Sterilization methods and monitoring: Dental assisting

Sterilization is a critical step in processing contaminated instruments, and it’s essential to prevent the transmission of infection. Sterilization is the only way to eliminate all forms of microbial life, including all types of microorganisms as well as bacterial spores.

But for it to be effective, the instruments must first be thoroughly cleaned by physically removing all debris and organic material, like blood and saliva, before being sterilized.

As a dental assistant, your knowledge of sterilization methods is an essential part of providing safe and effective patient care.

Okay, let’s first talk about how sterilization differs from disinfection. Disinfection primarily uses disinfectant solutions to kill most or all pathogenic microorganisms, but it can’t destroy bacterial spores. On the other hand, sterilization methods primarily use heat to remove all microorganisms and bacterial spores.

In dentistry, sterilization is most commonly achieved with heat, though liquid chemical sterilants may be used for certain heat-sensitive items.

Whether you’ll use sterilization or disinfection methods depends on the instrument and the potential risk of infection associated with its use during dental procedures.

Accordingly, instruments are classified into three levels based on their level of risk.

The critical level requires sterilization and is used for instruments that penetrate soft tissue or bone, like scalpels, forceps, and scalers. The semicritical level almost always requires sterilization and is used for instruments that touch mucous membranes or non-intact skin but do not penetrate bone or penetrate soft tissue, like mouth mirrors and amalgam condensers. For those instruments that aren’t heat tolerant, like certain X-ray accessories like X-ray positioning devices, high-level disinfection can be used if barriers aren’t an option.

Lastly, the noncritical level uses intermediate- to low-level disinfection or basic cleaning for instruments like light handles, dental chair controls, or X-ray machine heads.

Now, there are some different types of sterilization methods you need to be familiar with. The most common types used in dental settings include steam autoclaving and dry heat sterilization.

A steam autoclave heats water to generate moist heat under pressure. It’s used for metal instruments, heat-resistant plastic devices, dental handpieces, cotton rolls, and gauze.

On the flip side, dry heat sterilization heats the air and has two types. A static air sterilizer is like an oven, where the hot air doesn’t move within the sterilizer chamber. The process can take 1 to 2 hours to complete, so it tends to be time consuming. In contrast, in a forced air sterilizer, the hot air is circulated throughout the sterilizer chamber at a high velocity, which reduces the time needed to achieve sterilization.

Almost all commonly used dental items today are able to be heat sterilized or are single-use disposables or are covered with barriers. In rare situations where an item can’t be sterilized, thrown away after use, or covered...

The item can be immersed into a liquid chemical sterilant like 2% or 3.4% glutaraldehyde. To be effective, this type of sterilization requires the instrument to be in contact with the liquid sterilant for a full 10 hours. Liquid chemical sterilants or cold sterilants are rarely used today due to environmental concerns about safety to the dental staff and difficulty in verifying their sterility.

So, remember that personal protective equipment, or PPE, must always be worn when using chemical sterilants. These include puncture- and chemical-resistant heavy duty utility gloves, face mask, protective eye shield, and a gown, since splashing or spraying can occur during cleaning.