Title Panoramic Radiographs And Diagnosing Mandibular Asymmetry
Clinical Question Is a panoramic radiograph reliable for diagnosing mandibular asymmetry?
Clinical Bottom Line Panoramic radiographs should be used with caution when diagnosing mandibular asymmetry. It is more accurate for vertical measurements compared to horizontal or angular measurements. (See Comments on the CAT below)
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
18675198Van Elslande/2008127 articles were reviewed but only 11 met the inclusion criteria and were used in this systematic review, these studies included dry skulls, patients and steel wiressystematic review
Key resultsOne study found that the vertical measurements can be made off of a panoramic radiograph with a +/-10% accuracy. Horizontal measurement are not accurate and panoramic radiographs should not be used for this. A second study also found that vertical measurements were more reliable than horizontal but found a 18-21% magnification. Measurements at the gonial angle are the most reliable. The study also found that anything over 6% difference can be considered a true asymmetry and not a technical error. Another study found that an asymmetry could be detected in 67% of the cases, if the patient was in ideal position. Overall, the studies all agreed that vertical measurements can be used, but with caution. They also agreed that horizontal measurements are unreliable and should not be made on panoramic radiographs.
Evidence Search ("diagnosis"[Subheading] OR "diagnosis"[All Fields] OR "diagnosis"[MeSH Terms]) AND ("mandible"[MeSH Terms] OR "mandible"[All Fields] OR "mandibular"[All Fields]) AND asymmetry[All Fields] AND panoramic[All Fields]
Comments on
The Evidence
The majority of the studies used dry skulls to assess for accuracy of measurements using panoramic radiographs. The one concern is that dry skulls can be placed in the ideal position, and this isn't the case in clinical practice. It is difficult to control the patient's head position.
Applicability This study shows that panoramic radiographs can be used with caution to detect mandibular asymmetries. Anything greater than 6% difference can be attributed to an asymmetry, and anything less than 6% can be attributed to technical error. The panoramic radiograph can be used to detect large discrepencies but should not be used primarily as a screening tool for diagnosing mandibular asymmetries.
Specialty (Oral Medicine/Pathology/Radiology) (General Dentistry) (Oral Surgery) (Orthodontics)
Keywords mandibular asymmetry, diagnosis, panoramic radiographs
ID# 744
Date of submission 11/16/2010
E-mail zirbel@uthscsa.edu
Author Cassandra Zirbel, DDS
Co-author(s)
Co-author(s) e-mail
Faculty mentor Stephen Matteson, DDS
Faculty mentor e-mail MATTESON@uthscsa.edu
   
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
None available
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Comments and Evidence-Based Updates on the CAT
(FOR PRACTICING DENTISTS', FACULTY, RESIDENTS and/or STUDENTS COMMENTS ON PUBLISHED CATs)
by Momal Umrani (San Antonio, Texas) on 05/03/2012
A PubMed search conducted on 5/3/12 revealed that there is a no relevant evidence published since 2008. The systematic review published by Van Elsande is the most valid article to answer the clinical question: Is a panoramic radiograph reliable for diagnosing mandibular asymmetry?