How We Sterilise Instruments at Our Karachi Clinics
Medically reviewed byDr. Saad Irfan— MDS, MSc, BDS·
Almost nobody asks a dentist about infection control, which is odd given that it is the one thing in the practice that can genuinely harm you without anyone intending it.
We have set the whole protocol out here — not as reassurance, but as something you can check. The last section on this page works at any dental practice in Karachi, including the ones that are not us. That is deliberate. A standard you can only verify by taking our word for it is not a standard.
The Class B Autoclave
All three clinicsA vacuum steam steriliser that removes air from the chamber before the sterilisation cycle, then dries the load under vacuum afterwards.
Class B is the highest of the three autoclave classes and the only one rated for every instrument type used in dentistry — including hollow instruments such as handpieces and porous items such as wrapped pouches.
The distinction is the vacuum phase. Air trapped inside a hollow handpiece insulates the interior from steam, so a cycle that has not removed that air can leave the inside of an instrument unsterile while the outside is perfectly clean. Class N and Class S autoclaves, which are cheaper and common, do not have that fractionated vacuum phase.
This is not a marketing distinction. It determines whether a handpiece used in someone else's mouth an hour ago is safe to use in yours.
The Instrument Reprocessing Cycle
This runs as a sequence, and a break at any stage invalidates everything after it. That is why the order matters as much as the individual steps.
- 1
Chairside separation
Instruments are separated at the chair the moment treatment finishes. Single-use items go straight to clinical waste; reusable instruments go into a covered transport container rather than being carried loose.
- 2
Cleaning
Debris is removed before sterilisation, not during it. This matters more than it sounds: steam cannot penetrate dried blood or cement, so an instrument that goes into an autoclave still soiled comes out still contaminated underneath the soil.
- 3
Inspection
Every instrument is checked before packing. Anything pitted, corroded or damaged is withdrawn — a compromised surface can harbour material that cleaning will not reach.
- 4
Pouching
Instruments are sealed in sterilisation pouches with a chemical indicator that changes colour only when the correct temperature, pressure and exposure time have all been reached. The pouch is what keeps an instrument sterile between the autoclave and your appointment.
- 5
Class B autoclave cycle
A fractionated vacuum cycle removes air from the chamber and from inside hollow instruments before steam is introduced, then holds at temperature for the full exposure period, then dries the load under vacuum. Trapped air is the single most common cause of a failed sterilisation cycle, and the vacuum phase is what eliminates it.
- 6
Storage
Pouches are stored sealed and dated. A pouch is only opened in front of the patient it is being used on — which is also how you can tell, as a patient, that it was sealed.
Beyond the Autoclave
Single-use items are genuinely single-use
Needles, scalpel blades, suction tips, saliva ejectors, prophy cups, gloves, bibs and cups are used once and discarded. Nothing marked single-use is reprocessed, which sounds obvious and is not universal.
Surface disinfection between every patient
The chair, headrest, light handles, bracket table, handpiece couplings and switches are disinfected between patients, not between sessions. Barrier film is used on the surfaces that are touched most and changed with each patient.
Water line management
Dental unit water lines are flushed between patients. Stagnant water in narrow tubing forms biofilm, which is a contamination route most patients have never heard of and which is entirely preventable with routine flushing.
Clinical waste segregation
Sharps go into rigid puncture-proof containers; clinical waste is bagged separately from general waste and disposed of through a licensed route.
Personal protective equipment
Gloves, mask and eye protection for every clinical procedure, changed between patients. Patients are given protective eyewear too — for debris and for the operating light.
What You Can Check Yourself
None of this requires any dental knowledge, and all of it works at any practice you visit. Use it on us.
- Was your instrument pouch opened in front of you, rather than handed over already open?
- Did the pouch carry a colour-changed indicator strip?
- Did the clinician change gloves after touching anything outside the treatment field?
- Was the chair and bracket table visibly wiped or re-covered before you sat down?
- Was the needle taken from a sealed package in your presence?
- If you asked what class of autoclave the practice uses, did you get a straight answer?
If the answer to any of these is no, ask why
There are occasionally reasonable explanations. But a practice that becomes defensive about a straightforward infection-control question has told you something more useful than any answer would have.
The Same Protocol at All Three Clinics
Infection control does not vary by branch. The reprocessing cycle above runs identically at each.
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Frequently Asked Questions
What is a Class B autoclave and why does the class matter?
Class B is the highest of the three autoclave classes and the only one rated for every instrument type used in dentistry, including hollow instruments such as handpieces. The difference is a fractionated vacuum phase that removes trapped air before steam is introduced. Air inside a hollow instrument insulates it from steam, so a cycle without that vacuum phase can leave the inside of a handpiece unsterile while the outside is visibly clean.
Are dental handpieces sterilised between patients?
They must be, and at our clinics they are — in a Class B autoclave, which is the class rated for hollow instruments. Wiping a handpiece down is not sterilisation. This is worth asking about at any practice, because it is one of the more common shortcuts.
How can I tell whether instruments were actually sterilised?
The pouch should be opened in front of you, and it should carry an indicator strip that has changed colour — the strip only changes when the correct temperature, pressure and exposure time have all been reached. If instruments are already laid out and unwrapped when you sit down, you have no way of knowing when they were processed.
Why does cleaning matter if the instruments are going into an autoclave anyway?
Because steam cannot penetrate dried blood, saliva or cement. An instrument that goes into an autoclave still soiled comes out still contaminated underneath the soil, with a perfectly valid-looking cycle record. Cleaning before sterilisation is not an optional preliminary — it is what makes sterilisation possible.
What is single-use and what gets reprocessed?
Needles, scalpel blades, suction tips, saliva ejectors, prophy cups, gloves, bibs and cups are used once and discarded. Metal instruments — mirrors, probes, forceps, handpieces — are cleaned, inspected, pouched and autoclaved. Nothing marked single-use is ever reprocessed.
What are dental unit water lines and why do they matter?
They are the narrow tubes that carry water to the handpiece and the three-in-one syringe. Water sitting still in narrow tubing forms biofilm on the inner surface, which is a contamination route most patients have never heard of. It is entirely preventable with routine flushing between patients, which is what we do.
Do you follow a written protocol?
Yes. The reprocessing sequence set out on this page is followed at all three clinics, and instruments are stored pouched and dated rather than loose in a drawer.
Is infection control different for surgical procedures?
The reprocessing chain is the same, but surgical procedures add sterile drapes, a sterile field and a stricter separation between clean and contaminated zones during the procedure itself.
Should I tell you if I have a blood-borne infection?
It genuinely does not change how your instruments are processed — universal precautions mean every patient is treated as though they might, because otherwise the protocol depends on people knowing and disclosing their status. Tell us anyway, because it can affect treatment planning, healing and prescribing.
Can I ask to see the sterilisation area?
Yes. Ask at any appointment. A practice that is reluctant to show you where instruments are processed has answered the question.
Questions About Any of This?
Ask us directly. It is a reasonable thing to want to know before someone puts an instrument in your mouth.
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