Infection control

• What are the main methods of disinfection?

  Heat, physical methods, chemical methods
• What is pasteurization and its purpose?

  • Not a sterilization process
  • Applied to milk to delay souring
  • Raises milk temperature to 63-66˚ C for 30 min or 72˚ C for 15 s
  • Renders milk safe from Mycobacteria and Campylobacter
• Why is boiling water inadequate for sterilization of dental instruments?

  Short boiling periods allow bacterial spores to survive
• How do ultrasonics aid in disinfection?

  • Disrupt microbial cell membranes
  • Used for removing debris before autoclaving
  • Removes soil by cavitation
  • Enhances disinfectant efficacy when combined with chemicals
• What is UVGI used for in medical settings?

  To destroy airborne microorganisms
• What is a disadvantage of UVGI?

  Not all microbes can survive UVGI
• What are the three modes of action of chemical disinfectants?

  1. Membrane-active: damage cell membrane
  2. Fixation: block escape of cellular components
  3. Oxidizing agents: oxidize cellular constituents
• What is an example of a membrane-active disinfectant?

  Chlorhexidine
• What is an example of an oxidizing agent used as a disinfectant?

  Hypochlorite
• What are the properties of an ideal disinfectant?

  • Broad spectrum
  • Fast acting
  • Not affected by environmental factors
  • Nontoxic
  • Surface compatibility
  • Residual effect
  • Easy to use
  • Odorless
  • Economical
  • Solubility
  • Stability
  • Cleaner
  • Environmentally friendly
• What defines high-level disinfectants?

  Active against Gram-positive and Gram-negative bacteria
• What is the difference between intermediate-level and low-level disinfectants?

  Intermediate-level destroys M. tuberculosis, low-level does not
• How should critical, semi-critical, and non-critical items be processed?

  • Critical: Sterilization (e.g., surgical instruments)
  • Semi-Critical: Sterilization or high-level disinfection (e.g., dental handpieces)
  • Non-Critical: Low to intermediate-level disinfection (e.g., stethoscope)
• What is the main use of alcohols in dentistry?

  Skin antisepsis prior to procedures
• What is a disadvantage of using alcohols as disinfectants?

  Flammable and limited sporicidal activity
• What is glutaraldehyde used for in dentistry?

  High-level disinfection of equipment
• What happens to glutaraldehyde's activity when pH decreases?

  Its activity declines while stability increases
• What are the characteristics of halogen compounds as disinfectants?

  • Oxidizing agents releasing halide ions
  • Cheap and effective
  • Corrode metal and inactivated by organic matter
• What are the properties of phenolic disinfectants?

  • Clear, soluble fluids
  • Kill most bacteria
  • Not easily degraded by organic material
  • Poorly virucidal and sporicidal
• What personal protective equipment (PPE) is recommended in dental settings?

  • Clothes
  • Gloves
  • Facemask
  • Protective eyewear
  • Goggles
  • Face shields
• What is the minimum filtration efficiency for facemasks in dental settings?

  At least 95% for particles 3.0-5.0 μm
• What is the routine disinfection process for clinical contact surfaces?

  • Clean surfaces contaminated by patient materials
  • Examples: light handles, dental radiograph equipment
• What is the proper disinfection process for dental impressions?

  1. Clean blood and saliva from impressions
  2. Remove excess impression material
  3. Use proprietary disinfectants for decontamination
  4. Wrap and place in plastic bags for transport