Correlation among geometric, densitometric, and mechanical properties in mandible and femur of osteoporotic rats

Abstract

We have previously demonstrated bone loss of the mandible and femur in experimental osteoporotic rats and its prevention by medication, using peripheral quantitative computed tomography (pQCT). In the present study, the mechanical properties of the mandible and femur and the correlation to their geometric and densitometric properties were studied in ovariectomized rats with or without etidronate treatment. Fifty-four Wistar strain SPF female rats, 26 weeks old, were randomly assigned to four groups: (1) Basal group (12 rats, 1.0% Ca diet); (2) Sham group (Sham-operated, 12 rats, 0.1% Ca diet); (3) OVX group (ovariectomized, 15 rats, 0.1% Ca diet); (4) Treated group (OVX + etidronate, 15 rats, 0.1% Ca diet). Total bone mineral density (BMD), cortical BMD, cross-sectional cortical bone area, cross-sectional cortical bone thickness, crosssectional moment of inertia (CSMI), and polar strength index (SSI) of the mandible and femur were measured by pQCT. The failure load of mandible and femur was evaluated by three-point bending. The failure load of both bones was significantly lower in the Sham group compared with the Basal group. The OVX group further had a 8% and 7% decrease in the failure load for mandible and femur, respectively, compared to the Sham group. Treatment with etidronate led to an increase in the failure load compared with the OVX group. The failure load was related to the pQCT-assessed variables, especially with cortical bone area and total BMD. Moreover, the geometric and densitometric properties and failure load in the mandible showed a correlation to those in the femur.

Interrelationships between Tooth Properties and Biochemical Bone Turnover Markers Investigated on Six-Month-Old Pig Model

“…The second used method in this study is quantitative computed tomography (QCT) that allows for separate measurement of volumetric bone mineral density of the trabecular and cortical bone compartments (expressed in g/cm 3 ) as well as determination of mean volumetric tooth mineral density (TvBMD) and total tooth volume (Tvol). In contrast to DEXA, QCT eliminates the error in mineral density measurements present in the former method [4,8,10,15]. However, the resolution for miniature samples analysis is too small to provide precise results and relatively high doses of X-rays are emitted during the scanning procedure, which might not be particularly beneficial for living subjects.…”

Bone Quality Improvement in Ovariectomized Rats Dosed with New Osteoporosis-Preventive Compound: Analyses with Raman Spectroscopy and Polarized Light Microscopy

“…Peaks of hydroxyapatite-related functional groups were detected in the 4 spectra. PO 4 3-(FWHM), Phosphate/Amide I, Carbonate/ Phosphate, and Carbonate/Amide I were measured in the typical spectra of the ONMD and OAFD groups shown in Fig. 2.…”

“…These intensity ratios can be used to evaluate bone quality. Regarding crystallinity of hydroxyapatite, the full-width half-maximal (FWHM) of the Phosphate band (PO 4 3-) is used in many studies [22][23] . FWHM is an important index related to modulus of elasticity, yield stress, and breaking stress of bone.…”

Bone Quality of the Femoral Mid-Shaft of Ovariectomized Rats Fed a Low-Mineral Diet

“…Ovariectomized (OVX) rats are frequently used as a model for osteoporosis [6][7][8] . OVX rats develop bone mutations associated with reduced secretion of estrogen 9) and exhibit subsequent changes in bone metabolism and systemic conditions 10,11) and bone loss 7,9,12) .…”