Digital Intraoral Radiology: Standard of Care for Dental Diagnostics
By Jan Bellows, DVM, DAVDC, DABVP—All Pets Dental, Weston, Florida
Volume 3 No. 3
Introduction to Intraoral Dental Imaging
Standard of care in veterinary diagnostics involves following established processes for patient care, illness management, or clinical circumstances. Companion animal patients receiving dental care are prime candidates for intraoral dental imaging, a rapidly evolving standard. While crowns of teeth can be cleaned and polished, true dentistry requires visualizing structures below the gingiva. Intraoral radiographs are essential for quality dental diagnostics and therapy.
Diagnostic full-mouth survey films are best obtained using a dedicated dental unit, as skull films often result in superimposition of arches, hindering diagnostic clarity.
Analog vs. Digital Radiology
Traditional film processing involves manual development in tanks or using an automatic film processor. Alternatively, digital sensors capture images directly, displaying them on a computer screen. Digital dental imaging offers advantages in ease of use, economy, and diagnostic capability compared to the "analog" film method.
Benefits of Using Digital Radiology in Veterinary Dentistry
Time Saver
Digital radiology significantly reduces the time spent on tasks like staff teaching, tube head/sensor positioning, and film processing. Instant results eliminate the delays associated with traditional film development.
Money Saver
While initial investment for digital systems ranges from $6,000–$18,000 (U.S.) plus x-ray generator and computer costs, the long-term savings are substantial. The cost per processed analog film is estimated at $1.18. For procedures involving multiple films, digital systems offer considerable cost reduction. Furthermore, reduced staff and anesthesia time per patient (e.g., 20 minutes saved per patient) translate into thousands of dollars saved annually.
Good Medicine
Radiology is crucial for thorough dental care, as approximately 60% of a tooth lies below the gum line. Without radiographs, evaluation of periodontal and endodontic conditions is limited. Digital imaging allows for enlarged views on a large monitor within seconds, enhancing diagnostic information through electronic processing and enhancement. Images can be easily saved, shared for consultations, or included in client reports. Archived image storage is automatic and requires no physical space or sorting time.
Additional Advantages
- Lower radiation dosage: Digital systems require up to 80% less radiation than D-Speed film.
- Faster imaging: Direct, wired systems provide immediate results without film development or plate scanning.
- Electronic storage: Offers faster access, enhanced record safety, lower cost, and reduced space requirements with proper backup procedures.
- Electronic referrals: Digital files can be transmitted for consultations.
- Less time needed for retakes: Image adjustment capabilities reduce the need for re-exposing over- or underexposed radiographs.
Digital Intraoral Radiology Visual Examples
What Are the Intraoral Digital Capture Formats?
Digital technologies for dental imaging primarily fall into two categories: photosensitive phosphor (PSP) plates and direct-imaging sensors.
Photosensitive Phosphor (PSP) Plates
PSP technology uses an x-ray-sensitive plate that replaces film. After exposure, the plate is scanned to convert the latent image into a digital file. This process takes approximately 45 seconds. While plates are relatively rugged and offer fewer size restrictions, the equipment can be bulky. Plates require replacement after 50–500 exposures, costing about $25 (U.S.) each. Phosphor sensors and plates are available from manufacturers like All Pro Imaging.
Direct-Imaging Sensors
Direct-imaging sensors connect to a computer via wire or wirelessly, displaying images within seconds without additional handling. Early sensors used charge-coupled devices (CCD) combined with a scintillator. More recent systems utilize complementary metal oxide semiconductors (CMOS), which offer high efficiency and low noise. Manufacturers include Imageworks, Bio-Ray Dental Systems, XDR, Progeny by MIDMARK, Sopix, and Schick Technologies.
What Will You Need to Get Started or Convert to Digital Dental Radiology?
A dental x-ray unit is required. While traditional AC units are adequate, DC generators produce a more homogeneous beam optimal for sensors. As digital imaging requires less radiation than film, older dental x-ray units may need replacement.
A computer (desktop, tablet, or laptop) is needed to capture and display images. Sensors are portable but require easy USB connection unless a wireless system is used. USB-powered hubs can extend reach if the computer is in a cabinet.
The digital sensor replaces film in the patient's mouth. Sensors are available in sizes 0, 1, and 2, similar to film numbering. Phosphor plates come in sizes 0, 1, 2, 4, and 6. Proper sensor positioning uses parallel or bisecting angle techniques. Software downloaded into the computer allows operators to select the tooth or quadrant for exposure, with images appearing almost instantly.
Image quality is comparable to traditional films. Software offers tools for enhancement, such as enlargement, auto contrast, grayscale resolution, spotlight features, color inversion, and measurement rulers.
Which System?
Comparing dental digital vendors can be complex. A key criterion is resolution, measured in line pairs per millimeter (lp/mm). Other factors include sensor size, pixel matrix, pixel size, active image area, and readout time.
While many systems quote technical specifications, it is best to assess image quality directly. A live demonstration in your office using your own equipment is recommended. If this is not possible, request references from existing users.
Important Considerations When Evaluating Intraoral Digital Sensors
- Active Area: The measurable area of the sensor (in mm) where data is captured.
- Dynamic Range: The ratio of the largest to smallest output, measured in decibels (dB). A higher dB number indicates better image capability.
- Film Size Equivalent: Compares sensor/image size to traditional film systems.
- Pixel Matrix: The total number of pixels (horizontal x vertical).
- Pixel Size: The physical size of individual pixels (in microns).
- Readout Time: Time from x-ray exposure to data transmission completion (in seconds).
- Resolution: Ability to capture detail, measured in line pairs (lp).
- Sensor Dimensions: External measurements of the sensor (in mm).
- Signal-to-Noise Ratio: Ratio of signal to noise in the image.
Should I first purchase a film-based system and then convert?
Previously, the recommendation was to start with film, then move to automatic processing, and finally digital. Now, it is more practical to bypass film and processing entirely. Just as one would not buy a film camera today, the same logic applies to dental radiology; digital makes more sense.
Intraoral digital dental radiology is a user-friendly, economical diagnostic tool that enables veterinarians to provide superior dental and diagnostic care for their patients.
References
- Definition of "standard of care." MedicineNet.com Web site. http://www.medterms.com/script/main/art.asp?articlekey=33263. Accessed August 2, 2010.
- Feuerstein P. Digital radiography. Dental Economics. 2005;95(2):98.
