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Longitudinal changes of bone density and bone resorption in hyperthyroid girls during treatment.

Low bone mineral density (BMD) and increased bone turnover are common features of untreated hyperthyroidism in adult patients. The effect of treatment on BMD is still controversial. BMD and bone metabolism in hyperthyroid children have not been thoroughly investigated. In the present study, we measured spinal and whole body BMD by dual-energy X-ray absorptiometry in a group of 13 girls (aged 5.0-14.9 years) at diagnosis of hyperthyroidism. The bone resorption rate was assessed by urine measurement of N-terminal telopeptide of type I collagen (NTX). Hyperthyroid patients have been studied longitudinally during treatment. BMD values and NTX urine concentrations have been also determined in 155 healthy Caucasian girls (aged 2.4-24.2 years). Spinal and whole body bone density measurements were significantly lower compared with healthy controls in untreated hyperthyroid girls, after correction for differences in age and anthropometric measurements (p </= 0.033). Bone density measurements obtained after 12 and 24 months of treatment were no longer different from those of healthy girls. NTX urine levels at diagnosis of thyrotoxicosis were significantly higher than those found in healthy controls (p < 0.0001); 6 months after treatment, the urine levels did not show significant differences, and they remained stable after 12 and 24 months of therapy. Inverse correlations at diagnosis were found between serum-free thyroxine (FT4) serum levels and spinal (r = -0.42) and whole body bone density (r = -0.41); FT4 and free triiodothyronine serum levels directly correlated with the NTX concentration (r = 0. 77, and r = 0.71, respectively). In conclusion, the results of the present study demonstrate that low bone density values and high bone resorption rates are found in hyperthyroid children and adolescents at diagnosis of the disease. Our data also demonstrate that antithyroid treatment is able to reduce dramatically the bone resorption and to increase significantly both spinal and total body BMD, granting physiologic conditions for the achievement of the best obtainable peak bone mass.

Adolescent↗

The predictive value of biochemical markers of bone turnover for bone mineral density in postmenopausal Japanese women.

To examine the predictive value of biochemical markers of bone turnover for bone loss pre- and postmenopausally, we measured two markers of bone formation, bone-specific alkaline phosphatase (BALP) and intact osteocalcin (OC); four markers of bone resorption, urinary cross-linked N-telopeptides of type I collagen (NTx), type I collagen C-telopeptide breakdown products (CTx), hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP); serum OC N-terminal (OC-N); and two serum cytokines, soluble interleukin-6 receptor (sIL-6R) and IL-1r antagonist at baseline and 1 year, as well as lumbar spine bone mineral density (BMD) at baseline and 1, 2, 3, 4, and 5 years after trial in 82 premenopausal (44.8 +/- 5.4 years old) and 325 postmenopausal (60.2 +/- 6.1 years old) healthy Japanese women. In premenopausal women, stratification of the baseline value of each biochemical marker into quartiles did not cause any significant difference in the change in BMD. Stratification of the NTx baseline value in postmenopausal women showed significant differences in rate of bone loss to the first year among those subjects with each quartile (Q1 [0.28 +/- 0.28%], Q2 [-0.32 +/- 0.34%], Q3 [-1.50 +/- 0.31%], and Q4 [-2.43 +/- 0.35%]) except for the difference between Q1 and Q2. The predictive value of NTx for BMD was greater in early postmenopausal women within 5 years after menopause than in late postmenopausal women with more than 5 years since menopause (YSM). Quartile analysis of the other biochemical markers and serum cytokines did not show any significant capacity for differentiating between bone loss rates. Moreover, when the changes in the lumbar spine BMD to the second and third years were stratified into quartiles by the baseline NTx, the ratios of bone loss to the second and the third years were significantly higher in those women with higher NTx (Q4; -3.15 +/- 0.56% and -4.06 +/- 0.57%, respectively) than in those with lower NTx (Q1; -0.74 +/- 0.44% and -1.03 +/- 0.51%, respectively). In conclusion, baseline urinary NTx was the most sensitive predictor of bone loss in the lumbar spine after 1, 2, and 3 years. Markers of bone resorption can be used clinically to predict future BMD in postmenopausal women.

Adult↗

Cytokines, osteoprotegerin, and RANKL in vitro and histomorphometric indices of bone turnover in patients with different bone diseases.

Cytokines are supposed to play an essential role in the regulation of the bone metabolic unit. However, information on cytokine production of primary human osteoblasts from patients with metabolic bone disease is scarce, and few attempts have been made to correlate such data to histomorphometric parameters of individual patients. We investigated 11 patients with metabolic bone disease referred to our outpatient department for bone biopsy and analyzed interleukin (IL)-1, IL-6, and TNF-alpha protein release and gene expression in primary osteoblast cultures. Compared with four controls, five patients showed normal cytokine protein release, whereas six patients showed much higher levels of interleukin-6 (26-fold) and TNF-alpha (84-fold). All three cytokines were strongly correlated concerning gene expression and/or protein levels (r = 0.72-0.96). Histomorphometric analysis of the bone samples showed that eroded surface (ES/BS) as a parameter of bone resorption was significantly associated with TNF-a. In addition, RANKL gene expression was positively associated with ES/BS and osteoclast surface (Oc.S/BS). Finally, the formation parameters osteoid volume and osteoid surface were negatively associated with TNF-alpha. In conclusion, in an in vitro-ex vivo model of bone cells obtained from a group of 11 patients with different forms of metabolic bone disease, cytokine release in conditioned medium was significantly associated with bone resorption and bone formation, as quantified by histomorphometry. TNF-alpha seemed to be the more important cytokine; its effect on bone resorption could be mediated by RANKL.

Adult↗

Age-related changes of bone mineral density in human calcaneus, talus, and scaphoid bone.

To examine whether the bone mineral density (BMD) decreases uniformly with aging in any spongy bones, the authors investigated age-related changes of BMD in the calcaneus, talus, and scaphoid bone. After the ordinary dissection by medical students was finished, calcanei, tali, and scaphoid bones were resected from the subjects, and BMDs were measured by dual-energy X-ray absorptiometry. Their BMDs seemed to decrease gradually with aging in the calcanei, tali, and scaphoid bones. It was found that there were statistically significant relationships between age and BMD in the men's and women's scaphoid bones, women's tali, and women's calcanei, but not in the men's tali and calcanei. It should be noted that there were significant relationships between age and BMD in both men's and women's scaphoid bones. In regard to relationship in BMD between the bones of the upper and lower limbs in individuals, it was found that the relationship between the calcaneus and talus was higher than that between the calcaneus and scaphoid bone. This suggests that there is a higher relationship in BMD between the two tarsal bones compared with that between the tarsal and carpal bones.

Aged↗

Serum GH and IGF-I are significant determinants of bone turnover but not bone mineral density in active acromegaly: a prospective study of more than 70 consecutive patients.

OBJECTIVE: Acromegaly is characterized by a persistent hypersecretion of GH and provides information on long-term effects of GH on bone metabolism. The aim of this study was to examine the effect of gonadal status and disease activity on bone metabolism in active acromegaly. METHODS: Seventy-three consecutive patients with active acromegaly: 40 women and 33 men (50 +/- 13 (mean +/- s.d.) and 49 +/- 10 years respectively) were evaluated and compared with age-, sex-, and body mass index (BMI)-matched controls by X-ray absorptiometry and biochemical analysis (markers of disease activity and bone turnover). RESULTS: We found that bone turnover, as evaluated by biochemical bone markers, is coupled and markedly increased in relation to disease activity in active acromegaly. Acromegalic women, but not men, were characterized by an increased bone area and slightly decreased bone mineral content resulting in significantly decreased bone mineral density (BMD) in the ultradistal radius, proximal radius, and total body. No differences in bone turnover or BMD were found between eu-and hypogonadal subjects. Multivariate analysis identified age, BMI, and gender as independent predictors of total BMD in acromegaly. CONCLUSION: Our study demonstrates a decreased total body BMD in women, not men, with active acromegaly, regardless of gonadal status or disease activity. Bone turnover is markedly increased in relation to disease activity, possibly counteracting the anabolic effects of excess GH/IGF-I in these subjects. We suggest more focus on biomechanical analyses when investigating endocrine disorders affecting bone size and distribution between compartments.

Acromegaly↗

Risk assessment of bovine spongiform encephalopathy transmission through bone graft material derived from bovine bone used for dental applications.

BACKGROUND: Several commercial products are currently available for clinical application as bone graft substitutes. These products can be broadly classified into two categories: synthetic and natural. Bovine bone is a popular source for several of the natural bone substitutes. The availability of bovine derived xenogenic bone substitutes has made it possible to avoid traumatic and expensive secondary surgery to obtain autogenous bone once thought essential for effective bone replacement. While autogenous bone still remains the undisputed "gold standard" in bone grafting, the realization that bone requirement in several clinical applications is as effectively met by xenografts has lead to their widespread use. But the convenience of using xenografts is tempered by the possibility of disease transmission from cattle to humans. The recent incidents of bovine spongiform encephalopathies (BSE) in humans have underscored this likelihood. In this paper, we report a risk analysis performed to assess the possibility of such disease transmission from a commercially available bone graft substitute (BGS) that is popularly used in clinical dentistry. METHODS: An extensive review of current literature on the status of risk assessment of BSE transmission was conducted, and two risk assessment models were identified as applicable to the present study. Risk assessment models developed by the German Federal Ministry of Health and by the Pharmaceutical Research and Manufacturers Association of America were applied to BGS. RESULTS: Results from the analyses conducted using both models showed that the risk of disease (BSE) transmission from BGS was negligible and could be attributed to the stringent protocols followed in sourcing and processing of the raw bovine bone used in the commercial product. CONCLUSIONS: Based on the risk analysis, it is evident that the risk of BSE infection from BGS is several orders of magnitude less than that posed by the risk of death related to, lightning, tornadoes, or similar remote events. However, this low risk can only be maintained as long as an effective and active risk management program is implemented in operations that involve processing xenogenic tissue for human use.

Algorithms↗

Treatment of benign bone lesions with an injectable calcium sulfate-based bone graft substitute.

The treatment of benign bone lesions can be challenging due to the limited quantity of autogenous graft available for harvest and grafting of the defect. The use of an injectable calcium bone graft substitute, Minimally-Invasive Injectable Graft (MIIG) (Wright Medical Technology, Inc, Arlington, Tenn), material for treatment of these bone lesions is advantageous. Calcium sulfate has a long-standing history in the treatment of bone voids secondary to trauma, infection, or neoplastic processes. Minimally-Invasive Injectable Graft injectable calcium sulfate graft may be injected into surgically created osseous defects or bone defects secondary to traumatic injury. After hardening, the paste acts as a temporary intraosseous support through which internal fixation may be placed. Fifteen patients with benign space-occupying lesions were treated with curettage and grafting with an injectable, surgical-grade, calcium sulfate bone graft substitute. Bone healing was assessed postoperatively and defined as resorption of the bone graft substitute material and replacement with new bone formation. The grafted defects in 14 of the 15 patients showed complete incorporation of the graft material at an average of 8 weeks. One patient required incision and drainage for a deep infection 5 weeks postoperatively. The average follow-up was 6 months (range: 3-15 months), and Musculoskeletal Tumor Society functional outcome scores averaged 83%. This injectable, minimally invasive graft material is easy to use, provides a temporary structural support when grafting bone defects, and results in predictable rapid bone healing.

Adolescent↗

[Partial purification and characterization of bone-resorbing factor from bovine bone matrix].

The mechanism of bone remodeling has been investigated by many researchers. However, little is known about the role of the local factors which exist in the bone matrix. In this study, the author attempted to purify the bone-resorbing factor from the bovine bone matrix and to find its role in bone remodeling. The demineralized bovine bone matrix was extracted with 4M Gdn-HCl and the bone-resorbing factor was purified by means of heparin affinity and gel filtration chromatography. The analysis of bone resorption was carried out by the measurement of the released 45Ca from the pre-labeled mouse calvariae. The results of this study were that the bone-resorbing factor in the bone matrix was suggested to be a heat-stable glycoprotein having a molecular size higher than 150,000, which stimulated osteoclastic bone resorption via a prostaglandin-mediated mechanism.

Animals↗

[Prolonged suppressive L-thyroxine therapy. Longitudinal study of the effect of LT4 on bone mineral density and bone metabolism markers in 71 patients].

OBJECTIVES: A prospective longitudinal study was conducted to investigate the influence of prolonged suppressive L-thyroxin therapy on bone density and biochemical markers of bone remodeling. PATIENTS AND METHODS: Seventy-one patients (including 28 menopaused women) taking long-term L-T4 for thyroid carcinoma were divided into 3 groups according to their TSH level: low (TSH < 0.04 mlU/l), moderate (0.04 TSH < or = 0.10 mlU/l) and high (TSH > 0.10 mlU/l). Bone density was measured in lumbar vertebrae annually for a mean 4.5 years. Bone metabolism markers were measured over a 4 year period. Bone density measurements of the femur were also obtained for 2 years in 16 menopaused women. RESULTS: Lumbar bone density did not decline whatever the TSH level or the duration of L-T4 treatment. Likewise for menopaused women without substitution estroprogesterone therapy. Over the 4 years, biochemical markers of bone formation, including bone alkaline phosphatases and osteocalcin, or of bone resorption, including urinary hydroxyprolin, did not vary. In addition, in menopaused women, femoral bone density was not significantly lowered over the 2 years follow-up. No lumbar or femoral osteopenia was observed in these patients taking L-thyroxin, even for those with complete TSH blockade. Biochemical markers did not demonstrate a significant acceleration of bone turnover during prolonged administration of L-T4 at suppressive levels.

Adult↗

[Disseminated bone marrow metastases from gastric cancer: detection and monitoring the effectiveness of chemotherapy by bone marrow scintigraphy].

Disseminated bone marrow metastasis of cancer is a critical condition, frequently complicated by disseminated intravascular coagulation (DIC). A 32-year-old man with gastric cancer was diagnosed as having disseminated bone marrow metastases. Bone scintigraphy demonstrated many abnormal radionuclide accumulations in the whole body. Bone marrow aspiration revealed cancer cells. Bone marrow scintigraphy with 111In-Cl3 demonstrated central marrow failure and peripheral expansion. The remission of DIC was observed after sequential methotrexate and 5-FU therapy, then uptake of radionuclide in the central bone marrow was remarkably improved by bone marrow scan. After thirteen anti-cancer chemotherapies, recurrence of DIC was suspected because of the reduction of blood platelet count. Nevertheless, repeated bone marrow scan still demonstrated the central bone marrow clearly. The patient discharged from our hospital without the recurrence of DIC. We considered bone marrow scintigraphy is useful in the detection of disseminated bone marrow metastases of cancer and monitoring the effectiveness of chemotherapy.

Adult↗

Clinical utility of biochemical marker of bone remodelling in patients with bone metastases of solid tumors.

Bone turnover is characterized both by the formation of new bone by the osteoblasts and the resorption of old tissue by the osteoclast. This process takes place only on the surface of bone and can be described in terms of spatio-temporal events that are the bone metabolic unit and the bone remodelling cycle. The former consists of a discrete group of cells (osteoblasts and osteoclasts) involved in a particular remodelling event while the latter represents the succession of resorption and formation. In a typical remodelling cycle, resorption takes 7-10 days, whereas formation requires 2-3 months. Remodelling is regulated either by local or systemic factors, including electrical and mechanical forces, hormones (e.g. parathyroid hormone, sexual steroids, calcitriol, cortisol, thyroid hormones, calcitonin), growth factors and cytokines. Recently different circulating biochemical markers have been proposed for the investigation of bone turnover. In addition to classical parameters such as serum alkaline phosphatase and urinary calcium and hydroxyproline, new markers have gained clinical attention because of their accuracy in assessing the dynamic changes in bone remodelling (bone alkaline phosphatase, osteocalcin, propeptides PICP and PINP, tartrate-resistant acid phosphatase, deoxypyridinoline, pyridinoline, telopeptide CTx and NTx). The aim of this review is to present the recent advances in this field and the clinical application of markers of bone turnover in patients with bone metastases from solid tumors. Also the cellular and molecular bases of bone remodelling are reported with details.

Acid Phosphatase↗

[Biomechanical study on the composite of allogenic decalcified bone matrix gelatin and bone cement].

OBJECTIVE: To evaluate the biomechanical properties and structural characteristics of various composites of partially decalcified allogenic bone matrix gelatin and bone cement at different ratios. METHODS: According to Urist method, partially decalcified allogenic bone matrix gelatin was prepared and mixed with bone cement at different ratios of 0, 400, 500, and 600 mg/g. Then the comparisons of these composites were performed in microstructure, ultimate compression strength and ultimate bending strength properties. RESULTS: The electronic microscope showed that the bone particles and bone cement were distributed evenly in the composite, irregularly connecting by multiple points; with the increase of bone particles and decrease of bone cement in the composite, there were more and more natural crevices, varying from 100 microns to 400 microns in width, in the biomaterials. Of all the composites with the ratios of 0, 400, 500, and 600 mg/g, the measurements of ultimate compression strength were (71.7 +/- 2.0) MPa, (46.9 +/- 3.3) MPa, (39.8 +/- 4.1) MPa, and (32.2 +/- 3.4) MPa, respectively; and the measurements of ultimate bending strength were (65.0 +/- 3.4) MPa, (38.2 +/- 4.0) MPa, (33.1 +/- 4.3) MPa and (25.3 +/- 4.6) MPa, respectively. CONCLUSION: The composite of partially decalcified allogenic bone matrix gelatin and bone cement has a good biomechanical property and could be easily fabricated and re-shaped, which make it available to be used clinically as an idea bone graft biomaterial.

Biomechanical Phenomena↗

[Lifting of the maxillary sinus: complementary use of platelet rich plasma, autologous bone deproteinised bovine bone. Case report].

The present paper describes a clinical case in which autologous bone, removed during an operation from the maxillary tuberosity, platelet rich plasma (PRP) and deproteinised bovine bone (Bio-oss, Geistlich) were used as graft material in a bilateral maxillary sinus lift procedure. During the same operating session, it was planned to carry out the lift of the maxillary sinus, employing a "combined" graft (autologous bone, PRP, deproteinised bovine bone), and to insert 6 fixtures at maxillary level, 3 in each quadrant, and 6 fixtures at mandibular level. The use of PRP, or rather of the platelet gel derived from it, represented an improvement compared to standard bone graft techniques. A graft consisting of autologous bone and PRP (with or without deproteinised bovine bone) makes it possible in fact to carry out more demanding operations, such as a major lift of the maxillary sinus, without the need for a block graft, but employing autologous bone particulate, which is easier to find. Furthermore, a "combined" graft is easily malleable and adjustable and can be adapted perfectly to the bone defect in which it is inserted. Finally, it guarantees a better quality of cure both in terms of speed and degree of mineralisation. This is very important if we consider that usually, lifting of the maxillary sinus is carried out precisely to guarantee adequate bone volume in cases where bone has been lost and to permit the insertion of osteointegrated implants.

Aged↗

Safety of zygomatic bone harvesting: a prospective study of 32 consecutive patients with simultaneous zygomatic bone grafting and 1-stage implant placement.

PURPOSE: The purpose of this prospective study was to evaluate the safety of zygomatic bone harvesting and to determine whether a particulated zygomatic bone graft can be used simultaneously with 1-stage dental implants to reconstruct resorbed edentulous alveolar ridges. MATERIALS AND METHODS: Altogether, 82 dental implants were placed in 32 patients. Particulated bone grafts harvested from the zygomatic process were used in 72 of the implant sites. The volume of bone harvested, intraoperative complications, morbidity, and complications on follow-up visits were recorded. Implant survival was examined prospectively. RESULTS: As a harvest site, the zygoma yielded enough bone to complete the reconstructions in each case. The average zygomatic bone graft volume was 0.90 mL (SD 0.30). Perforation of the maxillary sinus occurred at 11 zygomatic sites. None of these perforations led to postoperative problems. No paresthesias or other complications were noted during follow-up examinations. Mean duration of postoperative swelling was 4.5 days, and patients used pain medication for a mean duration of 4 days. After the mean follow-up period of 26.9 months postplacement, 80 of 82 implants were osseointegrated (survival rate 97.6%). DISCUSSION: [corrected] Zygomatic bone is an alternative donor site for bone harvesting with low morbidity. The bone graft yielded is sufficient for use in 2 to 3 implant sites. CONCLUSIONS: The zygoma was a safe intraoral bone harvesting donor site in this patient population. Further, the use of simultaneous particulated zygomatic bone grafts and 1-stage implant placement appears to be an effective procedure.

Adolescent↗

[A study on the repair of bone defects with deproteinized bone surrounded by titanium mesh and osteoblasts].

To investigate the ability of composite graft of osteobalsts and deproteinized bone-titanium mesh (DPB-TM) scaffold to repair cranial bone defect. 30 rabbits were randomly divided into 3 groups. The passage 3 fetal rabbit osteoblasts were seeded into porous DPB-TM scaffolds at the density of 5 x 10(6) ml(-1) as the experimental group. The same defects were respectively reconstructed by DPB-TM or osteoblasts as the control groups. After 12 weeks, the result was evaluated by three-dimensional computed tomographic scanning, gross inspection, scanning electron microscopy, histological examination and mechanics test, respectively. In the experimental group, bone trabecula was observed to pass the defect and interface was mixed. No demarcation between the region of the bone defect and the normal bone was observed. There was plenty of new bone on the scaffold. Part of the scaffold was absorbed. In view of mechanics, the intensity of artificial bone (18.93+/-1.12 MPa) was higher than that of normal bone (16.96+/-1.60 MPa) (P<0.05). In the control groups, only fibrous tissue was observed in the defect region, there was no new bone formation. The tissue engineering bone constructed by osteoblasts and DPB-TM scaffold can be applied to the repair of bone defect.

Animals↗

Bone mastocytosis. A report of nine cases with a bone histomorphometric study.

Bone mastocytosis is characterized radiographically in some patients by diffuse osteosclerosis and in others by demineralization. The reason for these apparently conflicting bone features is unknown. Bone remodeling and marrow mastocytosis infiltration were studied in nine cases of mastocytosis with bone marrow involvement. Six men, ranging from 42 to 78 years of age, and three women, 43, 55, and 73 years old, comprised the series. Two patients had severe and diffuse osteosclerosis. Seven had diffuse demineralization, with crushed vertebrae in four, suggesting common osteoporosis. In three of the seven, cutaneous mastocytosis was absent. Bone biopsies were undecalcified and stained with toluidine blue. In the seven patients with demineralization, the number of marrow mastocytes was increased (154 +/- 24 versus 2 +/- 0.5/mm2 in normal postmenopausal osteoporosis). Mastocyte nodules covering 1-9% of the marrow area were present in all seven patients. These patients showed a significant increase in remodeling; bone formation rate was increased, coupled with a decrease in mean wall thickness. Concomitantly, osteoclast surfaces were increased, with an increased amount of bone resorbed. The two patients with diffuse osteosclerosis had a markedly different histology; mast cell infiltration was dramatically increased (mastocyte count greater than 1000/mm2) with diffuse marrow fibrosis. Bone volume was increased as well, and most of the bone was woven with an intratrabecular mineralization defect. High bone remodeling and decreased osteoblast activity can explain bone loss in mastocytosis with demineralization. Mastocytosis with osteosclerosis is characterized by a more extensive marrow mast-cell infiltration and fibrosis.

Adult↗

Mandibular alveolar bone mass, structure and thickness in relation to skeletal bone density in dentate women.

The aim of this series of studies was to investigate the relationship between skeletal bone mineral density (BMD) and mandibular alveolar bone mass (MABM), structure, and thickness, as well as to evaluate the possible effect of local functional factors on MABM and alveolar thickness. A further aim was to elucidate whether longitudinal changes in mandibular radiographic characteristics and the bucco-lingual dimension of the alveolar process were related to alterations of BMD. BMD was measured in 160 dentate women using dual X-ray absorptiometry of the forearm. On periapical radiographs MABM was estimated using densitometry and the grey-level value. The alveolar bone structure was evaluated with a visual index and by examining the bone texture on periapical radiographs. The thickness of the masseter was assessed with ultrasound imaging to estimate the masticatory functional factor, and the bucco-lingual alveolar thickness was measured on casts. MABM and alveolar structure were significantly correlated to BMD. The best correlation was found between BMD and trabecular pattern evaluated with the visual index (r = 0.62, p < 0.001). The alveolar thickness was correlated to BMD, and to masseter thickness. MABM was influenced of age, the alveolar thickness, the number of occluding teeth, and the masseter muscle thickness but these factors had no effect on the trabecular structure. After five years, all measurements except the ultrasound imaging of the masseter muscle were repeated in 136 women. The mean BMD, MABM, and alveolar thickness decreased significantly during this period, whereas no significant change was found in the bone structure. In posterior region, the alterations in alveolar bone thickness, radiographic grey-level value, and bone texture were significantly correlated to the changes in BMD. In the anterior region, the alterations in alveolar thickness were not correlated with the changes in BMD. Furthermore, no correlation was found between alterations in MABM, estimated by densitometry, and changes in BMD. In conclusion, a significant relationship exists between BMD and mandibular alveolar bone mass, structure, and thickness. The local functional factors mainly influence MABM and the alveolar thickness in the molar region, whereas BMD influences the trabecular structure. Dense trabeculation is a strong indicator of high BMD, whereas sparse trabeculation predicts low bone mass. In peri- and postmenopausal women the alveolar shape in the premolar region can be used to predict BMD level. In the lower premolar region, the longitudinal alterations in BMD are related to longitudinal changes in grey-level value, bone texture and alveolar thickness. The decrease in bucco-lingual alveolar thickness may be due to periosteal resorption related to skeletal bone loss.

Absorptiometry, Photon↗

[Application of allogeneic bone in surgical treatment of benign bone neoplasm].

OBJECTIVE: To evaluate the clinical outcomes of allogeneic bone grafting for bone defect resulting from benign neoplasm resection and discuss the clinical application and bone defect repair mechanisms of allogeneic bone. METHODS: A retrospective review was conducted of 135 patients with benign neoplasm resection who received bone defect filling with the allogeneic bone graft. RESULTS: In the 104 patients with complete clinical follow-up data, 96 achieved bone union, 7 experienced relapses to require surgical intervention and 1 had severe infection to lead to failure of the operation. The mean time for bone union was 9.7 months, and during the follow-up, no viral disease in relation to the graft was found after surgery. CONCLUSION: Bone defect filling with allogeneic bone graft can be simple and safe in comparison with that with autograft or other biomaterials, and the bone healing time, infection rate and local tumor recurrence can be comparable with the autograft.

Adolescent↗