Structural and radiological parameters for the characterization of jawbone.
OBJECTIVE
The aim of this study was to determine the Hounsfield values of selected bone sites on a computed tomography (CT) scan of the jaw and to investigate the relationship between this radiological parameter and structural parameters.


METHODS
A selection of 24 bone samples out of eight cadaver human jaws was made. The following parameters were measured: Hounsfield value in the jaw (HU1) determined by a first CT scan, Hounsfield value of the excised bone specimen (HU2) by a second CT scan, bone mineral density (BMD) by a dual-energy X-ray absorptiometry scan, bone volume (BV/TV) by the microfocus CT scan, first peak transmission time (T(US-1)) and first zero crossing transmission time (T(US-2)) by an ultrasound measurement and Young's modulus (E(MECH)) by a compression test.


RESULTS
Thirteen specimens were composed of a mix of trabecular and a small amount of cortical bone, while another 11 specimens were composed of trabecular bone only. A good correlation was found between the HU value of the specimen (HU2) and BMD (rho = 0.99), BV/TV (rho = 0.97), T(US-1) (rho = -0.83), T(US-2) (rho = -0.87) and E(MECH) (rho = 0.83). For the pure trabecular bone specimens, the HU value of the excised bone specimen (HU2) was highly correlated (rho = 0.95) with the HU value of the total jaw scan (HU1). For mixed trabecular-cortical bone specimens, this relationship was weak (rho = 0.57).


CONCLUSIONS
With the current CT scan technology, predictions of the mechanical properties of trabecular jaw bone based on Hounsfield values were only valid for jaws with a thin layer of cortical bone. For jaws with a thicker cortical layer, the prediction of the mechanical properties decreased significantly.
Department of Prosthetic Dentistry/BIOMAT Research Group, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Katholieke Universiteit Leuven, Leuven, Belgium.
Nele
N
Stoppie
Veerle
V
Pattijn
Tim
T
Van Cleynenbreugel
Martine
M
Wevers
Jos
J
Vander Sloten
Naert
N
Ignace
D015502:Absorptiometry, Photon; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000502:physiology; D002102:Cadaver; D004548:Elasticity; D005544:Forecasting; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008334:Mandible / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D008437:Maxilla / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed / Q000379:methods; D014463:Ultrasonography