Infection Prevention and Control in the Dental Laboratory
What is examined
How you stop the laboratory becoming a cross-infection link: standard precautions, disinfection of impressions and appliances, sterilisation and the records that prove each cycle worked.
Core principles
- Standard precautions apply to every patient and every impression; you do not decide who is low risk.
- Spaulding classification: critical items (penetrate tissue) must be sterilised; semi-critical items (contact mucosa) sterilised or high-level disinfected; non-critical items low-level disinfected.
- Hand hygiene, gloves, mask, eye protection and gown for all handling of contaminated items. Receive impressions in a signed, dedicated area.
Impressions and appliances
- Rinse under running water to remove blood and saliva, then disinfect as the manufacturer specifies - typically 1:10 sodium hypochlorite or an iodophor for alginate, a compatible disinfectant for addition silicone and polyether.
- Keep immersion times short; alginate imbibes water and distorts.
- Disinfect prostheses and appliances before delivery and again after any chairside adjustment.
Sterilisation and validation
- Cycles: 134 °C for 3 minutes (or 132 °C for 4 minutes), or 121 °C for 15 minutes.
- Three levels of validation: physical (cycle printout), chemical indicator in every load, and biological indicator (Geobacillus stearothermophilus) at a defined frequency.
- Record each load with a unique identifier so an instrument can be traced to a cycle and a patient.
- Prion-risk items are quarantined or single-use; standard autoclaving does not reliably inactivate prions.
Worked example
A pouch indicator turns brown but the printout shows a failed vacuum phase. The load is not released: a chemical indicator only proves exposure, not steam penetration. Re-run the load with a biological indicator and investigate the autoclave.
Traps
- Treating "cold sterilisation" as equivalent to sterilisation.
- Storing disinfected impressions alongside untreated ones.
- Wearing the same gloves from the bench to the phone or door handle.