This rabbit is displaying what is often the earliest sign of acquired dental disease.
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What is the condition, and how is it related to the teeth?
The rabbit has epiphora, which has caused a secondary superficial pyoderma and local alopecia below the eye.
In acquired dental disease, inadequate dental wear leads to excessive exposed crown length and consequent increased occlusal pressure.
This in turn resists further eruption, so that tooth growth continues in a retrograde direction.
In the case of the first maxillary incisor, this can impinge on the nasolacrimal duct, which runs close to the apex of the incisor, causing a partial or complete obstruction.
Secondary bacterial infection of the duct often follows (dacryocystitis), where milky fluid can be expressed from the lacrimal sac by gentle pressure below the medial canthus.
In more advanced dental disease, root elongation or a periapical abscess of the first maxillary premolar may also block the duct.
What other indicators of dental disease might be apparent on routine physical examination, even before inspecting the oral cavity?
Apical elongation of the lower cheek teeth can be appreciated as irregularities in the ventral margin of the mandible.
Maxillary masses may also be palpable.
Decreased lateral movement of the mandible may be present on gentle manipulation, due to elongation and abnormal curvature of the cheek teeth and spur formation.
Uneven molariform wear due to malocclusion forms sharp spurs that lacerate the buccal and lingual mucosa.
The pain associated with these lesions stimulates salivation and interferes with swallowing, resulting in ptyalism. This is seen as a wet or matted chin, brisket or forelimbs, perhaps with secondary dermatitis.
Inability to groom results in poor coat condition and may make existing ectoparasite infestations more severe (e.g. Cheyletiella parasitivorax).
Pain may also prevent caecotrophy, with consequent accumulation of caecotrophs around the anus. (There may also be a reduced appetite for caecotrophs with inappropriate diets.) This malodorous mass is often misinterpreted as diarrhoea by the owner, and predisposes to fly strike. Perineal skin may become inflamed, particularly if the passage of urine is impeded.
The rabbit may be currently anorexic (perhaps with gut stasis) and reluctant to drink from a dropper bottle, or the owner may report a history of periods of anorexia as a succession of lesions heal, only to reform once mastication resumes. This is reflected in a gradual net loss of body condition.
Buccal lesions may become infected and give rise to facial abscesses. Continued retrograde tooth elongation eventually results in perforation of the periosteum and extension of periodontal infection to form periapical abscesses. Those arising from maxillary cheek teeth may be associated with exophthalmus (molars), intrusion into the nasal passages, causing rhinitis and respiratory noise (PM1), or swelling below the medial canthus (PM2, PM3).
