Dental Infection Control and Sterilization

Infection Control and Sterilization in Dentistry

• Microorganisms can spread from one person to another through direct contact, indirect contact, droplet infection, and airborne infection.
• Cross-infection is the transmission of infectious agents among patients and staff within a clinical environment.

Rationale for Infection Control

• Microorganisms spread from one person to another through direct contact, indirect contact, droplet infection, and airborne infection.
• Cross-infection involves the transmission of infectious agents between patients and staff within a clinical setting.

Direct Contact

• Infectious agents spread through physical contact between the patient and dental healthcare provider (or instruments).
• Examples: skin-to-skin contact with oral lesions, blood exposure through open wounds.

Indirect Contact

• Contact with contaminated equipment and surfaces.
• Examples: using contaminated instruments, contacting contaminated surfaces, exposure to contaminated dental waterlines.

Droplet Infection

• Occurs due to large particle droplets that are transmitted through close contact.
• Spatter generated during dental procedures can transmit microorganisms to the dentist.

Objective of Infection Control

• The main objective is to eliminate or reduce the spread of infection from all types of microorganisms.
• Two key factors: preventing the spread of microorganisms from their hosts, and killing or removing microorganisms from objects and surfaces.

Universal Precautions

• Immunizations, such as hepatitis B vaccine, are important.
• Use of personal protective equipment (PPE) is essential, including gowns, face masks, protective eyewear, and gloves.
• Maintain hand hygiene.

Hand Hygiene

• For routine dental procedures, washing hands with plain, non-antimicrobial soap is sufficient.
• For invasive procedures, hand antisepsis using an antiseptic solution or alcohol-based handrub is necessary.
• Examples of hands-free equipment: foot-operated sink controls and sensor-operated towel dispensers

Definitions

• Cleaning: Physically removes contamination but does not destroy microorganisms. It's a prerequisite for disinfection or sterilization.
• Disinfection: Uses an agent to destroy or inactivate germs, but not necessarily spore or virus forms. Disinfectant is the chemical used for disinfection.
• Antisepsis: The destruction of pathogenic microorganisms on living tissue; antiseptic is the chemical used on living tissue.
• Sterilization: Any process, physical or chemical, that destroys all forms of life, including bacteria, fungi, spores, and viruses.

Methods of Sterilization

• Moist/steam heat sterilization (autoclave)
• Dry heat sterilization
• Chemical vapor pressure sterilization
• Ethylene oxide sterilization

Moist/Steam Heat Sterilization (Autoclave)

• Advantages: Time-efficient, good penetration, consistently good and reliable results, and instruments can be wrapped prior to sterilization.
• Disadvantages: Blunting and corrosion of sharp instruments, damage to rubber goods.

Dry Heat Sterilization

• Advantages: No corrosion of carbon-steel instruments (like excavators and burs), maintains sharpness of cutting instruments, and low cost of equipment.
• Disadvantages: Long cycle required, high temperature potentially damages some heat-sensitive items such as rubber or plastic goods (often not suitable for handpieces).

Chemical Vapor Pressure Sterilization

• Advantages: Carbon steel instruments and burs/instruments/pliers can be sterilized without rust or corrosion.
• Disadvantages: Items sensitive to elevated temperatures may be damaged. Instruments must be lightly packed.

Classification of Dental Instruments

• Critical instruments: penetrate mucous membranes, bone, or bloodstream. Sterilized between uses or use disposable versions. Examples: surgical instruments, scalpels, and some dental hand-scalers
• Semi-critical instruments: contact mucous membranes but do not penetrate soft tissue. Heat sterilization or high-level disinfection (e.g., with glutaraldehyde or ortho-phthalaldehyde). Examples: dental mouth mirrors, amalgam condensers, and some handpieces.
• Non-critical instruments: contact intact skin. Clean and disinfect with a low-to-intermediate-level disinfectant. Examples: x-ray heads, facebows, pulse oximeters, and blood pressure cuffs.

Disinfection of Dental Unit and Environmental Surfaces

• Dental Units: cleaned by disposable toweling, using an EPA-registered hospital disinfectant (e.g., phenolics, iodophores, chlorine-containing agents).
• Clinical Contact Surfaces: cleaned with soap and water or an EPA-registered detergent/hospital disinfectant.
• Housekeeping Surfaces: cleaned with soap and water or an EPA-registered detergent/hospital disinfectant, and mops/cloths are cleaned and dried before reuse. Fresh cleaning/disinfecting solutions are prepared daily.

Learn about infection control in dentistry, including direct and indirect contact transmission. Understand cross-infection risks between patients and staff. Learn more about microorganisms and maintaining a sterile dental environment.