What does the Standard indicate for the load and the sterilisation cycle?
The UNI EN 13060 Standard defines the term “load” as being “the set of articles that are to be sterilized in the sterilization chamber”. This definition therefore refers to the material for dentistry use that is to be placed in the autoclave for steam sterilization.
Steam sterilization is carried out in an autoclave, namely “a specific device for sterilizing (using steam), the fundamental parameters of which are bound to the maintenance of a specific temperature and pressure, for a specific time” (UNI EN 13060 Standard).
The sequence of the various work phases that a steam sterilizer carries out to sterilize instruments is called the “sterilization cycle”. The sterilization cycle varies according to the temperature, pressure and time characteristics, as indicated by the Standard.
How does the Standard classify the instruments?
When selecting the type of cycle, consider the type of instruments in the load to be steam-sterilized.

The UNI EN 13060 Standard classifies the loads to be placed in the autoclave as:
solid load: a non porous item, without hollows or other characteristics that can hinder the penetration of steam in the same or in a greater manner than a hollow load (e.g. mouth mirrors, probes);
porous load: material that can absorb fluids (e.g. surgical gown, gauze)
   A. complete porous load when the load occupies 95±5% of the usable space;
   B. reduced porous load when the load occupies 20-25% of the usable space;
   C. small porous load when the load occupies 2.5-5% of the usable space;
type A hollow load: with an open space at one end in which 1≤L/D≤750, where D is the diameter of the hollow and L is the length, with L≤1500 mm, or an open space at both ends in which 2≤L/D≤1500, with L≤3000 mm, and which is not a B-type hollow load (e.g. handpiece, turbine);
type B hollow load: an open space at one end in which 1≤L/D≤5, where D is the diameter of the hollow and L is the length, with D≤5 mm, or an open space at both ends in which 2≤L/D≤10, with D≥5 mm, and which is not a A-type hollow load (e.g. operating cup, surgical aspirator tips).

Each instrument must be combined with a sterilization cycle that can eliminate each living microbic form, both pathogen and not, including spores and fungi. The material can be considered sterile if the SAL (Sterility Assurance Level) is lower than 10-6, in other words the probability of finding a microorganism is less than 1 in a million.
How do I choose the correct sterilization cycle?
Instruments can be sterilized with the following cycles:

- N cycle: solid instruments that do not need to be placed in a pouch (e.g. mirrors, probes)
- S cycle: B-type hollow instruments, both loose and placed in a pouch (e.g. handpieces, resistant thermoplastic items or ferrous material)
- B cycle: solid instruments, A-type hollow instruments (e.g. aspirator tips, handpieces), B-type hollow instruments (e.g. glass, surgical cups), porous material, thermoplastic material, placed in a pouch or loose.

It is evident that choosing an autoclave that carries out B-type cycles means that a higher variety of instruments can be sterilized in a single piece of equipment
What does the Standard say about periodic sterilization tests?
The purpose of periodic testing is to verify the operational state of the autoclave and also to verify that sterilization has been carried out correctly. These tests must therefore be carried out systematically, following what is indicated in the dentist’s surgery sterilization protocol.

The UNI EN ISO 17665:2007 Standard specifies the obligation to prepare a sterilization process that checks steam penetration daily with physical proof. This is valid when the sterilization process is based on the removal of air from the sterilization chamber, in order to allow steam penetration (Vacuum test).
Monitoring and routine checks (colour change test), always in compliance with the Standard, must be carried out at each sterilization cycle and monitoring with chemical or biological indicators, if carried out, must comply with the specific regulations for chemical and biological indicators.
Which sterilization tests do I have to carry out?
Vacuum Test: verifies that the vacuum necessary for the autoclave to correctly carry out the sterilization process is reached and maintained.

Bowie & Dick test (or steam penetration test into porous bodies): verifies steam penetration into porous bodies. It consists of a pack of porous material (paper) with a reactant inside that changes colour if reached by the sterilizing agent (steam), giving the test result. The pack must be positioned inside the empty sterilization chamber, in the centre of the heater. It makes it possible to understand if porous loads are being sterilized correctly.

Helix Test (or steam penetration test into hollow bodies): verifies steam penetration into hollow bodies. It consists of a small Teflon tube with a bulb at the end called “capsule” that contains a chemical agent. The instrument should be placed inside the empty sterilization chamber, in the centre of the heater. The chemical agent, if reached by the sterilizing agent (steam), changes colour, giving the test results.

Colour change test: these indicators verify that steam has reached the object being sterilized. The chemical testing agent changes colour according to its exposure at a specific temperature and for a specific time. The tester must be positioned inside the sterilization chamber during the cycle.

Biological test: it consists of specimens containing bacteria in a vegetative form. A specimen is inserted into the autoclave during the packed instrument sterilization phase. At the end of the cycle, the phial is inserted into an incubator, together with another phial that has not been sterilized. If, after 48 hours, the colour of the liquid in the sterilized phial is the same colour as the liquid that has not been sterilized, the test result is successful.