Oral conditions and diseases are a diagnostic challenge. Several disease conditions are generally present simultaneously. The great majority of dogs and cats will have gingivitis and or periodontitis as well as other problems. Moreover, clinical signs are rarely specific; i.e., malodour, changing in eating patterns, and dysphagia are indications that there is a problem in the oral cavity, but they are not necessarily specific for a particular disease. Finally, manifestations of disease are often discrete and are often not detected on conscious clinical examination. Even if they are detected on conscious examination, general anaesthesia is required to evaluate the extent of pathology. The importance of a full oral exam under general anaesthesia (definitive examination) cannot be underestimated.
The recommended protocol for definitive examination of the oral cavity involves inspection of the oropharynx, lips, cheeks, oral mucous membranes, hard palate, floor of the mouth, tongue as well as teeth and periodontium. In general veterinary practice, examination of the periodontium is often omitted and periodontal disease is missed.
The periodontium of each tooth needs to be assessed to:
1. Identify the presence of periodontal disease (gingivitis and periodontitis)
2. Differentiate between gingivitis (inflammation of the gingiva) and periodontitis (inflammation of the periodontal tissues resulting in loss of attachment and eventually tooth loss)
3. Identify precise location of disease processes
4. Assess the extent of tissue destruction where there is periodontitis
The following periodontal indices and criteria should be evaluated for each tooth.
1. Gingivitis and gingival index
The presence and degree of gingivitis is assessed based on redness, swelling and presence or absence of bleeding on probing of the gingival sulcus. Various indices can be used to give a numerical value to the degree of gingival inflammation present. In the clinical situation, a simple bleeding index is the most useful.
2. Periodontal probing depth (PPD)
PPD measures the depth of the sulcus. A graduated periodontal probe is gently inserted to the base of the gingival sulcus; i.e., until resistance is felt. The depth from the free gingival margin to the base of the sulcus is measured in mm at several locations around the whole circumference of the tooth. The probe is moved gently horizontally, walking along the floor of the sulcus.
The gingival sulcus is 1–3 mm deep in the dog and 0.5–1 mm in the cat. Measurements in excess of these values usually indicate the presence of periodontitis when the periodontal ligament has been destroyed and alveolar bone resorbed, thus allowing the probe to be inserted to a greater depth. The term used to describe this situation is periodontal pocketing. All sites with periodontal pocketing should be accurately recorded. Gingival inflammation resulting in swelling or hyperplasia of the free gingiva will, of course, also result in measuring sulcus depths in excess of normal values. In these situations, the term pseudo-pocketing is used, as the periodontal ligament and bone are intact (i.e., there is no evidence of periodontitis) and the increase in PPD is due to swelling or hyperplasia of the gingiva.
3. Gingival recession
Gingival recession is the distance (in mm) from the cemento-enamel junction to the free gingival margin. It is also measured using a graduated periodontal probe. At sites with gingival recession, PPD may be within normal values despite loss of alveolar bone due to periodontitis.
4. Furcation involvement
Furcation involvement refers to the situation where the bone between the roots of multirooted teeth is destroyed due to periodontitis. The furcation sites of multirooted teeth should be examined with either a periodontal probe or a curved dental explorer.
5. Tooth mobility
Assessed using a suitable instrument; e.g., the blunt end of the handle of a dental mirror or probe.
Should not be assessed using fingers directly, since the yield of the soft tissues of the fingers will mask the extent of tooth mobility
6. Periodontal/clinical attachment level (PAL/CAL)
Periodontal attachment level records the distance from the cemento-enamel junction (or from a fixed point on the tooth) to the base or apical extension of the pathological pocket. PAL can be measured with a periodontal probe. It can also be calculated; i.e., PPD + gingival recession/PPD - gingival hyperplasia. PAL/CAL is a more accurate assessment of tissue loss in periodontitis than PPD.
The information resulting from the examination (and any treatment performed) needs to be recorded. A basic dental record consists of written notes and a completed dental chart. Additional diagnostic tests and radiographs are included as indicated. A dental chart is a diagrammatic representation of the dentition, where information (findings and treatment) can be entered in a pictorial and/or notational form. It provides a simple way of recording most of your findings and treatments. However, it is only a chart and needs to be supplemented by clinical notes, radiographs, etc. to make a complete dental record.
Radiography is a vital diagnostic tool in veterinary dentistry. Radiographs are required to:
1. Reach a diagnosis
2. Assess extent of pathology
3. Plan optimal treatment
4. Perform certain procedures
5. Assess outcome of treatment performed
General anaesthesia is required for radiography. Ideally, clinical examination and recording should precede the radiographic evaluation. It is also useful to clean the teeth before any radiographs are taken. Dental calculus, because it is radio-dense, can obscure pathological lesions on a radiograph.
For a dental radiograph to be diagnostic, it should be an accurate representation of the size and shape of the tooth without superimposition of adjacent structures. Intraoral (film placed inside mouth and x-ray beam directed from outside the mouth through tooth and adjacent structures onto the film) radiographic techniques are therefore required. The two basic techniques are:
1. Parallel technique for the mandibular premolars and molars
The patient is placed in lateral recumbency (with the side to be radiographed uppermost).
Film is placed between the tongue and the teeth and pushed as far down into the sublingual fossa as possible. The x-ray beam is then directed from lateral to medial at right angles to the long axis of the tooth.
2. Bisecting angle technique for all other teeth
The film is positioned at an angle behind the tooth. An imaginary plane is drawn half way between the plane of the film and a plane through the long axis of the tooth; i.e., at the bisecting angle, and the x-ray beam is directed perpendicular to this plane.
Full mouth radiographs describes a series of films where each tooth of the dentition is accurately depicted in at least one view. A full mouth radiographic series of all animals undergoing dental examination provides valuable information, but is not always practically or financially viable. However, it is strongly recommended that all adult cats have full mouth radiographs taken as part of the oral and dental examination. Odontoclastic resorptive lesions are common in cats and clinical examination without radiography will only detect end-stage lesions. In cats, it is necessary to take a minimum of 8 views, but 10 views are recommended, to ensure that all teeth are properly visualised. In the case of dogs, full mouth radiographs are encouraged, especially at first examination. If this is not possible (time or financial restrictions) then radiographs are taken where indicated based on the findings during the clinical examination. In the event of full mouth radiographs, the size of film and the number of films used will depend upon the breed of dog and the shape of its face.
Equipment and Materials for Conventional Intra-Oral Radiography
1. X-ray machine
2. X-ray film
3. Processing facilities
4. Mounts or envelopes for film storage
In the last five years, the major development has been in the introduction of digital dental radiography. The techniques for taking radiographs have not changed. However, the processing using digital is much simpler, cheaper and faster than conventional methods. Given the relative low cost of entry for a digital system and the benefits in terms of speed and ability to manipulate the images via the software I would strongly recommend investing in such a system from the outset. There is a fast payback of the initial investment.
Radiographs should be viewed on a viewing box with minimal peripheral light and preferably using magnification. It is recommended to radiograph the contra-lateral structures, to those being evaluated, for comparative purposes. A good knowledge of the radiographic appearance of normal structures of the upper jaw and mandible is imperative to avoid misdiagnosis.
The definitive oral examination, supplemented by radiographs will give a complete picture of the disease processes present and allow for targeted treatment. Clinical cases will be used to exemplify this approach.
References are available upon request.