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Veterinarian Technician February 2005 (Vol 26, No 2)

Diagnosing Dental Disease Film vs. Digital Radiography

by Ben H. Colmery III, DVM, DAVDC

    It may come as a surprise to most veterinary technicians, but the number one health care problem in companion animals over the age of 9 is not heart or liver disease but rather oral cavity disease. According to the US National Companion Animal Study from the University of Minnesota,1 which involved 39,556 dogs and 13,924 cats divided into three age categories, dental disease is the primary health problem in dogs and cats of all ages. The survey underscores the importance of adhering to a standard of care — throughout the pet's life — that incorporates an escalating schedule of dental checkups with intraoral radiographs to detect silent problems that can percolate below the surface.

    Staying on Top of Dental Disease

    Dental prophylaxis should begin in pets at about 18 months of age. The veterinarian should check for abnormalities such as abnormal crowns and roots as well as teeth crowding. Crowding, which is especially common among small breeds, can be corrected through extractions at the healthy age of 18 months (usually without complications) by simply removing the less critical teeth and making room for the important ones. The next routine dental examination should be conducted at 3 to 5 years of age. Once the animal passes midlife and moves into its senior years, annual checkups are recommended to help guard against cancer or other oral disease.

    A common mistake made in some veterinary practices is taking extraoral skull radiographs or "brain shots" to check for dental problems. Only intraoral radiology can depict lesions and clearly identify underlying problems. Extraoral radio­graphs will show a convoluted superimposition of teeth that is confusing and nearly impossible to read accurately. In short, taking extraoral films may actually waste time and money.

    Animal hospitals that provide dental services should be cautioned to do so only in conjunction with obtaining full-mouth intraoral radiographs. Anything less could leave a practice open to the risk of a malpractice suit.

    Digital Radiography - Fast, Effective Imaging

    The standard of oral cavity care and veterinary medical protocol requires intraoral radiographs. When taking these radiographs, the pet should first be anesthetized. Today's digital radiography dramatically minimizes the need for retakes because the computer allows the veterinarian to make adjustments to the images after they have been taken. These adjustments can include magnifying the suspected areas of interest, brightening and enhancing the image, and even colorizing portions for greater visibility.

    Moreover, digital radiography affords the veterinarian the luxury of seeing results in under a minute. Some processors allow veterinarians to see intraoral images on a computer screen 17 seconds after they are taken. If other views are needed, the technician can quickly take the additional radiographs while the animal is still under sedation. Precious time is not wasted waiting for chemical processing to reveal the results.

    Getting the Whole Picture

    When taking radiographs, it is not uncommon to concentrate only on the area in which there seems to be a problem; however, this can be a huge mistake. For example, a 9-year-old cat with facial swelling on the left side was presented to our clinic. Intraoral radiographs of the affected area suggested that the teeth were fine; however, the cat had a fractured tooth on the upper right maxilla, which was on the opposing side. Intraoral images from what appeared to be the unaffected side revealed a long-standing apical granuloma. The cat outwardly appeared asymptomatic on the right side, but the digital images showed a large abscess. A thorough oral cavity examination and full-mouth intraoral radiographs uncovered a problem. Therefore, it is important to remember that obtaining radiographs of a small area may not give the complete answer. Similarly, in cases of oral cancer, it is especially crucial for chest radiographs to be taken to check for metastasis.

    Intraoral Radiographs Speak Volumes

    Because veterinary patients cannot tell us what is wrong, the veterinarian must rely on diagnostic equipment to uncover the whole story. A male basset hound was recently referred to our practice because he was eating poorly and was obviously in discomfort. Outwardly, the dog's teeth appeared fine; however, intraoral imaging revealed that he had significant resorptive lesions involving the front mesial roots of his upper fourth premolars. The root structure was literally disintegrating, and the affected teeth had to be extracted. In this case, frequent monitoring with intraoral radiology will help the staff preserve the remaining teeth.

    Intraoral radiography is critical to diagnosis and proper treatment, so it is essential that technicians be fully trained in this area. Technicians who want to learn more should seek out courses in their area that cover this topic in detail.

    Equipping a practice with intraoral radiography equipment is relatively inexpensive, and x-ray machines are extremely affordable. The question for the veterinarian becomes whether to purchase a traditional or a somewhat more costly digital processor.

    Advantages of Digital Radiography

    Digital radiography has several advantages, including the three Cs — cleanliness, convenience, and cost-effectiveness. With digital radiography, there are no smelly chemicals to dispose of, no darkroom space requirements, no costly expendables to reorder, and no exposed films to store. The traditional film and chemical system is replaced by a phosphor storage plate that can be used thousands of times.

    Digital radiography has economic advantages as well. The hospital no longer needs to worry about costly and bothersome processor servicing. Most important, valuable space formerly allocated for the darkroom and film storage can be reclaimed and used for patient care. Records can be easily accessed and stored in patient files on a hard drive and on backup files. Films can no longer be misplaced. The ease and efficiency of recordkeeping is a major benefit of digital radiography.

    From the veterinarian's perspective, digital imaging makes radiography a superior analytical tool with clear, comprehensible images that can be enhanced to aid diagnosis and promote constructive consultations with pet owners. With a simple mouse click, previous radiographs can be retrieved onscreen to help illustrate a developing problem or successful healing can be demonstrated by showing side-by-side image comparisons. In addition, the efficiency and speed of digital radiography can shave almost 15 minutes off the patient visit.

    Digital Image Enhancement

    If the technician has not gotten close enough to the problem site with the radiograph, software is available that allows the veterinarian or radiologist to zoom in and magnify the area for a better view. In the case of traditional radiography, the technician would need to retake the radiograph to provide a closer view. Not having to retake the radiograph saves a great deal of time.

    Software programs allow the image to be manipulated in numerous ways, including:

    • Increasing or decreasing the contrast to lighten or darken an image
    • Changing the grayscale
    • Magnifying areas of interest
    • Changing the image from positive to negative and vice versa
    • Colorizing the image (to point out soft tissue lesions)

    Quick Consultation Convenience

    With digital radiography, images can be sent instantly in a bitmap or jpeg format via email to other specialists or radiologists for a consultation or confirmation of diagnosis. The pet owner no longer has to transport films to other locations, and there is no searching through boxes for baseline films. Everything is done electronically with the push of a button. Radiologists can view the images and manipulate them on their own software or post them to a special Web site designed to view and fine-tune the images online.

    Affordability and Profitability

    Many digital processors are available. For a new practice or one that is investing in its first system, digital equipment probably makes the most sense. From a practice management viewpoint, the cost will be amortized over time and there will not be ongoing film and chemical expenditures.


    The bottom line for veterinary practices that provide dental services is that intraoral radiography is an integral part of veterinary dental care. In the near future, this will be part of the standard of care for veterinary patients. For practitioners who want to add radiography capabilities rather than refer all routine patients to dental specialists, the question becomes whether to choose digital or traditional radiography. Management must carefully weigh the costs and benefits before deciding.

    1. University of Minnesota and Mark Morris Institute: National Companion Animal Study, Center for Companion Animal Health: 3, 1995.

    References »

    NEXT: Editorial: Bringing Technology to Technicians


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