Canis ISSN: 2398-2942

Radiography: intra-oral parallel and bisecting angle

Contributor(s): Alex Smithson

Introduction

  • See dental radiography overview Dental radiography: overview.
  • Positioning X-ray film inside mouth minimizes superimposition of irrelevant structures.

Uses

  • Parallel technique: if angle between tooth and film=<15°, ie mandibular, molars and (most) premolars.
  • Target teeth situated parallel to x-ray film with xray beam at 90° to film Dental radiography parallel technique 01 - for mandibular pre-molar and molar teeth Dental radiography parallel technique 02 - for mandibular molar and pre-molar teeth.
  • Bisecting angle technique: to give an image the same length as the object: if angle between tooth and film = >15° (maxillary molars/premolars, mandibular and maxillary incisors/canines, also mesial/anterior premolars due to mandibular symphysis) Dental radiography bisecting angle technique 01 - left maxillary canine Dental radiography bisecting angle technique 02 - right mandibular canine.

Advantages

  • Parallel: simple.
  • Bisecting angle: minimizes superimposition of other structures. Accurate images despite anatomy preventing parallel film placement.

Disadvantages

  • Parallel: limited to mandibular molars and pre-molars.
  • Bisecting angle: more technical to obtain; inaccuracies with flawed technique; good at casting 'shadow' due to superimposition if structures occurs.

Requirements

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Preparation

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Procedure

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Further Reading

Publications

Refereed papers

Other sources of information

  • Smithson A (2005) Oral radiology Part 1. UK Vet 10 (8), 57.
  • Smithson A (2005) Oral radiology Part 2. 11 (1),UK Vet 40-44.
  • Gorrel C (2004) Veterinary Dentistry for the General Practitioner. Saunders.
  • Mulligan, Aller, Williams (1998) Atlas of canine and feline dental radiography. In:Veterinary Learning Systems. Trenton, NJ, USA (Execllent reference for dental radiogaphy).


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