title: Diagnostic performance of mandibular bone density measurements in assessing osteoporotic status.
abstract: OBJECTIVE
  The study evaluated the diagnostic performance of computed tomography (CT) bone density measurements (in Hounsfield units [HU]) in assessing the osteoporotic status of edentulous subjects (21 men, 40 women) scheduled to receive mandibular implant-supported overdentures.
  
  
  METHODS
  Density (in HU) of 61 left and 61 right mandibular canine sites was measured. Each subject was also subject to body bone mineral density measurements (dual-energy x-ray absorptiometry). Bone density T-score values of total hip, femoral neck, spine (L1 to L4), and total body were assessed. Pearson correlations were conducted between HU of each mandibular bone site and the subject's T-score values. Sensitivity/specificity and receiver operating characteristic curve analyses were used to assess the diagnostic performance of HU in detecting subjects who were, based on each of the four T-scores: (1) "not osteonormal", ie, with a T-score at or below -1.0; or (2) osteoporotic, ie, with a T-score at or below -2.5.
  
  
  RESULTS
  HU measurements of mandibular bone sites were found to have modest but significant correlations with each bone density T-score value (total hip, femoral neck, spine, total body). CT mandibular site HU measurement has diagnostic value in detecting a "not osteonormal" condition when total hip, spine, or total body T-scores were used, but not when femoral neck T-score was used.
  
  
  CONCLUSIONS
  Based on the limited sample size, optimal HU cutoff values of ~530, ~600, and ~640 HU for total hip, spine, or total body T-scores, respectively, were proposed. CT mandibular site HU measurement had diagnostic value in detecting osteoporosis when spine T-score was used but not when total hip, femoral neck, and total body T-scores were used. An optimal HU cutoff value of ~460 HU for spine T-score was proposed.
authors.forename: John
authors.initials: J
authors.lastname: Chai
authors.forename: Anson C M
authors.initials: AC
authors.lastname: Chau
authors.forename: Frederick C S
authors.initials: FC
authors.lastname: Chu
authors.forename: Tak W
authors.initials: TW
authors.lastname: Chow
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D003828:Denture, Overlay; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging; D006615:Hip / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging*; D008875:Middle Aged; D009066:Mouth, Edentulous / Q000000981:diagnostic imaging / Q000534:rehabilitation; D010024:Osteoporosis / Q000000981:diagnostic imaging*; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013131:Spine / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*