Dental Infection Control: A Comprehensive Guide

Dental Infection Control: A Comprehensive Guide

Infection control in dentistry is essential to the health of the population as a whole. 

As a dental professional, you know how much work goes into keeping a clinic clean, the instruments and devices sterile, and the patients and staff safe. You’ve got to follow all of the guidelines for infection control in dental healthcare settings, from dental unit waterlines and tabletop sterilizers to instrument transport, sterilization and storage. You have to make sure everything is done right every time because you truly care about all patients’ well-being. 


Dental Infection Control: The Basics

Infection control isn’t exclusive to dentistry. Whether a facility has an infection preventionist  on-site or they’re able to designate several staff members with this responsibility to make sure they follow the guidelines, it’s a phenomenon that touches every corner of the healthcare industry

What are the basic principles for infection control?

  1. Chain of infection. To control or prevent infection, you need to understand how the chain of infection works, from what the microorganism is and where it lives, to how it spreads throughout a population. 
  2. Source identification. Did the infection stem from a healthcare setting or a non-healthcare setting?
  3. Risk of infection. How likely is it that the organism will infect the population? What environment does it thrive in?
  4. Modes of transmission. How does it spread to another person? Is it airborne, transmitted via respiratory droplets, through person-to-person or from an object to a person?

Although these principles apply to the entire healthcare industry, dentistry adapts the principles to develop and implement practices specific to dentistry that will protect patients. 

The Center for Disease Control (CDC) offers a summary of infection prevention practices in dental settings, including hand hygiene, use of personal protective equipment (PPE), standard precautions, and cough etiquette. These principles apply across the entire healthcare industry. Let’s explore the main points of these practices that are specific to dentistry. 

Dental Unit Waterlines

Dental unit waterlines encompass all lines and tubes connected to the dental chair through which water runs to reach instruments and items that will enter the patient’s mouth. When left unchecked, these tubes and lines are prone to bacteria, fungi, and protozoa growth, which can create a biofilm in the dental waterlines. This biofilm is incredibly difficult to remove and can contaminate a patient’s mouth, potentially leading to infection. 

How can dental healthcare personnel combat this nasty biofilm?

  • Self-Contained Water System: This independent water reservoir is filled, maintained, and controlled by the dental staff. Using this system, dentists can take the first step in providing safe water to patients. 
  • Talk to Your Dental Unit Manufacturer: Before deciding on your dental water unit, talk to the manufacturer. They’ll be able to explain all of your options, what will work best with your office setup, and how to maintain excellent water quality. 
  • Follow the Manufacturer’s Recommendations: You’re a dental professional, so people take your advice on oral hygiene, not stock trading. Treat your dental waterline unit manufacturer the same. They know their products and best practices, so follow the cleaning and disinfection recommendations in the owner’s manual. 
  • Run Water and Air: After each patient, run water and air for 20-30 seconds for any device connected to the system. 
  • CDC Boil Water Advisory: Follow the CDC’s guidelines for boiling water. 

Use these tips to keep biofilm out of your lines, your dental unit waterlines clean, and your patients safe. 


Dental Waterline Guidance From the FDA, CDC, and ADA

The three most important organizations regarding health and safety in water, healthcare, and dentistry have created a comprehensive list of infection control guidelines in dental offices nationwide. These recommendations cover:

  • Regular system disinfection
  • Monitoring water quality 
  • Developing waterline policies 
  • Holding staff accountable
  • Water reservoir separation
  • Surgical guidelines 

Dental Instrument Cleaning and Sterilization

A dental instrument cannot be sterilized until it has been cleaned. Otherwise, it’s still contaminated and very dangerous to use. Failure to properly clean, then sterilize equipment can result in infectious organism transmission or even bloodborne pathogen spread. 

There are three primary types of equipment:

  • Non-critical items. These only contact skin such as the Xray cone or a blood pressure cuff. These items require low- or intermediate-level disinfection with an EPA approved hospital-grade disinfectant spray or wipe
  • Semi-critical items. These contact mucous membranes or non-intact skin. Since this category includes mucous membrane contact, many of the instruments used in dentistry fall into this category. A good example is a dental mirror or digital X Ray holders. Semi-critical items should be high level disinfected at a minimum. However, both the CDC and ADA recommend sterilization if the item is heat tolerant per the manufacturer’s instructions.   
  • Critical items. These are items that contact sterile tissue  such as periodontal scalers and surgical instruments. Anything in this category must undergo sterilization. Heat sterilization (e.g., steam or dry heat) is most commonly used in dental practices. If a critical item can’t be heat sterilized, the CDC recommends replacing it with one that can or using sterile disposable items. 

Let’s explore the two primary ways of disinfecting critical items. 

Cold Chemical Sterilization

The American Dental Association (ADA) recognizes that there is a finite need for cold sterilization. This sterilization method involves the use of chemicals because the instruments are too sensitive to be exposed to high temperatures. Because heat sterilization is the most effective method available, cold chemical sterilization is just not quite as effective. 

While there are many chemicals that have been approved for high-level disinfection by the FDA, be sure the chemical you are using has been approved by the FDA for cold chemical sterilization. Common chemicals include: 

  • Glutaraldehyde
  • Ortho-phthalaldehyde or OPA
  • Hydrogen peroxide solutions
  • Peracetic acid


However, not all of these chemicals are approved for cold chemical sterilization and may differ based on the manufacturer.  Using the FDA registration number on the container, check to see if the chemical has been approved by the FDA  for cold chemical sterilization.   Even if the chemical has been approved for use in dental cold chemical sterilization, there are environmental and health concerns. The primary environmental concern is proper disposal, while the health concerns include:

  • Monitoring PEL (permissible exposure levels)
  • Respiratory effects from chemical vapors

Due to these safety concerns and existing efficacy concerns, cold chemical sterilization use is minimal. 

Tabletop Sterilizers

Because most dental tools aren’t disposable, ensuring the cleanliness and sterilization of dental instruments and devices is essential for any dental office. There is a lot that goes into device reprocessing, such as:

  • Transporting
  • Rinsing
  • Cleaning
  • Drying
  • Inspecting
  • Packaging
  • Cooling
  • Storing
  • Handling 

One way to expedite this lengthy process is using an automated instrument washer/disinfector. These instrument washers are used to clean (and possibly disinfect) instruments and devices. Some instrument washers are equipped for thermal disinfection. If using an automated washer that doesn’t disinfect (e.g., ultrasonic cleaners, some instrument washers), PPE must be worn while handling the instruments after cleaning.  

While tabletop steam sterilizers are common in dental practices, these sterilizers are not always loaded or maintained properly. Dental assistants and hygienists should receive inservices specific to the steam sterilizer used in the practice or clinic. According to the CDC infection control guidelines, steam sterilization is one of the most effective techniques because it is:

  • Inexpensive
  • Not toxic
  • Consistent and thorough
  • Quickly kills organisms
  • Eliminates spores and other infectious agents

It should be noted that steam can cause some materials to corrode or combust, which is why special training is needed to handle these machines. Loading a tabletop sterilizer is a complex, multi-step process. Learn more about what is involved in the loading process.  

Disposal of Multiple Use Syringes

Pre-filled plastic syringes or dispensing devices are common in dental settings. They’re made to be used to deliver composite and other materials to multiple patients, as long as the tips are disposed of after each patient and the barrel of the “syringe” is covered with an approved sheath or barrier. Dental professionals usually store these syringes out on the counter, in a drawer, or a bin. While they dispose of each tip immediately after use, the tip is replaced before storage and often left uncapped, creating major infection control concerns

  1. It’s common for the tips to touch the counter, drawer, or bin surface, potentially contaminating the tip, the syringe and the contents. 
  2. Syringes are exposed to operatory elements.
  3. Tips that touch the counter may be unintentionally ‘disinfected’ by chemicals used on the counter. 

Manufacturers recommend that the tip is thrown away after use but not replaced before the next use. Simply cap the syringe. If syringe contamination occurs, the FDA recommends the pre-filled syringe be thrown away immediately. Using a contaminated syringe can infect patients with deadly bloodborne pathogens, bacteria, or toxins. The FDA also recommends using new gloves each time you touch the syringe and protecting the syringe barrel with a cover during use to prevent contamination.  

How to Transport and Store Dental Instruments

Transporting contaminated equipment has been a long-time issue in dentistry. One does not simply transport instruments. There are a number of considerations to reduce the potential for contaminating people and the environment when transporting used instruments. What are all of the instrument transport and supply storage best practices?

  • Use a puncture proof rigid container with a lid to transport dirty instruments to comply with the OSHA Bloodborne pathogen standard. 
  • Regularly replace biohazard stickers to ensure they stay crisp and clear.
  • Do not keep sterile instruments, equipment, or supplies on counters during procedures. 
  • Store sterile and disposable instruments in a drawer or cabinet
  • Do not store supplies under sinks or other places that may get wet.
  • Always store clean or sterile supplies in a manner that protects them from contamination. 

Using these recommended methods, you will be able to keep your instruments clean and sterile from storage through use in the operatory. 

Does Your Dental Clinic Have an Infection Control Plan?

Infection control in dental clinics is absolutely essential. What sort of infection control plan does your clinic have in place? If your clinic doesn’t have a plan or you feel that your plan needs some revitalization, consider hiring an infection preventionist to help you ensure patient safety and compliance with OSHA standards.   

At Infection Control Results, our consultants can help you develop your infection control plan. One of our main areas of focus is education. We make sure all staff are as well educated as possible to keep instances of infection low and, should infection occur, guarantee everyone knows that there is a plan of action to follow (and what it is).