Intraoral Radiography Techniques

Intraoral Radiography Techniques

# The Bisecting Angle Technique

The bisecting angle technique is an intraoral radiography technique used to create clear images of the teeth. The principle of this technique is that the central ray must be perpendicular to the bisector of the angle formed by the long axis of the tooth and the plane of the film.

This technique was first introduced by Cieynski.

– If the central ray is perpendicular to the long axis of the tooth (lack of vertical angulation), the image will be elongated.

– If the central ray is perpendicular to the film (excess vertical angulation), the image will be foreshortened.

# Patient Positioning

To ensure accurate images, the patient should sit upright, comfortable, and with their head stabilized with:

– The midsagittal plane perpendicular to the floor.

– The occlusal plane parallel to the floor.

– The patient must not move during the exposure.

# Determining the Position of the Jaws

– Maxilla: Determined by the Camper’s plane. The Camper’s plane is a line connecting the tragus to the ala of the nose and is parallel to the floor.

– Mandible: Determined by a line connecting the corner of the mouth to the tragus and parallel to the floor.

# Vertical and Horizontal Angulation

– Vertical Angulation: The angle the central ray makes with the horizontal plane. The purpose of determining vertical angulation is to ensure that the central ray is perpendicular to the bisector (formed by the long axis of the tooth and the plane of the film).

– Horizontal Angulation: The angle the central ray makes with the midsagittal plane. The purpose of determining horizontal angulation is to avoid overlapping of the buccal surfaces of the teeth.

# Paralleling Technique

The paralleling technique is used to minimize distortion, blur, and magnification of the image.

# Bitewing Technique

This technique is indicated in the following cases:

– Survey the proximal surfaces of the teeth, the alveolar bone of the same group of teeth in both jaws.

– Detect early caries on the occlusal, mesial, and distal surfaces.

– Examine the size of the pulp chamber and any changes in the pulp.

– Check restorations such as crowns and bridges that are not properly placed.

Bitewing films are designed with a horizontal cardboard tab in the middle for biting, perpendicular to the film. During exposure, the upper half of the film is behind the maxillary teeth and the lower half is behind the mandibular teeth.

# Occlusal Technique

This technique is indicated in the following cases:

– Changes in the shape and size of the dental arches.

– Detection and location of foreign bodies, salivary stones.

– Detection of supernumerary or impacted teeth.

– Inflammatory lesions, benign and malignant tumors in the jaws.

– Detection of supernumerary or impacted teeth necessitates an occlusal radiograph.

– Detection of early caries on the occlusal, mesial, and distal surfaces necessitates a bitewing radiograph.