of any unerupted maxillary canines or supernumary teeth, using the vertical parallax
technique (Fig. 3.27).
Key Point
The 'SLOB' rule: if the tooth in question moves in the same direction as the xray tube,
then the tooth is lingually or palatally positioned (in relation to the reference point).
However, if the tooth moves in the opposite direction to the X-ray tube, it is buccally
placed.
Detection of pathology
Selected radiographs may be required in cases of suspected pathology. The actual
view is obviously dictated by the presenting complaint, but a periapical radiograph is
frequently indicated for localized pathologies, such as:
- periapical or interadicular infection (primary molars) associated with non-vital
teeth; - periodontal conditions;
- trauma-related sequelae, such as root resorption.
A panoral view is particularly valuable where the pathology involves more than one
quadrant or has extensive bony involvement. A sectional panoral radiograph may be
prescribed in some situations since this approach helps to reduce ionizing exposure.
Fig. 3.23 Left and right bitewing radiographs showing multiple approximal carious
lesions not evident clinically.