Document Detail


Accuracy of angular measurements and assessment of distortion in the mandibular third molar region on panoramic radiographs.
MedLine Citation:
PMID:  21420643     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: The objective of this study was to examine distortion on panoramic radiographs by assessing the accuracy of angular measurements in the mandibular third molar region on panoramic radiographs using computed tomography (CT).
METHODS: Images from patients referred to a radiology practice for low-dose CT scans of their lower third molars were used in this study. The angle between the long axes of the second and third molars was assessed on panoramic radiographs and the corresponding CT images. Apparent tilting of the tooth across the arch on the panoramic image and the bucco-lingual inclination on CT were also recorded and compared.
RESULTS: Eighty-eight patients had 163 mandibular third molars. The mean difference between the panoramic measurements and the CT measurements was -1.44 degrees, indicating that on the panoramic radiograph the third molar appeared less mesially inclined on average. This pattern was present in most cases, but in 64 cases the third molar appeared more mesially inclined on the panoramic radiograph. It was not possible to predict the direction of the discrepancy based on the radiographic findings. The discrepancy between the 2 measurements was greater if the third molar appeared tilted across the arch on the panoramic image, and tilted teeth showed a higher bucco-lingual inclination on reformatted CT images.
CONCLUSIONS: Distortions inherent in panoramic imaging because of projection geometry produce discrepancies in the angular measurements in the mandibular third molar regions on panoramic radiographs. Interpretation of third molar angulation from panoramic radiographs is often unreliable and may not accurately reflect the true orientation of the tooth. Apparent tilting of the tooth across the arch on the panoramic radiograph exacerbates the problem and appears to correlate with the bucco-lingual inclination of the third molar as visualized on reformatted CT images.
Authors:
Raahib Dudhia; Paul A Monsour; Neil W Savage; Richard J Wilson
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Publication Detail:
Type:  Comparative Study; Evaluation Studies; Journal Article    
Journal Detail:
Title:  Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics     Volume:  111     ISSN:  1528-395X     ISO Abbreviation:  Oral Surg Oral Med Oral Pathol Oral Radiol Endod     Publication Date:  2011 Apr 
Date Detail:
Created Date:  2011-03-22     Completed Date:  2011-07-18     Revised Date:  2011-10-20    
Medline Journal Info:
Nlm Unique ID:  9508562     Medline TA:  Oral Surg Oral Med Oral Pathol Oral Radiol Endod     Country:  United States    
Other Details:
Languages:  eng     Pagination:  508-16     Citation Subset:  D; IM    
Copyright Information:
Copyright © 2011 Mosby, Inc. All rights reserved.
Affiliation:
Queensland X-Ray, Brisbane, Queensland, Australia.
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MeSH Terms
Descriptor/Qualifier:
Adolescent
Adult
Artifacts*
Female
Humans
Linear Models
Male
Mandible / radiography*
Middle Aged
Molar, Third / radiography*
Radiographic Image Enhancement
Radiography, Dental, Digital
Radiography, Panoramic*
Reproducibility of Results
Tomography, X-Ray Computed
Tooth, Impacted / radiography
Young Adult
Comments/Corrections
Comment In:
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2011 Oct;112(4):415; author reply 415   [PMID:  21880517 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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