Are anterior occlusal radiographs indicated to supplement panoramic radiography during an orthodontic assessment?

Five hundred pairs of dental panoramic tomographs (DPT) and maxillary anterior occlusal radiographs (AO) from patients referred to the orthodontic department of a dental teaching hospital were examined to assess the diagnostic yield from a panoramic radiograph of the premaxillary region alone and then assess the additional yield when this view was supplemented by a maxillary anterior occlusal radiograph. Of the 500 DPTs assessed, 208 (42%) lacked clarity of the premaxillary region when the labial segments were used to locate the patient in the DPT machine. An association was found between patients who had abnormal incisor relationships and poor clarity in the premaxillary region of the DPT. Overall 165 (33%) of the supplementary AO views were used to support or refute findings identified on the DPT. It was concluded that in patients referred for an orthodontic assessment, supplementary radiography of the premaxilla may be justified in the following situations: 1. unsatisfactory image quality which may frequently be the case where there are abnormal incisor relationships, 2. localisation of tooth position by vertical parallax and 3. where a reasonable expectation that pathology exists on clinical grounds.