(1) Panoramic ExtraOral Radiographs. They show the entire dentition and surrounding tissues and structures on one film. The Panorex and Panelipse films are types of panoramic films taken as overall surveys of the jaws.
These extraoral radiographs are taken to diagnose:
• Pathology in tissue (growths or abnormal bone).
• Development of permanent dentition under deciduous.
• Position of impacted teeth.
• Jaw fractures.
• Location of foreign bodies (objects imbedded in tissue).
• Abnormalities of the temporomandibular joint (TMJ), the hinge joint of the lower jaw.
• Relationship of one jaw to the other.
The extraoral radiographs films are used mostly by oral surgeons and orthodontists to diagnose the areas which relate to their treatment. General dentists can use them as an aid to identify problems which may need the further attention.
However, these exposures do not give the sharp image of individual teeth needed to diagnose caries or the detailed conditions shown in bite-wing and periapical films.
(2) Cephalometric extraoral radiographs. The cephalometric (or cephalogram) radiograph is taken of the skull in the frontal or lateral view.
The cephalogram is used to
• Obtain measurements for prosthetics or orthodontics.
• See abnormal conditions in the head and face structures.
• See TMJ problems.
• Locate pathology.
• Locate fractures.
• See abnormal development of the relationship between the upper and lower jaw.
(3) Water’s projection. Another type of extraoral radiograph used mostly by specialists is called the Water’s projection. Tt is taken of the maxillary and frontal sinus areas to find the extent of a sinus condition or infection.