Felis ISSN 2398-2950

Dental radiography: overview

Contributor(s): Lisa Milella, Alex Smithson, Mark Thompson


  • Essential for viewing the largest part 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 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, eg feline odontoclastic resorptive lesions ('neck'/resorptive' lesions) Odontoclastic tooth resorption (resorptive lesions).
  • With the high incidence of feline odontoclastic resorptive lesions, feline dentistry should not be performed without the use of radiography.
  • Approximately 70% of cats over 3 years of age have some form of dental disease.


  • Intra-oral radiography Radiography: intra-oral parallel and bisecting angle (film inside mouth) allows an accurate representation of each tooth providing fine detail that would otherwise be missed.
  • Using an extra-oral technique Radiography: dental extra-oral parallel results in superimposition of structures and lower resolution images.
  • Two techniques are used:
    • Parallel technique: the film is placed parallel to the tooth structure to be radiographed Dental radiography: intra-oral placement of dental film . This is only possible for mandibular premolars and molars. The x-ray beam is then directed at 90º to the x-ray film. 
    • Bisecting angle technique Dental radiography: bisecting angle technique 01 - left maxillary canine  Dental radiography: bisecting angle technique 02 - right mandibular canine : when the film cannot be placed parallel to the tooth strucutre 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 90º to this 'bisecting angle' line.


  • Endodontics:
    • To assess loss of attachment, receding bone height relative to cemento-enamel junction, and 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.


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


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


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Further Reading


Refereed papers

Other sources of information

  • 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.
  • 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).