Once a practice commits to cassettes — and the case for doing so is strong — the next question is capacity. Too small and sets get split across cassettes, defeating the point; too large and you sterilise fresh air while the autoclave queue grows. Here is how the sizes map to real workflows.
1. Five instruments: the examination workhorse
The classic exam set — mirror, probe, tweezers, plus one or two — fits a five-instrument cassette exactly. That makes the 180 mm five-instrument cassette the highest-rotation size in most practices: one cassette per chair per patient, identical contents, gaps visible at a glance. A locking five-instrument version adds a positive latch for transport between decon room and surgery.
2. Seven: exam-plus
Add an excavator and a flat plastic to the exam set and five rails run out. The 18 × 11 cm seven-instrument cassette carries the “exam-plus” set without doubling up rails — the sweet spot for restorative check-up trays.
3. Ten and fifteen: procedure sets
Extraction and surgical set-ups run bigger. A 195 × 145 mm ten-instrument cassette holds a forceps-and-elevator selection; the 220 × 195 mm fifteen-instrument cassette carries a full minor-oral-surgery layout. Before committing, measure your autoclave chamber — the fifteen is A4-ish in footprint, and a cassette that will not sit flat on the shelf with steam space around it does not belong in the cycle.
4. The discipline that makes sizes work
Cassette sizing only pays off with fixed contents: same instruments, same rails, every cassette in the rotation identical. Three five-instrument cassettes per chair beats one of everything. Colour-coded silicone rails help; so does retiring instruments on schedule rather than letting odd ones migrate between sets — see when to retire an instrument and autoclave care for keeping the contents themselves in shape.
5. Practical notes
All cassettes in our sterilisation range are perforated stainless steel for steam penetration and dry cleanly after the cycle. If your practice is kitting out several surgeries at once, trade accounts get free UK delivery over £100 ex-VAT and monthly invoicing — the maths is in our trade buying guide.
Related reading
- The dental instruments buyer’s guide — how to judge steel, joints and finish, plus provenance and care — the guide that ties the range together.
- Cassettes vs trays — the case for cassette-based reprocessing in the first place.