Half-angle technology

Tooth axis, film axis and central beam in the half-angle technique

The half-angle technique (also: half-angle projection) is a dental X-ray technique according to Cieszyński (1907) and Dieck (1911).

Isometric rule according to Cieszyński and Dieck

According to the isometric rule according to Cieszyński and Dieck, the tooth is imaged isometrically when the central ray falls through the apex of the tooth perpendicular to the bisector that divides the angle between the tooth axis and the plane of the image carrier.

Action

The X-ray film (usually 2 × 3 cm or 3 × 4 cm) is placed in the mouth and kept as depressurized as possible by the patient. Tooth axis (dashed blue in the drawing) and the film plane form an angle (red in the drawing). The central ray (green in the drawing) is now set so that it is perpendicular to the imaginary line at the level of the root tip , which bisects the angle mentioned above.

Indications

• Periodontal diagnostics
• Caries diagnosis
• Apical changes
• Extraction diagnostics
• Endodontic measures

Technology according to LeMaster

A modification of the half-angle technique was specified by LeMaster in 1924 : Here, a cotton roll is inserted between the tooth and the film at the level of the tooth crown in order to reduce the angle. It is seldom used today because the buccal roots of a multi-rooted tooth are shown shortened and the limbus alveolaris (bony alveolar margin) is recorded.

See also

• Right angle technology
• Parallel technique
• X-ray status

literature

• W. Dieck: Anatomy and pathology of the teeth and jaws in x-rays with special consideration of the imaging technique. Lucas Gräfe & Sillem, Hamburg 1911.

Individual evidence

1. ↑ ^{a b} H.-J. Mentzel: radiography. ( Memento from March 4, 2016 in the Internet Archive ) Uni Jena

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !