Infection Prevention in Dental Radiography
Dental healthcare workers must always follow standard precautions and utilize appropriate infection control protocols to prevent cross-contamination and the transmission of disease. The chain of infection requires that sufficient levels of a pathogen are present to cause disease, that there is a source or reservoir for that pathogen, that a mode of transmission and entry portal are present, and that the host is susceptible. The ability to implement infection prevention protocols is an essential attribute for dental radiography equipment, accessories, and supplies.
The basic elements of the infection prevention cycle necessary to break the chain of infection are the same for dental radiography as for other dental procedures and can be broken down into distinct phases ? i.e., those steps taken before, during, and after patient care. As with other procedures, the dental healthcare worker must perform hand hygiene and wear medical gloves, as well as other personal protection equipment as required (mask, protective eyewear and clinical clothing). All staff must be trained in infection prevention procedures and offices must be OSHA-compliant. The sections below address the infection prevention protocol specifically as it relates to dental radiography.
Infection Prevention: Prior To and During Dental Radiography
Prior to seeing the patient for dental radiographs, clinical contact surfaces should be protected. Barrier protection can be used to protect X-ray unit tube heads and yokes, any connecting tubing or digital sensor cords, control panels and buttons. The chin rests, hand grips, and head positioning guides used for extraoral radiography can also be barrier protected. Extraoral cassettes may be handled with ungloved hands. Wireless digital sensors have been introduced; these remove potential contamination of wires attached to digital sensors from the equation. In addition, the computer keyboard and mouse used for digital radiography should receive barrier protection; alternatively, keyboards are available that are waterproof and wireless with a built-in mouse and that can be treated with surface disinfectants.
Semi-critical radiography accessories
Digital sensors, traditional film, bite guides used for extraoral radiography, as well as X-ray holders and positioners, including sensor holders, all contact intact oral mucosa and are thus classified as semicritical devices. Depending on the item, it may be single-use disposable, or non-disposable. Based on the guidelines from the Centers for Disease Control and Prevention, non-disposable semi-critical instruments should be heat-sterilized if possible (except for handpieces which must be autoclaved).
Sensor holders, positioners, and bite blocks are now available that can be safely autoclaved ? this is reliable, recommended over high-level disinfection or barrier protection plus surface wipe disinfection, reduces the use of chemicals, and compared to the use of disposable holders/positioners may save on costs. A further advantage is that autoclaved accessories can be stored unopened in their autoclave packaging in a dry place until the time of use, ensuring that they remain sterile. An additional option for most radiography accessories, if they are not disposable/autoclavable/immersible, is the use of barrier protection followed by cleaning and use of an intermediatelevel surface wipe disinfectant. Digital sensors should be placed in pre-shaped barrier protection or wrapped in barrier film. Specific manufacturer instructions should be followed to ensure appropriate processing and the longest life for accessories. For example, some accessories are intended to be autoclaved and not suitable for immersion in a cold sterilant, which could result in damage to the accessory. Misuse can cause many problems, including potentially not breaking the chain of infection, failure of the accessory to perform as expected, and additional costs to replace accessories that are incorrectly handled and fail.
Although traditional film is by definition singleuse, barrier pouches designed for X-ray film packets should be placed over it prior to use to reduce the risk of contamination of surfaces when the used film is being transported and then processed. Alternatively, films that are pre-packed in barrier envelopes can be used.
Assembling accessories and supplies
Assembling all prepared accessories and supplies that will be required to take the X-ray for the individual patient on a disposable tray prior to seeing the patient is helpful organizationally and helps reduce the risk of contamination. This also makes the radiographic procedure go more quickly. As mentioned above, the dental healthcare worker must perform hand hygiene and don medical gloves prior to handling X-ray accessories or barrier-wrapped traditional film and taking the radiograph.
Infection Prevention: After Taking Dental Radiographs
After taking the radiograph, contact with other surfaces should be avoided while wearing contaminated gloves. Barrier protection is removed from clinical contact surfaces and if compromised, or a surface is in contact with contaminated gloves during (or subsequent to) removal of the barrier protection, this must be treated with an EPA-registered low- to intermediate-level hospital disinfectant.
Semi-critical radiography accessories
Any disposable, single-use items should be discarded immediately after use. Accessories that will be autoclaved or immersed in high-level disinfectant should be transported in the same manner as other critical and semi-critical instruments to the instrument processing area. Barrier protection that was placed over accessories prior to use should be removed without touching the underlying object and the object then cleaned and treated with an intermediate- level disinfectant wipe. The manufacturer?s instructions should be reviewed by all appropriate staff to ensure the accessories are maintained appropriately.
Daylight loader film processors have cuffs for arms, and automatic processors have arm sleeves, that can become contaminated in addition to the developer and fixer itself. Traditional film packets can be aseptically dropped onto a clean cloth/towel surface while removing barrier protection, before transportation for film processing. If a film packet becomes contaminated during barrier removal, or no barrier protection was used, it should be wiped with an appropriate disinfectant before being placed on a paper towel or in a disposable container for transportation and film processing. For daylight loaders, another option is to first place film packets in a container into a daylight loader in the dark while wearing gloves, to unwrap the packet and aseptically, and carefully drop the film on a clean paper towel, remove gloves and close the lid before then proceeding with processing after performing hand hygiene and donning clean gloves. The importance of avoiding cross-contamination by used dental film is underscored by the fact that microorganisms transferred during processing of dental film have been shown to be viable in developer/fixer for up to 2 weeks. Using clean (i.e., unused) medical gloves during the loading of traditional film into processors reduces the risk of crosscontamination; consideration should be given to using powder-free gloves as glove powder can result in film artifacts.
Disposing of Radiographic Waste
Barrier wrapping, single-use disposable tabs, positioners and holders, as well as contaminated disposable trays are considered non-hazardous and can be discarded as waste. With traditional film radiography, the lead foil should be segregated and stored for collection or delivery. Developer and fixer chemicals must be disposed of in accordance with regulations. Dental offices should check State and local regulations and dispose of these items in accordance with the relevant regulations.
Standard infection prevention protocols break the chain of infection, protecting patients and dental healthcare workers from the risk of infection. A number of options are available for radiography accessories and equipment that offer effective infection prevention. Disposable and autoclavable accessories offer the greatest reliability, ease of implementation and time savings compared to other options. Depending on the accessory, it may be single-use disposable, autoclavable, chemical sterilized, or barrier protected and subsequently treated with an intermediate- level disinfectant. Following the manufacturer?s recommended infection control method will result in the best possible outcome for both patients and practitioners.
1. Centers for Disease Control and Prevention. Guidelines for infection control in dental health-care settings. MMWR. 2003;62:RR-17. Available at: http:// www.cdc.gov/OralHealth/InfectionControl/guidelines/ index.htm.
2. From Policy to Practice: OSAP?s Guide to the Guidelines
3. Hubar JS, Gardiner DM. Infection control procedures used in conjunction with computed dental radiography. Int J Comput Dent. 2000;3(4):259.
4. Occupational Safety and Health Administration. www.osha.gov/SLTC/dentistry/index.html
Dr. Fiona M. Collins has authored and presented CE courses to dental professionals and students in the United States and internationally, and is a consultant in the dental industry. She is a member of the American Dental Association and the Organization for Asepsis, Safety and Prevention.
Fiona earned her dental degree from Glasgow University and holds an MBA and MA from Boston University. Dr. Collins can be reached at email@example.com