In dental instrument reprocessing, it is easy to hear the steriliser beep, see “Cycle Complete”, remove the load and assume the instruments are ready for use.
But a completed cycle and a successfully processed load are not necessarily the same thing.
AS/NZS 5369:2023 – Reprocessing of reusable medical devices and other devices in health and non-health related facilities provides the Australian framework for effective and safe reprocessing, including validation, routine monitoring, release and maintaining process effectiveness. The standard applies to dental practices as well as other healthcare settings.
For dental teams, one of the most important practical skills is therefore knowing how to interpret the steriliser cycle record before releasing reusable medical devices (RMDs).
The printout is physical evidence of the cycle
A steriliser printout or electronic cycle record provides physical monitoring information about what happened during the cycle.
The key parameters are:
TIME + TEMPERATURE + PRESSURE
ADA guidance explains that regular steam-sterilisation monitoring uses physical indicators, such as cycle-parameter printouts, in combination with chemical indicators. The purpose is to establish whether the required sterilisation parameters were achieved.
This means staff should not simply look at the bottom of the printout for:
“PASS”
“COMPLETE”
or
“CYCLE ENDED”
They need to interpret the actual cycle information.
1. Start by identifying the cycle
Before interpreting individual numbers, confirm that you are looking at the correct cycle.
Depending on the steriliser, the record may include:
- Date and time;
- Steriliser identification;
- Cycle or batch number;
- Selected program;
- Cycle duration;
- Operator information;
- Temperature readings;
- Cycle stages;
- Alarms or fault codes;
- completion status.
The operator must also know whether the selected program was appropriate for the RMDs and load being processed.
Staff operating steam sterilisers should be trained in their correct use, the operator manual should be available, and the steriliser should be operated according to the manufacturer’s instructions.
2. Find the sterilisation holding phase
An autoclave cycle consists of several stages.
Depending on the steriliser and program, the printout may show phases associated with:
Air removal → Heating → Sterilisation/exposure → Exhaust → Drying → Cycle completion
Not every temperature appearing on the printout represents the sterilisation temperature.
This distinction is critical.
For example, seeing:
134°C
somewhere on a printout does not, by itself, demonstrate that the sterilisation process was satisfactory.
The operator needs to determine whether the required sterilisation conditions were achieved and maintained during the appropriate exposure/holding phase.
3. Check the TEMPERATURE 🌡️
Ask:
Did the steriliser achieve and maintain the required sterilisation temperature?
Don’t look only for the highest temperature reached.
The important question is whether the required conditions were maintained during the sterilisation exposure period.
For example, a machine briefly reaching 134°C during part of its operation does not, on its own, demonstrate successful sterilisation.
Temperature must therefore be interpreted alongside time and pressure.
4. Check the HOLDING TIME ⏱️
Next ask:
For how long were the required sterilisation conditions maintained?
The entire cycle time is not the sterilisation holding time.
A cycle may take considerably longer because it includes air removal, heating, sterilisation, exhaust and drying.
The relevant exposure/holding period is the period during which the required sterilising conditions are achieved and maintained.
NSW Health reproduces the following steam sterilisation time-temperature-pressure relationships from AS 5369:2023:
Temperature Pressure Minimum holding time
121°C 103 kPa 15 minutes
126°C 138 kPa 10 minutes
132°C 186 kPa 4 minutes
134°C 203 kPa 3 minutes
These relationships should not be used to override the validated process or the manufacturer’s instructions for the steriliser and RMD. The actual cycle needs to correspond to the applicable validated process.
5. Check the PRESSURE ⚙️
Pressure is the third key parameter.
Ask:
Was the pressure consistent with the required saturated-steam sterilisation conditions?
For example, the published relationship for 134°C is approximately 203 kPa, with a minimum three-minute holding time.
But pressure should not be treated as an isolated number or as independent proof that sterilisation occurred.
Think of the three parameters together:
TIME ↔️ TEMPERATURE ↔️ PRESSURE
They collectively provide information about whether the required physical cycle conditions were achieved.
6. Look at the whole cycle — not just one line
Imagine an autoclave record showing:
134.2°C
It would be incorrect to simply circle that number and declare:
PASS ✅
Ask instead:
- When did it reach that temperature?
- Was this during the sterilisation phase?
- How long were the required conditions maintained?
- What pressure was recorded?
- Were there any interruptions or errors?
- Did the cycle complete according to the validated process?
- This is why competent interpretation of the cycle record matters.
7. “Cycle Complete” is not the end of load release
The printout is important—but it is not the only evidence considered when releasing RMDs.
ADA guidance describes physical monitoring as being used in combination with chemical indicators and states that packaged sterilised RMDs can be released when the required cycle parameters have been followed and physical and chemical monitoring supports correct processing. Release should be recorded and signed off by the person undertaking the task.
After the cycle, staff therefore need to examine the processed load itself.
Check:
✅ Physical parameters
Were the required time, temperature and pressure achieved?
✅ Dryness
Are the packs completely dry?
A wet pack should not simply be treated as an acceptable sterile package.
✅ Packaging integrity
Check for:
- Tears;
- Punctures;
- Broken seals;
- Damaged packaging;
- Opened pouches;
- Other loss of package integrity.
✅ Chemical indicators
Check that applicable indicators demonstrate the expected result.
✅ Cycle faults
Check for:
- Alarms;
- Interruptions;
- Error messages;
- Abnormal readings;
- Other non-conformances.
NSW Health similarly instructs operators to check the autoclave printout for correct time, temperature and pressure, then examine whether the load is dry, packaging is undamaged and test indicators have achieved the expected change.
8. Chemical indicator colour change does NOT mean “sterile”
This is an important distinction for every dental team.
A Class 1 process indicator is primarily used to distinguish an item that has been exposed to a process from one that has not.
It does not demonstrate that all sterilisation conditions were achieved inside the package.
ADA guidance explains that Class 1 indicators respond to heat and do not provide information about conditions inside the pouch or package. Higher classes of chemical indicators provide information about additional critical variables.
So:
Colour changed ≠ proof of sterility.
This is precisely why load release relies on multiple pieces of evidence.
9. What if a parameter doesn’t look right? 🚨
If the required release criteria have not been met, the answer should not be:
“It probably passed.”
Nor should the immediate response simply be:
“Let’s run it through the steriliser again.”
The affected RMDs should not be released for clinical use until the discrepancy has been appropriately investigated and managed.
A useful framework is:
🛑 STOP
Prevent affected RMDs from being released.
📦 QUARANTINE
Control potentially affected items according to the facility’s procedures.
🔍 INVESTIGATE
Review the cycle record, physical parameters, chemical indicators, load configuration, packaging, equipment and operator process.
📝 DOCUMENT
Record the non-conformance and actions taken.
🛠️ CORRECT
Identify and address the cause.
✅ VERIFY
Confirm that the process is operating correctly before returning affected processes or equipment to routine use.
Where an internal Class 4, 5 or 6 chemical indicator gives an unacceptable result, ADA practical guidance states that the RMD should not be used; it should undergo the full reprocessing sequence again—re-cleaning, re-packaging and re-sterilisation—rather than simply being placed back into the steriliser.
10. The person releasing the load matters
Sterilisation monitoring is not simply a machine function.
It requires human competency.
ADA guidance states that the person undertaking steriliser load checking needs the appropriate knowledge and skills gained through education, training, qualification, experience or a combination of these. They need to understand all stages of load checking and recognise non-conforming items.
That means training should go beyond:
“This button starts the steriliser.”
Staff should be able to explain:
What am I looking at?
What are the acceptable parameters?
Where is the holding phase?
What does this indicator tell me?
What does it NOT tell me?
What would prevent me from releasing this load?
What do I do if something fails?
11. Validation and routine monitoring are connected
Another important concept in AS/NZS 5369:2023 is validation.
Routine monitoring doesn’t exist separately from validation.
Validation establishes evidence that the defined reprocessing process can consistently achieve the required result. Standards Australia highlights validation and monitoring as key components of AS 5369 and notes the importance of performance qualification and evaluating challenging loads/product families.
ADA guidance also explains that formal validation uses challenging or worst-case load configurations to establish the process conditions against which routine cycles can subsequently be assessed.
So when we review today’s steriliser printout, we are not just asking:
“Did the machine get hot?”
We are asking:
“Does the evidence from this cycle meet the established criteria for our validated reprocessing process?”
That is a very different question.
12. Documentation and traceability matter.
A good sterilisation system leaves evidence.
Depending on the practice’s system, this may include:
- Steriliser identification;
- Date;
- Cycle/load number;
- Cycle record or electronic data;
- Physical parameters;
- Chemical indicator results where applicable;
- Load-release decision;
- RMD/load information;
- Corrective actions;
- Relevant traceability information.
ADA guidance recommends that steriliser cycle data remain stored and accessible for at least seven years, while noting that longer retention periods may apply in some circumstances or jurisdictions.
Documentation should therefore be treated as part of the reprocessing quality system—not paperwork added afterwards.
A simple load-release framework
When teaching dental teams, I like to bring the process back to six questions:
1. RIGHT CYCLE?
Was the appropriate validated cycle used?
2. TIME?
Was the required holding time achieved?
3. TEMPERATURE?
Was the required temperature achieved and maintained?
4. PRESSURE?
Was pressure consistent with the required steam conditions?
5. LOAD?
Are the packs dry, intact and otherwise acceptable, with required indicators satisfactory?
6. DOCUMENTED?
Has a competent person reviewed and recorded the release?
If something doesn’t meet the required criteria:
DO NOT RELEASE THE LOAD.
The bigger IPC message
An autoclave is an extremely important piece of reprocessing equipment.
But the machine cannot replace a competent reprocessing system.
Sterilisation assurance comes from the complete process:
Cleaning → Inspection → Preparation → Packaging → Sterilisation → Monitoring → Load release → Storage → Traceability
A beautiful pouch and a “Cycle Complete” message are only parts of that chain.
The real question is:
Can your team explain why today’s steriliser load was safe to release?
If the answer is simply “because the autoclave said PASS,” there is an opportunity for education.
At Within Control – Infection Prevention & Training, our focus is not just teaching staff which buttons to press. It is helping dental teams understand why each IPC step matters, what evidence they need to review, how to recognise a failure and what to do when something goes wrong.
Knowledge creates confidence.
Competency creates consistency.
Strong systems protect patients.