Last year, a 10 year old Shih Tsu was referred to Veterinary Dental Specialties and Oral Surgery for a suspect mandibular fracture. This was based on the dental radiographs taken at the referring veterinarian. The patient was placed under general anesthesia and a complete oral exam and radiographs were performed. This revealed very slight laxity at the mandibular right first molar. However the jaw was overall stable.
Veterinary dental radiographs revealed severe bone loss in the area behind the first molar with periosteal reaction due to the chronic periodontal disease of the distal root of the right mandibular first molar (409). (Yellow Arrow) This had resulted in a partial pathologic fracture, but the jaw was still stable due to a fibrous union. (Red Arrow) However, the severe periodontal disease had also resulted in endodontic infection to the tooth, which created significant bone loss at the apex of the mesial root of that tooth. (white arrow) However, the coronal area was normal. Finally the fourth premolar was also non-vital. (blue arrow)
The mandibular first molar was sectioned and the distal root was easily extracted due to having no remaining bone. However, due to the relatively normal attachment of the fourth premolar and the complete lack of bone at the apex of the mesial root of the first molar, these teeth were not extracted. The decision was made to treat these teeth endodontically (root canal). The post-op radiographs revealed excellent endodontic fill and a stable “fracture” site. (white arrow) This avoided the surgical trauma that almost certainly would have resulted in an iatrogenic mandibular fracture.
The patient recovered uneventfully and the jaw remaining stable.
Six months following the treatment, the patient was represented for recheck radiographs. He had done very well with no jaw instability. Under anesthesia, the mandible palpated normally. Dental radiographs showed that there was significant bone regrowth in the area of the root canaled mesial root of the first molar (red arrow) Further, the weakened bone area was stable. (white arrow)
This case demonstrates the importance of understanding fracture biomechanics and deciding when is best to extract teeth as opposed to providing owners options to avoid fracture. It also proves that chronically infected teeth can respond very well to root canal therapy.