Temporomandibular joint fractures commonly occur in conjunction with other maxillofacial fractures.
Introduction to mandibular fractures
Mandibular fractures can be classified into region of the mandible and severity of the fracture.
Mandible fracture classification
Ramus (including the coronoid process)
Temporomandibular joint (mandibular head of the condylar process)
The mandible is complex because of the interaction of hard, soft tissue and teeth. The majority of the mandibular bone volume is occupied by teeth roots, blood vessels and nerves, making the application of internal fixation difficult.
The periodontal status of the teeth affects the bone quality of the mandible and should be considered when selecting the fracture fixation method.
In the mandible, form and function are interdependent. Minor anatomical malalignment affects the occlusion of the teeth and function.
Fracture comminution and soft tissue damage will affect the repair method chosen.
Imaging allows analysis of fracture patterns and assessment of the fracture complexity. Dental radiography combined with computed tomography (CT) and 3D reconstruction is ideal to assess fracture complexity and dental involvement.
Postoperative CT is recommended to assess the surgical results.
Cone beam CT technology for craniomaxillofacial surgery provides additional precision in 3D planning.
The soft tissue resolution is inferior to conventional CT.
3D printing of the skull provides for precise surgical planning.
The model can be used for:
Prebending of the plate
Evaluation of surgical results
The diagnostic yield of plain skull radiographs is very limited compared to CT. It should only be used alone if CT is unavailable. Diagnostic imaging of the entire skull is recommended because mandibular fractures can be associated with other skull trauma.
MRI or ultrasound can be helpful for soft tissue injuries but are not included in the standard diagnostic work up.
Imaging of temporomandibular joint fractures
Transverse CT image of a minimally displaced fracture of the mandibular head.
Fracture of the TMJ may involve the mandibular fossa (squamous part of the temporal bone).
Clinical signs of temporomandibular joint fractures
Clinical signs of temporomandibular joint fractures include:
Soft tissue trauma
Dysfunction and pain when eating
Pain on palpation
In isolated TMJ fractures malocclusion is rarely seen. Pain on opening the mouth and/or decreased range of motion of the mandible are additional signs of TMJ trauma.