Dental Radiography

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LESSON 4 - RADIOGRAPHIC EXPOSURE TECHNIQUES

After completing this lesson, you should be able to:

List the types of intraoral radiographic film.
Identify standard patient head positioning techniques.
Identify steps of procedure for placement of film packets in a patients mouth.
Identify the bisecting angle (short-cone) periapical exposure techniques.
Identify the paralleling (long-cone) periapical exposure techniques.
Identify the interproximal (bite-wing) exposure techniques.
Identify the occlusal exposure techniques.
Identify the panoramic exposure technique.

Section I. INTRODUCTION

4-1. GENERAL

Diagnostic and treatment procedures cannot be performed satisfactorily without a variety of radiographic exposure techniques. The dental specialist should be able to properly position the patient, the tube head, and the x-ray film for intraoral or panoramic film exposures. He must also be able to read and to follow manufacturer's instructions accurately.

4-2. INTRAORAL RADIOGRAPHY

Most dental radiographs are made on intraoral film. An intraoral radiograph is made with the film held in the mouth during exposure. Intraoral radiographs taken in closer relation to the object give more detail than is possible with extraoral radiographs, which are taken from outside the mouth, and have less superimposition of shadows.

4-3. TYPES OF INTRAORAL RADIOGRAPHIC FILM AND THEIR PURPOSES

Periapical. The periapical film provides information concerning the entire tooth and adjacent tissues.
Bite-wing (Interproximal). The bite-wing film aids in the detection and determination of depth of caries or other defects of the coronal two-thirds (the crown portion) of opposing teeth and the surrounding alveolar crest.
Occlusal. The occlusal film provides a means of examining larger areas of the jaws and does so from a different angle than is possible with other intraoral methods. It is valuable in locating and diagnosing fractures, salivary duct stones, and impacted teeth. Occlusal radiographs are used much less than periapical and interproximal radiographs.

4-4. PLACEMENT OF FILM PACKETS

Several factors must be considered in the placement and stabilization of intraoral film packets to achieve satisfactory results.

Ensure that the film is positioned correctly.
Center the film lingual to the tooth/teeth (except the bicuspid) being radiographed.
Avoid movement of the film during exposure.
In placing the film packet in the mouth, avoid contact between the film and oral tissues until the film is in approximately the desired position. Many patients tend to gag when film is moved along in contact with oral tissues. Patience and gentleness will help to reduce gagging. Allowing anesthetic lozenges to dissolve on the tongue before film is placed in the mouth is sometimes helpful. Instructing the patient to breathe deeply through the nose also aids in controlling the gag reflex.

4-5. PERIAPICAL RADIOGRAPHIC TECHNIQUES

Periapical radiography is designed to give diagnostic images of the apical portions of teeth and their adjacent tissues. A full mouth intraoral examination consists of 14 periapical radiographs with two bite-wing films and provides an image of all teeth and related structures. Single periapical radiographs are often made of individual teeth or groups of teeth to obtain information for treatment or diagnosis of localized diseases or abnormalities. The bisecting (short-cone) and paralleling (long-cone) techniques are two of the most commonly used techniques. Both techniques have advantages and disadvantages. The dental officer's preference determines which technique will be used.

Primary Content Providers: The U. S. Army, The U.S. Navy
David L. Heiserman, Editor
Publisher: SweetHaven Publishing Services