Canis ISSN: 2398-2942

Dental radiography: overview

Contributor(s): Alex Smithson, MarkThompson

Introduction

  • Essential for viewing the bulk of the teeth/roots and supporting structures which are hidden below gum line.
  • The roots and periodontium form the biggest portion of each tooth and can only be fully visualized by means of intra-oral radiographs.
  • The roots and periodontium are where much pathology will form.
  • As a result up to 70% of the pathology in the mouth may go undetected without the use of intra-oral radiography!
  • Some lesions may be detected clinically but the full extent of the lesion or disease can only be accurately assessed with radiographs.

technique

  • Intra-oral radiography (film inside mouth) allows an accurate representation of each tooth providing fine detail that would otherwise be missed without its use.
  • Using an extra-oral technique results in superimposition of structures and lower resolution images.
  • Two techniques are used:
    • Parallel technique Radiography: dental extra-oral parallel : the film is placed parallel to the tooth structure to be radiographed. This is only possible for mandibular premolars and molars. The X-ray beam is then directed at 90° to the xray film.
    • Bisecting angle technique Radiography: intra-oral parallel and bisecting angle : when the film cannot be placed parallel to the tooth structure to be radiographed (ie all incisors, canines, maxillary premolars/molars), an imaginary line is drawn dividing in half the angle between the tooth and the film. The X-ray beam is then directed at 90° to this 'bisecting angle' line.

Uses

  • Endodontics Endodontics: basic :
    • To assess loss of attachment, looking for receding bone height (relative to cemento-enamel junction level), and for bony pockets.
    • Assess suitability, eg absence of long axis fracture.
    • Planning the technique (endodontics).
    • Intra-operatively and post-operatively to assess pulp canal length, width and complications.
    • Check whether the pulp cavity has been breached.
  • Extractions Dental extraction :
    • Diagnosis and treatment planning of fractured teeth Dental fracture and surrounding tissues.
    • Post-extraction of teeth to check that all root tissue is extracted.
  • Detection of missing permanent teeth.
  • To differentiate permanent from temporary teeth.
  • Diagnosis of neoplasia, dentigerous cysts.

Advantages

  • Relatively standard procedure.
  • Equipment available in most practices.

Procedure

  • 15-30 min depending on skill of radiographer and views required.

Requirements

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Preparation

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Procedure

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Steinberg H & Galbreath E J (1998) Cerebellar medulloblastoma with multiple differentiation in a dog. Vet Pathol 35 (6), 543-546 PubMed.

Other sources of information

  • Smithson A (2005)Oral radioplogy Part 1.UK Vet10 (8), 57.
  • Smithson A (2005)Oral radiology Part 2.UK Vet11 (1), 40-44.
  • 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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