When taking dental radiographs, there is significant potential for cross-contamination of equipment and environmental surfaces with blood and/or saliva if proper aseptic techniques are not practiced. Dental healthcare personnel (DHCP) also can be at risk. Research indicates that oral micro-organisms can remain viable on inert radiographic equipment for up to 48 hours. Similar microbes have been shown to survive in x-ray developer/fixer for periods as long as 2 weeks.1-4
Infection control practices for dental radiography are identical to those used in the operatory. They are grounded in the practice of standard precautions and are directed toward preventing disease transmission from patients to DHCP, from DHCP to patients, from patient to patient, and from the practice to the surrounding locale.1-3
For infection control during radiographic procedures, a variety of procedures and materials are used, including use of (1) disposable and heat-sterilizable x-ray accessories; (2) immersion of heat-sensitive items in liquid chemical sterilants/high-level disinfectants; (3) surface covers and intermediate-level chemical disinfectants for clinical contact surfaces; (4) engineering and work practice controls; (5) personal protective equipment (PPE) and (6) DHCP training.1-3
The central element or greatest risk factor is the handling of exposed radiographic films. Limiting the spread of body fluids present on such films is an essential activity. Film packs used intraorally become contaminated, then they are handled and transported throughout the practice environment. Also important is the covering or decontamination of soiled items. There are many surfaces that could be touched and become contaminated, including tube heads, extension cones, control panels, exposure buttons, chair controls, film processors, surfaces in darkrooms, and any area touched by contaminated film, gloved hands, or equipment used orally.2-4
Infection control procedures for dental radiography can be divided into segments or components. These include activities before taking radiographs, activities performed while taking a radiograph, things to do after radiographs have been taken, and finally, tasks associated with film processing. All suggested activities first discussed apply to the taking of standard intraoral x-rays using film held within barrier protective pouches. Some films come pouched by the manufacturer, or pouches can be purchased separately and films can then be placed into them.2-4 Advice on using x-ray films without barrier pouches, taking panoramic/cephalometric x-rays, using a daylight loader for processing, and the use of digital radiography sensors will then be provided.
USING INTRAORAL FILMS HELD WITHIN BARRIER POUCHES
| Table 1. Prior to taking x-rays (modified from references 2 to 5). |
| Step |
Action |
| 1 |
Acquire all necessary disposable and heat-sterilized intraoral x-ray accessories |
| 2 |
Place surface covers on selected clinical contact surfaces |
| 3 |
Unit-dose necessary supplies, equipment, and instruments |
| 4 |
Provide patient with appropriate shielding apron |
| 5 |
Wash hands, dry well, and put on examination gloves |
| 6 |
Place other types of PPE if necessary |
|
| Table 2. While taking x-rays (modified from references 1 to 8). |
| Step |
Action |
| 7 |
Wear gloves while taking x-rays and when handling contaminated films |
| 8 |
Wear other PPE such as masks, protective eyewear, and gowns if spatter is expected |
| 9 |
Use films held within FDA-cleared barrier pouches |
| 10 |
Touch as few surfaces as possible |
| 11 |
After exposure and with gloved hands, dry each film with disposable gauze or paper towel to remove patient fluids |
| 12 |
Repeat process until all films are exposed |
|
| Table 3. After taking x-rays (modified from references 1 to 8). |
| Step |
Action |
| 13 |
Return reusable film-holding devices to the designated area. |
| 14 |
Carefully remove the film packets from their protective pouches to avoid contamination of the film surfaces. Allow the films to fall from the pouches into clean paper or plastic cups or onto clean paper towels—avoid touching the transport cups |
| 15 |
Discard all contaminated disposable materials |
| 16 |
Remove covers (barriers) from the surfaces protected and discard |
| 17 |
Disinfect uncovered surfaces that were contaminated while wearing gloves |
| 18 |
Remove gloves and wash hands properly |
|
Preparing to Take Dental Radiographs
It is important to prepare the area prior to seating the patient. Advanced preparation increases the chances of success. Whenever possible, items used in the mouth should either be single-use, disposable, or sterilized by heat (Table 1).
Covers generally involve plastic sheets, tubes, or pieces with adhesive edges. Examples of surfaces best covered include chair headrest and control adjustments, exposure buttons, control panels, and x-ray tube heads and yokes.2-4
Unit-dosing reduces the need to leave the immediate area in search of needed items, and it decreases the chances of DHCP contaminating large boxes or storage containers of materials while searching. Unit-dosing also reduces the chances of cross-contamination of environmental surfaces. Items best taken from a centralized supply area and unit-dosed include paper towels, mouth props, film holders (eg, cups), gloves, surface covers, film packs, and cotton rolls. Such items can be collected, stored, or segregated through the use of small plastic drinking cups.2-4
Film barriers have distinct advantages. First, barriers protect films from direct contamination. Second, barriers reduce the time needed for preparation and processing by eliminating the need for disinfection in the darkroom and the necessity of wearing additional pairs of gloves. Film barriers are the method of choice, especially when using daylight loaders. Their use eliminates almost all potential for equipment contamination.2-4
After the patient has been seated, hands can be washed, dried, and gloves placed. Then, heat-sterilized x-ray holding/positioning devices can be removed from their packages and assembled in view of the patient.2,3
Taking Dental Radiographs
Gloves should always be worn when taking radiographs and handling contaminated film packets. Other PPE should be used when the spattering of patient body fluids is likely. Ideally, only heat-tolerant intraoral x-ray accessories (eg, film holders and positioning devices) should be used. Some items such as mouth props can either be sterilized or be single-use and disposable (Table 2).
After Taking Dental Radiographs
Care must be taken when peeling or pulling open the protective barriers covering the x-ray films. Patient fluids must not reach either the films or the transport cups. Unsoiled films are the desired goal. Handling such items without gloves makes processing much easier in the darkroom and daylight loader1-4 (Table 3).
Developing Dental Radiographs
Once in the developing area, open film packets with clean, ungloved hands. Holding the tab, films can go into clean plastic cups or onto paper towels. Holding films by their edges, insert them into the processor. Just to be safe, it is best either to cover or to clean and disinfect the surfaces of developing equipment regularly1-4 (Table 4).
| Table 4. Processing x-rays (modified from references 1 to 8). |
| Step |
Action |
| 19 |
Transport films in disposable containers; gloves are not needed because the outside of the films and the containers is not contaminated |
| 20 |
Discard all contaminated disposable materials |
| 21 |
Prepare the processing area by unit-dosing out necessary items such as gloves, paper cups, paper towels, film mounts, and paper envelopes |
| 22 |
Unwrap films and process; hold films only by their edges |
| 23 |
Label film mounts or film envelopes |
| 24 |
Disinfect uncovered surfaces of the developing equipment |
|
| Table 5. Processing unprotected x-rays (modified from references 1 to 8). |
| Step |
Action |
| A |
Transport films in disposable container cups |
| B |
Place cups onto paper towels and prepare processing area |
| C |
Put on new gloves, open film packets, and allow film to fall onto clean paper towels |
| D |
Dispose of transport cups and empty film packets |
| E |
Remove gloves and wash hands |
| F |
Process films by holding them by their edges |
| G |
Label film mounts and envelopes |
| H |
Disinfect uncovered surfaces that were contaminated while wearing gloves |
|
| Table 6. Extraoral radiographs (modified from references 1 to 8). |
| Step |
Action |
| A |
Wash and dry hands—extraoral cassettes can be handled with ungloved hands |
| B |
Use sterile reusable or single-use disposable bite guides |
| C |
If deemed necessary, barrier protect chin rests, head positioning guides, and handgrips |
| D |
After exposure of the film, ask the patient to remove the bite guide and barrier covers |
| E |
If patient cannot or will not comply, the DHCP must put on gloves and handle bite guide and surface covers |
| F |
Remove gloves and wash hands prior to handling film cassettes |
|
USING INTRAORAL FILMS NOT HELD WITHIN BARRIER POUCHES
It is important when handling and processing films not held in protective barriers that they be well wiped off chairside after removal. It is very important either to cover or clean and disinfect any surface that may become contaminated2,3 (Table 5).
PANORAMIC/ CEPHALOMETRIC X-RAYS
Fewer intraoral pieces of equipment are used when taking extraoral radiographs such as panoramic and cephalometric films. The chances of contamination with patient blood or saliva are greatly reduced. Bite guides should be sterilized or be single-use disposable types. The use of covers over the bite guide is less desirable2,3 (Table 6).
PROCESSING X-RAY FILMS IN A DAYLIGHT LOADER
Daylight loaders commonly have cloth or rubber sleeves, cuffs, or flaps. These are used to allow for the passage of materials in and out of the daylight loader without allowing light to enter. This means that the equipment is difficult or impossible to clean or disinfect. Therefore, it is imperative that an effective yet efficient protocol for aseptic use be established and rigorously maintained. After reviewing the following steps, it should be obvious how useful barrier protected films are2-6 (Table 7).
DIGITAL X-RAYS AND OTHER TECHNOLOGIES
| Table 7. Using daylight loaders (modified from references 1 to 8). |
| Step |
Action |
| A |
Open the lid of the loader and place all necessary items inside: paper towels, plastic cups, and powder-free inexpensive gloves |
| B |
Place cups containing contaminated films next to clean plastic cups |
| C |
Close the lid and insert arms into the unit |
| D |
Put on gloves and select a single-film packet to be processed and open it as aseptically as possible. Repeat until all films have been opened |
| E |
Allow film to fall onto a clean paper towel |
| F |
Place all disposable materials into a plastic cup |
| G |
Remove gloves and place them into a cup |
| H |
Feed films into the processor, handling them only by the edges (or process films by hand by immersing them in the appropriate chemical-filled cups while wearing a new pair of gloves) |
| I |
Remove ungloved hands from the unit and wash them |
| J |
Lift lid and remove processed films—label film mounts or film envelopes |
| K |
Aseptically remove and dispose of waste materials |
|
Digital radiographic sensors and other high-technology instruments such as intraoral cameras, electronic periodontal probes, colossal analyzers, and lasers come into contact with mucous membranes. Such devices are considered to be semi-critical items. Ideally, they should be cleaned and heat-sterilized or high-level disinfected between patients. However, many cannot be heat-sterilized or undergo high-level disinfection.
Semi-critical items that cannot be reprocessed by heat sterilization or high- level disinfection should at a minimum be barrier-protected by using a FDA-cleared barrier to reduce gross contamination. Covers are not always totally protective. Therefore, after removing the barriers, devices should be cleaned and disinfected using an intermediate level disinfectant (tuberculocidal) after each patient. Manufacturers should be consulted as to sterilization and disinfection processes as well as to the types of covers to be used.1-6
SUMMARY
Infection control for dental radiography employs the same materials, processes, and techniques used in the operatory, yet unless proper procedures are established and followed, there is a definite potential for cross-contamination to clinical area surfaces and DHCP. In general, the aseptic practices used are relatively simple and inexpensive, yet they require complete application in every situation.
References
- Kohn WG, Collins AS, Cleveland JL, et al; Centers for Disease Control and Prevention. Guidelines for infection control in dental health-care settings—2003. MMWR Recomm Rep. 2003;52(RR-17):1-61.
- Organization for Safety & Asepsis Procedures. From Policy to Practice: OSAP’s Guide to the Guidelines. Annapolis, Md: Organization for Safety & Asepsis Procedures; 2004:91-97.
- USAF Dental Investigation Service. Infection control practices for dental radiology. Available at: http://www.brooks.af.mil/dis/DOWNLOAD/radiologyinfcontrol.pdf. Accessed April 2004.
- Organization for Safety & Asepsis Procedures. Infection control and dental radiography. Infection Control In Practice. 2003;2(November):1-8.
- Miller CH, Palenik CJ. Sterilization, disinfection, and asepsis in dentistry. In: Block SS, ed. Disinfection, Sterilization, and Preservation. 5th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2001:1049-1068.
- Miller CH, Palenik CJ. Infection Control and Management of Hazardous Materials for the Dental Team. 2nd ed. St Louis, Mo: Mosby; 1998:217-221.
- Haring JI, Jansen L. Infection control and the dental radiographer. In: Haring JI, Jansen L. Dental Radiography: Principles and Techniques. 2nd ed. Philadelphia, Pa: WB Saunders; 2000:194-204.
- Glass BJ, Terezhalmy GT. Infection control in dental radiology. In: Cottone JA, Terezhalmy GT, Molinari JA, eds. Practical Infection Control in Dentistry. 2nd ed. Baltimore, Md: Williams & Wilkins; 1996:229-238.
Dr. Palenik has held over the last 25 years a number of academic and administrative positions at Indiana University School of Dentistry. These include professor of oral microbiology, director of human health and safety, director of central sterilization services, and chairman of infection control and hazardous materials management committees. Currently he is director of infection control research and services. Dr. Palenik has published 125 articles, more than 290 monographs, 3 books, and 7 book chapters, the majority of which involve infection control and human safety and health. Also, he has provided more than 100 continuing education courses throughout the United States and 8 foreign countries. All questions should be directed to OSAP at office@osap.org.
