This involves shining a small, strong fiberoptic light through the tooth. This procedure can help detect the presence of cracks or fracture lines and can show subtle changes in the color of the injured teeth. These teeth do have a poorer prognosis for maintaining vitality than do teeth which are not darkened as a result of injury. If a tooth does change color, which can be several weeks to months after the accident, it is likely the tooth has lost its vitality. A root canal or extraction is required for permanent teeth that have died.
Percussion can help give information about the extent of injury to the apical tissues.
While it is not unusual for a recently traumatized tooth to be sensitive to percussion, teeth which do not have sensitivity to percussion have a better prognosis. Sound is also important when the tooth is percussed. If the sound is dull compared to non-injured teeth, this may indicate tooth displacement. Several radiographs may need to be taken to determine if root fractures exist. Different angles may also reveal an immediate loss in pulpal vitality.