Brushing Up on Sterile Processing in Dentistry

Infection Control TodayInfection Control Today, January/February 2022, (Vol. 26, No. 1)
Volume 26
Issue 1

Dental instruments may not seem as invasive as the instruments used in medical surgeries, but they still pose the same dangers.

The SARS-CoV-2 virus was concerning enough, but just when we thought we were getting a handle on it, the variants started to emerge. First the Delta variant appeared, then the Lambda variant. And by the end of 2021, the Omicron variant revealed itself. However, for all the permutations of the virus, there are standard precautions that help prevent the disease’s transmission. In fact, those standard precautions are in place to keep everyone safe.

Germs, viruses, and bacteria are all things that infection prevention endeavors to mitigate. In a dental environment, sterile reprocessing is how patients are protected from contaminants on instruments.

Dangers Posed

Dental instruments may not seem as invasive as the instruments used in medical surgeries, but they still pose the same dangers. “You’re working inside people’s mouths,” said Lisa Kane, DMD, dental consultant and owner of Dental Office Compliance of New England LLC in Dedham, Massachusetts. “You have access to their bloodstream. You want instruments and tools that are clean, and the only way to ensure cleanliness is to sterilize them.” (Kane is the author of another article on dentistry in this issue on page 32.)

“Dental procedures are invasive, meaning they often come in contact with blood,” said Shannon Mills, DDS, private health care consultant and chair of the American Dental Association Standards Committee for Dental Products Subcommittee on Dental Infection Control Products. “Dental instruments used for what we call restorative procedures—which would include crowns, fillings, and for orthodontics—are classified as semicritical.”

Those semicritical instruments touch but do not necessarily penetrate mucous membranes. However, if they do, they can come in contact with blood, potentially passing along blood-borne diseases, such as hepatitis B or human immunodeficiency virus.

Infection prevention consultant, Katherine Schrubbe, PhD, RDH, MEd, BS, said sterile instrument processing is a vital component of the dental practice. “If we don’t have sterile instruments to utilize for our patient care, then you’re certainly just not working,” Schrubbe said. “You might as well just close the doors because you can’t treat anybody. It’s the standard of care. Every patient has to be treated as if they have something infectious.”

Hot and Cold

The primary method for dental instrument sterilization is through steam. However, cold sterilization is a process by which sterilization is achieved through a chemical means.

“It’s usually glutaraldehyde and they would put [in] things that are plastic that they wanted to reuse,” Kane pointed out. “It’s a high-level disinfectant, but the problem is that once you take it out of there, you have to rinse off the chemical. Then once you rinse off the chemical, it’s not sterile anymore.”

Steam sterilization also provides a measure of protection for dental staff. Chemical sterilants are hazardous to inhale, and autoclaves remove that risk. Steam sterilization is the preferred method now, but that wasn’t always the case. “If you roll the clock back 40 years, most of these instruments were cold sterilized,” Mills said. “They were put in some kind of a chemical bath—not even necessarily glutaraldehyde. When I first started, we simply wiped our hand instruments with isopropyl alcohol and put them in a drawer on racks. We’ve come a long way since the 1970s.”

Even though cold sterilization is still occasionally used, Schrubbe said most dental practices should avoid it. “There’s no reason for a dental practice to have any cold sterile,” she said. “Cold sterile is usually glutaraldehyde and is very toxic to human beings.”


Infection control is critical in dentistry—as it is in any health care environment—and it’s something practices take very seriously. That being said, dental practices still make common missteps. For instance, before being put into an autoclave, instruments must be thoroughly washed. “Although ultrasonics can dislodge material, sadly, a lot of times their cleaning process may be incomplete because of people rushing through it,” Mills said. “They’re also manually rinsing the instruments in the sink to remove the soil.”

Both disinfection and sterilization are 2-step processes. “There are always 2 steps, no matter what piece of that you’re doing,” Schrubbe said. “There is always a cleaning step. If it’s a surface, it would be disinfection. If it’s instruments, it would be sterilization. For example, when we clean our environmental surfaces—high-touch areas—most people use a disinfectant wipe.”

It’s necessary to clean a surface or an instrument before sterilizing or disinfecting. Schrubbe likens it to detailing a car. “You can’t wax your car until you wash it,” she said. “It’s the same sort of thing.”

Kane notes that some of the inconvenient-to-reprocess equipment is often overlooked. “It’s very important to autoclave all your handpieces and all the motors for your handpieces,” she said. “That includes prophy handpieces, and that includes slow speeds. Anything that comes off that hose has to be autoclaved, and it has to be done in between every patient.”

Once instruments come out of the autoclave, they must remain in their pouches until ready for use. Too often, practices make the mistake of opening those pouches, unwittingly exposing sterile instruments to contaminants, as well as other mistakes, Kane said. “A lot of people autoclave instruments, then take them out of the bag to store them somewhere. That’s not clean or sterilized anymore. It only maintains its sterility while it’s in the bag,” she said. “You can’t overfill the autoclave. You have to fill it according to whatever the manufacturer says. Different autoclaves have different requirements.”

For instance, sterility can’t be achieved if items touch the sides of the autoclave, hinged items must be in the open position, and the instrument bags must be left in the autoclave until they are dry, Kane explained.

Worker Safety

How instruments are handled on the way to be reprocessed is also regulated, but in this case, it is out of concern for worker safety. “A lot of practices and team members don’t seem to be aware of this, but you must transport contaminated instruments a safe way from the operatory to your sterilization area. Occupational Safety and Health Administration [OSHA] mandates some guidance for that,”1 Schrubbe said. “And OSHA says if you’re going to transport your contaminated instruments from your operatory to a central sterilization area, you should have them contained. Basically, you should be transporting them in a container that is leak proof. It should have solid sides and bottom, and it should be labeled with a biohazard symbol.”

It is a common problem, as team members may not realize the reasoning behind having such a container. However, it is a means to avoid sharps injuries in the event somebody runs into a cart of loose, dirty instruments.

Team members must also wear the appropriate personal protective equipment (PPE) when handling dirty instruments. “When it comes to PPE, team members need to be wearing heavy-duty utility gloves anytime they do instrument processing where they’re handling contaminated sharps,” Schrubbe said. “Everybody says, ‘I don’t like to wear them.’ ‘They’re clumsy.’ ‘I’m going to have [more injuries] if I wear those, so I don’t.’ But we must remember our exam gloves are not chemical-resistant, and they’re not stick-resistant enough to protect us from a sharps injury when we’re handling all these instruments in the sterile processing area.”

Robert Elsenpeter is a freelance writer who lives in Blaine, Minnesota, and has been writing about dentistry and infection prevention since 2013. He is also the author of 18 technology books, including the award-winning Green IT: Reduce Your Information System’s Environmental Impact While Adding to the Bottom Line.


  1. Dentistry workers and employers. Occupational Safety and Health Administration. Accessed November 29, 2021.

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