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.

OK, 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 sterulants 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 3 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 scales.

The semi-critical 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 non-critical 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 sterilent for a full 10 hours.

Liquid chemical sterulants or cold sterulants 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.

Now it's essential to monitor the sterilization process to ensure all dental instruments are properly sterilized. There are 3 types of monitoring you'll use.

Physical monitoring involves checking the sterilizer's gauges and readings and recording the temperature, pressure, and exposure time.

Chemical monitoring uses tapes or strips that change color when exposed to time, temperature, or pressure. Process indicators, also known as single parameter indicators, are a type of chemical monitoring that's placed outside a package of instruments to verify exposure to a certain temperature.

While process integrators, also known as multi-parameter indicators, are placed inside a package of instruments to measure pressure, temperature, and time.

Although chemical monitoring provides an immediate and visual indication of sterilizing conditions, they don't guarantee that the item is sterile.

The only way to confirm the effectiveness of sterilization is through biologic monitoring, also called spore testing. This involves placing a biologic indicator, which is either a strip or a vial containing harmless bacterial spores, inside the sterilization chamber.

A normal sterilization cycle is run, after which the indicator is incubated to verify that no bacterial growth had occurred.

This type of monitoring is done weekly on the sterilizing equipment. As you follow established sterilization procedures, you must keep in mind some of the common errors that can result in sterilization failures.

One of the most common errors is failing to properly clean the instruments before sterilization, leaving substances like dried blood or other debris that can insulate pathogens and protect them from being killed.

Another error is overloading the sterilizer or placing the packages of instruments too close together. This increases the time it takes for the sterilizer to reach the proper temperature and prevents the heat from reaching all surfaces.

Other errors include improper timing, so there's insufficient time to sterilize the content and use of an improper temperature.

So there's insufficient heat to achieve adequate sterilization. As a dental assistant, properly sterilizing instruments used during patient care is one of your most important responsibilities.

You'll use your knowledge of potential pathogens, the types of sterilization processes, and the types of instruments used in your dental setting to prevent the spread of infection and promote a safe patient care environment.

You'll also ensure all established standards and protocols are consistently followed during sterilization procedures, while fostering a sense of shared responsibility for infection control in your dental setting.

All right, as a quick recap, sterilization of contaminated instruments is a critical step in managing 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.

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