Clinical history A 30 month old filly had a history of swelling on the mandible for several months - the owner did not know the cause of the injury or the exact time it began. On palpation, the swelling was hard and there was no discharging sinus Radiographs were made of the head Radiographic study Lateral view VD view Radiographic study - Oblique views Radiographic changes Marked focal thickening of the mandible at the level of the 4th lower cheek tooth on the left (double headed arrow) Dental sac of the 4th cheek tooth is difficult to identify but the tooth roots appears not damaged Lysis of periapical bone 4th cheek tooth with surrounding sclerosis Periodontal space around the 4th cheek tooth is poorly identified with loss of lamina dura Lucent cavity adjacent to the root of the 4th cheek tooth (arrows) Differential radiographic diagnosis Bony changes surrounding the 4th lower cheek tooth – associated with dental disease secondary to osteomyelitis – secondary to trauma including puncture wound (osteomyelitis) – associated with a healing mandibular fracture – associated with a mandibular cyst – due to a mandibular tumor (odontoma, adamantinoma, ameloblastoma) Because of incomplete evaluation of the lesion and the failure to determine whether the lesion was of dental or bony origin, a CT examination was performed. CT sections at the level of the 4th check tooth Radiographic changes seen on CT examination
- Thickened mandibular cortex with smooth surfaces
- Open tracts in the mandible both on the lingual and buccal surfaces
- Dense bony fragments within adjacent lucent cavities (sequestra) (arrows)
- Widened periodontal spaces
- Widened periapical space without injury to the tooth roots although there is bony filling of the dental sac
- No fracture line identified
- Deciduous cap missing from affected tooth
Diagnosis
- Osteomyelitis without evidence of fracture with drainage sinuses and cavitary lesions containing sequestra
- Etiology probably puncture wounds
- Tooth appears without severe injury although both vascular and nerve supply to the tooth may be compromised
