Examining mandibular problems in a dog

Examining mandibular problems in a dog

The first in a series chronicling the progression of periodontal bone destruction resulting in mandibular fractures in a dog
Nov 01, 2010

Dr. Brett Beckman
A neutered male rescued Shih Tzu of unknown age was brought to the referring veterinarian for a wellness evaluation. Oral examination showed generalized severe tartar, halitosis, gingivitis and gingival recession.

Photo 1: A radiograph of the left mandible after extraction of the premolars and molars by the referring veterinarian. (PHOTOS COURTESY OF DR. BECKMAN)
Full-mouth radiographs revealed generalized stage IV periodontal disease. Both mandibles were severely affected adjacent to the molar and premolar teeth. The referring veterinarian successfully performed multiple extractions (Photo 1). However, a bony swelling on the ventral aspect of the mandible adjacent to the mesial aspect of the right mandibular first molar (tooth 409) prompted referral to my facility.

An appointment was scheduled for later that month.

According to the clients, the patient did well three days after the extractions by the referring veterinarian. But on the third day, he escaped and roamed unattended outdoors for a few hours before he was found. For the next two days he was anorectic. The patient was brought back to the referring hospital, and a right mandibular fracture was found in the region of the previously noted swelling. Referral was then expedited to our next available appointment.

Patient evaluation and diagnosis

Photo 2: A radiograph of the right mandible demonstrating the fracture at the time of presentation to our practice.
On examination of the patient at our practice, palpation was consistent with a right midbody mandibular fracture. Bony enlargement was present on the lingual and vestibular portion of the mandible surrounding the fracture site. The patient would not tolerate oral examination and was anesthetized for a dental radiographic examination, which confirmed a right mandibular fracture bisecting the alveolus of the mesial root of the first molar (Photo 2).

Neoplasia is always a consideration, but the radiographs suggested a characteristic infrabony defect mesial to the mesial root of tooth 409 at the fracture site characteristic of a periodontal cause. Periodontal bone loss was severe in all four quadrants, further supporting a periodontal etiology. It is likely this patient had a pathologic mandibular fracture in the past with partial healing and stabilization. Concurrent focal osteomyelitis may also have played a role. In any case, this would create an ideal environment for refracture.

Treatment options

Edentulous pathologic mandibular fractures generally pose a challenge. In this case, tooth 409 required extraction before fracture repair, because leaving this tooth within the fracture line would beg failure. Traditional bone plates are usually poor options because of their intrusion on the mandibular canal and the presence of compromised bone density. External coaptation is generally futile for similar reasons. Interdental wiring or acrylic splints can be used to form the basis of primary repair only if adequate dentition is present surrounding the fracture site. Without teeth, creative measures are often needed to avoid mandibulectomy. In this case, a novel, malleable, titanium mesh material was chosen for primary repair.