Trismus, masticatory myositis and antibodies against type 2M fibers in a mixed breed cat.

CASE SUMMARY: A 1-year-old male neutered mixed breed cat presented with a 2 month history of inability to fully open the mouth when yawning and decreased ability to prehend food. Physical examination revealed severe bilaterally symmetrical masticatory muscle atrophy, a restricted vertical mandibular range of motion of 11-12 mm, and a normal body condition score. Skull radiography was normal. A canine ELISA system against unique masticatory muscle fibers (2M antibody titer), was positive at 1:1000 (reference interval <1:100 in dogs, and was <1:100 using serum from five archived normal cats), indicating the presence of cross-reacting antibodies. Owing to the chronicity and clinical severity, corticosteroid treatment did not result in improved jaw mobility, consistent with end-stage masticatory myositis. Masticatory muscle biopsy was declined at initial presentation. However, 1 year later at elective euthanasia, CT ruled out temporomandibular joint osseous restrictions, and masticatory and biceps femoral muscle histopathology evaluation confirmed end stage feline masticatory myositis with normal limb muscle. RELEVANCE AND NOVEL INFORMATION: Masticatory myositis should be included in the differential diagnosis of trismus in cats. A canine ELISA can be used to indicate the presence of feline 2M cross-reacting antibodies. More cases are needed to fully elucidate the clinical presentation and best course of treatment.

Thermoplastic inclined plane aligner for correction of bilateral mandibular canine tooth distoclusion in a cat.

Mandibular brachygnathia was the etiology for moderate mandibular distoclusion and bilateral palatal canine cusp penetrations in a kitten. The course of treatment included deciduous canine tooth exodontia, tooth extensions, and ultimately, aligners that incorporated inclined planes fabricated from a thermoplastic sheet that was "indirectly" vacuum thermoformed over a dental model. The thin, flexible aligners fit over the rostral maxillary teeth and palate, and were retained by a snug fit on the slightly divergent maxillary canine teeth. Advantages over "directly" applied composite inclined planes include: serial gradations of angulations for more gradual tooth movement, elimination of dental trauma from composite adhesions and removals, owner-removable and cleanable appliances, and a single anesthetic event required for dental impressions. Five progressively angled aligners were used sequentially over a 3-month period to achieve atraumatic "clinical" neutroclusion of the rostral dentition.

Mandibular periostitis ossificans in immature large breed dogs: 5 cases (1999-2006).

This case series describes clinical, radiographic, and histopathological features of mandibular swellings in 5 immature, large breed dogs. The dogs originated from different regions of the United States. In each case, intraoral dental radiography of the jaw swelling revealed a two-layered (double) ventral mandibular cortex. Biopsy was performed in 4 of the 5 puppies, revealing periosteal new bone formation. Resolution of the mandibular swelling was spontaneous in the 4 dogs available for follow-up examination. The authors postulate that the clinical, radiographic, and histopathological presentation of mandibular swelling in these 5 dogs is a distinct pathological entity consistent with an inflammatory condition of the maturing human mandible known as periostitis ossificans.