What is an autoclave & types of autoclaves in dentistry

Sterilization of dental instruments and materials is subject to stringent requirements. The most important thing depends on its quality – the safety of patients. Thanks to modern high-tech equipment, the necessary processing of tools, which was previously long and laborious, has become as simple and fast as possible. Today, autoclaving is considered the most advanced method of sterilization. It is used in various branches of medicine, including dentistry. In the article we will talk about what a dental autoclave is, how different types of this equipment differ from each other, and what criteria should be followed when choosing a device.

What is an autoclave and why does it serve in dentistry

An autoclave is a device for sterilizing instruments by high-temperature treatment. The impact is carried out by steam at a pressure above atmospheric. Compared to boiling, for example, this method is much more efficient because the temperature in the autoclave chamber is above 100°C. This method of sterilization ensures the destruction of various pathogens (subject to the requirements for different materials).

The design of an autoclave for sterilizing medical instruments is quite simple. The device is made in the form of a sealed thick-walled chamber equipped with a steam boiler, a thermometer, a pressure gauge and a safety valve. The principle of operation is also not complicated. The steam boiler boils water and turns it into steam, which is fed into the working chamber.

Due to tightness, the pressure increases, and the temperature rises proportionally to it. A manometer and a thermometer continuously monitor the parameters of the device. If their values ​​​​exceed the maximum allowable, the safety valve is activated, the device automatically turns off.

On the front panel of the device there is a display, where information is displayed during operation, and control buttons. With their help, the user can set the desired parameters (processing time, steam temperature), connect additional options or select one of the preset sterilization modes.

A modern autoclave for dentistry is equipped

with additional features, such as:

Pre-vacuum. The mode allows you to completely pump out air from small pores and hard-to-reach voids in tools. Thanks to this, 100% disinfection is achieved. The air remaining in the pores and thin tubes may contain microorganisms that are not always killed by high-temperature processing. The vacuum ensures that the hot steam is in full contact with the surface of the instruments and thus achieves the highest degree of sterility.

Vacuum drying. Tools and materials after processing must be not only clean, but also dry. The moisture remaining on them can serve as a breeding ground for pathogenic fungi and bacteria, so it must be removed. Thanks to the vacuum drying mode, the instruments are absolutely dry after autoclaving. This function is indispensable for the sterilization of textiles and porous materials.

Built-in printer  It is needed to record and document the results of sterilization. Some models do not have a built-in printer, but it is possible to connect an external printer through the appropriate connector.

Protection functions. In case of insufficient quantity or low quality of water in the steam generator when the tray is overloaded, the device will report the problem to the user.

Self-diagnostic programs. In some devices, test modes are provided to check the tightness in the working chamber and to control the quality of air removal.

An autoclave for medical instruments today can be considered an absolute must-have accessory for every dental clinic or office. Steam sterilization is a kind of gold standard procedure: a reliable, technologically advanced, multifunctional method. Of course, there are alternatives, but they are not as effective and do not solve such a wide range of problems.

For example, hot air treatment is not suitable for glass and small metal products (such as burs, channel fillers). Under the influence of excessively high temperatures – and in the chamber of the dry oven, the thermometer readings rise to 160 ° C and above – they lose strength. In addition, due to the lack of clear standards, the quality of air sterilization cannot be controlled. This method is now used only for materials that do not withstand moisture (ointments, powders, solutions), and is practically not used in dentistry.

As for other sterilization methods, such as treatment with ethylene oxide or formaldehyde, they are not safe at all. They are resorted to only in exceptional cases, when autoclaving for one reason or another is impossible.

Types of autoclaves

The main parameter that distinguishes autoclaves-sterilizers from each other is the device class assigned in accordance with the EN 13060:2004 standard. It defines the functionality and scope of the equipment.

Class N. It includes the simplest devices. Autoclaves of this type operate only in steam sterilization mode, they do not have the functions of vacuum drying and pre-vacuuming. They are suitable for processing smooth solid metal unwrapped tools. Products of complex geometry made of porous materials require a more advanced sterilization technology.

Class S combines devices with a vacuum drying function. Such autoclaves effectively handle the sterilization of smooth, all-metal packaged instruments. They can process products made of fabric, plastic and porous materials. But class S devices are not suitable for sterilizing instruments of complex configuration, with internal voids and channels. For example, it is not recommended to process dental handpieces in them.

Class B is assigned to the most high-tech devices. They are equipped with a full range of functions, including vacuum drying and pre-pulsing vacuum. This processing technology provides the highest quality sterilization, regardless of the material and configuration of the processed products. Class B autoclaves are suitable for all instruments, including dental handpieces.

Sterilization Chamber Volumn. The more instruments that can be loaded into the autoclave at the same time, the fewer processing cycles will be required and the faster the procedure will be. Naturally, the capacity should be selected taking into account the scale of activity: for an average dental clinic, a device with a working chamber volume of 12–23 liters is enough.

Number of preset programs. The more of them, the more convenient it is to use the device. The desired mode, for example “sterilization of smooth instruments in the package”, is set by pressing one button.

The presence of a built-in printer. It will allow you to quickly and easily create reports on the sterilization performed.

Ease of management. An easy-to-read display and clear button assignments are important features from an autoclave operator’s point of view.

External dimensions. Ideally, an autoclave for sterilizing dental instruments should be roomy yet compact. This is especially true if the size of the room is small.