Bone Height Measurements on Panoramic Radiographs

Dr. Sam-Sun Lee and researchers in­vestigated the influence that the horizontal relationship between the man­di­bular canal and the alveolar crest can have on the available bone height (ABH) measurement on panoramic ra­diographs. The study, published in Dentomaxillofacial Radi­ology, involved 92 mandibular edentulous sites of pan­oramic computed radiographs; reformatted computed tom­ography (CT) images of 77 patients were used. Selected CT images were categorized into 4 types according to the relative location of the peak of the alveolar crest to the mandibular canal. One oral and maxillofacial radiologist measured the ABH twice on both imaging modalities with an interval of 7 days and compared the measurement differences according to the type. The study found that the ab­so­lute average value of the differences in measurement between the values of ABHs on panoramic images and CT images was 0.97 mm. Signif­icant difference was found only be­tween the mean values of ABHs for Type 1 (0.60 mm), where the alveolar crest is located in the buccal side or cen­tral area with respect to the man­dibular canal, and Type 4 (1.46 mm), where the alveolar crest is in the lingual side to the mandibular canal. The authors conclude that the relative horizontal location of the alveolar crest with respect to the mandibular canal af­fected the ABH measurement on pan­oramic radiographs. In particular, ABH is overestimated when there has been resorption of the buccal aspect of the ridge, moving the alveolar crest lingually.
(Source: Den­to­maxillofacial Radiology, 2012, Vol­ume 41, pages 117 to 121; first published online November 24, 2011)
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