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PubMed1990

Relation of axial bone mass to habitual calcium intake and to cortical bone loss in healthy early postmenopausal women.

A group of 60 healthy early postmenopausal women participating in an ongoing study on the effect of habitual calcium intake on the rate of cortical bone loss at the radius, were subjected to additional skeletal measurements at the lumbar spine and femoral neck. The women were between 58 and 64 years of age, and 3 to 10 years postmenopausal. No correlations were found between habitual calcium intake (range 560 to 2580 mg/day) and either bone mineral content of the radius, the lumbar spine and the femoral neck, or spine deformity index. Body mass index was found to be positively correlated with bone mass indices of the radius (decrease of BMD and BMD) and femoral neck (BMC), but not with of the lumbar spine (BMC, BMD and SDI), even after adjustments had been made for confounding factors. Although the rate of cortical bone loss at the radius correlated significantly with bone mineral content of lumbar spine and femoral neck, the error in predicting bone mass of the lumbar spine or the femoral neck from longitudinal measurements of cortical bone at the radius was high. The rate of cortical bone loss did not correlate with the spine deformity index. We conclude that in healthy women in early menopause, the bone mineral content of both the appendicular and the axial skeleton are not influenced by habitual calcium intake. A higher body mass index has a protective effect on the appendicular skeleton but appears to be less protective to the axial skeleton. Longitudinal measurements of cortical bone mass are of limited value to predict bone density of the appendicular and axial skeleton.

Absorptiometry, Photon↗
PubMed1990

Stimulation of bone formation in vivo by transforming growth factor-beta: remodeling of woven bone and lack of inhibition by indomethacin.

Local effects of transforming growth factor-beta (TGF beta) on bone have been investigated in growing mice. The influence of indomethacin on TGF beta effects was also examined. Five daily injections of TGF beta-1 or -2 were administered subcutaneously over the frontal and parietal bones of seven-week-old mice. In animals treated with TGF beta alone or TGF beta and indomethacin, then killed on day 19 (day 1 = day of first TGF beta injection), the combined frontal and parietal bones were heavier and the frontal bones were thicker than in controls. On day 4, multiple layers of differentiating osteoblasts were visible in the periosteum of calvariae from TGF beta-treated animals. On day 8, highly vascularised periosteal woven bone was seen in the calvariae of TGF beta-treated animals. On day 19 (14 days after the last injection) the woven bone had been partially remodeled into lamellar bone containing bone marrow, and was still actively being remodeled. The histological appearance of bones from animals treated concurrently with TGF beta and indomethacin was identical to that of animals treated with TGF beta alone, and there appeared to be no difference between TGF beta-1 and TGF beta-2. Thus TGF beta-stimulated bone formation in vivo is a long term effect that appears to be independent of prostaglandins. Osteoclast counts in sections of TGF beta-treated animals were not elevated on day 4, although at this stage effects on osteoblastic cells were already morphologically apparent. Osteoclast counts in TGF beta-treated bones were significantly increased over control values on days 8 and 19.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Comparison between bone density and bone strength in glucocorticoid-treated aged ewes.

In order to assess if bone densitometry could be used as an indicator to evaluate bone fragility in short term studies performed on glucocorticoid-treated ewes, correlations between DXA measurements and biomechanical parameters obtained on the same bones were established in 27 aged ewes including sixteen animals treated with methylprednisolone 15 mg/day for 4 months and eleven untreated animals. DXA measurements were performed ex-vivo on HOLOGIC QDR-1000+ device. Biomechanical testings included a three-point bending test on the femur and a compression test on cylinders of cancellous bone excised from two lumbar vertebrae selected between L6 and L4. At the femoral site, bone mineral density was correlated with the bending stiffness (r = 0.65) and the ultimate bending strength (r = 0.64) whereas, at the vertebral site, biomechanical parameters failed to correlate with bone mineral density assessed by DXA. This apparent lack of correlation between vertebral bone mass and trabecular bone strength is mainly linked to anatomical characteristics of the ewe: in this species, the vertebral posterior arches, which consist mainly of cortical bone, are very large compared to the vertebral body and strongly influence the bone mineral density evaluated on the intact vertebra. This is not the case with other large animals, for instance non-human primates. In conclusion, DXA can give a good evaluation of bone strength for ewe femurs, but results must be interpreted carefully at the vertebral site due to the anatomical characteristics of this animal species.

Absorptiometry, Photon↗
PubMed2006

Mandibular bone stiffening and increased bone calcium mass in rats permanently stunted by hypophysectomy.

OBJECTIVE: This investigation was designed to obtain information on the changes induced by hypophysectomy on biometric parameters, bone calcium mass, and material and architectural properties during ontogenesis of the rat mandible. DESIGN: Female Sprague-Dawley rats were hypophysectomised (HX) at 30 days of age. A "basal control group" (BC) was sacrificed on the same day surgery was performed. An "age-matched intact control group" (CON) was also included. HX and CON rats were sacrificed when aged 6 months. Body weight was monitored weekly. Mandibular growth was estimated directly on the right hemimandible by taking measurements between stable anatomical points. Its mechanical properties were determined using a three-point bending mechanical test. Load was applied transversely to the bone axis at a point immediately posterior to the posterior surface of the third molar. The left hemimandibles were ashed in a muffle furnace at 600 degrees C for 18h and the ash weight obtained. Calcium content in the ashes was determined by atomic absorption spectrophotometry. It was taken as the mandibular calcium mass. Histomorphometric studies were performed on decalcified hemimandibles: total interradicular bone, bone volume, and height of the periodontal ligament were measured. CONCLUSIONS: Morphometric studies indicated that hypophysectomy in juvenile rats induced mandibular growth cessation, which was limited to the posterior part of the bone. Thus, the mandible maintained its juvenile proportions and showed an important deformation relative to age. In spite of the reduced bone size, both the mandibular weight and the calcium bone mass increased more than two times in ontogenia. Histomorphometric studies revealed that the interradicular bone volume was markedly increased. These findings strongly suggest that the bone that forms the mandible of the hypophysectomised rat under the conditions of the present study showed a higher than normal density. As evidenced from biomechanical studies, these bone properties, plus the significant stiffening of bone material tissue, were presumably responsible for the unnecessary and marked increment in the "load capacity" suffered by the mandible of the hypophysectomised rat during ontogenesis.

Animals↗
PubMed1982

Pretreatment of donor bone marrow with monoclonal antibody OKT3 for prevention of acute graft-versus-host disease in allogeneic histocompatible bone-marrow transplantation.

Ten consecutive patients undergoing transplantation of bone marrow from histocompatible siblings for treatment of haematological malignancy took part in a pilot study to test the safety of in-vitro treatment of donor bone marrow with monoclonal antibody OKT3. Three male and seven female patients aged 7-34 years received concentrated bone marrow buffy-coat cells which had been incubated with OKT3 before infusion. In-vitro studies confirmed that almost all immunocompetent T lymphocytes in the bone-marrow samples were coated with OKT3 at the time of infusion. In vitro, neonatal rabbit complement inhibited the proliferation of bone-marrow T lymphocytes in samples preincubated with OKT3 to less than 4% of the mitogenic responses of the untreated bone marrow. In contrast, fresh autologous complement did not effectively lyse OKT3-treated bone-marrow cells. Infusion of OKT3-treated bone marrow was safely accomplished, and engraftment was achieved in all patients (mean 23 days). Nine of ten patients survived for more than 100 days after bone-marrow transplantation, but significant acute graft-versus-host disease (GvHD) requiring treatment with steroids developed in five of the ten. This finding suggests that further modifications for bone-marrow pretreatment will be needed to achieve effective prophylaxis against acute GvHD in histocompatible bone-marrow transplantation.

Acute Disease↗
PubMed2001

Compressive properties of cancellous bone defects in a rabbit model treated with particles of natural bone mineral and synthetic hydroxyapatite.

A rabbit model was developed to evaluate the compressive mechanical properties of cancellous bone defects treated with particles of selected bone graft substitute materials. A novel feature of the model was the precise retrieval of the site of implantation. A notable finding was a 9-fold increase in the modulus of elasticity of the defect implanted with a synthetic hydroxyapatite material after 26 weeks when compared to the modulus of the trabecular bone normally at the site. The compressive modulus of lesions treated with particles of a natural bovine bone mineral (anorganic bovine bone) was closer to the normal modulus of the cancellous bone at the site. While the compressive strength of the anorganic bone particles was less than that of normal bone, the site implanted with the bone mineral particles achieved compressive strength greater than normal after 6 weeks. Moreover, the anorganic bone particles accelerated the increase in strength of the lesion, at 6 weeks exceeding the strength achieved by the untreated defect after 26 weeks. The potential problem associated with the disparity in the compressive modulus between sites implanted with the synthetic HA particles and surrounding bone is discussed.

Animals↗
PubMed2001

Early anchoring collagen fibers at the bone-tendon interface are conducted by woven bone formation: light microscope and scanning electron microscope observation using a canine model.

To clarify the early process of recovery at the bone-tendon interface, we used light microscopy and SEM to examine the process of anchoring of collagen fibers to bone in a canine model. At two weeks, tendon, scar tissue, woven bone and lamellar bone were present at the insertion site. SEM revealed anchoring of collagen fibril bundles of the scar to the woven bone. By 4 weeks, the number of anchoring fibers had increased and a parallel arrangement of fibers was observed. SEM demonstrated deep penetration of fibers into the woven bone layer. In addition, the fibers were observed to project into and intermingle with the scar tissue. By 6 weeks, the anchoring fibers had developed fully and were distributed densely over the interface. SEM also revealed that the collagen fibril bundles in the scar tissue had connected with the collagen fibrils of the woven bone by way of the anchoring bundles. The woven bone was identifiable throughout the early stages of recovery as the interface between soft tissue and hard tissue. Throughout all experimental periods, no staining was observed at the interface of the tendon and bone by Saffranin-O. The formation of woven bone was important during early recovery of the tendon-bone interface prior to the completion of fibrocartilage-mediated insertion.

Animals↗
PubMed2000

Alendronate increases bone strength by increasing the mean degree of mineralization of bone tissue in osteoporotic women.

The mean degree of mineralization of bone (MDMB) was measured by quantitative microradiography on transiliac bone biopsies taken from 53 postmenopausal osteoporotic women who had been treated with alendronate (ALN; 10 mg/day) during 2 (9 patients) or 3 years (16 patients) or with placebo (PLA; 15 and 13 patients, respectively). In the same patients, bone mineral density (BMD) values were obtained by dual-energy X-ray absorptiometry of the lumbar spine and femoral neck at the beginning and end of treatment. Histomorphometric parameters and activation frequency of new remodeling units were also measured on the iliac biopsies. After 2 years of ALN, MDMB in compact bone was 9.3% (p = 0.0035) and in cancellous bone was 7.3% (p = 0.0009) higher, respectively, than PLA. After 3 years of ALN, MDMB in compact bone was 11.6% (p = 0.0002) and in cancellous bone was 11.4% (p = 0.0001) higher, respectively, than PLA. After 2 and 3 years of ALN, and compared with the corresponding PLA, the distribution of the degree of mineralization in compact and cancellous bone showed a clear shift toward the highest mineralization values and a decrease in the number of bone structure units having low values of mineralization. The between-group differences in MDMB were similar to those of BMD at the lumbar spine BMD (+8.7% after 2 years and +9.6% after 3 years, respectively), suggesting that MDMB augmentation probably accounted for the majority of the increase in BMD seen with ALN. The data support the hypothesis that the reduction in activation frequency caused by the antiresorptive effect of ALN is followed by a prolonged secondary mineralization that increases the percentage of bone structure units having reached a maximum degree of secondary mineralization and, through this mechanism, MDMB. That these effects contribute to improved bone strength is demonstrated by the reduction in fracture incidence previously demonstrated in these patients.

Absorptiometry, Photon↗
PubMed2002

Bipedal stance exercise and prostaglandin E2 (PGE2) and its synergistic effect in increasing bone mass and in lowering the PGE2 dose required to prevent ovariectomized-induced cancellous bone loss in aged rats.

Previous reports have shown that bone loss was partially prevented by bipedal stance "exercise" following ovariectomy (ovx), and it was well documented that prostaglandin E2 (PGE(2)) had an anabolic effect on the rat skeleton. The aim of this study was to determine whether lower doses of PGE(2) could prevent ovx-induced cancellous bone loss with the combination of bipedal stance exercise. Seventy-eight 10-month-old female Sprague-Dawley rats were either ovariectomized or sham-operated on day 0 and then treated with PGE(2) (0, 0.3, or 1 mg/kg per day) and/or housed in normal height cages (NC, 28 cm) or raised cages (RC, 33 cm) for 8 weeks. Bone histomorphometry was performed on the double-fluorescent-labeled proximal tibial metaphysis. In sham rats, 1 mg/kg PGE(2) + RC had synergistic effects in increasing trabecular bone area, width, and number by stimulating mineral apposition rate and bone formation rate. As expected, ovx induced cancellous bone loss, accompanied by elevated activation frequency. Without RC, PGE(2) monotherapy prevented ovx-induced bone loss at the 1 mg/kg per day dose, whereas this prevention effect was observed at the 0.3 mg/kg per day dose when combined with RC. Similar to their effects in sham rats, PGE(2) and RC had synergistic effects in augmenting cancellous bone mass and architecture and maintaining the elevated bone formation but depressing bone resorption and activation frequency. We conclude that bipedal stance exercise lowers the PGE(2) dose required to prevent ovx-induced cancellous bone loss in the proximal tibial metaphysis in aged rats.

Animals↗
PubMed1995

Bone disease in predialysis, hemodialysis, and CAPD patients: evidence of a better bone response to PTH.

The spectrum of bone disease in predialysis and dialysis patients has changed during the last decade. The incidence of aplastic bone disease has increased and this can not be attributed to bone aluminum deposition; moreover, low bone cellular activity is present despite a moderate elevation in PTH levels. This study compares PTH levels and types of bone disease in both predialysis and dialysis patients from the same geographical area. We prospectively studied 119 unselected end-stage renal disease patients: 38 were immediately predialysis (PreD), 49 on hemodialysis (HD), and 32 on CAPD. A bone biopsy was performed in all patients. Aplastic bone disease with < 5% bone surface aluminum was a common finding (48%, 32%, and 48%, in PreD, HD, and CAPD, respectively). In all groups, an intact PTH level below 120 pg/ml was highly predictive of low bone turnover. Conversely, a PTH level above 450 pg/ml was always associated with histologic features of hyperparathyroid bone disease. Among the bone histomorphometric parameters, osteoblast surface showed the best correlation with intact PTH in each group, and the slope of the regression line for this correlation was significantly steeper in HD and CAPD than PreD patients. Thus, the range of PTH (95% confidence limit bands) needed to obtain a normal osteoblast surface of 1.5% was greater in preD than in HD and CAPD patients (300 to 500 vs. 75 to 260 pg/ml, respectively). In all groups some degree of marrow fibrosis was observed when PTH levels were greater than 250 pg/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium↗
PubMed1999

Magnetic resonance imaging of bone marrow versus bone marrow biopsy in malignant lymphoma.

Bone marrow involvement is a frequent finding in malignant lymphoma. Bone marrow biopsy of the posterior iliac crest is routinely performed for staging. Abnormal magnetic resonance imaging (MRI) signals of bone marrow was also reported to be indicative of bone marrow involvement. This study included 60 patients with malignant lymphoma. Unilateral bone marrow biopsy of the posterior iliac crest was performed. MRI of lumbar spine was studied within 24 hours of bone marrow biopsy. 22 healthy controls were used for the detection of MRI objectivity during visual evaluation. In 83% of patients (50/60), biopsy and MRI results agreed completely. In two patients, histologic sections failed to show any evidence of bone marrow involvement despite abnormal MRI signals suggestive of involvement. In three patients, MRI was completely normal despite biopsy proven bone marrow infiltration. False negativity (3/60) and false positivity (2/60) rates were very low. Negative biopsy findings with positive or equivocal MRI results should not exclude bone marrow involvement and needs further evaluation with bilateral or guided biopsy. Thus, we conclude that MRI of bone marrow is a fairly sensitive, noninvasive modality and might be of potential value in detecting bone marrow infiltration in malignant lymphoid neoplasms which can be utilized as a useful adjunct to standard staging procedures.

Adult↗
PubMed2006

[Trabecular bone mineral density measured by quantitative CT of the lumbar spine in children and adolescents: reference values and peak bone mass].

PURPOSE: The aim of this study was to assess bone density values in the trabecular substance of the lumbar vertebral column in children and young adults in Germany from infancy to the age of peak bone mass. MATERIALS AND METHODS: We performed quantitative computed tomography (QCT) on the first lumbar vertebra in 28 children and adolescents without diseases that may influence bone metabolism (15 boys, 13 girls, mean ages 11 and 8 years, respectively). We also measured 17 healthy young adults (9 men, 8 women, mean ages 20 and 21 years). We used a Somatom Balance Scanner (Siemens, Erlangen) and the Siemens Osteo software. Scan parameters: Slice thickness 1 cm, 80 kV, 81 or 114 mAs. We measured the trabecular bone density and the area and height of the vertebra and calculated the volume and content of calcium hydroxyapatite (Ca-HA) in the trabecular substance of the first lumbar vertebra. RESULTS: Prepubertal boys had a mean bone density of 148.5 (median [med] 150.1, standard deviation [SD] 15.4) mg/Ca-HA per ml bone, and prepubertal girls had a mean density of 149.5 (med 150.8, SD 23.5) mg/ml. We did not observe a difference between prepubertal boys and girls. After puberty there was a significant difference (p < 0.001) between males and females: Mean density (male) 158.0, med 162.5, SD 24.0 mg/ml, mean density (female) 191.2, med 191.3, SD 17.7 mg/ml. The Ca-HA content in the trabecular bone of the first lumbar vertebra was 1.1 (med 1.1, SD 0.5) g for prepubertal boys and 1.1 (0.9, 0.4) g for prepubertal girls. For post-pubertal males, the mean Ca-HA content was 3.5 g, med 3.5, SD 0.5 g, and for post-pubertal females, the mean content was 2.8, med 2.7, SD 0.4 g. CONCLUSION: The normal trabecular bone mineral density is 150 mg/ml with a standard deviation of 20 mg/ml independent of age or gender until the beginning of puberty. Peak bone mass (bone mineral content) in the trabecular substance of the lumbar vertebral column is higher in males than in females, and peak bone density is higher in young female adults than in young male adults.

Absorptiometry, Photon↗
PubMed2007

The effect of chronic nicotine administration on bone mineral content and bone strength in normal and castrated male rats.

Tobacco, containing nicotine as the principal pharmacologically active chemical, has been identified as being a risk factor for the development of osteoporosis. Thirty-two male Wistar rats of two months of age were castrated or sham operated to evaluate the effects of long-term administration (four months) of nicotine in drinking water (9.0 mg/kg/day). The presence of cotinine in urine confirmed successful delivery of nicotine. The bones were tested mechanically by a three point bending test in a Mini Bionix (MTA) testing system. The bones from castrated rats were characterized by a reduction in bone density as well as ash, calcium and phosphate content. Castration significantly altered mechanical properties of bone (9%) and femoral cortical thickness. When intact rats were treated with a high dose of nicotine, nicotine had negative effect on tibial bone density as well as ash, calcium, phosphate content and significantly altered the mechanical properties of bone (12%) and femoral cortical thickness compared to intact animals. Nicotine itself does not exert any anti-androgenic effect and does not produce changes in the weight of seminal vesicles. Nicotine-induced bone loss is associated with high bone turnover in the male rats as expressed by increased TrACP and B-ALP. When castrated rats were treated with the high dose of nicotine the changes in bone density resulting from castration were not further potentiated. These results document the efficacy of nicotine at high doses to cause bone loss and loss of bone mechanical strength in intact rats. The results of the present study may be interpreted as supporting the hypothesis of nicotine as a risk factor for osteoporosis.

Alkaline Phosphatase↗
PubMed2001

Bone volume after secondary bone grafting in unilateral and bilateral clefts determined by computed tomography scans.

OBJECTIVE: The purpose of this study was to evaluate the outcome of bone grafts in cleft palate patients, thus assessing the amount of bone necessary to facilitate eruption-especially in the buccopalatal direction-of the permanent canine into the bone graft. STUDY DESIGN: Computed tomography scans taken immediately postoperatively and 1 year postoperatively of 42 unilateral and of 8 bilateral cleft lip and palate patients who underwent surgery at the age of 9 years (early secondary bone graft) or 12 years (late secondary bone graft) were compared. Three slices from the computed tomography scans taken immediately after the surgery were selected from the center of the bone graft and were then compared with corresponding slices from the 1-year postoperative computed tomography scans. Statistical analysis was performed by using the Wilcoxon 2-sample rank sum test. RESULTS: In the unilateral cleft group, 70% of the transplanted bone remained in the cleft area after 1 year, whereas in the bilateral cleft group, only 45% of the initial bone graft remained after 1 year. CONCLUSION: No statistically significant difference was found between early secondary bone grafting and late secondary bone grafting. In most cases, a sufficient amount of bone was present in the target area to facilitate eruption of the permanent canine.

Age Factors↗
PubMed2003

Material changes in osteoporotic human cancellous bone following infiltration with acrylic bone cement for a vertebral cement augmentation.

Bone cement infiltration can be effective at mechanically augmenting osteoporotic vertebrae. While most published literature describes the gain in mechanical strength of augmented vertebrae, we report the first measurements of viscoelastic material changes of cancellous bone due to cement infiltration. We infiltrated cancellous core specimen harvested from osteoporotic cadaveric spines with acrylic bone cement. Bone specimen before and after cement infiltration were subjected to identical quasi-static and relaxation loading in confined and free compression. Testing data were fitted to a linear viscoelastic model of compressible material and the model parameters for cement, native cancellous bone, and cancellous bone infiltrated (composite) with cement were identified. The fitting demonstrated that the linear viscoelastic model presented in this paper accurately describes the mechanical behaviour of cement and bone, before and after infiltration. Although the composite specimen did not completely adopt the properties of bulk bone cement, the stiffening of cancellous bone due to cement infiltration is considerable. The composite was, for example, 8.5 times stiffer than native bone. The local stiffening of cancellous bone in patients may alter the load transfer of the augmented motion segment and may be the cause of subsequent fractures in the vertebrae adjacent to the ones infiltrated with cement. The material model and parameters in this paper, together with an adequate finite-element model, can be helpful to investigate the load shift, the mechanism for subsequent fractures, and filling patterns for ideal cement infiltration.

Bone Density↗
PubMed1994

Comparison of bone and 67Ga scintigraphy in the initial diagnosis of bone involvement in children with malignant lymphoma.

The accurate staging of Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) in children has important therapeutic and prognostic implications. The presence of secondary bone involvement or primary malignant lymphoma of bone can be determined by both radiographic and radionuclide methods. We wished to compare the relative efficacy of bone and 67Ga scintigraphy for detecting the presence of bone involvement by malignant lymphoma. We evaluated 83 children (mean age 12 years) with histologically proven HD and NHL utilizing bone and 67Ga scintigraphy which were performed prior to treatment. Three of these patients had biopsy proven primary malignant lymphoma of bone. Bone scintigraphy detected 18 bone lesions in 13 patients and 67Ga scintigraphy detected the same 18 bone lesions and in addition 101 extraosseous lesions. Radiography confirmed the presence of focal bone lesions. Both osteolytic and osteoblastic lesions were identified. We conclude that bone scintigraphy is not necessary in the initial staging of children with malignant lymphoma unless there are specific osseous symptoms. 67Ga scintigraphy is the radionuclide method of choice in the initial staging of children with malignant lymphoma.

Adolescent↗
PubMed2000

Histometric evaluation of bone regeneration around immediate implants partially in contact with bone: a pilot study in dogs.

Bone regeneration was evaluated around immediate implants partially in contact with bone, with or without the concurrent application of a combination of platelet-derived growth factor (PDGF) and insulin-like growth factor (IGF-1). Mandibular premolars were removed, and the implant osteotomies were prepared; a uniform circumferential gap was prepared 1.25 mm beyond the width of the implant bed in the coronal half. Twelve implants (8.5 x 3.75 mm) were inserted in six dogs. Before insertion, an implant received a single application of 5 micrograms/mL of PDGF and IGF-1 delivered in 0.10 mL of 4% methylcellulose gel or 0.10 mL of 4% methylcellulose gel only as a control. To label regenerated bone, a 2% calcein green solution was administered by intramuscular injection at 0, 7, 15, 30, and 45 days after implant insertion Three and 8 weeks after implant insertion undecalcified sections were obtained, and the degree of bone to implant contact, the bone area, and the intensity of bone labeling were measured into the limits of the eight most coronal threads of the implant (four threads on each side of each implant). The results showed a greater extension of bone-to-implant contact, a larger percentage of bone area, and greater intensity of bone labeling for test versus control implants (P < .01). Within the limits of the present study, it was concluded that the combination of PDGF/IGF-1 might be an alternative for enhancing bone healing around implants partially in contact with bone.

Animals↗
PubMedDate not supplied

Effect of estrogen use on tooth retention, oral bone height, and oral bone porosity in Japanese postmenopausal women.

OBJECTIVE: Recent studies in the United States support the protective effect of estrogen use on tooth retention; however, little is known as to how estrogen promotes tooth retention. The aims of this study were to investigate the effects of estrogen use on tooth retention, oral bone height, and oral bone porosity in Japanese postmenopausal women and to clarify how estrogen promotes tooth retention. DESIGN: Relationships among the number of teeth remaining (total, anterior, and posterior teeth), oral bone height, oral bone porosity, bone mineral density of the lumbar spine and the femoral neck, estrogen use status, and the duration of estrogen use were evaluated in 330 Japanese postmenopausal women (mean age +/- SD, 56.8 +/- 7.6 y). RESULTS: Analysis of covariance adjusted for confounding variables revealed that estrogen users (66 women) tended to have more posterior teeth than did nonusers (264 women) (P = 0.065), although there were no significant differences in number of total (P = 0.196) and anterior (P = 0.751) teeth remaining, oral bone height (P = 0.970), oral bone porosity (P = 0.745), and bone mineral density of the lumbar spine (P = 0.459) and the femoral neck (P = 0.749) between estrogen users and nonusers. Multiple regression analysis showed that the duration of estrogen use was significantly associated with number of total (P = 0.019) and posterior (P = 0.007) teeth remaining, independent of age and oral bone height. CONCLUSION: Our results suggest that estrogen may promote tooth retention by strengthening the periodontal attachment surrounding the teeth, but not increasing oral bone height and not decreasing oral bone porosity.

Absorptiometry, Photon↗