9.2 Infection Control and Patient Safety in the Dental Clinic
Key Takeaways
Under the Spaulding classification, critical items (forceps, scalers, surgical burs) must be sterilized, semi-critical items (mirrors, impression trays) are sterilized or receive high-level disinfection if heat-sensitive, and non-critical items need low- or intermediate-level disinfection.
CDC guidance calls for mechanical and chemical monitoring of every sterilizer cycle and biological (spore) testing with Geobacillus stearothermophilus at least weekly and with every load containing implantable devices.
Dental unit water for non-surgical care should meet the drinking-water standard of 500 CFU/mL or less of heterotrophic bacteria, and surgical procedures need sterile irrigant.
After a needlestick, wash with soap and water, report immediately, assess the source, and start HIV post-exposure prophylaxis as soon as possible (ideally within hours and no later than 72 hours) for 28 days when indicated.
A healthcare worker with documented anti-HBs of 10 mIU/mL or more after vaccination needs no hepatitis B post-exposure prophylaxis.
Infection control and patient safety are blueprint subsections of Restorative Dentistry and themes common to every SDLE section. SCFHS lists the CDC Basic Guide to Infection Prevention and Control in Dentistry among its references, so the CDC framework is the safest basis for answers; Saudi facilities also follow Ministry of Health infection-prevention policies and accreditation standards.
Standard and Transmission-Based Precautions
Standard precautions apply to every patient: hand hygiene, personal protective equipment (PPE), respiratory hygiene, sharps safety, safe injection practices, sterile instruments, and clean and disinfected surfaces. Transmission-based precautions are added for known or suspected infections: contact, droplet, or airborne (for example active pulmonary tuberculosis, which needs a fitted N95 respirator and deferral of elective care).
Hand Hygiene and PPE
- Use an alcohol-based hand rub (about 20-30 seconds) when hands are not visibly soiled; wash with soap and water (about 40-60 seconds) when visibly soiled.
- Perform surgical hand antisepsis before surgical procedures.
- Gloves: a new pair for every patient; never wash or reuse gloves; sterile gloves for surgery.
- Masks and eye protection protect against spatter and aerosols; use respirators for airborne threats.
- Donning order (CDC): gown, mask or respirator, eye protection, gloves. Doffing order: gloves, eye protection, gown, mask or respirator, followed by hand hygiene.
The Spaulding Classification
| Category | Contact | Examples | Reprocessing |
|---|---|---|---|
| Critical | Penetrates soft tissue or bone | Forceps, scalpels, scalers, surgical burs, endodontic files | Sterilization |
| Semi-critical | Contacts mucosa, no penetration | Mirrors, amalgam condensers, impression trays, handpieces | Sterilization (heat-sensitive items: high-level disinfection) |
| Non-critical | Intact skin | Blood pressure cuff, light handles (if not barrier-protected) | Low- or intermediate-level disinfection |
Handpieces must be heat-sterilized between patients even though they are classified as semi-critical.
Instrument Reprocessing
- Transport contaminated instruments in closed containers.
- Clean with an ultrasonic cleaner or washer-disinfector (manual scrubbing increases sharps injuries).
- Package in pouches or wraps with internal chemical indicators.
- Sterilize: steam autoclave (for example about 121 degrees Celsius for 30 minutes in a gravity cycle, or about 132-134 degrees Celsius for 3-4 minutes in a pre-vacuum cycle, following the manufacturer), dry heat, or unsaturated chemical vapor.
- Store packages dry and intact; packages that are wet, torn or dropped are reprocessed.
Sterilizer Monitoring
| Monitor | What it shows | Frequency |
|---|---|---|
| Mechanical (physical) | Time, temperature, pressure readings | Every cycle |
| Chemical | External tape and internal indicators changing color | Every package |
| Biological (spore test) | Kills resistant spores (Geobacillus stearothermophilus for steam and chemical vapor; Bacillus atrophaeus for dry heat) | At least weekly, every load with implantable devices, and after repairs |
A positive spore test means removing the sterilizer from service, reviewing loading and procedures, retesting, and recalling items processed since the last negative test if the repeat test is positive.
Dental Unit Waterlines and Surfaces
- Waterlines form biofilm; treat them and monitor so output water meets 500 CFU/mL or less of heterotrophic bacteria.
- Flush waterlines for about 20-30 seconds between patients; use sterile water or saline for surgical procedures.
- Clinical contact surfaces are covered with barriers or cleaned and disinfected between patients.
Sharps and Waste
- Never recap needles with two hands; use the one-handed scoop technique or a recapping device.
- Dispose of sharps at the point of use in puncture-resistant containers, replaced before they are overfilled.
- Segregate infectious waste, sharps, pharmaceutical and chemical waste (including amalgam, which needs separators and recycling) according to local regulations.
Occupational Exposure Management
- First aid: wash wounds with soap and water; flush mucous membranes with water. Do not squeeze or apply bleach.
- Report immediately and document the incident.
- Assess the source (HIV, hepatitis B and C status) with consent and test the exposed worker at baseline.
| Pathogen | Post-exposure action |
|---|---|
| HIV | Start antiretroviral PEP as soon as possible, ideally within hours and no later than 72 hours, for 28 days when the exposure warrants it |
| Hepatitis B | Vaccinated worker with anti-HBs of 10 mIU/mL or more: no PEP; unvaccinated: hepatitis B immune globulin plus vaccine series; known non-responder: immune globulin (often two doses) |
| Hepatitis C | No PEP; test the source and follow up the worker with HCV RNA and antibody testing to detect infection early |
All dental healthcare personnel should complete hepatitis B vaccination with post-vaccination anti-HBs testing.
Patient Safety
- Wrong-site or wrong-tooth procedures: confirm the tooth number in the chart, radiograph and referral, mark or point to it, and perform a time-out before extraction.
- Aspiration or ingestion of instruments and crowns: use rubber dam, gauze throat screens and floss ligatures on small instruments.
- Medical history and allergies (latex, local anesthetic additives, antibiotics) updated at each course of treatment.
- Medication safety: check doses by weight for children and maximum local anesthetic doses.
- Incident reporting: report errors and near misses through the facility system so root-cause analysis can prevent recurrence; open disclosure to the patient is part of professionalism.
Exam Traps
- Disinfecting a handpiece by wiping is not acceptable; it must be heat-sterilized.
- A chemical indicator color change alone does not prove sterility.
- Supplemental oxygen and other emergency drugs must be checked regularly, but sterilizer spore testing is weekly, not monthly.
Which reprocessing is required for a dental handpiece between patients?
High-level chemical disinfection only, because heat damages every handpiece
Heat sterilization after cleaning and lubrication according to the manufacturer
Wiping with an intermediate-level disinfectant, as is done for all other non-critical items
Rinsing with water, because handpieces never contact blood or saliva directly
A clinic uses a steam autoclave daily. How often should biological (spore) monitoring be performed according to CDC guidance?
At least weekly, and with every load that contains an implantable device
Once a year during the annual service of the sterilizer by a qualified engineer
Every cycle, because mechanical gauges are not considered reliable
Only when a chemical indicator fails to change color during a cycle
A dental assistant sustains a needlestick from a used local anesthetic needle. Her records show anti-HBs of 120 mIU/mL after hepatitis B vaccination. What hepatitis B post-exposure management does she need?
Antiretroviral prophylaxis for 28 days, because it also prevents hepatitis B
Hepatitis B immune globulin plus a full repeat course of hepatitis B vaccine
No hepatitis B prophylaxis, because she is a documented vaccine responder
Immediate interferon therapy, because hepatitis B transmission is certain
Sections you finish are checked off in the contents.