Learn Orthodontics


Radiographs are justified only when the management of the patient is dependent on the information obtained. A clinical examination is mandatory before any radiograph is taken.

Before taking any radiograph you should ask yourself 'will the results of this radiograph affect my management of this patient?'

Indications for radiographs

When the clinician requires the following diagnostic information from the radiographs:

  1. The absence of permanent teeth
  2. When the presence and position of misplaced or supernumary teeth is suspected from the clinical examination
  3. To assess the stage of development of permanent teeth
  4. The morphology of unerupted and sometimes erupted teeth
  5. The presence and extent of dental disease (caries etc)
  6. The presence of orofacial disease
  7. The presence, extent and type of any developmental abnormalities.
  8. The relationships of the teeth to the jaws and the jaws to the rest of the facial skeleton when a skeletal discrepency is present (eg Skeletall II or Skeletal III)

The common orthodontic views are Panoramic and Cephalometric

  1. Panoramic - Dental Panoramic Tomograph (DPT)

  2. Indications for Dental Panoramic Tomograph
    • As part of an orthodontic assessment where there is a clinical need to know the state of the dentition and presence/absence of unerupted teeth. An intra oral film may be indicated to complement the DPT when:
      • examination of the anterior teeth suggests the presence of an abnormality (e.g. unable to palpate canine)
      • an abnormality found on examination of the DPT film
    • Where a boney lesion or unerupted tooth cannot be completely demonstrated by intra oral views
    • As part of a periodontal assessment where pocketing is greater than 5mm in depth
    • Prior to dental surgery under general anesthetic
    • Prior to a 'dental clearance'
    • Panoramic views should only be taken in the presence of specified clinical signs and symptoms. There is no justification for review examinations at arbitrary time intervals.
  3. Cephalometric - lateral skull radiograph

  4. Cephalometric lateral skull views are taken to aid diagnosis and treatment planning and also to provide a baseline for monitoring progress. These radiographs must be appropriately analyzed to obtain the maximum clinical information.

    Indications for Cephalometric lateral skull radiograph include
    • Patients with a skeletal discrepancy
    • When functional appliances are to be used
    • When 2 arched fixed appliances are to be used for appreciable apical movement of incisors
    • Location and assessment of unerupted, malformed or misplaced teeth

Choice of view for radiographic examination

Projection Function
  1. Identification of the devloping dentition
  2. Confirmation of the presence/absence of teeth
  3. Preliminary assessment of caries, apical condition. periodontal state
Standard occlusal view
  1. Identification of abnormal pathology
  2. To show presence of unerupted teeth
  3. Vertical parallax localisation either with DPT or periapical film
  4. To supplement bimolar film
Mandibular occlusal Localisation of unerupted teeth
  1. To assess root morphology
  2. To assess root resporption
  3. To assess apical pathology
  4. In combination with a standard occlusal or second periapical to localise unerupted teeth by horizontal parallax
  1. To assesss teeth of doubtful prognosis
  2. Caries identification and periodontal bone levels
Lateral Cephalometric view
  1. To assess skeletal pattern and labial segment angulation
  2. To aid assessment of unerupted teeth