A short guide to... Dental disease in small-breed dogs

Periodontal disease

Periodontal disease is the most commonly diagnosed disease of dogs 1. Small-breed dogs are particularly prone to periodontal disease, in part due to crowding of their teeth, decreased chewing behavior compared to large-breed dogs, and owner inability to effectively perform tooth brushing. Eventually, periodontitis [i.e., inflammation of the periodontium) develops, resulting in attachment loss, i.e., loss of alveolar bone, destruction of the periodontal ligament, and gingival recession.

The degree of plaque and calculus accumulation does not always correlate with the degree of periodontitis. Some small-breed dogs are noted to have significant calculus accumulation on oral examination and yet there exists only mild periodontitis radiographically (Figure 1a) (Figure 1b), whereas in other dogs the stage of calculus accumulation significantly underestimates the extent of periodontitis (Figure 2a) (Figure 2b). Judging the degree of periodontal disease on an awake oral examination is an important component of the general physical examination; however, a thorough evaluation under general anesthesia, including periodontal probing and dental radiographs, is necessary in order to determine the true extent of the patient’s periodontal disease and thus what treatment is indicated.

Indications for extraction due to periodontal disease include 50% or more clinical attachment loss (as evaluated on dental radiographs and periodontal probing), furcation exposure, and excessive tooth mobility. Owners may be distressed to discover that their dog needs full-mouth extractions (Figure 3a) (Figure 3b) (Figure 3c) but small-breed dogs typically adapt quite well to an edentulous status and owners often report their dog is “acting like a puppy again” at the postoperative recheck. In some small-breed dogs with moderate periodontitis, the health of the periodontium can be restored through guided tissue regeneration (Figure 4a) (Figure 4b) 2 3. This technique-sensitive procedure allows for osseous and periodontal regeneration and thus can improve the periodontal health of a tooth.

Oronasal fistula

An oronasal fistula is a communication between the oral and nasal cavities, lined by epithelium. Fistulae can either be congenital (e.g., cleft palate) or acquired (e.g., penetrating trauma). The most common causes of acquired oronasal fistulae are periodontitis (Figure 5a) (Figure 5b) (Figure 5c) and failure of a maxillary canine tooth extraction site to properly heal (Figure 6a) (Figure 6b) (Figure 6c) (Figure 6d). Small-breed dogs, notoriously Dachshunds and Miniature Poodles, are prone to developing oronasal fistulae at their maxillary canine teeth, although they can occur at any maxillary tooth, and in any breed of dog. The clinician should be concerned about possible oronasal fistula if the owner reports a history of sneezing, particularly associated with eating or drinking, and nasal discharge, which may be mucoid, serous, or serosanguinous. Oronasal fistula repair most often fails because the surgical flap is too small and/or there is tension on the sutures placed. Furthermore, the clinician must take care to remove the epithelialized edges of the defect to ensure healing between fresh, bleeding edges of tissue.

Draining tracts of endodontal origin

A draining tract of endodontal origin is a granulation-tissue-lined tract through which purulent discharge drains from a periapical lesion onto the facial skin. Classically, this appears as a suborbital swelling and is associated with the maxillary fourth premolar tooth, due to endodontic disease or combined periodontal-endodontic pathology of the offending tooth. However, any endodontically diseased tooth can form a draining tract 4. Intra-oral draining tracts exit through a parulis, typically located at or apical to the mucogingival junction. Patients with chronic facial lesions should undergo comprehensive oral examination, including charting and dental radiographs, to rule out an underlying dental etiology (Figure 7a) (Figure 7b) (Figure 7c).

Mandibular fracture

Small-breed dogs are vulnerable to mandibular fracture. Fractures may be traumatic, pathologic, or iatrogenic in origin. Traumatic causes of fracture include vehicular accidents or bites from other (larger) dogs. The most common cause of pathologic fracture in small-breed dogs is severe, chronic periodontitis (Figure 8a) (Figure 8b) (Figure 8c). Small-breed dogs are also at risk for iatrogenic fracture, e.g., from excessive force used during dental extractions.

Oral ulcers

Chronic ulcerative paradental stomatitis (CUPS) is characterized by painful oral ulcers which are most often located on the buccal oral mucosa (mucositis), but can also occur on the tongue (glossitis) or palatal mucosa. The patient suffers from an over-reaction to plaque, resulting in contact ulcers (Figure 9). Interestingly, these dogs often have normal-to-excessive plaque accumulation, with a less-than-expected amount of calculus formation. Treatment options include a tooth-sparing approach or full-mouth extractions. Tooth-sparing management, which can be frustrating for owners, includes comprehensive oral health assessment with dental radiographs and periodontal charting, extraction of any teeth meeting extraction criteria, biopsy of representative ulcer lesion(s) to confirm the diagnosis, periodontal treatment, and anti-inflammatory, antibiotic, and analgesic therapy. To delay the recurrence of debilitating oral pain, oral hygiene must be meticulous, including daily tooth brushing by the owners and professional periodontal treatment under anesthesia every 3-6 months, or as needed to maintain oral comfort. Performing full-mouth extractions is more surgically invasive, but eliminates plaque aside from that on the dorsum of the tongue, and can thus be a more lasting, permanent treatment option than conservative tooth-sparing management.

Persistent deciduous teeth

Persistent deciduous teeth are primary teeth that have not exfoliated by the time the permanent successor has erupted. They most commonly occur with the canine and incisor teeth of toy breed dogs (Figure 10) 5. Persistent deciduous teeth cause crowding and alter the gingival contour, predisposing the permanent teeth to accelerated periodontal disease. Additionally, they can alter the pathway of permanent tooth eruption, resulting in malocclusion. However, if there is no permanent successor to the persistent deciduous tooth, and if it is periodontally and endodontically healthy, then there is no indication to extract it.

Malocclusion

Many small-breed dogs display malocclusion. This malocclusion may be skeletal (i.e., discrepancy in jaw position, size, or length), dental (i.e., malposition of individual teeth), or a combination of both (Figure 11). Brachycephalic breeds, for example, are bred to have skeletal malocclusion (i.e., relative maxillary brachygnathism). Malocclusion requires treatment only if it results in dental or soft tissue trauma. Treatment options may include extraction of the offending tooth, orthodontic movement, and crown-height reduction followed by root canal treatment or vital pulp therapy.