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The importance of correct patient positioning

From Volume 42, Issue 3, April 2015 | Pages 294-295

Authors

Maria Irena Kwiatkowski

London

Articles by Maria Irena Kwiatkowski

Emily Carter

BDS, MFDS RCSEd, Dip Con Sed, CILT, AFHEA, MOS RCSEd

BDS, MFDS, Dip Con Sed, CILT, AFHEA, MOralSurg, Specialist Oral Surgeon, Clinical Lead, Dental Emergency Clinic; Newcastle upon Tyne Hospitals NHS Foundation Trust

Articles by Emily Carter

Jimmy Makdissi

DDS, MMedSc, FDS RCS(Eng), DDRRCR, FHEA

Clinical Senior Lecturer and Honorary Consultant, Dental and Maxillofacial Radiology, Institute of Dentistry, Queen Mary University of London and Barts and The London School of Medicine and Dentistry, The Royal London Dental Hospital; Clinical Director, JM Radiology CBCT Training

Articles by Jimmy Makdissi

Email Jimmy Makdissi

Article

We came across this case which demonstrates the importance of correct patient positioning within the focal trough in dental panoramic radiography to visualize the anterior mandible adequately.

The patient presented for a surgical assessment of an impacted upper right canine. A panoramic radiograph was taken (Figure 1). Incidentally, the anterior mandible, apical to the lower anterior teeth, demonstrated what appeared to be a well-defined, large unilocular radiolucency, with partial cortication at its superior aspect. The lower border of the mandible was intact.

Figure 1. An OPG of patient's impacted upper right canine.

The presence of an odontogenic cyst or tumour could not be ruled out therefore, to characterize this area further, a lower 45° occlusal radiograph was acquired (Figure 2). This demonstrated normal trabecular pattern of the mandible with normal length and morphology of the anterior incisor roots.

Figure 2. A lower 45° occlusal radiograph of same patient as Figure 1.

This case highlights the importance of understanding the diagnostic limitations of tomography and, in particular, the role of the focal trough in relation to a change in the patient's position. In this case, the slight chin down position has resulted in the anterior mandible being outside of the focal trough and therefore blurred out.

This is important as the radiograph cannot either exclude or confirm disease in this area. The diagnostic usefulness of a radiograph relies heavily on its presence within the focal trough. It is therefore essential to optimize the image quality by ensuring the correct patient position, reducing the potential for tissues to be outside the focal trough.