title: Quantitative evaluation of bone density using the Hounsfield index.
abstract: OBJECTIVE
  The primary aims of this retrospective study were to: (1) evaluate bone quality in different segments of the edentulous jaw and correlate it with demographic data and (2) establish a quantitative and objective assessment of bone quality based on the Hounsfield scale.
  
  
  METHODS
  One hundred one randomly selected computerized tomographic (CT) scans were used for the analysis. Edentulous segments ranging from 10 to 30 mm were selected for evaluation, and the findings were analyzed and correlated to demographics. Implant recipient sites were evaluated visually for bone classification by 2 independent examiners. The same sites were subsequently evaluated digitally using the Hounsfield scale, and the results were correlated with the visual classification.
  
  
  RESULTS
  The 4 quadrants of the mouth displayed Hounsfield unit (HU) values ranging from -240 HU to 1,159 HU. The highest unit/mean density value (559 +/- 208 HU) was found in the anterior mandible, followed by 517 +/- 177 HU for the anterior maxilla, 333 +/- 199 HU for the posterior maxilla, and 321 +/- 132 HU for the posterior mandible. There was no association between the Hounsfield value and density and age or gender. When subjective bone quality was correlated to Hounsfield index findings, only the relationship between HU and type 4 bone was found to be significant.
  
  
  CONCLUSIONS
  Knowledge of the Hounsfield value as a quantitative measurement of bone density can be helpful as a diagnostic tool. It can provide the implant surgeon with an objective assessment of bone density, which could result in modification of surgical techniques or extended healing time, especially in situations where poor bone quality is suspected.
authors.affiliation: Department of Periodontology, Tufts University School of Dental Medicine, Boston, Massachusetts 02111, USA. tannaz.shapurian@tufts.edu
authors.forename: Tannaz
authors.initials: T
authors.lastname: Shapurian
authors.forename: Petros D
authors.initials: PD
authors.lastname: Damoulis
authors.forename: Gary M
authors.initials: GM
authors.lastname: Reiser
authors.forename: Terrence J
authors.initials: TJ
authors.lastname: Griffin
authors.forename: William M
authors.initials: WM
authors.lastname: Rand
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000539:Alveolar Process / Q000502:physiology*; D000704:Analysis of Variance; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000145:classification* / Q000000981:diagnostic imaging; D015921:Dental Implants; D005260:Female; D006801:Humans; D007575:Jaw, Edentulous / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012189:Retrospective Studies; D036542:Tomography, Spiral Computed
chemical_list: D015921:Dental Implants