Managing jaw fractures (Proceedings)
The diagnosis and treatment of oral trauma includes the management of jaw fractures and the management of temporomandibular luxations.
Prior to correction of jaw fractures the patient must be thoroughly evaluated for other traumatic injuries. Following stabilization of life-threatening injuries jaw fractures can be evaluated under sedation or general anesthesia. The mandible, maxillofacial bones, and temporomandibular joints are palpated both extra- and intraorally for fractures. Radiographs are taken to localize the fracture sites. It is important to assess the full extent of all injuries keeping in mind that multiple fractures may be present. In cases of severe maxillofacial trauma, computed tomography may be helpful in the recognition of all lesions.
The teeth need to be evaluated for periodontal and endodontic disease and their relationship to fracture lines must be determined. Previous reports indicate that pathologic fractures may occur in the mandible of dogs with severe periodontal disease through deep periodontal pockets. These pathologic fractures occur most frequently in the region of the mandibular first molars and canine teeth. Periodontally diseased teeth in a fracture line need to be extracted or hemisected to remove the periodontally affected tooth or root that predisposed the dog to the pathologic fracture. Retention of a periodontally diseased tooth or root in a fracture site inhibits fracture healing. If hemisection is chosen as the method of treatment, the retained root must be treated endodontically. In addition teeth that are fractured with pulpal exposure require endodontic therapy.Teeth that are not diseased but are located in the fracture site can generally be retained. Prognostic factors of teeth in the fracture site have been reported with fractures extending along the periodontal ligament to the apex having the poorest prognosis. In general it is probably best to retain teeth that significantly contribute to fracture stability as long as severe periodontal disease is not present and the fracture is acute.
Basic principles of jaw fracture management include the following: (1) restoration of occlusion and anatomic reduction of the fracture, (2) neutralization of forces on the fracture line and stable fixation, (3) avoidance of soft tissue entrapment by the fixation technique, (4) avoidance of further dental trauma, (5) proper assessment of tissue viability, (6) removal of diseased teeth with the fracture site, (7) avoidance of excessive elevation of soft tissue from the surface of the bone and covering of exposed bone with soft tissue, and (8) rapid restoration of function.
Several techniques for the management of mandibular and maxillary fractures have been described and include: (1) tape muzzles, (2) circumferential wiring, (3) interdental splints, (4) percutaneous skeletal fixation, (5) bone plating, and (6) partial mandibulectomy.
Tape muzzles are an inexpensive, noninvasive technique of aligning and stabilizing jaw fractures. They can be used to temporarily stabilize jaw fractures prior to definitive repair. Tape muzzles can also be utilized as the primary repair technique in minimally displaced stable fractures especially fractures of the mandibular ramus or fractures occurring in young animals in which bone healing occurs rapidly.
Interdental splints are an easy, noninvasive, versatile, and inexpensive technique for repairing jaw fractures. Prior to application of an interdental splint the teeth should be cleaned, polished, acid-etched, rinsed and dried. A self-mixing Bis Acryl-composite material can then be applied to the lingual surface of mandibular teeth or the labial aspect of maxillary teeth in the fabrication of interdental acrylic splints. Interdental splints are removed by sectioning the splint interdentally with a bur and gently removing the splint in segments using extraction forceps in a shearing motion to avoid fracturing teeth. Following splint removal the teeth are polished.
Percutaneous skeletal fixation devices may be used to repair jaw fractures. This technique is particularly useful in fractures in which there is significant soft tissue trauma, in severely comminuted fractures and in fractures in which a significant boney defect is present.
Bone plates provide rigid fixation and rapid return to function. However, bone plates can be technically challenging to place without damaging teeth. Significant soft tissue elevation is necessary for the placement of bone plates which may further compromise the blood supply of the fractured bone. It is also difficult to apply a bone plate to a fractured mandible or maxilla without further traumatizing tooth roots or neurovascular structures. It is also difficult to achieve normal postoperative occlusion using plates for jaw fracture repair because even slight errors in reduction of a fracture particularly in caudal fractures will result in a significant malocclusion with inability of the patient to close the mouth in some cases. Miniplates may be utilized in the repair of mandibular and maxillary fractures. The small size of these implants allows placement close to the alveolar border and the screws may be angled to avoid impringement on tooth roots.