Desensitization is defined as gradually exposing the child to new stimuli or experiences of increasing intensity. An example of this is introducing the patient to x-rays by initially taking an anterior radiograph, which is easier to tolerate than a posterior radiograph.
Some patients, young and old, have an exaggerated gag reflex. The etiology of an exaggerated gag reflex had been attributed to psychological and physical factors. There are numerous techniques to control the gag reflex during the radiograph procedure. The easiest is through diversion and positive suggestion. The operator suggests to the patient the gag reflex can be reduced by concentrating on something other than the procedure (Figure 18). The patient can look at a mirror, count fingers, raise and lower legs on a count, or employ audio-video distraction. However, this technique is not always successful so other techniques must be brought into play.
An alternative is the use of nitrous oxide analgesia. One of the effects of nitrous oxide analgesia is it reduces the gag reflex, but unlike general anesthesia it does not affect the cough reflex. Another alternative is to place the radiograph in such a manner to not contact the palate or tongue. This is accomplished by either extraoral placement of the film or placing the film between the cheek and the tooth and exposing the film from the opposite jaw. In the reverse radiograph the film is placed on the buccal surface of the tooth between the tooth and the cheek. The film side of the packet (the solid color side) is facing the buccal surface of the tooth.
The x-ray head is placed at the opposing side, and the cone is positioned under the angle of the ramus on the opposite side. The radiation is directed through the tongue, through the tooth structure, and onto the film. As the x-ray beam is traveling a longer distance to the film than in the typical positioning, it is necessary to double the exposure time. The prevalence of dental trauma in children is estimated at around 18%. Following trauma resulting in tooth fracture and concurrent lip laceration, it is always important to obtain a radiograph of the soft tissue to rule out any impregnation of tooth fragments inside the soft tissue. For this purpose, the exposure time is reduced to one fourth of the original exposure (Figure 19).
Some of the newer digital panoramic radiographic units, i.e., Planmeca Promax, Sirona Panorex have programs that can take bitewing radiographs through extraoral techniques. This has shown to have better patient compliance, easy patient positioning, and faster appointments using less radiation than conventional radiographs yet providing images of diagnostic quality (Figure 20).