FIRST CHOICE REPAIR of Arizona has repaired many dental handpieces over the years that obviously have not had appropriate maintenance and care, damage often contributed by no, or improper handpiece sterilization.
STERILIZING DENTAL HANDPIECESby Noel Kelsch, RDHAP
Integrity is doing the right thing even when no one is looking. Ethics are the rules for deciding correct conduct based on the available information. There are times in our lives when we have to take a stand. Sometimes those are in the strangest places during the most trying times. Other times the everyday little things make an impact on someone’s life. Using integrity and ethics in our decision making in infection control is how each of us can decrease the infection risks in dental care.
For many years we have known that reusing a dental handpiece without autoclaving it can put patients at risk. The studies surrounding this issue have repeatedly shown that both high speed and low speed hand pieces that are not autoclaved can be a source of cross contamination.1,2 In one study using a low-speed air-driven handpiece used with prophy angles, the investigators assessed contamination inside the nosecone, motor, and prophy angles.
Using two handpiece types in 160 tests where the prophy angle end was contaminated in vitro with Geobacillus stearothermophilus, it was determined that the motor became contaminated in 20% of the cases. On the other hand, when the internal motor was contaminated, the microbes were transmitted to the prophy angle in 47% of 160 other samples. In another in vivo study of 20 subjects, 75% of the 420 samples obtained from low-speed handpiece/prophy angle systems were contaminated with oral flora.
The part that is really important for all dental health-care professionals (DHCP) to remember is that these studies show that even with the use of a simple prophy angle, the internal unit of the handpiece became contaminated, and cross contamination became a strong possibility.
In 2008, the Centers for Disease Control (CDC), in its Guideline for Disinfection and Sterilization in Healthcare Facilities, reminded us that “Handpieces can be contaminated internally with patient material and should be heat sterilized after each patient. Handpieces that cannot be heat sterilized should not be used.” No handpiece should be used on more than one patient without being autoclaved between patients. Barrier protection and wiping down with a disinfectant does not assure no cross contamination. The internal part of the angle is as important as the external.
The acceptable methods of sterilization include chemical vapor sterilizers, dry heat, and autoclaves. Ethylene oxide gas is not recommended for dental handpieces.
What to look for in a handpiece from a sterilization aspect
Some things to consider when purchasing a handpiece:
- Is it designed to be autoclavable
- Does it have sleek, smooth designs that will not hold debris
- Is the finish able to withstand the sterilization process over a long period of time? Titanium withstands chemicals and the sterilization process better than chrome plate.
- Does it have smooth surfaces that do not trap debris and bacteria, and a seamless finish with no gap between outer casings
But sterilization could destroy the handpiece, and they cost so much
Yes, the life expectancy of a handpiece can be decreased from the sterilization process. But that is not the only factor that plays into handpiece longevity. While it is difficult to determine just what factors shorten the life expectancy of a handpiece, there have been studies of handpieces that are being actively used and sterilized. One study from the United States Air Force Dental Investigation Services is a reminder how important maintenance is for these tools. This study concluded that with a properly sterilized handpiece, you can expect about 500 sterilization cycles without significant reduction in performance if the handpiece is properly maintained. That translates to about one year of use per handpiece. Purchasing and maintaining handpieces is the price DHCP need to pay in order to comply with the CDC recommendations and many state laws.
How do we care for the handpiece?
There are many resources to help you with the longevity and maintenance of these units. As DHCPs, we need to all read and follow the directions that come with our equipment. If we do not understand the care and maintenance recommendations, we need to call the manufacturer and ask for more details.
The mission of the National Dental Handpiece Association is to improve clients’ ability to deliver patient care by maintaining their powered instruments with exceptional service and integrity. The following guidelines represent a general approach to handpiece maintenance. Always follow the suggested maintenance procedures supplied with the handpiece. It is important to follow these instructions to the letter to avoid disputed warranty claims, especially during the warranty period.
Surface clean the handpiece.
CDC guidelines call for flushing water through the handpiece in the operatory for 30 seconds to remove potential contaminants from the internal water line. In the sterilization area, clean off any bioburden using a brush under running water. A mild detergent is acceptable. Bioburden left on dental instruments may act as a protective shield for microorganisms in the sterilizer. Alcohol should never be used as a cleaning agent as it can dehydrate spores and increase resistance to sterilization. Do not use any chemical solutions for cleaning. Foreign substances may have a detrimental effect on the sterilizer or the handpiece, through a harmful reaction during the sterilization cycle.
Dry off the handpiece.
This step is very important if the office is using a chemiclave sterilizer. Excess water will allow oxidation to occur in the chamber, leading to corrosion.
Lubricate the handpiece.
Use the proper lubricating tip to spray oil into the drive airline. Spray until oil comes out of the handpiece head. This ensures that lubricant has penetrated to the bearings. Even if the lubricant is delivered incorrectly, oil coming from the head indicates it has reached the bearings. Note: Using spray oil has become less popular because of perceived mess and waste. Many offices are moving to dropper-style applicators to oil the handpiece. Use of a dropper makes the next step — running out the excess oil — critical because the droplets will not be delivered to the bearings without being propelled by pressurized air. If you prefer a dropper, apply two to three good size drops to the drive air hole and immediately run the handpiece.
Run the handpiece to expel excess oil
. After lubrication, it is important to run the handpiece to evenly distribute the oil through the bearings, and to expel excess oil to prevent coagulation during autoclaving. Install a bur in the chuck and run the handpiece for 20 seconds. Do not use bur blanks, as they are not made to ISO specifications and do not run concentrically, which could possibly damage the turbine. (*Note: some manufacturers specifically state NOT to install a bur prior to operation. Air flush stations located in the sterilization area are an excellent investment. A flush station eliminates a trip back to the operatory to run the handpiece. These stations are readily available from many sources and only require a connection to an airline. Most stations have a handpiece adapter that operates the handpiece when pressed. Using an air station also prevents oil from being exhausted back into the handpiece tubing, which can lead to discoloration and stiffening. After operating, remove the bur. Lever style handpieces must remain in the closed position during sterilization.)
Clean fiber-optic surfaces.
Alcohol and a Q-Tip may be used to remove excess oil and debris from all fiber-optic surfaces.
Bag the handpiece.
CDC guidelines recommend bagging instruments and handpieces to maintain sterility. A paper/plastic combination bag is preferred, which allows steam to dissipate through the paper side while contents remain readily identifiable.
Autoclave the handpiece following manufacturer guidelines. Allow the sterilizer to completely process through the dry cycle.
Dry the handpiece.
After the cycle, place the bag containing the handpiece paper side up on top of the sterilizer to thoroughly dry. This is a warm area. As the heat from the sterilizer rises, the handpiece will dry more thoroughly. New sterilizer models feature dry/storage compartments outside the chamber. Paper side up allows the moisture from the condensing steam to evaporate easily. Leaving the plastic side up traps condensation in the bag, creating a corrosive atmosphere for the handpiece.
Many manufacturers offer a fully automatic clean and lube station to take staff time and guesswork out of the maintenance process. Most units have one-touch operation, applying a cleaner and lubricant before running the handpiece. Although costly, these maintenance centers reduce staff time associated with handpiece maintenance. Some manufacturers extend handpiece warranties if their automatic station is used.
Low speed motors and attachments
CDC guidelines indicate, “only the portion of the attachment that comes in contact with patient tissue” is required to be sterilized or disposed of. It is not necessary to sterilize the motor if a barrier is used. If you are not autoclaving motors, make sure they are removed from the tubing and lubricated at least once a week. Not removing motors at some interval leads to the accumulated disinfectant corroding the threads onto the tubing permanently.
Motors, especially vane rotors, do not require much oil. Dental motors and attachments require higher viscosity oil than a high-speed spray. One or two drops of oil in the drive airline are all that is necessary. Run the motor to distribute the oil. Also apply some oil as a preventive measure to forward/reverse valves, shift rings, and sheath attachment points. Wipe away excess oil with a paper towel.
Most straight sheaths do not require lubrication. An external cleaning is recommended with a brush under running water prior to bagging the nose cone for sterilization.
It is very important to take latch angles apart for proper lubrication. At least once a day unscrew the head from the sheath and remove the transmission gear for cleaning and oiling. I suggest this first thing in the morning as part of the opening routine. A Star latch angle requires the knuckle in the middle to be unscrewed in order to remove the transmission gear. Apply a drop of oil under each gear on the transmission gear as well as into the center hole. Apply several drops of oil to the exposed cartridge while the transmission gear is removed.
Each DHCP must make decisions in infection control that involve integrity and ethics. In doing so, each of us can decrease the risks involved in dental care.
Noel Brandon Kelsch, RDHAP, is a syndicated columnist, writer, speaker, and cartoonist. She serves on the editorial review committee for the Organization for Safety, Asepsis and Prevention newsletter and has received many national awards. Kelsch owns her dental hygiene practice that focuses on access to care for all and helps facilitate the Simi Valley Free Dental Clinic. She has devoted much of her 35 years in dentistry to educating people about the devastating effects of methamphetamines and drug use. She is a past president of the California Dental Hygienists’ Association.