health care workers are at a greater risk than the general population, of acuquiring hepatitis B and AIDS through contact with patient. 64
  65. 65. Immunization procedure available to dental health care workers. 65
  66. 66. Serum hepatitis vaccine Recombivax (by merck) and Engerix-B (Smithklin Beecham) for hepatitis B are used. Vaccine is given in three separte doses. 2nd dose is given after month of first dose and third dose is given after six month of first dose. The vaccine offers immunity for at least 7 years. However some authorities in the uk have suggested that a booster dose may be required after 5-7 years. Infection control in dental practice s revised edition 2006 s.Anil, Georges kryier 66
  67. 67. Prevent environmental contamination All procedures and manipulation of potentially infective materials should be performed carefully to minimize droplates, splatters and aerosols 67
  68. 68. Use of sharp instruments and needlesAll sharp instrument should be disposed of in designated puncture- resistant containers. Orthodontics wire and bands also considered sharps, and disposed off accordingly. Unsheathed needles should not remain on the instrument tray or in operating. 68
  69. 69. 69
  70. 70. Clinical operating area Special designated plastic are used to cover the chair and unit Changes the bag after each patient 70
  71. 71. Handling biopsy specimens Should put in sturdy containers with with sacure lid to prevent leaking during transportation. 71
  72. 72. prosthodontic Dentist or dental assistant prepares a potentially infectious impression for by rinsing the impression and placing it in a biohazard labeled plastic bag without contaminating the bag’s outer surface. 72
  73. 73. Dental radiograph The staff working in radiology department usually, is not aware of the medical history . Hence ,it is essential to take certain precaution 73
  74. 74. Waste disposal in health care settingWho classification of waste is follows: General nonhazardous Sharps Chemical and pharmaceutical Infectious Other hazardous medical wastes. 74
  75. 75. Aims of Waste Treatment: Disinfection Reduction in the bulk volume Making surgical waste unrecognizable Rendition of the dangerous recyclable itams unusable 75
  76. 76. 76
  77. 77. 77
  78. 78. Other precaution Use of antimicrobial mouth rinse. Rubber dam isolation Minimizing dental aerosols and splatter Minimize biofilm formation in water line. 78
  79. 79. Needle stick injuryMeasure for prevention: Ensuring that the needle is covered, when not in use. Keeping full control and concentration while handling. Used needle should never be recapped utilizing both hand. 79
  80. 80. An uncapped needle or syringe should not be passed from assistant to surgeon. Needle should not be purposely bent or broken by hand. Needle can safely re-capped by help of forceps to grasp the cap. 80
  81. 81. Risk of HBV, HCV and HIV Transmission after Occupational Per-cutaneous Exposure HBV risk varies depending on e-antigen status of source person – If e-antigen positive, risk is up to 30% – If e-antigen negative, risk is 1-6% • HCV risk is 1.8% • HIV risk is 0.3% Elise M. BELtrami Risk and Management of Blood-Borne Infections in Health Care Workers Clin Microbiol Rev. Jul 2000; 13(3): 385–407. 81
  82. 82. Post-accidental management: Remove the gloves Wash the site with running water and soap Inform the patient about the incident To take blood specimens of both 82
  83. 83. If the patient is known or suspected HBV carrier. prophylactic Clinician never had vaccination HBIG withi 48 hr. Course of HB vaccination Clinician have been vaccinated If Ab titre is more then 100 IU/L Within the previous yr. No further action Low Ab titer Booster dose 83
  84. 84. Presently, there is no prophylaxis for HCV. Monitoring the liver function and testing for anti-HCV antibody. May respond favourably, is treated at the earliest sign of infection with IF-a 84
  85. 85. In case ,the patient is seropsitive, has AIDS or refuses the test. Evaluated clinically and serologically. Advice to report if any febrile illness that may occur within 12 week. The HIV test should then be repeated approximately 6 to 12 weeks after contamination and on a periodic basis if seronegative . 85
  86. 86. Type Drugs regimen Basic (28 days) Zidovudine + lamivudine 600 mg/day (300 mg bid, 200 mg or 100 mg 4 hourly) + 150 mg Expanded (28 days) As above + indinavire or Nelfinavir or neviriapine 800 mg 8hourly, 750 mg tid, or 200 mg bid HIV post exposure chemoprophylaxis for health worker Textbook of oral and maxillofacial surgery second edition by NEElima Anil Malik 86
  87. 87. Title Occupationally Acquired Human Immunodeficiency Virus (HIV) Infection: National Case Surveillance Data During 20 Years of the HIV Epidemic in the United States Author Ann N. Do , MD; Carol A. Ciesielski , MD; Russ P. Metler , JD, MSPH; Teresa A. Hammett , MPH; Jianmin Li , DPE, MEd; Patricia L. Fleming , PhD Journal Infection Control and Hospital Epidemiolog Vol. 24, No. 2 (February 2003) (pp. 86-96). Level of evidence III Objectives: To characterize occupationally acquired human immunodeficiency virus (HIV) infection detected through case surveillance efforts in the United States. Materials and Methods Review of data reported through December 2001 in the HIV/AIDS Reporting System and the National Surveillance for Occupationally Acquired HIV Infection. 87
  88. 88. Result Of 57 healthcare workers with occupationally acquired HIV infection, most (86%) were exposed to blood, and most (88%) had percutaneous injuries. The circumstances varied among 51 percutaneous injuries, with the largest proportion (41%) occurring after a procedure, 35% occurring during a procedure, and 20% occurring during disposal of sharp objects. Unexpected circumstances difficult to anticipate during or after procedures accounted for 20% of all injuries. Of 55 known source patients, most (69%) had acquired immunodeficiency syndrome (AIDS) at the time of occupational exposure, but some (11%) had asymptomatic HIV infection. Eight (14%) of the healthcare workers were infected despite receiving postexposure prophylaxis (PEP). . conclusion Prevention strategies for occupationally acquired HIV infection should continue to emphasize avoiding blood exposures. Healthcare workers should be educated about both the benefits and the limitations of PEP, which does not always prevent HIV infection following an exposure. Technologic advances (eg, safety‐engineered devices) may further enhance safety in the healthcare workplace. 88
  89. 89. Conclusion The most of postoperative infections result from the faulty surgical technique, inadequate asepsis and disinfection. The success of prevention and control of infection in healthcare areas is largely dependent on the aseptic technique of all personnel, who perform the invasive procedures, the sterility of all items directly concerned in such procedure and the disinfection of all surface. 89
  90. 90. Bibliography 1. Infection control in dental practice s revised edition 2006 S.Anil, Georges kryier 2. Textbook of oral and maxillofacial surgery second edition by Neelima Anil Malik 3. EID Journel Volume 7, Number 2—April 2001 Author affiliation: Centers for Disease Control and Prevention, Atlanta GA, USA 4. Essential of preventive and community dentistry 4th edition soben peter 5. Occupational safety and health administration: blood born pathogen 90
  91. 91. 6. Guidelines for Infection Control in Dental Health Care Settings , Sharon K. Dickinson, CDA, CDPMA, RDA; Richard D. Bebermeyer, DDS, MBA 7. Text book of pediatric dentistry third edition Nikhil Marwah 8. Journal ofInfection Control and Hospital Epidemiolog Vol. 24, No. 2 (February 2003) (pp. 86- 96).Ann N. Do , MD; Carol A. Ciesielski , MD; Russ P. Metler , JD, MSPH; Teresa A. Hammett , MPH; Jianmin Li , DPE, MEd; Patricia L. Fleming , PhD 91
  92. 92. Thank you 92
  93. 93. Dr. Akash Ardeshana 1st MDS Paedodontics and preventive dentistry 93
  94. 94. • application of standard precautions rather than universal precautions; • work restrictions for health-care personnel (HCP) infected with or occupationally exposed to infectious diseases; • management of occupational exposures to bloodborne pathogens, including postexposure prophylaxis. • Selection and use of devices with features designed to prevent sharps injury; • hand-hygiene products and surgical hand antisepsis; • contact dermatitis and latex hypersensitivity; • sterilization of unwrapped instruments; CDC Guidelines for Infection Control in Dental Health-Care Settings --- 2003 94
  95. 95. • dental water-quality concerns • dental radiology; • aseptic technique for parenteral medications; • preprocedural mouth rinsing for patients; • oral surgical procedures; • laser/electrosurgery plumes; • tuberculosis (TB); • Creutzfeldt-Jakob disease (CJD) and other prion-related diseases; • infection-control program evaluation; and • research considerations. 95
  96. 96. contents Introduction and history Definition of various terminology A rational approach to disinfection and sterilization Changes in Disinfection and Sterilization Principles of sterilization Factors that affect the efficacy of disinfection and sterilization 96
  97. 97. Method of sterilization Sterilization control Operation room procedure. Decontamination cycle Conclusion bibliography 97
  98. 98. introduction Microorganism are ubiquitous . Since they cause contamination, infection and decay, it becomes necessary to remove or destroy them from material or from areas. The process of sterilization is used to prevent contamination by extraneous organisms. The method of sterilization employed depend on the purpose for which it is carried out 98
  99. 99. B A C K G R O U N D 99
  100. 100. Definition of various terminology Sterilization: Sterilization describes a process that destroys or eliminates all forms of microbial life and is carried out in health-care facilities by physical or chemical methods . Disinfection: Disinfection describes a process that eliminates many or all pathogenic microorganisms, except bacterial spores, on inanimate objects 100
  101. 101. Cleaning: Cleaning is the removal of visible soil (e.g., organic and inorganic material) from objects . Asepsis is the state of being free from disease-causing contaminants (such as bacteria, viruses, fungi, and parasites) or, preventing contact with microorganisms. Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008 William A. Rutala, Ph.D., M.P.H.1,2, David J. Weber, M.D., M.P.H.1,2, 101
  102. 102. A RATIONAL APPROACH TO DISINFECTION AND STERILIZATION More than 30 years ago, Earle H. Spaulding devised a rational approach to disinfection and sterilization of patient-care items and equipment. This classification scheme is so clear and logical that it has been retained, refined, and successfully used by infection control professionals and others when planning methods for disinfection or sterilization. Spaulding believed the nature of disinfection could be understood readily if instruments and items for patient care were categorized as critical, semicritical, and noncritical according to the degree of risk for infection involved in use of the items. 102
  103. 103. Critical Items Critical items confer a high risk for infection if they are contaminated with any microorganism. This category includes surgical instruments, scaling instruments, surgical burs, implants. sterilized with steam if possible. Heat-sensitive objects can be treated with EtO, hydrogen peroxide gas plasma. if other methods are unsuitable, sterilized by liquid chemical sterilants. 103
  104. 104. Semi-critical Items Sem-icritical items contact mucous membranes or nonintact skin . E.g Mirrors, Plastic instruments, amalgam condensers Semicritical items minimally require high-level disinfection using chemical disinfectant . 104
  105. 105. Noncritical Items Noncritical items are those that come in contact with intact skin but not mucous membranes. E.g. , blood pressure cuffs, , stethoscope . 105
  106. 106. Changes in Disinfection and Sterilization Since 1981 First, formaldehyde-alcohol has been deleted as a recommended chemical sterilant or high-level disinfectant . Second, several new chemical sterilants have been added, including hydrogen peroxide, peracetic acid, peracetic acid and hydrogen peroxide in combination. Third, 3% phenolics and iodophors have been deleted as high-level disinfectants. 106
  107. 107. Fourth, isopropyl alcohol and ethyl alcohol have been excluded as high-level disinfectants . Fifth, a 1:16 dilution of 2.0% glutaraldehyde-7.05% phenol- 1.20% sodium phenate has been deleted as a high-level disinfectant. Sixth, the exposure time required to achieve high-level disinfection has been changed from 10-30 minutes to 12 minutes or more . Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008 William A. Rutala, Ph.D., M.P.H.1,2, David J. Weber, M.D., M.P.H.1,2, 107
  108. 108. Principles of sterilization All used instrument should thoroughly cleaned. The sterilizing agent to be contact with every surface of each item. All sterilizing equipment must be regularly serviced and maintained. Follow the manufacturer’s instruction. 108
  109. 109. Factors that affect the efficacy of disinfection and sterilization Types of organisms Number of organisms Concentration of disinfecting agent Presence of organic material (e.g., serum, blood) Nature (composition) of surface to be disinfected Contact time Temperature pH Biofilms 109
  110. 110. Russell AD. Bacterial resistance to disinfectants: present knowledge and future problems. J. Hosp. Infect. 1998;43:S57-68. 110
  111. 111. Number of organisms Microbial load-the total number of organisms which determine the exposure time of killing agent not all organisms die at the same time higher numbers of organisms require longer exposure 111
  112. 112. Concentration of disinfecting agent a proper concentration of disinfecting agents ensure the activation of target organisms, e.g., povidone-iodine should be dilluted with water before use because there is not enough free iodine to kill microorganisms in concentrated solution 112
  113. 113. Presence of organic material (such as blood, mucus, pus) affects killing activity by inactivating the disinfecting agent, e.g, by coating the surface to be treated, prevents full contact between object and agent (Glutaraldehyde) easily inactivate bleach (Sodium hypochlorite) For optimal killing activity, instruments and surfaces should be cleansed of excess organic material before disinfection !!! 113
  114. 114. Nature (composition) of surface to be disinfected some medical instruments are manufactured of biomaterials that exclude the use of certain disinfection and sterlization methods because of possible damage, e.g., endoscopic instruments cannot be sterilized by the heat in an autoclave 114
  115. 115. Contact time the amount of time a disinfectant or sterilant is in contact with the object is critical!e.g., Betadine(alcohol and iodine) must be in contact with object for at least 1 to 2 kill microorg. the spores of bacteria and fungi need a muchlonger time determine whether it is disinfecting or sterilizing the object. 115
  116. 116. Temperature Disinfectants are generally used at room temp. (20C-22) their activity is increased by an increased temp. and decreased by a drop in temp 116
  117. 117. Biofilms communities of microorganisms can be on a surface of either inanimate or animate objects, e.g., make disinfection more difficult the concentration of the disinfectant and the contact time need to be increased 117
  118. 118. pH An increase in pH improves the antimicrobial activity of some disinfectants (e.g., glutaraldehyde, quaternary ammonium compounds) but decreases the antimicrobial activity of others (e.g., phenols, hypochlorites, and iodine). The pH influences the antimicrobial activity by altering the disinfectant molecule or the cell surface 118
  119. 119. method of sterilization Physical method Chemical method 119
  120. 120. Physical methods 120
  121. 121. Sunlight Appreciable bactericidal activity Primary action due to ultraviolet rays Semple and greg studied that typhoid bacilli exposed to the sun on pieces of white cloth were killed in 2 hours whereas in dark they were alive after six days 121
  122. 122. Drying Moisture is esssential for growth of bacteria Drying in air has deletorius effect on some bacteria Unreliable method Spores are unaffected 122
  123. 123. Heat Most reliable method Method of choice unless contraindicated Factors influencing heat sterilization : 1. Nature of heat (Dry / Moist) 2. Temperature and time 3. Number of microorganisms 4. Characteristics of microorganisms 5. Type of material to be sterilize 123
  124. 124. Principles of different heat sterilizations Dry Heat Moist Heat Protein denaturation, oxidative damage and toxic effect of elevated levels of electrolytes Denaturation and coagulation of protein 124
  125. 125. Dry heat sterilization It involves heating air with transfer of heat energy from the air to the instrument. Alternative method particularly ,the sharp instrument. Advantage : the instrument do not rust, low cost Disadvantage: time consuming and high temperature require. 125
  126. 126. Hot air oven: For laboratory glassware , glass syringe and instrument. Kelsey (1969) reported that the long time require for sterilization , due to poor conduction of air and poor penetration by dry heat. Custer and coyle (1970) found that carbon steel instrument can loose their hardness because of dry heat. 126
  127. 127. Relation of temperature and time. C f TIME (MINUTE) 160 320 120 170 340 60 150 300 150 140 2050 180 127 Journal of American Dental Association Vol 122 December 1991
  128. 128. Spore testing should be done once a week to verify proper functioning of the sterilization with the help of bacillus atrophaeus strips. 128
  129. 129. Moist heat sterilization : autoclave Steam sterilization involves heating water to generate steam in closes chamber. Known for destruction of all forms of microorganism because high penetrating capacity and give up a large amount of latent heat. 129
  130. 130. Advantages The results are consistently good, and reliable The instrument can be wrapped prior to sterilization Time efficient Good penetration Disadvantages: Blunting and corrosion of sharp instrument Damage to certain rubber goods 130
  131. 131. Principle of Autoclave Large reduction in volume sucks inn more steam to the area This process continues till the temperature of that surface is raised to that of steam Steam (Condensed water) under pressure ensures killling of microbes present Temperature at which water boils also increases Saturated steam comes in contact with cooler surface Condenses to water and gives up latant heat to that surface When water boils when its vapour pressure is equal to surrounding atmosphere Pressure inside closed vessel increases 131
  132. 132. Autoclave Temperature and Time Pressure Chart Sterilizer temperature` Pressure time Unwrapped items 121 15psi 15 min 132 30psi 3 min Lighty wrapped 132 30psi 8 min Heavily wrapped 132 30psi 8 min Journal of American Dental Association Vol 122 December 1991 132
  133. 133. The two basic types of steam sterilizers (autoclaves) are the gravity displacement autoclave and the high-speed prevacuum sterilizer. 133
  134. 134. 134
  135. 135. The gravity displacement autoclaves are primarily used to process laboratory media, water, pharmaceutical products, regulated medical waste, and nonporous articles whose surfaces have direct steam contact. The advantage of using a vacuum pump is that there is nearly instantaneous steam penetration even into porous loads. The Bowie-Dick test is used to detect air leaks and inadequate air removal 135
  136. 136. To avoid minimize corrosive action of steam on metals, crawford and oldenburg (1967) recommended the addition of ammonia to the autoclave. Accepted dental therapeutics (1977) recommendeds use of dicyclohyxylammonium nitrate or cyclohexylamine and decylamine Bertlotti and hurts (1978) recommended 2 percent sodium nitrate. 136
  137. 137. Flash Sterilization Overview. “Flash” steam sterilization was originally defined by Underwood and Perkins as sterilization of an unwrapped object at 132C for 3 minutes at 27-28 lbs. of pressure in a gravity displacement sterilizer. Flash sterilization is a modification of conventional steam sterilization. 137
  138. 138. Uses. Flash sterilization is considered acceptable for processing cleaned patient-care items that cannot be packaged, sterilized, and stored before use 138
  139. 139. Glass beads sterilization: This method employs a heat transfer device. The temperature achieved is of 220*c. Warm–up time of at least 20 minutes The media used are glass beads, molten metal or salt kept in a cup. Use for small instrument like endodontic files, burs, rotary instruments Sterilization time 10 sec. 139
  140. 140. Oliet et al (1958) reported that temperatures vary in different areas of sterilization. Grossman (1974) recommended the use of salt media. 140
  141. 141. low-temperature sterilization Ethylene oxide (ETO) (has been widely used as a low- temperature sterilant since the 1950s . Overview ETO is a colorless gas that is flammable and explosive. parameters (operational ranges) are: gas concentration (450 to 1200 mg/l); temperature (37 to 63oC); relative humidity (40 to 80%)(water molecules carry ETO to reactive sites); and exposure time (1 to 6 hours) Association for the Advancement of Medical Instrumentation. Ethylene oxide sterilization in health care facilities: Safety and effectiveness. AAMI. Arlington, VA, 1999. 141
  142. 142. 142 Mode of Action. The microbicidal activity of ETO is considered to be the result of alkylation of protein, DNA, and RNA. ETO inactivates all microorganisms although bacterial spores (especially B. atrophaeus) are more resistant than other microorganisms. For this reason B. atrophaeus is the recommended biological indicator. Uses. ETO is used in healthcare facilities to sterilize critical items (and sometimes semicritical items) that are moisture or heat sensitive and cannot be sterilized by steam sterilization.
  143. 143. Hydrogen Peroxide Gas Plasma Overview. New sterilization technology based on plasma was patented in 1987 and marketed in the United States in 1993. 143
  144. 144. Mode of Action This process inactivates microorganisms primarily by the combined use of hydrogen peroxide gas and the generation of free radicals (hydroxyl and hydroproxyl free radicals) during the plasma phase of the cycle. Uses : Materials and devices that cannot tolerate high temperatures and humidity, such as some plastics, electrical devices, and corrosion-susceptible metal alloys, can be sterilized by hydrogen peroxide gas plasma 144
  145. 145. Irradiation: Ionizing radiation Non ionizing radiation 145
  146. 146. Ionizindiation: Include x-ray , gamma rays, and high speed electron. It is effective for heat labile items. Bellamy(1959) it has greater penetration properties. The lethal action is due to effect on the DNA of nucleus and on the other vital cell compound. commonly used by industry to sterilize disposable material. 146
  147. 147. Non-ionizing radiation Ultraviolet Radiation (UV) The wavelength of UV radiation ranges from 328 nm to 210 nm. Its maximum bactericidal effect occurs at 240–280 nm. Inactivation of microorganisms results from destruction of nucleic acid through induction of thymine dimers. Use: operating rooms, isolation rooms, and biologic safety cabinets. 147
  148. 148. 148
  149. 149. Infrared: Another form of dry heat sterilization Most commonly use to purify air, such as in the operating room 149
  150. 150. Boiling water Boiling water produces a temperature of 100 c at normal atmospheric pressure. It require 10 minutes exposure to this temperature, to kill many bacteria and some viruses. However , prolonged time of 24 hr is require to kill bacterial spores, and even this prolong time will not kill many viruses. 150
  151. 151. STERILIZATION CONTROL To ensure that potentially infectious agents are destroyed by adequate sterilisation regimes Three levels: physical: measuring device control (temp., time, pressure) chemical: substances that undergo a colour change or have melting points within the sterilizing range -Browne's tubes, Bowie Dick tape -give an immediate indication of a successful or non- successful sterilization 151
  152. 152. Browne's tubes are glass tubes that contain heat sensitive dyes. These change colour after sufficient time at the desired temperature. Before heat exposure, the contents of the tube appear red. As heating progresses, the colour changes to green. Only when the tube is green sterilisation conditions can be considered adequate. 152
  153. 153. Bowie Dick tapeis applied to articles being autoclaved. Before heat exposure, the tape is uniformly buff in colour. After adequate heating, the tape develops dark brown stripes. The pack on the left has been properly sterilised; that on the right has not. Chemical indicator 153
  154. 154. biological: Bacillus stearothermophilus spores survives steam heat at 121ºC for 5 min. and is killed at 121ºC in 13 min. validate and determine the adequacy of steam or chemical vapor sterilisation Bacillus subtilisspores validate and determine the adequacy of ethylene oxide or dry heat sterilisation 154
  156. 156. Properties of an ideal disinfectant. Broad spectrum: should have a wide antimicrobial spectrum Fast acting: should produce a rapid kill Not affected by environmental factors: should be active in the presence of organic matter (e.g., blood, sputum, feces) and compatible with soaps, detergents, and other chemicals encountered in use Nontoxic: should not be harmful to the user or patient Surface compatibility: should not corrode instruments and metallic surfaces and should not cause the deterioration of cloth, rubber, plastics, and other materials Residual effect on treated surfaces: should leave an antimicrobial film on the treated surface Easy to use with clear label directions . 156
  157. 157. Odorless: should have a pleasant odor or no odor to facilitate its routine use Economical: should not be prohibitively high in cost Solubility: should be soluble in water Stability: should be stable in concentrate and use- dilution Cleaner: should have good cleaning properties Environmentally friendly: should not damage the environment on disposal 157
  158. 158. alcohol Overview. two water-soluble chemical compounds—ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria; they also are tuberculocidal, fungicidal, and virucidal but do not destroy bacterial spores. Their cidal activity drops sharply when diluted below 50% concentration, and the optimum bactericidal concentration is 60%–90% solutions in water. 158
  159. 159. Mode of Action The most feasible explanation for the antimicrobial action of alcohol is denaturation of proteins. Microbicidal activity: Ethyl alcohol, at concentrations of 60%– 80%, is a potent virucidal agent. Isopropyl alcohol (20%) is effective in killing the cysts of Acanthamoeba culbertsoni. 159
  160. 160. Phenols Used as Disinfectant Used by Joseph Lister in form of carbolic acid High concentration phenolic compounds Acts as a protoplasmic poisons Precipitate Protein Destroy cellwall 160
  161. 161. Lipophillic virus are susceptible Spores are resistant Two or more synthetic phenols in combination Action against hydrophilic viruses Accepted by ADA for surface disinfectant on precleaned surfaces 161
  162. 162. Aldehydes formaldehyde ( HCHO)the most imporatant is a water- soluble gas -formalin (35% solution of this gas in water) or glutaraldehyde (disinfectant and sterilizer!!!) denaturat proteins and nucleic acids irritate mucosa, skin contact may result inflamations or allergic eczemas broad-sepctrum: againts bacteria, fungi, and viruses chemosterilizerin higher concetrations (sporicidial) Application: -disinfectionof surfaces and objects (plastic and rubber items) sterilizerof choice for heat-sensitive medical equipment 162
  163. 163. A 2 percent glutaraldehyde (cidex) require immersion of 20 minutes for disinfection. Stonehill et al (1963) reported that cidex kills vegetative bacteria , spores, fungi and virus by alkylation on a 10 hr contact. 163
  164. 164. Chloride compound: Overview. Hypochlorites, the most widely used of the chlorine disinfectants, are available as liquid (e.g., sodium hypochlorite) or solid (e.g., calcium hypochlorite). The most prevalent chlorine 5.25%–6.15% sodium hypochlorite is used. 164
  165. 165. They have a broad spectrum of antimicrobial activity, do not leave toxic residues, unaffected by water hardness, a inexpensive and fast acting, remove dried or fixed organisms and biofilms from surfaces. 165
  166. 166. Hydrogen peroxide: Hydrogen peroxide works by producing destructive hydroxyl free radicals that can attack membrane lipids, DNA, and other essential cell components. A 0.5% accelerated hydrogen peroxide demonstrated bactericidal and virucidal activity in 1 minute and mycobactericidal and fungicidal activity in 5 minutes . Commercially available 3% hydrogen peroxide is a stable and effective disinfectant 166
  167. 167. Iodophors Iodine solutions or tinctures long have been used by health professionals primarily as antiseptics on skin or tissue . Iodine can penetrate the cell wall of microorganisms quickly, and the lethal effects are believed to result from disruption of protein and nucleic acid structure and synthesis. iodophors are bactericidal, mycobactericidal, and virucidal but can require prolonged contact times to kill certain fungi and bacterial spores 167
  168. 168. Operating room procedure Through cleaning of the floor. Cleaning of the wall with hand compression sprayer. 168
  169. 169. Fumigation is initiated after setting up of instrument (steri trax) in place The chemical used is 40 % formalin for 30 minutes. About 180 ml is used for a room of the size 1000 cubic feet. 169
  170. 170. Parameters Optimal level 1 Relative humidity Over 70% 2 Temperature 30-40 C 3 Formaldehyde levels 5 ppm or more Parameter and the optimum levels for effective fumigation 170
  171. 171. Masks Eye protection hair/bread cover Footwear Antiseptic enviroment Hand scrub and hand disinfection Preparation of surgical site 171
  172. 172. Decontamination cycle 172
  173. 173. Cleaning Disinfection Inspection manual ultrasonic 173
  174. 174. Packing Sterilization Storage use 174
  175. 175. Recommended sterilization procedures for commonly used dental instruments / equipments 175
  176. 176. 176Infection control in dental practice revised edition2006 S.anil Georges krygier
  177. 177. 177Infection control in dental practice revised edition2006 S.anil Georges krygier
  178. 178. Title Knowledge and attitude of general dentists of Ahwaz about disinfection of dental impressions Author Raju, T. B. V. G.1 Garapati, Satish2Agrawal, Rupika3Reddy, Sridhara4Razdan, Ankur5 Kumar, S. Kishore6 Level of evidence journal Journal of International Oral Health. Nov/Dec2013, Vol. 5 Issue 6, p108-112. 5p. 4 Color Photographs, 1 Chart, 1 Graph. aim Aim of the study was to compare 4 different methods of sterilizing endodontic files in dental practice. Methods and material The present study was performed on 100 K-files, 21 mm long and of size 25. Of these, 20 files were taken as control group, and the remaining 80 files were divided into 4 groups of 20 files each and they were tested for the efficacy of sterilization with different methods: Autoclave, glass bead, glutaraldehyde and CO2 laser Results The study showed that the files sterilized by autoclave and lasers were completely sterile. Those sterilized by glass bead were 90% sterile and those with glutaraldehyde were 80% sterile conclusion The study concluded that autoclave or laser could be used as a method of sterilization in clinical practice and in advanced clinics; laser can be used also as a chair side method of sterilization 178
  179. 179. Title Knowledge and attitude of general dentists of Ahwaz about disinfection of dental impressions Author Lavaf, Shirin Azizi, Arash1 Shantia, Maryam Level of evidence journal Journal of Isfahan Dental School. 2013, Vol. 8 Issue 7, p676-683. 8p. aim The aim of this study was to evaluate the knowledge and attitudes of dentists about disinfection of dental impressions Methods and material In this descriptive study 93 general dentists were randomly selected in Ahvaz in 2010. To collect data, a questionnaire which included demographic data and 15 questions about knowledge and 14 questions about attitude was prepared. Results The results of this study showed that the majority of dentists in Ahwaz have good attitude toward disinfection and the related equipment but they have poor knowledge about the use of disinfecting agents, necessitating continuous educational programs in this respect 179
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  182. 182. conclsion When properly used, disinfection and sterilization can ensure the safe use of invasive and non-invasive medical devices. However, current disinfection and sterilization guidelines must be strictly followed. 182
  183. 183. Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008 William A. Rutala, Ph.D., M.P.H.1,2, David J. Weber, M.D., M.P.H.1,2, 183
  184. 184. 1. Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008 William A. Rutala, Ph.D., M.P.H.1,2, David J. Weber, M.D., M.P.H.1,2, 2. Infection control in dental practice revised edition2006 S.anil Georges krygier. 3. Text book of microbilogy 8th edition ananthnarayan 4. Text book of oral and maxillofacial surgery 2nd edition Neelima MaliK 5. Text book of pediatric dentistry third edition Nekhil Marwah. 184
  185. 185. 6. 7. Association for the Advancement of Medical Instrumentation. Ethylene oxide sterilization in health care facilities: Safety and effectiveness. AAMI. Arlington, VA, 1999. 8. Journal of American Dental Association Vol 122 December 1991 9. Russell AD. Bacterial resistance to disinfectants: present knowledge and future problems. J. Hosp. Infect. 1998;43:S57-68. 185
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