Guide for dental office managers · United States
What to do when a dental sterilizer fails a spore test
When a spore test comes back positive, take the sterilizer out of service and repeat the test immediately, on the same cycle that produced the failure (CDC, 2003 dental infection-control guidelines).
If the repeat test is negative and the mechanical and chemical indicators are within normal limits, the sterilizer goes back in service; if it is positive, it stays out until it has been inspected or repaired, or the exact reason is found (CDC, 2003 dental infection-control guidelines).
Take the sterilizer out of service
Two things happen at the same time: the machine stops, and its loads get checked.
Remove the sterilizer from service and review the sterilization procedures, for example work practices and the use of mechanical and chemical indicators, to see whether operator error could be responsible (CDC, 2003 dental infection-control guidelines).
Do not use instrument packs if the mechanical or chemical indicators show inadequate processing; items in that load are not used until they are reprocessed (CDC, 2003 dental infection-control guidelines).
Repeat the spore test on the same cycle
Repeat the spore test immediately, after correctly loading the sterilizer and using the same cycle that produced the failure (CDC, 2003 dental infection-control guidelines).
While it runs, review the chemical and mechanical monitoring records back to the last negative spore test (CDC, 2003 dental infection-control guidelines).
The unit goes back in service
If the repeat spore test is negative and the mechanical and chemical indicators are within normal limits, put the sterilizer back in service (CDC, 2003 dental infection-control guidelines).
Dental Logbook will close the failure file here, with the negative repeat result and the reviewed records in it.
The unit stays out
Do not use the sterilizer until it has been inspected or repaired, or the exact reason for the positive test has been determined (CDC, 2003 dental infection-control guidelines).
Recall, to the extent possible, and reprocess all items processed since the last negative spore test (CDC, 2003 dental infection-control guidelines).
Recall and quarantine any implantable items, and do not use them until they are shown to be sterile (CDC, sterilization monitoring page for dental settings, 2024).
Three passing tests in a row
The 2003 dental guidelines call for a rechallenge with biological indicator tests in three consecutive empty-chamber sterilization cycles, once the cause of the failure has been determined and corrected (CDC, 2003 dental infection-control guidelines).
The 2008 disinfection and sterilization guideline adds that each type of steam cycle used, for example vacuum-assisted or gravity, is tested separately (CDC, 2008 guideline for disinfection and sterilization in healthcare facilities).
On a pre-vacuum steam sterilizer, three consecutive empty cycles are also run with a Bowie-Dick test, the air-removal check for that kind of unit (CDC, 2008 guideline for disinfection and sterilization in healthcare facilities).
The same pattern applies after installation, relocation, a redesign or a major repair, not only after a failure (CDC, 2008 guideline for disinfection and sterilization in healthcare facilities).
The sources do not agree on one detail. The 2003 dental guidelines and the 2008 guideline say empty-chamber cycles (CDC, 2003 dental infection-control guidelines; CDC, 2008 guideline for disinfection and sterilization in healthcare facilities). CDC's 2024 page for dental settings says fully loaded chamber cycles (CDC, sterilization monitoring page for dental settings, 2024).
Dental Logbook will record the chamber state of every requalification cycle and will not pick one for you. A good log shows which state you used.
If the sterilizer is not a steam unit
For sterilization methods other than steam, the more conservative approach should always be used (CDC, 2003 dental infection-control guidelines).
After a single positive test with a method other than steam, treat as nonsterile everything processed in that sterilizer since the last negative spore test, up to the next cycle with satisfactory results (CDC, 2008 guideline for disinfection and sterilization in healthcare facilities).
Liquid chemical sterilants cannot be verified with biological indicators (CDC, 2003 dental infection-control guidelines).
When to talk to the health department
Identifying a lapse of this kind may warrant immediate consultation with the state or local health department, and appropriate notification and testing of potentially affected patients (CDC, infection prevention checklist for dental settings).
The same checklist expects policies and procedures to be in place for the practice's response to a reprocessing error or failure, for example recall of a device or a risk assessment (CDC, infection prevention checklist for dental settings).
What to record
A failure is also a record to keep. Dental Logbook will follow the event from trigger to return to service:
- What triggered the failure: a positive spore test, a failed mechanical or chemical check, or a failed air-removal test on a pre-vacuum unit.
- When the unit went out of service, and who took it out.
- The procedure review: loading, packaging, operator error.
- Every load since the last negative spore test, listed from your own records.
- Implant items recalled and quarantined, with their load numbers.
- The repeat spore test: same cycle type, result and date.
- Inspection or repair if it came to that: who did it, the date and the report.
- The requalification runs, with the chamber state of each and the Bowie-Dick tests on pre-vacuum units.
- Whether the health department was consulted, with the date and the contact. Patient notification stays outside the logbook.
- Return to service: when, and who decided.
This guide is not legal advice; check your state board's current rules.