OVERVIEW OF THE BISECTING ANGLE EXPOSURE TECHNIQUES
a. The bisecting method of periapical radiography is used to varying degrees in Army dental clinics. The dental specialist should be familiar with its techniques. The following paragraphs describe techniques using this method to produce a 14-exposure set of radiographs of an adult dentition. Discussion of the techniques for exposure of each area of the mouth will include illustrations and descriptions of film placement, film holding, direction of the central ray, and average angulation. Slight contouring of a corner may facilitate film placement in restricted areas of the mouth, such as those of the maxillary incisors or the maxillary third molar, and make it more comfortable. To shape the film, press it over the rounded contour of a finger to pre-adapt it to the position in the mouth. Use only slight contouring to prevent distortion of the image. (A flat image produces the best image.) Paragraph 4-7 covers proper head positioning and other instructions for intraoral radiograp.
b. Various film holding devices may be used to secure the film in place when using the bisecting technique: the Rinn EEZEE-GRIP Film Holder, a hemostat, a plastic or Styrofoam film holder (with 105º angle) (see figure 4-9). When such film holding devices are not available, the finger or thumb may be used.
