OSHA and Infection Control in Dental Settings

Core Review

Regulatory Framework

Infection control in dental settings is governed by several overlapping authorities:

• OSHA (Occupational Safety and Health Administration): Enforces workplace safety standards including the Bloodborne Pathogens Standard and Hazard Communication Standard. OSHA protects EMPLOYEES.
• CDC (Centers for Disease Control and Prevention): Publishes evidence-based guidelines for infection prevention in dental settings. The CDC makes RECOMMENDATIONS; OSHA makes REGULATIONS.
• EPA (Environmental Protection Agency): Regulates surface disinfectants and medical waste disposal.
• FDA (Food and Drug Administration): Regulates sterilization equipment and medical devices.
• State dental boards: May have additional requirements.

CDC Standard Precautions

Standard precautions are the foundation of infection control. They apply to ALL patients regardless of known or suspected infection status. The core principle: treat ALL patients as potentially infectious.

Standard Precautions include:

1. Hand hygiene
2. Personal protective equipment (PPE)
3. Respiratory hygiene/cough etiquette
4. Sharps safety
5. Safe injection practices
6. Sterilization and disinfection of instruments and devices
7. Environmental surface disinfection
8. Dental unit water quality management

Hand Hygiene

Hand hygiene is the single most important measure to prevent healthcare-associated infections.

When to perform hand hygiene:

• Before and after treating each patient (before putting on gloves and after removing them)
• After touching contaminated objects or surfaces
• Before leaving the operatory
• When hands are visibly soiled

Methods:

• Alcohol-based hand rub (ABHR): Preferred when hands are not visibly soiled. Apply to all surfaces of hands and rub until dry (~20 seconds). More effective than soap and water against most pathogens.
• Antimicrobial soap and water: When hands are visibly soiled, before eating, and after using the restroom. Wash for at least 20 seconds (the time it takes to sing "Happy Birthday" twice).
• Plain soap: Acceptable for routine hand washing when hands are not visibly soiled.

Nails: Fingernails must be kept short and clean. Artificial nails and nail extenders are NOT permitted when having direct patient contact (they harbor bacteria and can puncture gloves).

Jewelry: Rings, watches, and bracelets should be removed before hand hygiene (they interfere with effective hand cleaning).

Personal Protective Equipment (PPE)

PPE creates a barrier between the clinician and potentially infectious materials. The OSHA Bloodborne Pathogens Standard requires employers to provide appropriate PPE at no cost to employees.

Gloves:

• Worn: Whenever there is potential for contact with blood, saliva, mucous membranes, non-intact skin, or contaminated items.
• Changed: Between patients, and immediately if torn, punctured, or heavily contaminated.
• Types:
  • Examination gloves (latex, nitrile, vinyl) — the primary glove for patient care
  • Sterile surgical gloves — for surgical procedures
  • Utility gloves (heavy-duty) — for instrument processing, cleaning, and handling chemicals
• Latex allergy: Use nitrile or vinyl alternatives. Powdered latex gloves are not recommended due to increased latex allergen aerosolization.
• Hand hygiene: Perform BEFORE putting on gloves and AFTER removing gloves.

Masks:

• Worn to protect the clinician from splashes and spatter of blood, saliva, and other potentially infectious materials
• Must cover both the nose and mouth
• Should be changed between patients and when they become wet
• Surgical masks protect against droplet and spatter, not aerosols. For aerosol-generating procedures, N95 or higher respirators are recommended.

Protective Eyewear:

• Must have solid side shields
• Worn by both the clinician and the patient
• Cleaned and disinfected between patients
• Prescription glasses alone are NOT adequate — they lack side shields

Protective Clothing (Gowns/Lab Coats):

• Worn to protect skin and street clothes
• Changed when visibly soiled and at least daily
• Should be removed before leaving the dental treatment area
• Fluid-resistant gowns are recommended

OSHA Bloodborne Pathogens Standard

The Bloodborne Pathogens Standard (29 CFR 1910.1030) applies to all occupational exposure to blood or other potentially infectious materials (OPIM).

Key Requirements:

1. Exposure Control Plan:

• A written plan identifying job classifications with occupational exposure risk
• Describes methods of compliance (universal/standard precautions, engineering controls, work practice controls)
• Updated annually
• Accessible to all employees

2. Hepatitis B Vaccination:

• Must be offered to all employees with occupational exposure at no cost to the employee
• Must be offered within 10 days of initial assignment
• Three-dose series (0, 1, and 6 months)
• Employee may decline, but must sign a declination form
• Post-vaccination titer testing (anti-HBs) is recommended 1-2 months after series completion for healthcare workers

3. Engineering and Work Practice Controls:

• Hand hygiene facilities (sinks, soap, ABHR)
• Sharps containers (puncture-resistant, leak-proof, labeled, located as close as feasible to the point of use)
• Needle recapping: use a one-handed "scoop" technique or a recapping device. NEVER use a two-handed recapping technique.
• Prohibition on eating, drinking, applying cosmetics, or handling contact lenses in areas of potential exposure
• No mouth pipetting

4. Sharps Safety:

• Needles are considered contaminated sharps and must be disposed of in designated sharps containers immediately after use
• Sharps containers must be closed when ¾ full and disposed of according to state medical waste regulations
• Never bend, break, or manipulate contaminated needles by hand
• The Needlestick Safety and Prevention Act requires use of safety-engineered sharps devices (e.g., safety syringes, self-sheathing needles) when available

5. Post-Exposure Management: If an occupational exposure occurs (needlestick, sharps injury, or blood/OPIM splash to mucous membranes or non-intact skin):

• Immediate: Wash the site with soap and water. For mucous membrane exposure, flush with water or saline for 15 minutes.
• Report: Report the exposure to the employer immediately. The employer must provide a confidential medical evaluation and follow-up.
• Source patient testing: The source patient should be tested for HBV, HCV, and HIV (with consent, per state law). Rapid HIV testing allows timely decisions about post-exposure prophylaxis (PEP).
• Exposed employee testing: Baseline testing for HBV, HCV, and HIV.
• Post-exposure prophylaxis (PEP):
  • HBV: If the exposed employee is unvaccinated or has inadequate antibody titer, administer hepatitis B immune globulin (HBIG) and initiate the HBV vaccine series. Ideally initiated within 24 hours.
  • HIV: If the source is HIV-positive, initiate PEP as soon as possible (ideally within 2 hours, no later than 72 hours). PEP is a 28-day course of antiretroviral medication.
• Documentation: The exposure incident must be documented in the sharps injury log and the employee's confidential medical record.

6. Recordkeeping:

• Medical records for employees with occupational exposure must be maintained for the duration of employment plus 30 years
• Training records must be maintained for 3 years
• Sharps injury log

Sterilization and Disinfection: Spaulding Classification

The Spaulding Classification determines the level of processing required based on the intended use of the instrument and the risk of infection transmission:

Critical NBDHE point: In dentistry, virtually all reusable instruments that contact the oral cavity are critical or semi-critical and require sterilization. The non-critical items are environmental surfaces and objects that do not enter the mouth.

Sterilization Methods

1. Steam Autoclave (Moist Heat):

• Mechanism: Steam under pressure. The combination of heat, moisture, and pressure denatures microbial proteins.
• Parameters:
  • Gravity displacement: 121°C (250°F), 15-20 psi, 30 minutes (minimum) for wrapped instruments
  • Pre-vacuum (Class B): 132-135°C (270-275°F), 27-30 psi, 4 minutes for wrapped instruments
• Advantages: Rapid, effective, reliable, non-toxic, inexpensive
• Disadvantages: Corrodes carbon steel instruments, dulls cutting edges over time, may not be suitable for heat-sensitive items
• Most common method in dental practices

2. Dry Heat Sterilization:

• Mechanism: Hot air at high temperatures. Kills by oxidation and protein coagulation.
• Parameters: 170°C (340°F), 60 minutes; or 160°C (320°F), 120 minutes
• Advantages: No corrosion, no dulling of instruments
• Disadvantages: Longer cycle times, higher temperatures, may damage some materials

3. Unsaturated Chemical Vapor (Chemiclave):

• Mechanism: Heated chemical vapors (alcohol + formaldehyde) under pressure
• Parameters: 132°C (270°F), 20-40 psi, 20 minutes
• Advantages: Less corrosion than steam
• Disadvantages: Chemicals are toxic; requires ventilation; ventilation cycle needed at end

4. Liquid Chemical Sterilants (Cold Sterilization):

• Mechanism: Immersion in chemical sterilant for extended time
• Agents: Glutaraldehyde (≥2.4%), hydrogen peroxide (≥7.5%), peracetic acid
• Contact time: Typically 6-10 hours for sterilization (varies by product)
• Indication: ONLY for heat-sensitive instruments that cannot be heat-sterilized
• Limitations: No packaging/storage (items must be used immediately after rinsing with sterile water); requires monitoring of chemical concentration; prolonged exposure time; chemicals are irritating/toxic

Disinfection Levels

Common Disinfectants:

Surface Disinfection Protocol:

1. Clean the surface to remove debris (disinfectants are inactivated by organic matter)
2. Apply disinfectant and allow the recommended contact time (often 2-10 minutes)
3. Wipe dry or allow to air dry
4. Use surface barriers (plastic wrap, barrier sleeves) on high-touch areas; change between patients

Sterilization Monitoring

Three types of monitoring are required:

1. Mechanical (Physical) Monitoring:

• Observe and record the sterilizer's gauges, timers, and displays during each cycle
• Verifies: temperature, pressure, and time were reached
• If parameters are not met, the load is NOT sterile
• Documentation: date, cycle parameters, and operator initials for each load

2. Chemical Indicators (Process Indicators):

• External: Tape, pouches with color-change indicator strips. Distinguishes processed from unprocessed items. Does NOT verify sterility — only that the item passed through the sterilization cycle.
• Internal (Integrators): Placed inside packages. Multi-parameter indicators that respond to temperature, time, and pressure. More reliable than external indicators.
• Placed in every package, tray, or cassette
• Check after the cycle: if the indicator has not changed, the item is NOT sterile

3. Biological Monitoring (Spore Testing):

• THE GOLD STANDARD for verifying sterilization
• Uses highly resistant bacterial spores (Geobacillus stearothermophilus for steam, Bacillus atrophaeus for dry heat)
• Spore test vial is run through a normal sterilization cycle, then incubated to check for growth
• Frequency: At LEAST WEEKLY (CDC recommendation; some states require more frequently). Always test after repairs or relocation.
• Results:
  • No growth (negative) = sterilization achieved. Service/test vials also incubated.
  • Growth (positive) = sterilization FAILED. Remove the sterilizer from service immediately. Investigate the cause. Re-sterilize all loads since the last negative test. Retest.
• Documentation: date of test, results, operator, corrective actions if positive

Instrument Processing Area Design

The instrument processing area should be divided into distinct zones to prevent cross-contamination:

1. Contaminated (Receiving/Cleaning) Area:

• Contaminated instruments arrive here
• Cleaning occurs (ultrasonic cleaner, manual scrubbing, instrument washer)
• PPE: utility gloves, mask, eyewear, gown
• Sink, ultrasonic cleaner, instrument washer

2. Packaging Area:

• Clean, dried instruments are inspected, assembled, and packaged
• Clean, dry area separate from the contaminated area
• Packaging materials: sterilization pouches, wrapped cassettes, sterilization wrap

3. Sterilization Area:

• Sterilizers are located here
• Loaded packaged instruments, run cycle, monitor

4. Sterile Storage Area:

• Sterile items stored in clean, dry, dust-free area
• Away from sinks, moisture, and direct sunlight
• Event-related sterility: items remain sterile until the package is compromised (not based on a fixed expiration date)
• Rotate stock (first in, first out)

Critical workflow: Contaminated → Clean → Sterile. Instruments should flow in ONE DIRECTION and must never cross-contaminate.

Dental Unit Water Quality

Dental unit waterlines (DUWLs) can harbor thick biofilms of bacteria (Pseudomonas, Legionella, nontuberculous mycobacteria). Water from these lines may contain extremely high bacterial counts if not treated.

Standard: Dental unit water used for non-surgical procedures must meet the EPA standard for drinking water: ≤500 colony-forming units (CFU) per mL of heterotrophic bacteria.

Surgical procedures: Sterile water or sterile saline must be used.

DUWL Maintenance:

• Self-contained water systems: Flush with chemical treatment (per manufacturer) and monitor.
• Flushing: Flush waterlines for 20-30 seconds between patients and for 2-3 minutes at the beginning of each day. This reduces but does NOT eliminate biofilm.
• Chemical treatment: Continuous or periodic chemical treatment (iodine, silver, hydrogen peroxide, citric acid-based products). Follow manufacturer instructions.
• Water source: Use water of appropriate quality. Do NOT use tap water directly without treatment.
• Boil-water advisories: Do not use municipal water during advisories. Use sterile water or water meeting EPA standards from an alternative source.

Hazard Communication

OSHA's Hazard Communication Standard requires:

• Chemical inventory: List of all hazardous chemicals in the workplace
• Safety Data Sheets (SDS): Maintained for each hazardous chemical, accessible to all employees
• Labeling: All chemical containers must be labeled with product name, hazard warnings, and manufacturer information
• Employee training: On chemical hazards, safe use, and emergency procedures

Medical Waste Management

Regulated Medical Waste (requires special handling per state regulations):

• Blood-soaked items
• Pathological waste (extracted teeth — unless returned to patient)
• Sharps (needles, scalpel blades, anesthetic cartridges, broken instruments)
• Items that would release blood or OPIM if compressed

Non-Regulated Waste (general office trash):

• Gloves, masks, gowns not saturated with blood
• Saliva-contaminated items without visible blood
• Disposable barriers, patient bibs
• Most dental office waste falls into this category

Extracted teeth:

• Considered regulated medical waste in most states
• May be returned to the patient on request
• May be used for educational purposes if disinfected (autoclaved)
• Teeth with amalgam restorations should NOT be autoclaved (mercury vapor release) — use other disinfection methods

Clinical Application

Scenario: During instrument processing, the biological monitor (spore test) from yesterday's steam autoclave load comes back positive. This is the first positive result in months.

Response:

1. Remove the sterilizer from service immediately
2. Recall all items processed since the last negative test (yesterday's load and any loads since then). Re-sterilize them in a different sterilizer.
3. If no backup sterilizer is available, recall and re-sterilize when the unit is back in service
4. Investigate the cause: Was the unit overloaded? Were cycle parameters correct? Was the water level adequate? Is maintenance needed?
5. Run another spore test (with two vials — one as control)
6. Document the incident, investigation, and corrective actions
7. Do NOT release any instruments from the compromised load until they have been re-sterilized and confirmed sterile

Common Traps

• TRAP: Thinking that a chemical indicator inside a package means the item is sterile. Chemical indicators ONLY show the package was processed. Biological monitoring (spore testing) verifies sterility.
• TRAP: Using liquid chemical sterilants (cold sterile) for routine instrument processing. These are ONLY for heat-sensitive items that cannot be autoclaved. They do not allow wrapping/storage.
• TRAP: Disinfecting a dental mirror or handpiece with a surface wipe. Semi-critical items that contact mucous membranes require sterilization or high-level disinfection — not surface disinfection.
• TRAP: Recapping a needle with two hands. Use the one-handed scoop technique, a recapping device, or a safety-engineered device. Two-handed recapping accounts for a large percentage of needlestick injuries.
• TRAP: Thinking extracted teeth are just regular trash. They are regulated medical waste in most states unless returned to the patient.