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The importance of dental radiography

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01 December 2015, at 12:00am

MATTHEW OXFORD explains why radiography is so important in general practice dentistry and why, with the prevalence of dental disease within our domestic species, it should be mandatory

DENTAL radiography is an essential component of effective veterinary dentistry.

Standard medical radiography is taken for granted within veterinary practice now, and even advanced imaging modalities such as computed tomography and magnetic resonance imaging can now be found in first opinion practice.

So why is dental radiography, an inexpensive yet essential tool in our day-to-day surgical caseload, so often overlooked?

This article will look at why dental imaging is so important in general practice dentistry.

Dental radiography provides us with three areas of information that are essential in planning and carrying out dental surgery.

1. Dental anatomy

Perhaps more than any other body system, there is a huge variation in the normal anatomy of teeth and their supporting structures. Many organs have very little anatomical variation between individuals and even between vastly different breeds. Yet the anatomy of the skull between, for example, a boxer and a greyhound, varies immensely.

This anatomical variation of skull bones affects the position of the teeth within the oral cavity, and relative to each other. It affects the position, angle and shape of the tooth roots.

The teeth themselves also show significant variation with 1, 2 and 3 rooted teeth as normal, but then also variants of these with either fused or additional roots (Figures 1, 2 and 3).

Teeth undergo a maturation process, and knowledge of the degree of maturation may affect our decision making about treatment options.

Knowledge of the individual anatomy of each patient is essential for planning and executing dental surgery. If a normally two-rooted tooth only has a single fused root, then extraction may change from an open to a closed technique (Figure 1).

Similarly, if a normally two-rooted tooth has an additional root, then this must be taken into consideration and all three roots must be extracted. Without dental radiography, the additional third root may be missed and left as a root remnant (Figures 2 and 3). Sharp angulation of a root (dilaceration) may alter our surgical technique to allow extraction without fracturing the root.

2. Dental pathology

Examination of the oral cavity will give us some information about the visible structure such as the crown and gingiva.

However, without radiography we have no indication of disease processes with the pulp system (endodontic

disease), within the periapical area and disease of the surrounding alveolar bone (Figure 4a, 4b and 4c).

As vets we are very comfortable that we need to carry out radiographs for assessment of the internal structures of the thorax, abdomen and musculoskeletal system, yet in dentistry we are forced to make decisions regarding treatment options with only the equivalent of an abdominal palpation or cardiac auscultation.

Whilst this does provide invaluable information, it does not give us a complete picture with which to develop an effective treatment plan.

Dental radiography is essential in assessment of tooth resorption in cats (Figure 5), endodontic disease such as pulp exposure and necrosis with periapical disease (Figure 6a and 6b, Figures 7 and 8), and oral neoplasia.

In addition to these it provides valuable information for treatment planning in cases of alveolar bone loss and external root resorption with periodontal disease (Figures 9, 10a and 10b). Once the pathology has been identified, then suitable treatment planning can be made.

In the example of tooth resorption, dental radiography will give us essential information regarding the type and extent of tooth resorption, where simple oral examination will not.

If, for example, extensive type 2 (replacement) resorption is identified, then treatment moves away from fruitlessly trying to extract a root which is essentially no longer there, to a very straightforward crown amputation (Figure 11a, 11b and 11c). This has clear benefits both to the patient and the veterinary surgeon.

3. Assessing treatment

When orthopaedic surgery is carried out, radiography is almost always carried out post-operatively.

Surgeons want to assess their fracture reduction and plate positioning, and they want a permanent record of this to refer back to when future assessments are carried out. It also provides an invaluable medico-legal document.

Dental radiography is no different. Following treatment, we want to ensure that our treatment has been effective. For the majority of general practice dentistry, this means radiographing the jaws following extractions to ensure those extractions have been completed and there are no residual root fragments (Figures 12, 13 and 14).

Inadvertently retained root fragments can form a persistent focus of inflammation. This is particularly true when the pathological process for which the tooth was extracted has not been resolved.

For example, if the root of a fractured tooth with a necrotic pulp is incompletely extracted, then there will still be necrotic and infected pulp within that root fragment. This material will still stimulate a periapical inflammatory response.

Similarly, inadvertently retained root fragments in a cat with feline chronic gingivostomatitis will continue to stimulate mucogingival inflammation and prevent the potential resolution of clinical signs.

In advanced dentistry, dental radiography is mandatory for carrying out and assessing the response to endodontic treatment (Figures 15 and 16).

This article has demonstrated how invaluable dental radiography is. Given the prevalence of dental disease within our domestic species, it is the author’s opinion that dental radiography should now be mandatory within general veterinary practice.