Assessment of bone density changes following two-jaw surgery using multidetector computed tomography: A pilot study.

Background There are few dual X-ray absorptiometry (DXA) studies on periacetabular bone density changes after cup implantation. This study was designed to analyze the load-transfer mechanism and stress pattern of periacetabular cortical and cancellous bone after implantation of a ihemispherical titanium alloy press-fit cup with alumina-alumina pairing in vivo. We introduced a novel method of computed tomography (CT)-assisted osteodensitometry.Method We investigated 26 hips (26 patients) with osteoarthritis using conventional sequential CT examinations performed within the first 10 days after implantation, and after a mean period of 1.1 years postoperatively. Bone density of full, cancellous and cortical bone (mgCaHA/mL) was measured.Results At the time of follow-up, the mean bone density values of the cortical bone cranial to the cup increased by 3.6% (p = 0.03) while the cancellous bone density decreased by 18%. Cancellous bone loss was greater in the region ventral to the cup (–35%) than in the dorsal region (–30%). Cortical bone density decreased ventral to the cup (–6.4%). All these changes were statistically significant. The bone density changes in the dorsal cortical region were not significant.Interpretation The method presented is an excellent tool for detailed measurement of bone density changes around the cup after total hip arthroplasty, and allows a thorough assessment of stress shielding phenomena in vivo. The hemispherical titanium alloy press-fit cup is a rigid implant which stress shields cancellous bone and enhances load transfer to the cranial cortical bone. Further investigations will demonstrate the impact these factors have on the long-term results of the implant, and may allow a type-related predictable prognosis of the longevity of the prosthesis.

A Structural Approach to Renal Bone Disease

As a follow-up of a previously reported three-year study, we analyzed the periprosthetic acetabular cortical and cancellous bone density changes at ten years after implantation of a press-fit cup. Prospective clinical, radiographic, and quantitative computed tomography examinations were performed within ten days and at mean periods of one, three, and ten years after total hip arthroplasty with a press-fit cup, a femoral stem with a tapered design, and alumina-alumina pairing. Periacetabular cortical and cancellous bone density (mg CaHA/mL) in the cranial, ventral, and dorsal regions about the cup were measured for twenty-four hips in vivo. All acetabular cups showed radiographic signs of stable ingrowth, and no acetabular component had to be revised. The loss of periacetabular cancellous bone density about the cup was as much as -37% cranially, -60% ventrally, and -71% dorsally; the decrease was progressive between the one-year and three-year examinations only. In contrast, cortical bone density above the dome of the acetabular cup remained constant throughout the ten-year follow-up. A moderate change in cortical bone density of -5% to -18% was seen at the level of the cup ten years postoperatively. Both periacetabular cortical and cancellous bone density changes were nonprogressive between the three-year and ten-year examinations after press-fit cup fixation.

BackgroundThe anterior-middle superior alveolar (AMSA) anesthetic technique has been reported to be a less traumatic alternative to several conventional nerve blocks and local infiltration for anesthesia of the maxillary teeth, their periodontium, and the palate. However, its anatomic basis remains controversial. The present study aimed to determine if the pattern of cortical and cancellous bone density in the maxillary premolar region can provide a rationale for the success of the AMSA anesthetic technique.MethodsCone-beam computed tomography scans of 66 maxillary quadrants from 34 patients (16 men and 18 women) were evaluated using a volumetric imaging software for cortical and cancellous bone densities in three interdental regions between the canine and first molar. Bone density was measured in Hounsfield units (HU) separately for the buccal cortical, palatal cortical, buccal cancellous, and palatal cancellous bones. Mean HU values were compared using the Mann-Whitney U test and one-way ANOVA with post-hoc analysis.ResultsCancellous bone density was significantly lower (P ≤ 0.001) in the palatal half than in the buccal half across all three interdental regions. However, there was no significant difference (P = 0.106) between the buccal and palatal cortical bone densities at the site of AMSA injection. No significant difference was observed between the two genders for any of the evaluated parameters.ConclusionsThe palatal half of the cancellous bone had a significantly lower density than the buccal half, which could be a reason for the effective diffusion of the anesthetic solution following a palatal injection during the AMSA anesthetic technique.

Beginning with the report in 1994 that an adult male with homozygous loss of estrogen receptor α (ERα) had unfused epiphyses and osteopenia,(1) there is now considerable evidence from observational and interventional studies (summarized in Khosla and colleagues(2)) that estrogen is the dominant regulator of bone metabolism in men. Indeed, a legitimate argument can be made that testosterone is largely a prohormone for the skeleton, with its effects on bone mediated principally via aromatization to estrogen, although it remains likely that testosterone contributes to bone size via effects on periosteal apposition and perhaps indirectly to bone mass by increasing muscle mass.

Bone loss around uncemented femoral components is suspected to precede implant loosening and contribute to problems in revision surgery. Short-stemmed cementless femoral components are designed to preserve proximal femoral bone stock and ultimately the longevity of the prosthesis. With quantitative computed tomography-assisted osteodensitometry, we prospectively analyzed femoral cortical and cancellous bone density (BD) and contact area changes of an uncemented collum femoris preserving stem (n=38) 10days, 1, 3 and 7years post-operatively. Seven years post-operatively, cancellous BD (mg CaHA/mL) had decreased by as much as -66% and cortical BD by up to -27% at the metaphyseal portion of the femur; the decrease was progressive between the 1- and 3-year examinations and halted thereafter. Contact area (in % out of a possible 100%) decreased proximally between the 1- and 3-year follow-up. Proximal cortical and cancellous bone density loss and decrease of contact area indicate that metaphyseal fixation cannot be achieved. The lack of cortical BD loss and increase of contact area values below the trochanter minor suggest diaphyseal fixation.

Introduction This study compared the alveolar bone density of the mandible according to gender, age and position using Cone-beam computed tomography (CT). Materials and Methods The maxillofacial CT scan data was obtained from 60 Korean patients. In addition, the alveloar bone density of 5 males and 5 females with normal occlusion aged from 10 to 70 years was measured at the buccal cortical bone, cancellous bone and lingual cortical bone, as well as at the position of the incisors, canines, premolars and molars. Results The age-specific mean bone density was highest in patients in their third decade. The buccal cortical bone of the molars showed the highest bone density. Males in their fifties and sixties had a higher bone density in the cancellous bone in the region of the premolars and the buccal cortical bone of the molars, respectively, than females but there was no significant difference between males and females in the other parts. The cancellous bone density was highest in those in their twenties and thirties, and tended to decline up to their seventh decade. Conclusion These results revealed a significantly different bone density according to gender, age and position in the Korean population. In addition, it is possible to predict the bone density based on these results.

Hypoxemia has been recognized as a risk factor for bone loss. The aim of the present study is to investigate the relationship of bone mass and density measures with anemia and hemoglobin levels in a large sample of older community-dwelling persons. The study is based on data from 950 participants enrolled in the "Invecchiare in Chianti" (Aging in the Chianti area, InCHIANTI) study. All the analyses were performed considering continuous hemoglobin levels as well as the dichotomous anemia variable (defined according to WHO criteria as hemoglobin < 12 g/dl in women and < 13 g/dl in men). A peripheral quantitative computerized tomography (pQCT) scan of the right calf was performed in all participants to evaluate total bone density, trabecular bone density, cortical bone density, and the ratio between cortical and total bone area. Linear regression analyses were used to assess the multivariate relationship of pQCT bone measures with anemia and hemoglobin levels after adjustment for demographics, chronic conditions, muscle strength and biological variables. Participants were 75.0 (SD 6.9) years old. In our sample, 101 participants (10.6%) were anemic. In women, coefficients from adjusted linear regression analyses evaluating the association between pQCT bone measures (per SD increase) and hemoglobin levels/anemia showed significant associations of anemia with total bone density (beta = -0.335, SE = 0.163; P = 0.04) and cortical bone density (beta = -0.428, SE = 0.160; P = 0.008). Relationships with borderline significance were found for the associations of anemia with trabecular bone density and the ratio between cortical and total bone area. Significant associations were found between hemoglobin levels and trabecular bone density (beta = 0.112, SE = 0.049; P = 0.02), total bone density (beta = 0.101, SE = 0.046; P = 0.03), cortical bone density (beta = 0.100, SE = 0.046; P = 0.03) and the ratio between cortical bone and total area (beta = 0.092, SE = 0.045; P = 0.04). In men, significant associations were found for hemoglobin levels with total bone density (beta = 0.076, SE = 0.036; P = 0.03) and cortical bone density (beta = 0.095, SE = 0.41; P = 0.02). A borderline significance was reported for the association between anemia and cortical bone density. We concluded that anemia and low hemoglobin levels are negatively and independently associated with bone mass and density. The bone loss associated with hemoglobin levels mainly occurs in the cortical bone. Women with lower hemoglobin levels demonstrate a higher bone loss than male counterparts.

The aim of this study was to monitor changes in bone density and bone quality (microarchitecture) in the femoral epiphyseal region in rats with bone loss induced by oestrogen deficiency and accelerated by mineral deficiency. Forty-eight Wistar rats were divided into 3 groups (n = 16 per group): Group 1, sham-operated rats on a normal diet; Group 2, ovariectomised rats on a normal diet; and Group 3, ovariectomised rats on a mineral-deficient diet. Observations were conducted 4, 8, 16, and 24 weeks after the operation (sham or ovariectomy), while the rats were on their respective diets. Microscopic computed tomography of the femoral epiphyseal region was used to generate 3-dimensional bone density distribution maps, and to compute bone density values. Densities of cortical and cancellous bone in Groups 2 and 3 were significantly less than densities in Group 1, and densities in Group 3 were significantly less than densities in Group 2 at nearly every post-operative time interval.This study demonstrated that: a) ovariectomy in rats induces bone loss; b) a mineral-deficient diet accelerates bone loss that has been induced by oestrogen deficiency; and c) 3-dimensional bone density distribution maps may be useful in diagnosing osteoporosis and other diseases causing bone loss. Microscopic computed tomography is a powerful analytical tool for measuring spatial variations in bone density, and temporal changes in the patterns of 3-dimensional bone density distribution maps.

Biomechanical effectiveness of cortical bone thickness on orthodontic microimplant stability: An evaluation based on the load share between cortical and cancellous bone

Inhibition of cortical and cancellous bone formation in glucocorticoid-treated OVX sheep

We measured indices of bone volume (cancellous and cortical) and bone surface (cancellous, endocortical, and intracortical) in intact, full-thickness transiliac bone biopsies obtained from 47 healthy white women (23 premenopausal and 24 postmenopausal) and 82 patients with postmenopausal osteoporosis. In the normal subjects there was the expected loss of cancellous bone with age, best shown by a reduction in bone surface/tissue volume, but no fall in cortical thickness with age despite a significant reduction in forearm bone density measured by single-photon absorptiometry. Bone surface/bone volume was about four times higher in cancellous than in cortical bone, and cancellous bone contributed about one-third of the total bone volume and about two-thirds of the bone surface when related to the core volume referent. In the osteoporotic patients, core width, an index of iliac bone thickness at the biopsy site, was reduced by 10%, but we could not determine whether this was the result of compaction of the core or of bone slenderness. All indices of bone volume, cortical as well as cancellous, were significantly smaller, as were the values for forearm bone densitometry; the relative deficits at different sites depended on whether they were expressed as percentages or as zeta scores. Bone surface/bone volume was increased in both cancellous and cortical bone, but bone surface/tissue volume was reduced in cancellous bone and increased in cortical bone. The proportions of total bone volume and surface contributed by cancellous and cortical bone were almost the same as in normal postmenopausal women.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term effects of high doses of inhaled corticosteroids (ICS) on bone density and metabolism are still uncertain. Fifty-one patients (37 male, 14 female) using beclomethasone or budesonide at a daily dose > 800 microgram/d (high-dose group [Group HD] mean: 983 microgram/d [prescribed dose x estimated compliance]) or no or < 500 microgram/d (control group [Group C] mean: 309 microgram/d) for more than 5 yr were enrolled in this study. Each had, 3 yr ago and at this last evaluation, a clinical evaluation and measurements of expiratory flows and of bone density and bone metabolism markers. Lumbar spine bone density (last visit) was similar in the two groups with respective values of 0.94 +/- 0.03 (HD) and 0.96 +/- 0.03 g/cm2 (C) (p > 0.05). T and Z scores were -1.21 +/- 0.19 and -0.70 +/- 0.18 (HD), -0.95 +/- 0.25 and -0.47 +/- 0.21 (C) respectively (p > 0.05). A correlation was found between the decrease in bone density and the mean daily dose of corticosteroid in Group HD although these changes were quite small, mean bone density being unchanged over the 3-yr period. Serum and urinary parameters were similar in the two groups. Furthermore, neither initial bone density nor any of the biological parameters could predict changes in bone density over a period of 3 yr. In conclusion, bone density was similar in both study groups and not significantly different over a 3-yr period. Neither initial bone density nor biological markers of bone metabolism helped to predict changes in bone mass.

The purpose of this study was to explore the relationship between bone mineral density and histopathological features of mandibular alveolar bone evaluated quantitatively by Hounsfield units [HU] and by histopathology in human subjects. Fifty-six mandibular molars were extracted in 50 patients. Computed tomography was obtained preoperatively, and a cortical bone biopsy was obtained on the extracted sites for histopathological evaluation. The mean cortical and cancellous bone radiodensity was 1846±118 HU and 926±436 HU, respectively. There was no correlation between age and cortical bone HU (r = −0.004, P = 0.976); however, the correlation between age and cancellous bone HU was significant (r = 0.574, P<0.0000). Significant differences in the cancellous bone between young (0–30 years), middle (31–60 years) and old patient groups (61< years) were evident (P<0.05), whereas the cortical bone presented no significant differences. The histopathological evaluation showed that the young patient group had relatively few osteomyelitis, whereas the old patient group showed 100% focal sclerotic osteomyelitis regardless of the fact that the patients had no clinical symptoms. The mean osteocyte number/unit bone area was 170.7±82.2. Negative correlation between age and osteocyte number was significant (r = −0.51, P<0.0001). Mean lacunae numbers/unit cortical bone area were 413.1±130 with non-significant negative correlation (r = −0.257, P = 0.056). The mean empty lacunae numbers/cortical bone were 242.5±145, with no correlation (r = 0.081, P = 0.559). The young patients had high osteocyte number, whereas the old patients showed reduction of the osteocytes in the cortical bone (P<0.05). Bone quality might correlate better to viable cell numbers, which influenced the osseous healing. It is suggested that the outermost layer of cortical bone may have lost its cellular activities over the years due to chronic infection, which may have provoked sclerotic changes in the cancellous bone around tooth.

The goal of this study was to evaluate the effects of chronically-elevated male levels of the potent androgen testosterone on the quality and quantity of both cancellous and cortical bone in a young (mean age 8.0 years), nonhuman female primate model (M. fascicularis). Thirteen intact female monkeys received continuous testosterone supplementation via subcutaneous implants over a 24-month period. A group of 16 untreated, intact, age-matched female monkeys served as controls. At sacrifice, the lumbar vertebrae and femora were recovered in order to analyze the bone mineral quality and quantity of cancellous and cortical bone, respectively, and compared to the control group. Mineralization profiles of the vertebrae and femora were obtained using the density fractionation technique. Chemical analysis of the three largest fractions retrieved by density fractionation was performed to evaluate differences in %Ca, %P, Ca/P ratio, and mineral content (%Ca + %PO4) between the control and experimental groups. In addition, unfractionated bone powder was examined by X-ray diffraction to identify any changes in crystal size. Coronal sections of vertebrae were analyzed for structural parameters using histomorphometry and image analysis. Cross sections taken at the midshaft diaphyseal femora were analyzed for structural macroscopic and intracortical parameters. A nonsignificant shift in the mineralization profile of the vertebrae was observed whereas there was a significant shift in the mineralization profile towards more dense bone in the treated femora as compared with controls (P < 0.05). There was no difference in terms of size/strain of the cortical or cancellous bone crystal as detected by X-ray diffraction. There was a trend towards an increase in cancellous bone area (B.Ar.) in the testosterone-treated vertebrae (P = 0.08) as compared with controls. The architecture of the cancellous bone remained nonsignificantly different between the treatment and control groups as evaluated by image analysis. There was a decrease in osteoid perimeter (P = 0.05) in the experimental group as compared with controls. There was a significant decrease in eroded perimeter measurements in the experimental group as compared with controls (P < 0.03). Although there was a trend towards an increase in cancellous bone area, mineralization was not significantly different in the vertebrae of testosterone-treated female monkeys, indicating that the newly-formed bone tissue became relatively normally mineralized over the two-year period. An increase in bone area, with indices of an overall decreased remodelling pattern as compared with controls, suggests that cancellous bone in the young, nonhuman female primate had been receptive to supraphysiologic levels of testosterone supplementation over the two-year period. There was a trend for an increase in cortical bone area and width with an increased periosteal perimeter in the testosterone-treated group as compare with controls. There was an increase in intracortical remodelling activity with a significant increase in percent porosity (P < 0.05), osteonal bone (P < 0.05), and mean wall width (P < 0.05) in the testosterone-treated group. In conclusion, the cancellous bone from female monkeys appeared to respond to the antiresorptive stimulus of male levels of testosterone with significantly diminished turnover parameters in this compartment. In contrast, the cortical bone compartment responded by displaying significant intracortical remodelling over a two-year period.