Trauma to the teeth and facial skeleton
Injuries to the teeth and facial skeleton are, unfortunately, common. The type and severity of injuries can vary considerably, from minor damage to the teeth to grossly comminuted fractures of the skull.
Whatever the suspected injury, radiography is an essential requirement both in the initial assessment and in the follow-up appraisal. However, the radiographic examination may be restricted and limited by the general state of the patient and the type and severity of other injuries. For example, severe facial injuries are often associated with intracranial damage and/or cervical spine injuries, the importance of which far outweighs any damage to the teeth and their supporting structures. The radiographic investigation must therefore be tailored to each patient’s needs.
This chapter outlines the approach to radiographic investigation of trauma by separating injuries into four distinct categories:
Injuries to the teeth and their supporting structures
Types of injury
Based broadly on the classification suggested by Andreasen and Andreasen (2001), the different types of dental injuries can be divided into:
• Luxation injuries to the teeth
• Fractures of the alveolar bone
Fractures of the teeth
• Displacement of an underlying developing tooth which may become dilacerated as a result
• Soft tissue injuries, such as:
• Iatrogenic injuries, such as:
– Injuries sustained during extractions, including damage to adjacent teeth and fracture of the associated alveolar bone
– Perforation of the tooth apex or side of the root during conservative or endodontic treatment
Although the type of injury may be evident clinically, radiographic investigation of all traumatized teeth is needed initially, to assess fully the degree of underlying damage. Radiographs are also required later to assess healing and/or the development of post-trauma complications. The ideal radiographic requirements include:
• Two views of the injured tooth from different angles, ideally at right angles to one another, but more usually with the X-ray tubehead in two different positions in the vertical plane.
• Small volume CBCT (if available) providing coronal, sagittal and axial images.
• Reproducible views to provide a base-line assessment and to allow subsequent follow-up evaluation
• Views of the chest and/or abdomen if a tooth or foreign body is thought to have been inhaled or swallowed, including:
Diagnostic information provided
The diagnostic information provided by these radiographs may include:
• The type of injury to the teeth
• The degree of displacement of the tooth fragments
• The stage of root development
• The condition of the apical tissues
• The presence, site and displacement of alveolar bone fractures
• The condition of adjacent or underlying teeth
• Post-trauma complications, including:
The expected radiographic features indicating a fractured root are shown in Fig. 29.1 and include:
• A radiolucent line between the fragments
• An alteration in the outline shape of the root and discontinuity of the periodontal ligament shadow.
Examples of injured teeth and some of the more common post-injury complications evident radiographically are shown in Figs 29.2 and 29.3.
Limitations of radiographic interpretation of fractured roots
Unfortunately, as a result of the inherent limitations of a two-dimensional image, radiographic interpretation of traumatized teeth is not always straightforward.
As shown in Fig. 29.4 the radiographic appearances can be influenced by:
• The position and severity of the fracture
• The degree of displacement or separation of the fragments
• The position of the film and X-ray tubehead in relation to the fracture line(s).
It is for these reasons that a minimum of two views, from two different angles, is essential if small volume CBCT is not available.
As mentioned earlier, radiographs are an essential part of the initial assessment and follow-up appraisal of all patients with suspected facial fractures. They are crucial in evaluating:
• The site and direction of the fracture line(s)
• The degree of displacement and separation of the bone ends
• The relationship of teeth to the fracture line
• The location of associated foreign bodies in hard and soft tissues
• The presence of coincidental or contributory disease
• The alignment of the bone fragments after treatment
• Healing and the identification of post-trauma complications including infection, non-union or malunion.
Fractures of the mandible
• Where the mandible tends to fracture
• Which radiographic views are required to show each of the fracture sites
• What radiological features indicate the presence of fracture(s)
Radiographic projections required
Several different views are used to show the various fracture sites. Once again, the ideal minimum requirement in all cases is two views at right angles to one another. When that is not possible, two views at two different angles should be used. In addition, intraoral views (either periapicals or occlusals) are requi/>