Bone Mineral Density Of Cortical Bone Research Articles

Assessment of Role of Bisphosphonates on Dental Implant Treatment in Post-menopausal Ladies.

To examine the impact of bisphosphonates (BPs) on dental implant treatment and alveolar bone in post-menopausal ladies. Twenty post-menopausal ladies who had at least one dental implant within the previous 5 years participated in the current study. Ten subjects were categorized into two groups: Group A had BP medication for 1.5 years, and group B received parathyroid hormone (PTH). Both groups' bone thickness and bone mineral density (BMD) were measured. Group A had 5%, and group B had 5% of dental implants failures. BMD of cortical bone was 1468 ± 136 mg/mL and 1008 ± 84 mg/mL in groups A and B, correspondingly. The cortical and cancellous bone densities in both the groups were statically significant. Cortical bone thickness was insignificant in comparison. Both cortical and cancellous bones' bone mineral density decreased in both groups. With continued usage of BPs, the cortical bone thickness increased.

Regional differences in microarchitecture and mineralization of the atrophic edentulous mandible: A microcomputed tomography study

ObjectiveThe aim of the present study was to assess mineralization and trabecular microarchitecture in atrophic edentulous mandibles and to identify regional differences and relations with the extent of resorption. MethodsCortical and trabecular bone volumes in anterior, premolar and molar regions of 10 edentulous cadaveric mandibles (5 males and 5 females; mean age ± SD: 85.4 ± 8.3 years) were assessed by microcomputed tomography. Mandibular height and Cawood & Howell classes were recorded. Concerning trabecular volumes, bone mineral density (BMD), bone volume fraction, trabecular tissue volume fraction, connectivity density, trabecular number, trabecular thickness, trabecular separation, degree of anisotropy, and structural model index were measured; concerning cortical volumes porosity, BMD and cortical thickness were measured. ResultsIn molar regions, the bone volume fraction and trabecular number were lower, whereas trabecular separation, degree of anisotropy and cortical BMD were higher compared to anterior regions. In premolar regions, mandibular height correlated negatively with trabecular number (Spearman’s correlation r = 0.73, p = 0.017) and connectivity density (Spearman’s correlation r = 0.82, p = 0.004), and correlated positively with trabecular separation (Spearman’s correlation r = − 0.65, p = 0.04). Cortical BMD was higher at bucco-inferior cortex of molar and inferior border of premolar region and lower at anterior cranial buccal and lingual surface. ConclusionsIn the premolar region, increased resorption coincides with local impairment of trabecular bone quality. Cortical bone BMD is higher in areas with highest strains and lower in areas with most mandibular resorption. Trabecular bone volume and quality is superior in the anterior region of the edentulous mandible, which might explain improved primary stability of dental implants in this region.

Evaluation of Effect of Bisphosphonates on Dental Implant Therapy in Postmenopausal Women Using Cone Beam Computed Tomography

Osteoporosis is one of the diseases which show significant bone mass reduction especially in post menopausal women. The present study was conducted to determine the effect of Bisphosphonates (BP) on alveolar bone and dental implant therapy in women after menopause. The present study was conducted on 30 postmenopausal women who received at least one dental implant in the last 5 years. Group I comprised of 15 patients who were on BP therapy for 1.5 years, and group II consisted of 15 patients who were on parathyroid hormone (PTH). Bone mineral density (BMD) and bone thickness were assessed in both groups. Group I had 3.85% and group II had 3.15% of dental implants failures. BMD of cortical bone was 1552± 145 mg/mL and 1012 ± 94 mg/mL in groups I and II respectively. BMD of cancellous bone was 80 ± 15 mg/mL and 104 ± 72 mg/mL in group I and group II respectively. The difference was significant (p < 0.05). Cortical bone thickness was 2.5 ± 0.6 mm in group I and 2.2 ± 0.8 mm in group II. The difference was non-significant (p >0.05). There was a reduction in BMD (mg/mL) of cortical and cancellous bone. There was an increase in cortical bone thickness with the use of BPs over the years. The difference was significant (p < 0.05). There was a decrease in bone mineral density of both cortical and cancellous bone in both groups. There was increase cortical bone thickness on prolonging use of BPs. Patients on BPs therapy should be carefully evaluated both clinically and radiographically before dental implant treatment as these agents affect the quantity and quality of cortical bone especially in the posterior mandibular region in patients with osteoporosis.

The main autoimmune and nonautoimmune etiologies of endogenous hyperthyroidism do not seem to influence the increased prevalence of morphometric vertebral fractures and osteoporosis in Portuguese men

ObjectivesThe purpose of this study was to evaluate the effects of hyperthyroidism and their etiology on bone mineral density (BMD), on body soft tissue composition, on the prevalence of vertebral fractures detected by vertebral fracture assessment (VFA) and on the trabecular bone score (TBS). MethodsFrom an initial population of 119 Portuguese men (78 with hyperthyroidism [HT]+ 41 controls [CTs]) admitted to the Endocrinology Department we selected 41 men aged over 50 with clinical hyperthyroidism to participate; each one was matched by age and height with a control person. BMD (g/cm2) at the lumbar spine, hip, radius 33% and whole body and the total body masses (kg) were studied by dual-energy X-ray absorptiometry (DXA). VFA with Genant semiquantitative method was used to detect fractures. The TBS was obtained from lumbar spine DXA images. No patient had been treated previously for hyperthyroidism or osteoporosis. Adequate statistical tests were used. ResultsIn the hyperthyroidism group, total lean mass (CT 58.16 ± 7.7 vs. HT 52.3 ± 5.7, P = 0.03) and distal radius BMD (CT 0.769 ± 0.05 vs. HT 0.722 ± 0.08, P = 0.005) were lower; there was a significantly higher prevalence of osteoporosis (CT 9.7% vs. HT 29.3%, P = 0.015) and vertebral fractures (CT 2.4% vs. HT 24.4%, P = 0.007). TBS was similar in both groups (CT 1.328 ± 0.11 vs. HT 1.356 ± 0.11, P = not significant). Comparing patients with Graves' disease with patients with toxic goiter, there were no differences regarding BMD, BMD qualification, prevalence of fractures and TBS and just total lean mass was significantly lower in patients with Graves' disease. ConclusionsThese results suggest that in a group of hyperthyroid men aged over 50 there are significant decreases in cortical bone BMD and lean mass and a higher prevalence of osteoporosis and silent vertebral fractures, but the etiology of the hyperthyroidism does not seem to influence it. Besides the antithyroid drugs, some patients may benefit from bone-directed treatments.

Analysis of cortical bone of the mandibular body in psychological stressed rats by micro-CT

To calculate the bone mineral density (BMD) of buccal and lingual mandibular cortical bone in psychological stressed rats. One hundred adult male SD rats were randomly divided into psychological stress group(PS group, 40 rats), control group (C group, 40 rats) and foot shock group (FS group, 20 rats). In addition, the PS group and C group were equally divided into week 1, week 2, week 3, week 4 and week 5 subgroup at random. The animals placed intervally in the communication box to receive the psychological stimuli were considered as the PS group animals. The stressors were from their neighboring FS group rats which were receiving foot shock. After observing the behavioral changes of the PS group rats and C group rats with elevated plus maze test, the mandibles were removed carefully and BMD of regions of interest (ROI) in the mandible were calculated by Micro-CT. The ROI were located at the equidistant five points, i.e. A, B, C, D and E, along the anteroposterior border and approximately halfway between the superior and inferior border of the mandible. Significant decrease of time spent in the open arms, ratio of open arms time and ratio of open arms entries were observed in PS group [time spent in the open arms: (16.6 ± 2.3), (17.1 ± 2.4), (15.8 ± 1.6), (15.8 ± 2.2), (17.9 ± 2.6) s]; ratio of open arms time: [(30.5 ± 3.7)%, (30.3 ± 2.5)%, (26.8 ± 3.8)%, (26.5 ± 2.0)%, (27.4 ± 2.6)%]; ratio of open arms entries: [(34.1 ± 4.4)%, (34.6 ± 4.1)%, (32.6 ± 3.9)%, (34.5 ± 4.8)%, (31.8 ± 3.3)%] compared with control group at each time point (P < 0.05), no differences were observed among PS groups (P > 0.05). On the buccal side of mandibular body, BMD in point D of week 5 PS group [(1 085.4 ± 88.5) mg/cm³] was higher than that of matched control group [(782.3 ± 53.7) mg/cm³) ]and week 1 PS group [(825.2 ± 88.5) mg/cm³] (P < 0.05). Similar results of BMD were obtained in point E between week 5 PS group [(657.2 ± 101.7) mg/cm³] and control group [(415.9 ± 99.7)mg/cm³], week 1 and 2 PS group [(348.1 ± 111.3), (339.3 ± 74.0) mg/cm³] (P < 0.05). On the lingual side of mandibular body, the alterations of BMD were observed in point B and C between week 5 PS group [(1 755.6 ± 156.6), (1 367.8 ± 115.8) mg/cm³]and matched control group [(1 364.6 ± 120.2), (922.6 ± 102.6) mg/cm³] and week 1 PS group [(1 299.7 ± 172.9), (1 052.3 ± 107.9) mg/cm³] (P < 0.05). No differences of BMD were observed in the other points between PS group and control group at each time point(P > 0.05). Psychological stress induced by communication box could result in the anxious behavior of SD rats and increase the BMD of cortical bone in certain regions of the mandibular body.

Miniscrew stability evaluated with computerized tomography scanning

In this study, we aimed to determine the effect of bone mineral density (BMD), cortical bone thickness (CBT), screw position, and screw design on the stability of miniscrews. Ninety-six miniscrews of both cylindrical and tapered types were placed in 6 beagle dogs. The BMD and CBT were measured by computerized tomography and correlated with the placement and removal torque and mobility. A regression equation to predict the placement torque was calculated based on BMD, CBT, screw type, and screw position. The placement torque showed a positive correlation in the order of removal torque (0.66), BMD of the cortical bone (0.58), and CBT (0.48). Placement and removal torque values were significantly higher in the mandible compared with the maxilla. Tapered miniscrews had higher placement torque than did the cylindrical type (P <0.001). However, the removal torque was similar in both groups. Placement torque was affected by screw position, screw type, and BMD of cortical bone, in that order. BMD of cortical bone, screw type, and screw position significantly influence the primary stability of miniscrews.

The study of bone mineral density and structure in proximal femur by quantitative CT in elderly Chinese women

Objective To evaluate the bone mineral density (BMD) and structure of proximal femur in elderly Chinese women by quantatitive computed tomography (QCT) and dual energy X-ray absorptiometry (DXA), and to further compare the results of these two methods. Methods Sixty-six healthy Chinese women over 65 years old participated in this study. The left hips of all subjects were measured with DXA and the BMD of femoral neck and trochanteric region were calculated. With QCT, the BMD and tissue volume of cortical, trabecular and integral bone were calculated for femoral neck, trochanteric and total femur regions in both hips. Appropriate statistical analyses were performed with SPSS 11.5. Results The BMD and structural parameters in different regions and different compartments of the proximal femur could be precisely assessed with QCT technique. The BMD of cortical bone in femoral neck [ ( 0. 52 ± 0. 04) g/cm3 ], BMD of cortical bone in troehanterie region [ (0. 49 ± 0. 03 ) g/cm3 ] and BMD of integral bone in trochanteric region [ (0. 22 ± 0. 04 ) g/cm3 ] were greater in the right than those in the left [ (0. 51 ± 0. 04), (0. 48±0. 03), (0. 21±0. 04) g/cm3 ]. The difference had statistical signification (P 0. 05). All QCT parameters of the right hip correlated well with their corresponding ones of left hip with correlation coefficients ranging from 0. 656---0. 955, P < 0. 05. QCT-derived simulated DXA femoral neck and trochanteric BMD were correlated well with real DXA measurements ( r 0. 685 and 0. 855, P < 0. 05). Conclusion With QCT technique the BMD and structural parameters in different regions and different compartments of the proximal femur can be precisely assessed. QCT is a powerful technique in the researches of osteoporosis. Key words: Bone density; Tomography, X-ray computed ; Densitometry, X-ray