Dental Radiography Processing and Techniques

Dental Radiography Processing Steps

1 Revealed: After exposure to an X-ray plate, the silver bromide crystals are excited by the energy they have received. When the plate comes into contact with the developer, an alkaline liquid, silver leaves the emulsion and precipitates on the base of the film, causing it to darken. Those crystals that were less excited by less radiation will be less likely to precipitate and will wash out, resulting in grays. The initial development stage lasts about 1 minute.

2 Wash: It is very important to wash the film for 20 seconds.

3 The Mordant (Stop Bath): This step removes precipitated silver crystals from the emulsion and stabilizes the image in the fixer for 3 minutes, or not less than 10 minutes.

4 Fixing Solution Removal: The fixing solution is removed with water, and the film is dried for several minutes. Longer time and temperature during development lead to more precipitation.

The larger the size of the silver bromide crystals, the shorter the exposure required.

Types of Intraoral Radiographs

Periapical Radiographs

These reproduce the entire tooth, including the crown and root. They are essential for assessing the status of the root and bone, and for endodontics.

Interproximal or Bitewing Radiographs

These reproduce the crowns of the molars and premolars on the same plate, but not their roots. They are used for the study of interproximal caries.

Occlusal Radiographs

Used for the study of impacted teeth or the presence of stones in the salivary gland ducts.

Radiographic Techniques

Bisector Technique

The X-ray beam is directed perpendicular to the bisector (midline) of the angle formed between the plate and the long axis of the tooth. This results in minimal tooth distortion; the image size corresponds to the actual tooth size, though component proportions may vary. This technique involves vertical placement of the film on anterior teeth and subsequent horizontal placement.

Paralleling Technique

This technique uses devices placed parallel to the film, with the beam directed perpendicular to the film. It yields a truer picture of anatomical structures in terms of size, although the image appears larger. It is often used in periodontics to study alveolar bone height.

Bitewing Radiographs Technique

These consist of a horizontal flap that fits between both arches to be held by the bite. The tube is placed perpendicular to the plate, forming an angle of 8 to 10 degrees to the vertical.

Occlusal Radiographs Technique

• Upper Arch: The plate should be placed horizontally with its axis from left to right. The X-ray tube is directed at an angle of 60° downward in the midline.
• Mandibular Patient: The plate is held between both arches, with the white side facing up. The X-ray tube is placed under the patient's chin, and the head is tilted back so that the tube can deliver a beam as perpendicular as possible to the plate.