An aiming device for an extraoral radiographic technique.

To assist certain patient populations who are unable to tolerate intraoral films and/or sensors during endodontic therapy, an alternative technique (extraoral film placement) has been innovated by Newman and Friedman (2003). In this study, we devise and test a film/sensor-beam alignment aiming device for taking a periapical radiograph using this extraoral radiographic technique. An instrument is assembled from the following components: (1) two locator rings for bite-wing radiography, (2) two metal supporting indicator rods for bite-wing radiography, (3) a bite block for horizontal bite-wing radiography, and (4) a rubber tube of about 2 cm in length. Using our newly-devised aiming device to take periapical radiographs using the extraoral technique, appropriate images of the left upper and right lower molar areas for a series of 12 adult volunteers were successfully obtained. Angulation of the x-ray cone, with reference to the horizontal plane, was -20 degrees to -30 degrees and -10 degrees to -15 degrees for the upper and lower teeth, respectively. This study therefore shows that appropriate images can be easily obtained using this aiming device.