Canis ISSN: 2398-2942

Radiography: dental extra-oral parallel

Contributor(s): Alex Smithson, MarkThompson

Introduction

  • See also dental radiography overview Dental radiography: overview.
  • Extra-oral technique positions the X-ray film outside the mouth.
  • Parallel technique positions the film parallel with the object (tooth).

Uses

  • Maxillary pre-molars and molars.
    Less useful for mandibular molars/pre-molars because mandible narrower than maxilla → more superimposition of tooth images.
  • Good for large lesions such as oral neoplasms.

Advantages

  • Can use standard cassettes with intensifying screens.
  • Can use non-screen film of varying sizes, eg dental film sizes 2 and 4.
  • Reduces superimposition by the zygomatic arch.

Disadvantages

  • Accurate interpretation difficult because of superimposition of other irrelevant images.
  • Proper evaluation of other individual teeth is difficult.
  • Teeth may appear magnified, poor detail.

Requirements

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Preparation

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Procedure

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Aftercare

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Smithson A (2006) Oral radiology Part 2. UK Vet 11 (1), 40-44.
  • Smithson A (2005) Oral radiology Part 1. UK Vet 10 (8), 57.

Other sources of information

  • Gorrel C (2004)Veterinary Dentistry for the General Practitioner.Saunders.
  • Mulligan, Allen, Williams (1998)Atlas of canine and feline dental radiography.In:Veterinary Learning Systems. Trenton, NJ, USA (Excellent reference for dental radiography).


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