Dental radiographs provide practitioners with a tremendous amount of information. The most important thing you can do to increase
the quality of dental care in your practice is to use dental radiography when evaluating patients presented for routine dental
care or dental problems. In addition, the AAHA Dental Care Guidelines for Dogs and Cats state that preoperative and postoperative
dental radiographs are mandated for all extractions.1 Furthermore, standard radiographic views of the skull are inadequate, and full-mouth dental radiographs are an essential
step in dental cleaning and are necessary for accurate oral evaluation and diagnosis.
In this article, I'll provide information to help you avoid common dental radiography errors and to perfect your dental radiography
techniques by reviewing the basics of positioning, exposure, and development, including how to capture hard-to-image teeth
in dogs and cats.
THE RIGHT PLACEMENT, THE RIGHT TIMING
To obtain a diagnostic radiograph, it is crucial to get the patient, film, and beam head in just the right position and set
the correct amount of X-ray exposure. Follow this systematic approach.
Step 1: Patient positioning
The first step in creating high-quality dental images is to ensure correct patient positioning.2-6 Sand bags, V-shaped troughs or holders, and other implements will aid in stability and patient placement. Make sure the
area of interest is appropriately positioned in the radiographic beam. Except in rare instances, the object or tooth to be
radiographed is positioned on the up side. To help you determine the bisecting angles, position the patient as follows:
- Mandibular premolar and molar teeth: Place the patient in lateral recumbency with the side to be imaged up.
- Maxillary teeth: Place the patient in ventral recumbency.
- Mandibular canine and incisor teeth: Place the patient in dorsal recumbency.
Once an operator is proficient in visualizing the correct bisecting angle, several maxillary images can be obtained with the
patient in lateral recumbency, which avoids repositioning the patient numerous times during procedures.
Step 2: Film placement
Film placement in veterinary dentistry can be challenging because of the anatomy of the tooth roots and the inability to see
the roots. Correct film placement minimizes retakes.
When standard dental film (e.g. Eastman Kodak Company HSD/Dental Products) is used (Figure 1), an embossed dot (or dimple) is evident on the corner of the film. The side of the film with the palpable dimple should
be placed toward the X-ray beam; with most film types, this side of the film is typically white. The opposite or back side
of the film is usually colored.
Place the film in the mouth, ensuring that the entire tooth (including the root) will be imaged. The most common sizes of
film used in veterinary dentistry are size 4 and size 2. Size 4 film is used for large patients, whole quadrants, or exposing
full-mouth radiograph sets. Size 2 is used for individual teeth or for smaller patients. Sizes 0 and 1 are occasionally used
for small and pediatric patients. Size 3 is known as bite wing and is rarely used in veterinary dentistry. The roots are much longer than the crowns in veterinary patients. This is especially
true of canine teeth, which have roots that are at least twice as long as the visible crown. Always err on the side of having
the film too far into the mouth to ensure you capture the complete root structure. In addition, place the film as close as
possible to the tooth or teeth of interest (generally touching the tooth and gingiva) to minimize distortion (Figure 2).