By Amy Knepshield Condrin, OSHA Review, Inc.

Disinfection and sterilization are essential for preventing transmission of infectious pathogens to patients and your staff. How do you know if you and your staff are effectively performing these tasks? The Texas Administrative Code (TAC) defines disinfection and sterilization requirements for Texas dentists . Additionally, the Centers for Disease Control and Prevention (CDC) recommends varying levels of disinfection and sterilization (determined by the type of procedure and equipment used). Using these requirements and recommendations as a guide, this article will help you and your staff determine how to properly disinfect and sterilize, and what to look for in the products you use to do the job.

Before we get started, you’ll need to be familiar with a few terms.

Cleaning is an essential first step before sterilization and disinfection. Cleaning is defined as the removal of visible soil, blood, proteins, microorganisms, and other debris from surfaces, crevices, serrations, joints, and lumens, or instruments, devices, and equipment. This step prepares items for safe handling and/or further decontamination. Debris removal is usually accomplished through use of detergent and water, or enzyme cleaner and water, by a manual or mechanical process.

Disinfection is a process that eliminates many or all pathogenic organisms, except bacterial spores. It’s usually accomplished with liquid chemicals.

A disinfectant is defined as a physical or chemical agent that removes, inactivates, or destroys pathogens on a surface or item to the point where the surface or item is no longer capable of transmitting infectious particles, thereby rendering the surface or item safe for handling, use, or disposal.

A note about disinfectants: You might assume disinfectants can be used as cleaners, or vice versa. However, unless a disinfectant is also labeled as a cleaner, it cannot be used to clean. Consider using a US Environmental Protection Agency (EPA)-registered product labeled for both cleaning and disinfecting—but be certain both steps are performed separately.

Sterilization is a process that kills all forms of microbial life.

Note: Many liquid disinfectants and sterilants are used alone or in combinations in the healthcare setting. (These include alcohols, chlorine compounds, formaldehyde, glutaraldehyde, ortho-phthalaldeyde, hydrogen peroxide, iodophors, peracetic acid, phenolics, and quaternary ammonium compounds.) Commercial formulations of these chemical mixtures are considered unique products, and are not interchangeable. Misuse can create excessive costs and/or safety hazards. Users should read labels carefully to ensure the correct product is selected for an intended use, and that it is applied properly.

Environmental Surfaces (and Equipment)

Environmental Surface Disinfection refers to the disinfection of clinical and environmental surfaces. Texas State Board of Dental Examiners (TSBDE) requires all contaminated surfaces and equipment be disinfected between each patient.

Clean. Then Disinfect.

Surfaces MUST be cleaned of debris prior to disinfection. Surfaces cannot be adequately covered with disinfecting solution if dirt and debris remain on the surfaces. After cleaning surfaces with a cleaning solution, coat with a chemical disinfectant for the recommended contact time, and then wipe dry if necessary. Dental staff must follow product label and safety data sheet (SDS) instructions for safety, efficacy and proper disinfection.

Housekeeping surfaces such as walls and floors should be cleaned using a detergent or a product that combines a cleaner and disinfectant on a regular basis, when spills occur, and when surfaces are visibly soiled. Housekeeping surfaces only need to be disinfected if they were potentially contaminated with blood or other infectious material.

Clinical contact surfaces such as countertops, dental units, should be disinfected with an EPA-registered surface disinfectant (low-level or intermediate-level), or barrier-protected and cleaned at the end of the day.

Your Surface Disinfectants (Pesticides) Should Be:

Registered with EPA and Texas Department of Agriculture.
In dentistry, antimicrobials (such as surface disinfectants, sanitizers, and dental unit waterline cleaners) designed to destroy or inactivate disease-producing bacteria and other microorganisms are considered pesticides. (The term “pesticide” encompasses any chemical intended to destroy pests, control their activity, or prevent them from causing damage.) In Texas, all pesticides must be registered and approved for use by EPA and Texas Department of Agriculture.

All surface disinfectants regulated by EPA must be labeled with an EPA registration number. Labels on EPA-approved surface disinfectants also specify: technical and safety information, indications for use (contact time, application methods), and approved efficacy claims. Only claims listed on the registered label can be made regarding a disinfectant’s efficacy.

Your surface disinfectant must have hospital-efficacy claims, which are defined by the EPA as broad-spectrum disinfectants with demonstrated efficacy against Salmonella choleraesuis, Staphylococcus aureus, and Pseudomonas aeruginosa.

Labeled as Effective Against HIV/HBV or TB.
In dental settings, a surface disinfectant should also list label claims against human immunodeficiency virus (HIV) and hepatitis B virus (HBV), or Mycobacterium bovis (TB).

Stronger disinfectants are not necessarily better, and can actually harm equipment, the environment, and your staff. It’s important to select a disinfectant that provides the least hazardous side effects, yet is still efficacious for bloodborne pathogens of concern in a dental office.


Note that care should be taken when transporting contaminated dental instruments to the central processing area. Instruments should be containerized, and staff should never reach hands into containers holding contaminated instruments or handle the instruments with their hands.

Disposable Instruments

If disposable needles must be recapped, either the one-handed scoop technique or an actual recapping device must be used. Safe needle-handling practices during dental treatment are required by Occupational Safety & Health Administration (OSHA) and recommended by CDC. Disposable sharps must be disposed of in a sharps container. (OSHA’s Bloodborne Pathogens

[BBP] Standard mandates additional needle safety provisions.)

Disposable items labeled for single use only—such as high-speed suction tips and saliva ejectors—must not be used on more than one patient.

Reusable Instruments

Instruments that contact intact skin should be cleaned and disinfected. Otherwise, reusable instruments should undergo three steps prior to reuse: cleaning, packaging and sterilization.


Reusable instruments must be cleaned before sterilization. Debris can prevent heat or chemical vapor from contacting instrument surface area, and hinder sterilization. Reusable instruments should be cleaned with hands-free, automated cleaning equipment such as an ultrasonic unit. If manual scrubbing is necessary, a long-handled brush should be used to keep hands away from the contaminated sharp instruments. If instruments cannot be cleaned immediately, pre-soaking them can improve the cleaning process.

2. Package

After cleaning, all instruments should be packaged or wrapped before sterilization if they are not to be used immediately after being sterilized. The packages/wraps should remain sealed until the day they will be used and must be stored in a way so as to prevent contamination.

Packaging materials include: wrapped perforated instrument cassettes, plastic or paper pouches, and woven or nonwoven sterilization wraps. Materials should be compatible with the type of sterilization process being used. To maintain the integrity of the package, follow only manufacturer’s instructions for sealing the package. Do not use staples, pins, or paper clips to seal packages.

3. Sterilize

The CDC classifies reusable dental instruments as critical, semi-critical, or noncritical.

Critical instruments penetrate soft tissue or bone (i.e. scalpels, scalers, and burs).
Semi-critical instruments contact oral tissue without penetration (i.e. dental mouth mirrors and dental impression trays).
Non-critical instruments contact intact skin.

Critical and semi-critical instruments require sterilization after use. Sterilants used to process these types of instruments must be approved by the US Food and Drug Administration (FDA). Non-critical instruments are not required to be sterilized, and may be wiped down with a surface disinfectant that’s been registered with the EPA.

The TSBDE refers to five acceptable sterilization methods in the dental setting :

1. Steam sterilization use pressure to produce steam that is hotter than the 212F at which water normally vaporizes, increasing the autoclave water’s boiling point up to 260F. The sterilization cycle generally runs 15 to 20 minutes.
2. Chemical vapor sterilization occurs when a liquid chemical, usually formaldehyde, is heated to produce a vapor that kills all microorganisms on the dental instruments.
3. Dry-heat sterilization requires a higher temperature, 300F and up, and a longer cycle time than steam sterilization since dry air contains less heat than steam.
4. Ethylene oxide gas (ETO) can be used for sterilizing heat-sensitive or moisture-sensitive instruments. Because they have long cycle times, are costly, and pose potential hazards, ETO sterilizers are not frequently used in dental offices.
5. Chemical Sterilants (often referred to as cold sterile solutions) should be used on heat-sensitive items only. Such items should be soaked in the chemical sterilant for the required duration—often eight to ten hours—and then rinsed with sterile water. Contact the instrument manufacturer to make sure your “heat-sensitive” item is in fact heat-sensitive.

Sterilization Equipment

All sterilization must be performed using sterilization equipment cleared by the FDA. Additionally, all staff members who operate the sterilizer must receive training on proper sterilizer operation procedures and instrument processing techniques in the office.

Your staff should keep the following points in mind when operating a sterilizer:

  • Packages should be positioned to maximize the exposure of the paper portion of the package, because neither steam nor chemical vapor can penetrate plastic.
  • The sterilizer must not be overloaded, and there should be as much space as possible between pouches.
  • Operating parameters recommended by the equipment manufacturer should always be followed (sterilization times, temperatures, and others provided).
  • Before a sterilizer is unloaded, the wrapped packages must be visibly dry. If they’re wet, they may draw bacteria into the packaging material, which could contaminate the instruments.

Wet packages may indicate a problem with the sterilizer. Common factors of improper sterilization include chamber overload, low temperature/pressure, inadequate time, failure to preheat sterilizer, cycle interruption, and expired chemical (chemiclaves).


Sterilized instruments should be stored in a clean, dry environment to maintain the integrity of the package. It’s a good practice to rotate the packages so that those sterilized first are used first. However, instruments remain sterile until the package is opened or compromised. If packaging is compromised, instruments should be re-cleaned, repackaged, and re-sterilized. While not required, it’s recommended that all packages be marked with the date of sterilization and the sterilizer that processed the package to facilitate easy identification and recall of affected packages, should there be a sterilization failure.

Sterilizer Monitoring

The TAC states that “sterilization equipment and its adequacy shall be tested and verified in accord with American Dental Association (ADA) recommendations.” The ADA recommends that dental offices monitor sterilizers at least weekly with biological indicators.

Biological monitoring is the standard for assuring proper sterilization of dental instruments. Biological test strips with non-pathogenic bacterial spores are placed in the sterilizer and processed with a normal load. If a sterilizer is operating properly, the spores should not survive the sterilization process. To verify effective sterilization, the test strips are cultured to determine if the spores exhibit any growth.

Here are two tips on where to place spore test strips:

  • Place a test strip in the sterilizer according to the sterilizer manufacturer’s instructions. If there are no instructions, a strip should be placed within a wrapped set of instruments in the most difficult area to be sterilized, normally the lower front area of the sterilizer.
  • It’s a good practice to place the spore test strip in a different location of the sterilizer each week to help identify any “cold spots” within the sterilizer.

Chemical indicators can help assess physical conditions and identify procedural errors. These are recommended to be included in each load. External indicators that change color when a specific parameter is reached should be applied on the outside of the sterilization packages. Internal chemical indicators should be placed inside each package next to the instruments to ensure that the sterilizing agent reached the inside of the package.

Physical Parameters including cycle time, temperature, and pressure—which are evaluated by checking the gauges and displays on the sterilizer—should be checked. Correct readings don’t verify sterilization, but incorrect readings can help identify a problem with the sterilization cycle.

You should also periodically check door gaskets, vents, and internal/external surfaces. Refer to the sterilizer manufacturer’s instructions for maintaining and cleaning the sterilizer.

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