Many conditions affect the oral cavity and the teeth. Many surveys have been undertaken looking at the incidence of various oral and dental conditions in pets, most showing high levels of disease: 60% to 80% of middle aged and older cats and dogs presented in small animal practices having sufficient disease to warrant immediate professional treatment. The most frequent disease seen is periodontitis associated with bacterial plaque and calculus build-up. Traumatic lesions are also quite frequent, but other problems are much less frequent. All conditions require a thorough diagnostic work-up.
There are many anatomical and physiological variations between species and breeds. These features need to be known before it is possible to decide whether what is present is normal or not, i.e., to diagnose health or disease during either the initial conscious examination or the later definitive examination which needs to be undertaken under general anaesthesia.
The Oral Cavity
1. Soft tissues may be completely pigmented, partially pigmented or unpigmented.
2. Lips. Clear distinction between haired skin and the smooth hairless keratinised stratified squamous external lip epithelium. Lip epithelium merges with oral lining epithelium.
3. Oral lining mucosa. This is the highly sensitive covering of the insides of the lips and cheeks, is also found on the floor of the oral cavity and under surface of the tongue. It is a loosely attached unkeratinised stratified squamous epithelium with a smooth moist surface. There are multiple minor salivary glands beneath its surface. The major salivary gland duct openings pass through it: mandibular and sublingual caruncle lateral to frenulum, zygomatic and parotid papillae on buccal surface opposite maxillary carnassial and first molar. There is a distinct "muco-gingival line" separating it from the gingiva.
4. Gingiva and palate. The gingiva is a firmly attached and relatively insensitive keratinised epithelium found adjacent to the teeth. Its surface is slightly pitted like orange skin. A similar but ridged epithelium covers the hard palate. There is frequently inflammation at the gingival margin where it contacts the teeth. In true health the gingival margin is attached to the tooth by hemidesmosomes. In practice this is unlikely to be the case as inflammation and some swelling is normally present leading to creation of a gingival sulcus. Progression of disease may result in loss of gingiva or periodontal detachment.
5. Teeth. The enamel of the tooth crowns should be smooth and near white without surface deposits. Adult dogs typically have 42 adult teeth (6 incisors, 4 canines, 16 premolars and 10 molars). These should all be fully erupted by about 9 months of age. Cats have evolved to have a reduced number of teeth, their dentition being adapted to a truly carnivorous diet. The 28 teeth typically present in adult cats are made up of 6 incisors, 4 canines, 10 premolars and 4 molars.
6. Occlusion. The teeth are normally arranged so that those in the maxilla and mandible come together in a functional arrangement. The conformation of many breeds disturbs this arrangement.
Recognition of Disease
When the normal and its variations can be recognised, disease can be diagnosed. The animal's history and presenting signs need to be considered, but an oral examination is essential. The initial examination is generally performed on a conscious patient. The extent of this will vary with species and temperament, but even in the most cooperative animal of a species that can open its mouth wide it is still not possible to complete a full examination as this requires exploration and probing which are potentially painful. In addition, radiography is essential for determination of the extent of sub-epithelial dental/jaw disease.
The most frequent oral disease is periodontal disease. This encompasses gingivitis and periodontitis and may progress to extensive tissue damage and destruction. Whilst the accompanying redness and swelling is usually clearly visible in gingivitis, periodontal involvement may be hidden, hence the need to probe for areas of lost tooth attachment to the adjacent bone. As periodontal disease is on the vast majority of cases related to bacterial plaque deposits on the tooth surfaces, and bacterial growth conditions are generally bilaterally symmetrical, the pattern of disease is expected to be nearly symmetrical though one side may be affected to a greater degree than the other.
Diagnosing Oral Disease
As with other areas of medicine, oral diagnosis involves obtaining a basic database on the patient, obtaining the clinical and management history from the client and determining the reason for presentation. This may not be the reason stated by the client as it is quite common for owners to be concerned about something else, for example the possibility of "cancer" or they may be embarrassed about the problem the animal has.
Once a history is available a routine physical examination is required. This should not concentrate on the primary problem until a general health assessment has been performed unless the primary problem is life threatening. Once the general examination is completed a closer examination of the oral cavity is indicated. It is very important to inform clients that it is not possible to adequately assess this area in a conscious animal (poor visibility, poor patient compliance, need to explore and probe dentition plus need for radiography to assess tooth roots and supporting bone, etc.). The conscious examination may be sufficient to make a diagnosis. But it will not be a complete diagnosis and should generally be considered as provisional and needing confirmation.
After discussing differential diagnoses, what further investigations are needed and the likely treatment requirements with the owner, arrangements should be made for more definitive examination under general anaesthesia. With the patient anaesthetised and the airway secured with an endotracheal tube the detailed definitive oral examination can be performed and the results recorded. There are many types of dental chart available from many sources. (Examples are available for free download from the download page at http://www.dacross.com/.) Use of dental charts (plus radiographs and photographs) makes record keeping and explanation of findings to clients easy. Client satisfaction can be greatly enhanced by giving them a copy of the dental chart and an appropriate information leaflet concerning the condition their pet has and how to manage/control/prevent recurrence of it.
Treatment and Follow-up
Once a diagnosis has been made it is possible to plan treatment appropriately. Unfortunately we do not always get the diagnosis correct! Follow-up of cases is extremely important so that we can check that there is an appropriate response to treatment, and in the longer term that control measures for prevention of recurrence have been effective. Should the patient not respond to treatment as expected or further signs appear the whole cycle of examination and diagnosis needs to be repeated:
1. Bojrab & Tholen. Small Animal Oral Medicine and Surgery. Lea & Febiger 1990
2. Crossley & Penman (eds) (1996) BSAVA Manual of Small Animal Dentistry. BSAVA, Cheltenham
3. Harvey & Emily. Small Animal Dentistry. Mosby 1993
4. Linde. Textbook of Clinical Periodontology. Munksgaard 1983
5. Marx RE, Stern D. Oral and Maxillofacial Pathology: A Rationale for Diagnosis and Treatment. Quintessence Publishing 2002
6. Page, Schroeder. Periodontics in man and other animals. Karger 1982
7. Ten Cate AR.Oral Histology: Development, Structure and Function, fifth edition. Mosby, St Louis 1998
8. Wiggs RB, Lobprise HB, Veterinary Dentistry: Principles and Practice. Lippincott - Raven, Philadelphia 1977