Sterilization in dentistry 2
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Sterilization in dentistry 2






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Sterilization in dentistry 2 Sterilization in dentistry 2 Presentation Transcript

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  • Sterilization in Dentistry Presented by;M. Humayun Afridi Assisted By; Taif Ahmad And Saqib Habib Khyber College Of Dentistry Peshawar 2
  • OBJECTIVE  At the end of the presentation the 2nd year BDS students will know all about the sterilization. 4
  • Contents Definition  Introduction  Need of sterilization  Classification of Instruments  Methods of sterilization  Sterilization monitoring  5
  • What is Sterilization?  DEFINITION “Sterilization is the process by which all forms of microbial life from surface,medium and instruments are destroyed by various physical and chemical methods” 6
  • Sterilization in Dentistry Sterilization procedures are very important to any good dental practice  Patients mouth are teeming with microbes.  As Dental unit come across large number of patients , an inherent potential for spreading infectious germs between patients and dental staff, through contaminated instruments and surfaces.  7
  • Why we need Sterilization? Microorganisms capable of causing infection are constantly present in the external environment and on the human body.  Microorganisms are responsible for contamination and infection.  The aim of sterilization is to remove or destroy them from materials or from surfaces.  8
  • How sterilization destroys microbes? Alteration of cell wall or cytoplasmic membrane;  Cell wall maintains the integrity of cell. a)  When disrupted cannot prevent cell from bursting and cellular contents leak out. 9
  • b) Protein denaturing  Functions of protein depends on its specific 3-D shape.  Various sterilization methods denature proteins and as a result 3-D shape and their functions are lost. 10
  • c) Interference with Nucleic Acid  Nucleic Acid is considered as controlling centre of the cell.  Various methods of sterilization methods can I. II. Produce mutation, Interfere the process of transcription. 11
  • Sterilization of Dental Instruments  Spaulding in 1968, classify dental instruments into three categories depending on the risk of transmitting infection. Critical  Semi critical  Non critical  12
  • CRITICAL INSTRUMENTS Critical instruments are those that penetrate soft tissue, bone or blood stream.  They have the greatest risk of transmitting infection  They should be heat sterilized between patient uses.  Examples of critical instruments include surgical instruments,forceps, scal pels, scalers, and burs.  13
  •    SEMI CRITICAL INSTRUMENTS Semi-critical instruments are those that do not penetrate soft tissues or bone but contact mucous membranes These instruments should be sterilized or high-level disinfection is appropriate. Examples: Mirrors, reusable impression trays and amalgam condensers etc 14
  • NON CRITICAL INSTRUMENTS    Non-critical instruments are those that come in contact with intact skin. Risk of transmission of infection is minimum. Examples:X-ray heads,pulse oximeter,BP cuff ,dental chair etc. 15
  • Methods of Sterilization There are two types of sterilization: Microbial 1. Physical Control 2. Chemical Methods Physical Methods  Heat  Radiation Physical Chemical Agents Agents 17
  • Agents used in sterilization  Physical agents: Dry heat: flaming, Moist heat: boiling, steam under pressure. 2. Radiation 1. Chemical agents: 1. Phenols 2. Alcohols 3. Aldehydes 4. Gases: ethylene oxide, Formalde hyde gas, ozone……  18
  • Physical Agents Heat Dry Direct Flaming Radiation Moist Steam Under Pressure (autoclaving) Ionizing X Ray, Cathode, Gamma Non Ionizing UV 19
  • Dry Heat: “To sterilize Forceps, Scissor s, Scalpels.” • Direct Flaming: Used to sterilize inoculating loops and needles. Heat metal until it has a red glow. 20
  • MOIST HEAT  Moist heat is more effective than dry heat because water is good conductor of heat than air  Mode of action: Denaturing of protein  TYPES ◦ Boiling ◦ Steam under pressure(autoclaving) 21
  • AUTOCLAVING Invented by Charles Chamberland in 1879  Most economical method of sterilization  Time required at 121 C is 15 mins at 15 lbs of pressure  Main Components of autoclave: • Consists of vertical or horizontal cylinder of stainless steel  • Lid , pressure gauge and a safety valve. 22
  • ADVANTAGES 1. Short efficient cycle time. 2. Rapid and effective 3. Ability to process a wide range of materials 4.Good penetration 23
  • RADIATION  1. 2. There are mainly two types of Radiations used in dentistry. Ionizing radiation Non Ionizing radiation. 25
  • Ionizing radiations:  Ionizing radiation includes X-Rays and Gamma rays.  Cause mutations in DNA and produce peroxides.  These are commercially used for sterilization of disposable items. (cold sterilization). 26
  • Nonionizing radiation Non ionizing radiation includes  UV light and Infrared.  Affects 3-D structure of Proteins and nucleic acids.  Suitable for transparent fluids, and surfaces of objects.  27
  • CHEMICAL METHODS In Chemical methods of Sterilization we use various chemical agents that includes, 1) Phenolic compounds 2) Alcohols 3) Aldehydes 4) Gaseous sterilizers  28
  • 1. Phenols and Phenolics:  Phenol acts as protoplasmic poison, penetrates & disrupts cell wall and cause bacterial death by inactivation of essential enzyme systems.  Used for decontamination of hospital laboratory noncritical items. environment surfaces, medical & including & for surgical 29
  • 2. Alcohols:     Kill bacteria (bactericidal), fungi and viruses. Act by denaturing proteins and disrupting cell membranes. . Used as skin antiseptic to wipe microbes off skin before injections. Also used for disinfection of thermometer, probes and external surfaces of stethoscope. 30
  • 3. Aldehydes:     Inactivate proteins by forming covalent cross links with several functional groups. Commonly used aldehyde is FORMALIN (37% aqueous solution). used extensively to inactivate viruses & bacteria in vaccines. Also used to sterilize metal instruments. 31
  • 4. Gaseous Sterilizers: Denature proteins, by replacing functional groups with alkyl groups. Also reacts with DNA & RNA.  These includes 1) Ethylene Oxide 2) Formaldehyde gas 3) Ozone…….  32
  • Methods of Sterilization Heat Chemicals Sterilization Radiation Gases 33
  • STERILIZATION MONITORING  There are 3 methods of monitoring sterilization: Mechanical techniques  Chemical indicators  Biological indicators   These parameters evaluate both the sterilization conditions and procedure’s effectiveness 34
  •  MECHANICAL INDICATORS: Includes assessing cycle time,temperature and pressure by observing the displays on the sterlizers  CHEMICAL INDICATORS: They allow detection of equipment malfuctioning and help in identifying procedural errors  BIOLOGICAL INDICATORS: Most accepted for monitoring sterilization process 35
  • References Wikipedia  SS Hiremath  Google Images  Slide share  36
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