Infection Control in the Dental Office – Exam Review

Unit 1. Principles and Fundamentals of Infection Control

Unit 2. Sterilization and Disinfection

Chain of Infection

  • Transmission always requires all three links:

    • Causative agent (pathogen)

    • Susceptible host

    • Mode of transmission

  • If any one link is broken, the disease cannot spread.

  • PPE can eliminate (or greatly reduce) the mode of transmission.

Key Terms

  • Causative agent = micro-organism/pathogen that can cause disease.

  • Susceptible host = person whose immune system cannot resist the pathogen.

  • Mode of transmission = pathway by which the infectious agent spreads.

Immunization & Post-Exposure Management

  • CDC strongly recommends vaccination for: influenza, measles, mumps, rubella, chickenpox (varicella).

  • Every dental office should maintain written policies indicating which immunizations are required/recommended for team members.

Post-Exposure Protocol

  • Exposure routes: skin, eyes, mucous membranes, parenteral contact with blood/OPIM (other potentially infectious materials).

  • Essential steps:

    • Immediate post-exposure evaluation & follow-up.

    • Confidential written exposure report.

    • Report handled by a designated infection-control coordinator.

Standard Precautions (Universal Precautions)

  • Treat all blood & body fluids as if they are infectious.

  • Core element: proper use of Personal Protective Equipment (PPE).

Personal Protective Equipment (PPE)

Overview

  • Categories: protective eyewear/face shields, protective clothing, masks, gloves.

  • Purpose: shield skin & mucous membranes from blood/OPIM.

Protective Eyewear

  • Protects eyes & ocular mucosa from spatter.

  • Types: safety glasses, goggles, full face shield.

  • Cleaning: wash with soap & water when soiled.

Protective Clothing

  • Lab coats, jackets, gowns, aprons.

  • OSHA: long-sleeved gown required for procedures with potential spatter.

  • Scrubs/street clothes ≠ PPE.

Masks

  • Protect both wearer & patient.

  • Requirements:

    • Snug facial seal.

    • Change between patients.

    • Remove by strings; contaminated gloves must never touch face/hair.

    • Never hang a used mask around the neck.

Gloves

  • Worn for exams, treatment, clean-up, or touching contaminated surfaces.

  • Change & discard between patients.

  • Hand hygiene before donning & after removing.

  • If torn/punctured: remove, wash with antimicrobial soap, don new pair.

  • Utility gloves (puncture-resistant, reusable) for disinfection/clean-up only.

  • Latex allergy/contact dermatitis: supply non-latex alternatives.

Oral Surgery–Specific Measures

  • Pre-op antimicrobial handwash.

  • If glove tear occurs: remove → hand hygiene → reglove.

  • Use sterile surgical gloves; option to double-glove or add glove liners.

  • Water supply: employ sterile water delivery systems (single-use, disposable or autoclavable tubing) rather than standard dental unit water.

Cleaning, Disinfection & Sterilization – Core Definitions

  • Cleaning: physical removal of debris; lowers microbial load.

  • Disinfection: kills most micro-organisms but may not destroy bacterial endospores.

  • Sterilization: destroys all micro-organisms including bacterial endospores.

Instrument Classification

Category

Tissue Interaction

Examples

Post-Use Requirement

Critical

Penetrate soft tissue, contact bone, enter bloodstream/sterile sites

Scalers, surgical forceps, burs used in surgery

Discard or sterilize after each patient

Semi-critical

Contact mucosa or non-intact skin but do not penetrate tissue

Mouth mirrors, dental handpieces, amalgam condensers

If heat-stable → sterilize; if heat-sensitive → high-level disinfect

Non-critical

Contact intact skin only

BP cuffs, radiograph tube heads, facebows

Clean; disinfect with intermediate-level if visibly soiled or blood-contaminated

Sterilization Methods

1. Steam (Autoclave)

  • High-temperature steam under pressure.

  • Pros: economical, reliable, rapid, can sterilize bagged/wrapped instruments.

  • Cons: potential rust/corrosion, may dull sharps & damage plastics.

2. Dry Heat

  • For moisture-sensitive instruments (e.g., orthodontic pliers, burs).

  • Pros: inexpensive, no rust/corrosion.

  • Cons: long cycles, very high temperatures may damage items; loading time longer.

3. Unsaturated Chemical Vapor

  • Uses heated chemical solution (formaldehyde, alcohols) under pressure.

  • Pros: fast, reliable, non-corrosive, compatible with paper packaging.

  • Cons: can damage plastics, higher operating cost, poor penetration of heavy packages, requires ventilation, chemical waste disposal.

Instrument Processing Area (Four Zones)

1. Receiving/Cleaning/Decontamination
2. Preparation & Packaging
3. Sterilization
4. Storage

Zone Details

  • Cleaning (Zone 1)

    • Remove blood/saliva/tissue via hand scrubbing (with puncture-resistant gloves) or ultrasonic cleaner.

  • Preparation & Packaging (Zone 2)

    • Arrange instruments on preset trays or in pouches/wraps to keep items sterile after processing.

  • Sterilization (Zone 3)

    • Monitoring:

    • Mechanical (time-temperature gauges).

    • Chemical indicators (internal & external) each load.

    • Biological indicators (spore tests) per schedule/state law to verify microbial kill.

    • Failure in any monitor → re-sterilize before use.

  • Storage (Zone 4)

    • Store sterile items in clean, enclosed area.

    • Packages must remain dry & intact; if compromised → re-process.

Levels of Disinfection

Level

Tuberculocidal?

Sporicidal?

Typical Use

High

Yes

Not necessarily

Heat-sensitive semi-critical items

Intermediate

Yes (TB)

No

Surfaces visibly contaminated with blood/OPIM

Low

No (not TB)

No

General housekeeping, surfaces with no visible blood

  • Effectiveness depends on concentration & contact time → always follow manufacturer’s IFU.

Environmental Surfaces

Clinical Contact Surfaces

  • Frequently touched during care or splattered (countertops, light handles, X-ray controls).

  • Prefer barriers; if none used:

    • Intermediate-level disinfectant if visibly soiled or blood-contaminated.

    • Low-level disinfectant if no visible contamination.

Housekeeping Surfaces

  • Walls, floors, sinks, etc. — low infection risk.

  • Clean on regular schedule with detergent + water or low-level disinfectant.

  • Always wear appropriate PPE; mix fresh solutions daily.

Blood Spills

  • Decontaminate immediately with intermediate-level disinfectant; wear utility gloves & full PPE.

Waste Management

  • Non-regulated waste (majority): used gowns/masks, lightly soiled gauze, barriers → discard with regular office trash.

  • Regulated waste: items soaked/dripping with blood/OPIM, sharps, syringes, scalpel blades.

    • Follow OSHA & state rules for packaging, labeling, disposal.

  • Sharps: puncture-proof, leak-proof, biohazard-labeled containers.

  • Biopsy specimens: sealed, leak-proof, rigid container with secure lid; exterior disinfected if contaminated; biohazard label.

  • Disposal of liquid blood/OPIM into sanitary sewer → comply with local regulations.

Dental Unit Water Quality

  • Maintain ≤ 500 CFU/ml (colony-forming units per milliliter) as per CDC.

  • Strategies: independent water reservoirs, chemical treatments, in-line filters.

  • Flush waterlines 20–30 seconds after each patient.

Prostheses & Impressions

  • Rinse under running water → spray/immerse with intermediate-level disinfectant → record agent & exposure time on lab slip.

Chairside & Pretreatment Protocols

Before Patient Arrives

  • Remove unnecessary items from operatory.

  • Set up three-tray system (instruments, supplies, disposables) to avoid opening cabinets mid-procedure.

  • Decide barrier vs chemical disinfection plan for surfaces.

  • Prepare waterlines per manufacturer maintenance schedule.

  • Perform hand hygiene; don PPE.

During Patient Care

  • Follow neutral-zone or cassette system for passing sharps; avoid hand-to-hand transfer.

  • Keep sharp tips oriented away from clinicians.

  • Never recap needles with two hands (use one-hand scoop or engineered device).

Radiographic Infection Control

  • Barrier covers on tube head, exposure switch, sensor/film holders.

  • After exposure: wipe saliva/blood; place films in cup; in darkroom peel outer wrap, drop film onto clean surface.

  • Digital sensors: FDA-cleared barriers + intermediate-level disinfection between patients.

Summary – Key Takeaways

  • Break the chain of infection by controlling at least one link: agent, host, or transmission.

  • Adhere to CDC vaccination recommendations & maintain written office protocols.

  • Implement Standard Precautions at all times; PPE is mandatory.

  • Understand instrument categories (critical/semi-critical/non-critical) & process accordingly (clean → disinfect → sterilize).

  • Choose the appropriate sterilization method (steam, dry heat, chemical vapor) & verify with mechanical, chemical, and biological monitoring.

  • Use the four-zone processing area to prevent cross-contamination.

  • Match disinfectant level (high/intermediate/low) to the clinical scenario.

  • Manage environmental surfaces, water quality, and waste per CDC/OSHA/state regulations.

  • Maintain rigorous sharps safety and radiographic infection-control measures to protect both patients and the dental team.