Figure 4-21. Maxillary molar area.
4-21. MAXILLARY BICUSPIDS
Position the posterior instrument assembly in the patient's mouth with the
bicuspids centered on the film parallel to the long axis of the teeth (see figure 4-22).
Some patients have small mouths. Therefore, the bicuspids may not be centered on
the film. The first priority is to parallel the film to the two bicuspids both vertically and
possibly touching the anterior hard palate. Gently contour the anterior superior corner
of the film to aid positioning. With the bite-block held on the occlusal surfaces of the
maxillary bicuspids, insert a cotton roll between the underside of the block and the
mandibular teeth. Have the patient close his teeth holding the film in place. Slide the
locator ring along the indicator rod to approximate the skin surface and align the x-ray
unit extension tube with the rod and the ring on the horizontal and vertical planes.