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Bone Quality (bone + quality)
Selected AbstractsEffect of Hormone Replacement Therapy on Bone Quality in Early Postmenopausal WomenJOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2003Ep Paschalis PhD Abstract HRT is an effective prophylaxis against postmenopausal bone loss. Infrared imaging of paired iliac crest biopsies obtained at baseline and after 2 years of HRT therapy demonstrate an effect on the mineral crystallinity and collagen cross-links that may affect bone quality. Several studies have demonstrated that hormonal replacement therapy (HRT) is an effective prophylaxis against postmenopausal bone loss, although the underlying mechanisms are still debated. Infrared spectroscopy has been used previously for analyzing bone mineral crystallinity and three-dimensional structures of collagen and other proteins. In the present study, the technique of Fourier transform infrared microscopic imaging (FTIRI) was used to investigate the effect of estrogen on bone quality (arbitrarily defined as mineral/matrix ratio, mineral crystallinity/maturity, and relative ratio of collagen cross-links [pyridinoline/deH-DHLNL]) at the ultrastructural level, in mineralized, thin tissue sections from double (before and after administration of HRT regimen; cyclic estrogen and progestogen [norethisterone acetate]) iliac crest biopsy specimens from 10 healthy, early postmenopausal women who were not on any medication with known influence on calcium metabolism. FTIRI allows the analysis of undemineralized thin tissue sections (each image analyzes a 400 × 400 ,m2 area with a spatial resolution of ,6.3 mm). For each bone quality variable considered, the after-treatment data exhibited an increase in the mean value, signifying definite changes in bone properties at the molecular level after HRT treatment. Furthermore, these findings are consistent with suppressed osteoclastic activity. [source] Menatetrenone (Vitamin K2) and Bone Quality in the Treatment of Postmenopausal OsteoporosisNUTRITION REVIEWS, Issue 12 2006Jun Iwamoto MD Menatetrenone (vitamin K2) reduces the incidence of vertebral fractures but has only modest effects on bone mineral density (BMD) in postmenopausal women with osteoporosis. Combined treatment with bisphosphonates and menatetrenone may be more effective than treatment with bisphosphonates alone in preventing vertebral fractures, despite the lack of an additive effect of menatetrenone on the BMD increase by bisphosphonates. Menatetrenone improves bone architecture in ovariectomized rats, and the mineral/ matrix ratio of the bone in terms of matrix volume and bone strength (without increasing bone mass) in rats with magnesium deficiency. Thus, available evidence supports an effect of menatetrenone on bone quality during osteoporosis treatment [source] Assessing the skeleton in children and adolescents with disabilities: Avoiding pitfalls, maximising outcomes.JOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 6 2009A guide for the general paediatrician Abstract: Assessment of bone health of a young person with a severe disability is complex. Age of onset of disability, degree of physical limitation, nutritional status, calcium and vitamin D intake and pubertal progress all contribute to adult outcomes. Concomitant medical conditions may further adversely affect bone accrual. Bone quality, until growth is complete, must be interpreted in light of growth, height and puberty. For those children and adolescents who have disabilities where weight bearing is limited, satisfactory and reproducible measurements of bone density may be impossible to obtain. Fracture risk is dependent on the degree of immobilisation and on bone quality at any age. Meeting the goal of reducing extent and complications of adult osteoporosis is dependent upon an understanding of the nature and contribution of individual components of bone accrual, so that interventions can be appropriately targeted to optimise outcomes. [source] Glucocorticoid-induced bone loss in mice can be reversed by the actions of parathyroid hormone and risedronate on different pathways for bone formation and mineralizationARTHRITIS & RHEUMATISM, Issue 11 2008Wei Yao Objective Glucocorticoid excess decreases bone mineralization and microarchitecture and leads to reduced bone strength. Both anabolic (parathyroid hormone [PTH]) and antiresorptive agents are used to prevent and treat glucocorticoid-induced bone loss, yet these bone-active agents alter bone turnover by very different mechanisms. This study was undertaken to determine how PTH and risedronate alter bone quality following glucocorticoid excess. Methods Five-month-old male Swiss-Webster mice were treated with the glucocorticoid prednisolone (5 mg/kg in a 60-day slow-release pellet) or placebo. From day 28 to day 56, 2 groups of glucocorticoid-treated animals received either PTH (5 ,g/kg) or risedronate (5 ,g/kg) 5 times per week. Bone quality and quantity were measured using x-ray tomography for the degree of bone mineralization, microfocal computed tomography for bone microarchitecture, compression testing for trabecular bone strength, and biochemistry and histomorphometry for bone turnover. In addition, real-time polymerase chain reaction (PCR) and immunohistochemistry were performed to monitor the expression of several key genes regulating Wnt signaling (bone formation) and mineralization. Results Compared with placebo, glucocorticoid treatment decreased trabecular bone volume (bone volume/total volume [BV/TV]) and serum osteocalcin, but increased serum CTX and osteoclast surface, with a peak at day 28. Glucocorticoids plus PTH increased BV/TV, and glucocorticoids plus risedronate restored BV/TV to placebo levels after 28 days. The average degree of bone mineralization was decreased after glucocorticoid treatment (,27%), but was restored to placebo levels after treatment with glucocorticoids plus risedronate or glucocorticoids plus PTH. On day 56, RT-PCR revealed that expression of genes that inhibit bone mineralization (Dmp1 and Phex) was increased by continuous exposure to glucocorticoids and glucocorticoids plus PTH and decreased by glucocorticoids plus risedronate, compared with placebo. Wnt signaling antagonists Dkk-1, Sost, and Wif1 were up-regulated by glucocorticoid treatment but down-regulated after glucocorticoid plus PTH treatment. Immunohistochemistry of bone sections showed that glucocorticoids increased N-terminal Dmp-1 staining while PTH treatment increased both N- and C-terminal Dmp-1 staining around osteocytes. Conclusion Our findings indicate that both PTH and risedronate improve bone mass, degree of bone mineralization, and bone strength in glucocorticoid-treated mice, and that PTH increases bone formation while risedronate reverses the deterioration of bone mineralization. [source] Effect of cortical thickness and cancellous bone density on the holding strength of internal fixator screwsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 6 2004J. Seebeck Abstract Internal fixators are a new class of implants designed to preserve the periosteal blood supply of the bone. In contrast to conventional plate fixation in which the screws have spherical heads and are loaded mainly by axial pullout forces, screws in internal fixators are "locked" within the plate and therefore subjected to axial as well as bending loads. In this study the ultimate loads of screws of a commercially available internal fixator system were tested in a pullout (n = 72) and cantilever bending mode (n = 72) in metaphyseal and diaphyseal regions of four pairs of human tibiae with different bone qualities. Cortical thickness and cancellous bone density were determined at the screw insertion sites. Stepwise multiple linear regression revealed that cortical thickness and cancellous density can explain 93% and 98% of the variance of the ultimate load of the screws in an axial pullout and cantilever bending mode. Screws in internal fixators are better suited to transmit shear forces and thereby make better use of the strength potential of bone than screws used in conventional plate fixation: this is especially advantageous when bone strength is reduced, e.g. due to osteoporosis. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] A Study on Variances in Multivariate Analyses of Oral Implant OutcomeCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 1 2007Irene Herrmann LDS, Odont Lic ABSTRACT Background:, Elaborate studies have shown that interdependency exists between implants being placed in the same patient/jaw. Therefore, interdependency ought to be an important aspect to address, whenever performing statistical analyses of oral implant outcomes. A Jackknife method could be an option when conducting statistical evaluations of oral implant failure prognoses. Purpose:, The aim of this study was to evaluate whether a statistical difference can be detected by using the Jackknife method in conjunction with life table analyses and/or a log rank test of four different combinations of jaw density and quantity. Materials and Methods:, Four multicenter studies were pooled and adjusted in order to create a research database consisting of 486 patients and 1,737 implants in preparation for the Jackknife resampling method. Combinations of jaw shapes and bone qualities were constructed to select at-risk patients. Statistical Methods:, Life tables with confidence intervals were calculated and a log rank test was used to determine whether a statistical difference between the combinations could be established. Results:, Both statistical analyses, after the Jackknife resampling method, showed that patients with poor bone quality and resorbed jaws (combination IV) had a statistically higher risk of implant failure. Conclusion:, By rearranging data using the Jackknife method, standardized statistical tests seem to work well even when the study population tested was affected by interdependency. [source] Is self-reported alcohol consumption associated with osteoporotic mandibular bone loss in women?EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2009Olivia Nackaerts The aim of this study was to determine whether alcohol consumption would predict mandibular bone quality and quantity in a large European female population. In total, 672 middle-aged and elderly women (45,70 yr of age; standard deviation = 6) were recruited in the study. Alcohol consumption was recorded through a self-reported questionnaire. Mandibular cortical width was measured, by five observers, in the mental foramen region on panoramic radiographs. Mandibular bone density, expressed as aluminium thickness, was recorded on intra-oral radiographs. Alcohol consumption was associated with a reduction of mandibular bone density and cortical width. This association was higher in subjects with excessive alcohol consumption, defined in the present study as > 14 units consumed per week. This study showed reduced jaw-bone quality in older individuals and in those with increased alcohol consumption. [source] IBD and skeletal health: Children are not small adults!INFLAMMATORY BOWEL DISEASES, Issue 11 2005Francisco A Sylvester MD Abstract Patients with inflammatory bowel disease often have decreased bone mass, and fragility fractures can occur. Multiple disease- and treatment related factors, including malnutrition, inflammation, malabsorption, decreased weight-bearing physical activity, and corticosteroids negatively influence bone metabolic activity. Because low-impact fracture is the pathologic expression of critically reduced bone mass and bone quality, knowing the relative risk of fractures in patients with IBD is of great interest. The absolute risk for incident fractures in these patients is still being debated. Clinical and laboratory research is clarifying mechanisms by which IBD can affect the function of osteoblasts and osteoclasts. In this concise review, we aim to provide an update on this topic, with focus on how pediatric IBD affects bone health. [source] Microdamage in osteoporosis, bone quality and remodellingJOURNAL OF ANATOMY, Issue 2 2003T. C. Lee No abstract is available for this article. [source] Inhibition of Lamin A/C Attenuates Osteoblast Differentiation and Enhances RANKL-Dependent Osteoclastogenesis,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2009Martina Rauner Abstract Age-related osteoporosis is characterized by low bone mass, poor bone quality, and impaired osteoblastogenesis. Recently, the Hutchinson-Gilford progeria syndrome (HGPS), a disease of accelerated aging and premature osteoporosis, has been linked to mutations in the gene encoding for the nuclear lamina protein lamin A/C. Here, we tested the hypothesis that inhibition of lamin A/C in osteoblastic lineage cells impairs osteoblastogenesis and accelerates osteoclastogenesis. Lamin A/C was knocked-down with small interfering (si)RNA molecules in human bone marrow stromal cells (BMSCs) differentiating toward osteoblasts. Lamin A/C knockdown led to an inhibition of osteoblast proliferation by 26% and impaired osteoblast differentiation by 48% based on the formation of mineralized matrix. In mature osteoblasts, expression levels of runx2 and osteocalcin mRNA were decreased by lamin A/C knockdown by 44% and 78%, respectively. Furthermore, protein analysis showed that osteoblasts with diminished levels of lamin A/C also secreted less osteocalcin and expressed a lower alkaline phosphatase activity (,50%). Lamin A/C inhibition increased RANKL mRNA and protein levels, whereas osteoprotegerin (OPG) expression was decreased, resulting in an increased RANKL/OPG ratio and an enhanced ability to support osteoclastogenesis, as reflected by a 34% increase of TRACP+ multinucleated cells. Our data indicate that lamin A/C is essential for proper osteoblastogenesis. Moreover, lack of lamin A/C favors an osteoclastogenic milieu and contributes to enhanced osteoclastogenesis. [source] Exercise When Young Provides Lifelong Benefits to Bone Structure and Strength,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2007Stuart J Warden PT Abstract Short-term exercise in growing rodents provided lifelong benefits to bone structure, strength, and fatigue resistance. Consequently, exercise when young may reduce the risk for fractures later in life, and the old exercise adage of "use it or lose it" may not be entirely applicable to the skeleton. Introduction: The growing skeleton is most responsive to exercise, but low-trauma fractures predominantly occur in adults. This disparity has raised the question of whether exercised-induced skeletal changes during growth persist into adulthood where they may have antifracture benefits. This study investigated whether brief exercise during growth results in lifelong changes in bone quantity, structure, quality, and mechanical properties. Materials and Methods: Right forearms of 5-week-old Sprague-Dawley rats were exercised 3 days/week for 7 weeks using the forearm axial compression loading model. Left forearms were internal controls and not exercised. Bone quantity (mineral content and areal density) and structure (cortical area and minimum second moment of area [IMIN]) were assessed before and after exercise and during detraining (restriction to home cage activity). Ulnas were removed after 92 weeks of detraining (at 2 years of age) and assessed for bone quality (mineralization) and mechanical properties (ultimate force and fatigue life). Results: Exercise induced consistent bone quantity and structural adaptation. The largest effect was on IMIN, which was 25.4% (95% CI, 15.6,35.3%) greater in exercised ulnas compared with nonexercised ulnas. Bone quantity differences did not persist with detraining, whereas all of the absolute difference in bone structure between exercised and nonexercised ulnas was maintained. After detraining, exercised ulnas had 23.7% (95% CI, 13.0,34.3%) greater ultimate force, indicating enhanced bone strength. However, exercised ulnas also had lower postyield displacement (,26.4%; 95% CI, ,43.6% to ,9.1%), indicating increased brittleness. This resulted from greater mineralization (0.56%; 95% CI, 0.12,1.00%), but did not influence fatigue life, which was 10-fold greater in exercised ulnas. Conclusions: These data indicate that exercise when young can have lifelong benefits on bone structure and strength, and potentially, fracture risk. They suggest that the old exercise adage of "use it or lose it" may not be entirely applicable to the skeleton and that individuals undergoing skeletal growth should be encouraged to perform impact exercise. [source] Effect of Hormone Replacement Therapy on Bone Quality in Early Postmenopausal WomenJOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2003Ep Paschalis PhD Abstract HRT is an effective prophylaxis against postmenopausal bone loss. Infrared imaging of paired iliac crest biopsies obtained at baseline and after 2 years of HRT therapy demonstrate an effect on the mineral crystallinity and collagen cross-links that may affect bone quality. Several studies have demonstrated that hormonal replacement therapy (HRT) is an effective prophylaxis against postmenopausal bone loss, although the underlying mechanisms are still debated. Infrared spectroscopy has been used previously for analyzing bone mineral crystallinity and three-dimensional structures of collagen and other proteins. In the present study, the technique of Fourier transform infrared microscopic imaging (FTIRI) was used to investigate the effect of estrogen on bone quality (arbitrarily defined as mineral/matrix ratio, mineral crystallinity/maturity, and relative ratio of collagen cross-links [pyridinoline/deH-DHLNL]) at the ultrastructural level, in mineralized, thin tissue sections from double (before and after administration of HRT regimen; cyclic estrogen and progestogen [norethisterone acetate]) iliac crest biopsy specimens from 10 healthy, early postmenopausal women who were not on any medication with known influence on calcium metabolism. FTIRI allows the analysis of undemineralized thin tissue sections (each image analyzes a 400 × 400 ,m2 area with a spatial resolution of ,6.3 mm). For each bone quality variable considered, the after-treatment data exhibited an increase in the mean value, signifying definite changes in bone properties at the molecular level after HRT treatment. Furthermore, these findings are consistent with suppressed osteoclastic activity. [source] High-Turnover Periprosthetic Bone Remodeling and Immature Bone Formation Around Loose Cemented Total Hip JointsJOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2001Michiaki Takagi Abstract Aseptic loosening and periprosthetic osteolysis are the major problems awaiting solution in total hip surgery. The clinical investigation focused on the analysis of periprosthetic bone remodeling to clarify one important key event in the cascade of periprosthetic connective tissue weakening and osteolysis around loose artificial hip joints. Twelve acetabular bone samples adjacent to granulomatous synovial-like membrane of loose hip prosthesis were retrieved at revision surgery and processed for Villanueva bone staining for morphological observation and bone histomorphometric analysis. Eight well-fixed bony samples were used as control. Although osteoclastic surface and eroded surface by osteoclasts were evident in the periprosthetic bone from loose hip joints (p = 0.003 and p = 0.027), increased osteoid/low-mineralized bone matrix (p < 0.001) and osteoid width (p < 0.001) also were significant findings in structural analysis. In addition, not only elevated mineral apposition rate (MAR; p = 0.044) but also increased mineralizing surface (p = 0.044) and bone formation rate (BFR; p = 0.002) in loose periprosthetic bones were shown in dynamic data analysis. These results were confirmed by precise morphological observation by confocal laser scanning microscopy. Active coupling of bone formation and resorption and increased osteocytes with abundant bone canalicular projections were found in combined with the presence of immature bone matrices (osteoid and low-mineralized bone areas) in periprosthetic bones from loose hip joints. These results indicated that active osteoclastic bone resorption and/or defective bone formation are coupled with monocyte/macrophage-mediated foreign body-type granuloma in the synovial-like interface membrane of loose hip joints. Thus, this unique high-turnover periprosthetic bone remodeling with bad bone quality probably is caused by the result of cellular host response combined with inappropriate cyclic mechanical loading. The fragile periprosthetic bone may contribute to hip prosthesis loosening. [source] A biomechanical assessment of the relation between the oral implant stability at insertion and subjective bone quality assessmentJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 4 2007Ghada Alsaadi Abstract Aim: The study was set to evaluate the validity of subjective jaw bone quality assessment. Materials and Methods: A total of 298 patients (198 females, mean age 56.4) were treated with oral implants at the Periodontology Department at the University Hospital of KUL. A total of 761 TiUniteÔ implants have been installed. Subjective bone quality assessment was performed on radiographs and by the surgeon's tactile sensation and was compared with torque measurements. In a subset of patients, implant stability was also assessed by implant stability quotient and/or periotest values. Results: Subjective assessment of bone quality was related to the PTV, ISQ and placement torque [in the crestal, the second and the apical third (N cm)], respectively; in grade 1: ,5.3, 73.3 (4.2, 9.6, 15.2), and grade 3 or 4: ,1.6, 55 (3.3, 5.5, 8.4). For the surgeon's tactile sensation, a good correlation was noted for the presence of a thick cortex: ,4.6, 70.3 (4.2, 9.7, 15.1), or a thin one: ,0.3, 65.9 (3.6, 6.9, 10.1). For dense trabecular bone, the values were ,2.8, 69.4 (4.4, 9.7,14.8), while for poor trabecular bone, the values were,1.7, 66.4 (3.6, 6.4, 9.8). Conclusions: Subjective assessment of bone quality is related to PTV, ISQ and placement torque measurements at implant insertion. [source] IMMEDIATE LOADING OF IMPLANTS IN THE ESTHETIC ZONEJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 5 2005Saj Jivraj DDS The predictability of dental implants using the traditional Branemark protocol has been well documented. Since its inception, this protocol has been progressively challenged to decrease treatment time, minimize the number of surgical procedures, and maximize esthetic outcomes. Today, in specific clinical situations, implants may be placed and immediately loaded with provisional restorations. Immediate loading in the edentulous mandible has been well documented. There are also good data to show that immediate loading of the edentulous maxilla is also feasible if bone quality is suitable. The focus now has shifted toward immediate loading of implants placed in the esthetic zone. Clinicians have recognized that the challenge of providing anterior tooth replacements is in preserving the hard and soft tissue components that exist around natural teeth. The advantages of immediate restoration are obvious; however, the application of immediate or early load may pose an increased risk of implant failure in single-tooth situations. The prerequisites for achieving and maintaining acceptable results are not fully known. This review examines some of the literature concerning the reliability of early or immediate loading of implants placed in the esthetic zone. [source] The Effects of Chemical and Heat Maceration Techniques on the Recovery of Nuclear and Mitochondrial DNA from Bone,JOURNAL OF FORENSIC SCIENCES, Issue 1 2006Dawnie Wolfe Steadman Ph.D. ABSTRACT: Forensic anthropologists use a number of maceration techniques to facilitate skeletal analysis of personal identity and trauma, but they may unwittingly eliminate valuable DNA evidence in the process. This study evaluated the effect of 10 maceration methods on gross bone structure and the preservation of DNA in ribs of 12 pigs (Sus scrofa). A scoring system was applied to evaluate the ease of maceration and resulting bone quality while DNA purity was quantified by optical densitometry analysis, followed by polymerase chain reaction (PCR) amplification of three mitochondrial and three nuclear loci. The results demonstrated that while mitochondrial DNA could be amplified for all experiments, cleaning treatments using bleach, hydrogen peroxide, ethylenediaminetetraacetic acid/papain, room temperature water and detergent/sodium carbonate followed by degreasing had low DNA concentrations and failed to generate nuclear PCR products. In general, treatments performed at high temperatures (90°C or above) for short durations performed best. This study shows that traditionally "conservative" maceration techniques are not necessarily the best methods to yield DNA from skeletal tissue. [source] Assessment of correlation between computerized tomography values of the bone, and maximum torque and resonance frequency values at dental implant placementJOURNAL OF ORAL REHABILITATION, Issue 12 2006I. TURKYILMAZ summary, The aim of this study was to determine the bone density in the designated implant sites using computerized tomography (CT), the fastening torque values of dental implants, and the implant stability values using resonance frequency analysis. Further aim was to evaluate a possible correlation between bone density, fastening torque and implant stability. Eighty-five patients were treated with 158 Brånemark System implants. CT machine was used for preoperative evaluation of the jawbone for each patient, and bone densities were recorded in Hounsfield units (HU). The fastening torque values of all implants were recorded with the OsseoCare equipment. Implant stability measurements were performed with the Osstell machine. The average bone density and fastening torque values were 751·4 ± 256 HU and 39·7 ± 7 Ncm for 158 implants. The average primary implant stability was 73·2 ± 6 ISQ for seventy implants. Strong correlations were observed between the bone density, fastening torque and implant stability values of Brånemark System TiUnite MKIII implants at implant placement (P < 0·001). These results strengthen the hypothesis that it may be possible to predict and quantify initial implant stability and bone quality from pre-surgical CT diagnosis. [source] Anatomical study of the pyramidal process of the palatine bone in relation to implant placement in the posterior maxillaJOURNAL OF ORAL REHABILITATION, Issue 2 2001S. P. Lee The placement of dental implants in the molar region of the maxilla is often difficult because of insufficient bone volume and the inferior bone quality. In order to avoid these limitations, the pillar of bone, which is composed of the maxillary tuberosity, the pyramidal process of the palatine bone and the pterygoid process of the sphenoid bone, was introduced for implant placement. In fact, the pyramidal process is the posterior structure where implants are placed but until now, there is no available data of the size or shape of the pyramidal process. Therefore, we measured the height, anteroposterior distance and mediolateral distance of the pyramidal process and observed the shape of lateral and posterior surfaces of the pyramidal process of 54 Korean edentulous dry skulls in this study. The height was 13·1 mm (male: 13·6 mm, female: 12·4 mm). The anteroposterior distance was 6·5 mm (male: 6·7 mm, female: 6·1 mm). The mediolateral distance was 9·5 mm (male: 9·9 mm, female: 9·0 mm). The most common type was the right-angled triangle in the lateral surface (44·4%) and in the posterior surface (66·7%). There was no statistical significance between the male and the female in all items (P > 0·05). These results provide anatomical features in relation to placement of dental implants in the molar region of the maxilla and would be useful in treatment planning of partially or completely edentulous patients. [source] Influence of bone density on the cement fixation of femoral hip resurfacing componentsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 8 2010Rudi G. Bitsch Abstract In clinical outcome studies, small component sizes, female gender, femoral shape, focal bone defects, bad bone quality, and biomechanics have been associated with failures of resurfacing arthroplasties. We used a well-established experimental setup and human bone specimens to analyze the effects of bone density on cement fixation of femoral hip resurfacing components. Thirty-one fresh frozen femora were prepared for resurfacing using the original instruments. ASRÔ resurfacing prostheses were implanted after dual-energy X-ray densitometer scans. Real-time measurements of pressure and temperature during implantation, analyses of cement penetration, and measurements of micro motions under torque application were performed. The associations of bone density and measurement data were examined calculating regression lines and multiple correlation coefficients; acceptability was tested with ANOVA. We found significant relations between bone density and micro motion, cement penetration, cement mantle thickness, cement pressure, and interface temperature. Mean bone density of the femora was 0.82,±,0.13,g/cm2, t- score was ,0.7,±,1.0, and mean micro motion between bone and femoral resurfacing component was 17.5,±,9.1,µm/Nm. The regression line between bone density and micro motion was equal to ,56.7,×, bone density,+,63.8, R,=,0.815 (p,<,0.001). Bone density scans are most helpful for patient selection in hip resurfacing, and a better bone quality leads to higher initial component stability. A sophisticated cementing technique is recommended to avoid vigorous impaction and incomplete seating, since increasing bone density also results in higher cement pressures, lower cement penetration, lower interface temperatures, and thicker cement mantles. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:986,991, 2010 [source] Osteointegration of titanium and hydroxyapatite rough surfaces in healthy and compromised cortical and trabecular bone: in vivo comparative study on young, aged, and estrogen-deficient sheepJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 9 2007Veronica Borsari Abstract The osteointegration rate of titanium (Ti; TI01) and duplex Ti plus HA (HT01) coating systems with high surface roughness was investigated in healthy, aged, and oestrogen-deficient sheep. After having evaluated the bone quality, TI01 and HT01 rods were implanted in the tibial diaphyses (two implants for each tibia) and epiphyses (1 implant for each tibia) of five young (YOUNG), five aged (AGED), and five aged and ovariectomized (OVX) sheep. The iliac crest trabecular bone volume (BV/TV) and number (Tb.N) in OVX sheep were respectively 33.5% and 28.5% lower than in YOUNG sheep (p,<,0.005) and lower than in the AGED group (BV/TV, ,17%; Tb.N, ,13.5%; not significant); in the OVX group the trabecular separation was 77.9% higher than in YOUNG (p,<,0.05) and 30.9% higher than in AGED animals. Lumbar vertebrae L5 bone mineral density was significantly lower in AGED (8.9%, p,<,0.05) and OVX sheep (19.3%, p,<,0.0005) when compared with YOUNG animals. Five samples of five sheep from each group were analyzed for each observation. At 3 months, in cortical bone both affinity index and pushout test results showed no significant differences between the two materials in each group of animals. In trabecular bone, the affinity index of HT01 was significantly higher than that of TI01 in each group of animals (YOUNG, 90.7%; AGED, 76.9%; OVX, 49.9%) with no significant differences between groups. In conclusion, the performance of TI01 and HT01 surfaces was high not only in YOUNG, but also in OVX animals and, therefore, they might be useful for aged and osteoporotic patients. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1250,1260, 2007 [source] Long-term ovariectomy decreases ovine compact bone viscoelasticityJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2005C. M. Les Abstract Changes in bone mineral density associated with estrogen depletion in humans do not account for all of the associated change in fracture risk, and it is possible that some of this variation may lie in changes of other aspects of bone quality. The purpose of this study was to investigate changes in viscoelastic behavior of compact bone that may be associated with estrogen depletion. Changes in compact bone viscoelastic properties associated with three years of ovariectomy were investigated with dynamic mechanical analysis (low-amplitude 3-point bending at frequencies of 1,20 Hz) using beams milled from the diaphysis of the ovine radius. The viscoelastic storage modulus was significantly (5.2%) lower at the higher frequencies for the ovariectomized animals. The general anatomic variation in storage modulus, in which cranial sectors had higher values than caudal sectors, did not change with ovariectomy. The loss tangent (tan ,, a measure of damping) was also greatly decreased (up to 83%) at high frequencies in the ovariectomized animals. Anatomic variation in tan , at low (6,12 Hz) frequencies (cranial and caudal sectors having higher values than lateral or medial sectors) was enhanced with ovariectomy. Changes in viscoelastic properties associated with long term estrogen depletion could be responsible for a significant reduction in the toughness or strength of a bone without concomitant changes in screening modalities used to evaluate bone quality (e.g., DXA, QCT, QUA). © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] Assessing the skeleton in children and adolescents with disabilities: Avoiding pitfalls, maximising outcomes.JOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 6 2009A guide for the general paediatrician Abstract: Assessment of bone health of a young person with a severe disability is complex. Age of onset of disability, degree of physical limitation, nutritional status, calcium and vitamin D intake and pubertal progress all contribute to adult outcomes. Concomitant medical conditions may further adversely affect bone accrual. Bone quality, until growth is complete, must be interpreted in light of growth, height and puberty. For those children and adolescents who have disabilities where weight bearing is limited, satisfactory and reproducible measurements of bone density may be impossible to obtain. Fracture risk is dependent on the degree of immobilisation and on bone quality at any age. Meeting the goal of reducing extent and complications of adult osteoporosis is dependent upon an understanding of the nature and contribution of individual components of bone accrual, so that interventions can be appropriately targeted to optimise outcomes. [source] Bone response to different strength orthodontic forces in animals with periodontitisJOURNAL OF PERIODONTAL RESEARCH, Issue 6 2005J. A. Garat Background:, Occlusal alterations resulting from tooth movements caused by periodontitis-related bone loss are often corrected with orthodontic treatments. Although the outcome is usually satisfactory, a quantitative histomorphometric study of bone response would contribute to improving treatment planning and optimizing results. Methods and Results:, This study is a histomorphometric analysis of alveolar bone response to 51 and 75-g orthodontic forces applied to rat molars subjected to experimental periodontitis by placing a ligature around the neck of the molar during 48 h. The orthodontic device consisted of two bands with a tube welded to their palatine aspect, through which the arms of a helicoidal spring were threaded so as to exert force toward palatine. The device was placed immediately and 48 h after removing the ligatures. When applied 48 h post-removal of the ligature, both orthodontic forces caused an increase in bone volume in the periodontitis group. Conclusions:, Our study shows that application of orthodontic forces once periodontal infection has been controlled contributes to increasing alveolar bone volume, consequently improving bone quality. [source] Menatetrenone (Vitamin K2) and Bone Quality in the Treatment of Postmenopausal OsteoporosisNUTRITION REVIEWS, Issue 12 2006Jun Iwamoto MD Menatetrenone (vitamin K2) reduces the incidence of vertebral fractures but has only modest effects on bone mineral density (BMD) in postmenopausal women with osteoporosis. Combined treatment with bisphosphonates and menatetrenone may be more effective than treatment with bisphosphonates alone in preventing vertebral fractures, despite the lack of an additive effect of menatetrenone on the BMD increase by bisphosphonates. Menatetrenone improves bone architecture in ovariectomized rats, and the mineral/ matrix ratio of the bone in terms of matrix volume and bone strength (without increasing bone mass) in rats with magnesium deficiency. Thus, available evidence supports an effect of menatetrenone on bone quality during osteoporosis treatment [source] Glucocorticoid-induced bone loss in mice can be reversed by the actions of parathyroid hormone and risedronate on different pathways for bone formation and mineralizationARTHRITIS & RHEUMATISM, Issue 11 2008Wei Yao Objective Glucocorticoid excess decreases bone mineralization and microarchitecture and leads to reduced bone strength. Both anabolic (parathyroid hormone [PTH]) and antiresorptive agents are used to prevent and treat glucocorticoid-induced bone loss, yet these bone-active agents alter bone turnover by very different mechanisms. This study was undertaken to determine how PTH and risedronate alter bone quality following glucocorticoid excess. Methods Five-month-old male Swiss-Webster mice were treated with the glucocorticoid prednisolone (5 mg/kg in a 60-day slow-release pellet) or placebo. From day 28 to day 56, 2 groups of glucocorticoid-treated animals received either PTH (5 ,g/kg) or risedronate (5 ,g/kg) 5 times per week. Bone quality and quantity were measured using x-ray tomography for the degree of bone mineralization, microfocal computed tomography for bone microarchitecture, compression testing for trabecular bone strength, and biochemistry and histomorphometry for bone turnover. In addition, real-time polymerase chain reaction (PCR) and immunohistochemistry were performed to monitor the expression of several key genes regulating Wnt signaling (bone formation) and mineralization. Results Compared with placebo, glucocorticoid treatment decreased trabecular bone volume (bone volume/total volume [BV/TV]) and serum osteocalcin, but increased serum CTX and osteoclast surface, with a peak at day 28. Glucocorticoids plus PTH increased BV/TV, and glucocorticoids plus risedronate restored BV/TV to placebo levels after 28 days. The average degree of bone mineralization was decreased after glucocorticoid treatment (,27%), but was restored to placebo levels after treatment with glucocorticoids plus risedronate or glucocorticoids plus PTH. On day 56, RT-PCR revealed that expression of genes that inhibit bone mineralization (Dmp1 and Phex) was increased by continuous exposure to glucocorticoids and glucocorticoids plus PTH and decreased by glucocorticoids plus risedronate, compared with placebo. Wnt signaling antagonists Dkk-1, Sost, and Wif1 were up-regulated by glucocorticoid treatment but down-regulated after glucocorticoid plus PTH treatment. Immunohistochemistry of bone sections showed that glucocorticoids increased N-terminal Dmp-1 staining while PTH treatment increased both N- and C-terminal Dmp-1 staining around osteocytes. Conclusion Our findings indicate that both PTH and risedronate improve bone mass, degree of bone mineralization, and bone strength in glucocorticoid-treated mice, and that PTH increases bone formation while risedronate reverses the deterioration of bone mineralization. [source] RFA Values of Implants Placed in Sinus Grafted and Nongrafted Sites after 6 and 12 MonthsCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 3 2009Marco Degidi MD ABSTRACT Background: Maxillary sinus floor elevation surgery is widely used as a preimplantology method to permit implant insertion. Nevertheless, very few data are available about long-term stability of dental implants inserted in grafted sites. Purpose: The aims of the present study were to evaluate the evolution of resonance frequency analysis (RFA) values at 6 and 12 months from the implant insertion in sinus grafted sites and nongrafted sites. Materials and Methods: In 14 patients, 80 Xive implants (Dentsply Friadent GmbH, Mannheim, Germany) were inserted. Sixty-three implants were inserted in a site previously treated with a sinus lift; 17 implants were inserted in healed or postextraction sites. For each implant diameter, length, bone density, insertion torque, and percentage of implant fixed to a nongrafted bone were recorded. RFA values at implant insertion after 6 and 12 months were recorded. Results: After 6 and 12 months, grafted sites showed higher RFA values than the control sites; after 12 months, the difference was statistically significant (.007). A statistically significant positive correlation was found between resonance frequency values and bone quality after 12 months (.05). No statistically significant correlation between RFA values and all the other variables considered was found. Conclusions: Sites treated with sinus lift can offer good long-term stability. After 6 and 12 months, the geometric characteristics of the implant are no longer important to obtain high RFA values, and the bone,implant interface seems to be determinant. [source] A Study on Variances in Multivariate Analyses of Oral Implant OutcomeCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 1 2007Irene Herrmann LDS, Odont Lic ABSTRACT Background:, Elaborate studies have shown that interdependency exists between implants being placed in the same patient/jaw. Therefore, interdependency ought to be an important aspect to address, whenever performing statistical analyses of oral implant outcomes. A Jackknife method could be an option when conducting statistical evaluations of oral implant failure prognoses. Purpose:, The aim of this study was to evaluate whether a statistical difference can be detected by using the Jackknife method in conjunction with life table analyses and/or a log rank test of four different combinations of jaw density and quantity. Materials and Methods:, Four multicenter studies were pooled and adjusted in order to create a research database consisting of 486 patients and 1,737 implants in preparation for the Jackknife resampling method. Combinations of jaw shapes and bone qualities were constructed to select at-risk patients. Statistical Methods:, Life tables with confidence intervals were calculated and a log rank test was used to determine whether a statistical difference between the combinations could be established. Results:, Both statistical analyses, after the Jackknife resampling method, showed that patients with poor bone quality and resorbed jaws (combination IV) had a statistically higher risk of implant failure. Conclusion:, By rearranging data using the Jackknife method, standardized statistical tests seem to work well even when the study population tested was affected by interdependency. [source] Report of a Case Receiving Full-Arch Rehabilitation in Both Jaws Using Immediate Implant Loading Protocols: A 1-Year Resonance Frequency Analysis Follow-UpCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 1 2006Michael Portmann DDS ABSTRACT Background:, Immediate occlusal implant loading has been documented as a viable treatment option for various indications. However, documentations related to full-arch rehabilitation are usually limited to treatment of one jaw at a time, thereby leaving the opposing dentition unchanged. Furthermore, clinical documentation using traditional, well-accepted measuring techniques may not be adequate when it comes to short-term evaluation of the success or failure of implants subjected to immediate occlusal loading. Purpose:, The purpose of this case report is to (1) present an implant stability follow-up of a patient receiving an immediate, implant-supported full-arch rehabilitation in both jaws and (2) evaluate the patient's acceptance of this rehabilitation. Materials and Methods:, A 68-year-old patient scheduled for implant treatment was selected for an immediate implant loading protocol in both jaws. During two surgical events 3 weeks apart, eight maxillary and four mandibular Brånemark System® Mk IV TiUniteTM fixtures (Nobel Biocare AB, Göteborg, Sweden) were inserted and subsequently used to immediately support a cross-arch fixed prosthesis in the maxilla and a bar-retained overdenture in the mandible. Implant stability was recorded from the day of surgery periodically during a 1-year follow-up using resonance frequency analysis (RFA). Results:, At the 1-year follow-up, based on clinical, RFA, and radiographic evaluations, all implants and the reconstructions were classified as successful. All maxillary implants showed a decrease in the implant stability quotient (ISQ) value from the measurement at the time of surgery to the first follow-up, whereas two of four mandibular implants revealed an initial drop in stability. Irrespective of a specific ISQ level measured at implant surgery (ISQ range 53,74) and despite an initial decrease in stability, measurements recorded at the 12-month follow-up indicated similar stability levels for all maxillary implants (ISQ range 64,68) or the group of mandibular implants (ISQ range 72,75) but with a higher ISQ level for mandibular implants. Furthermore, the patient's acceptance of the immediate full-arch rehabilitation in both jaws was high. Conclusions:, The present case report demonstrates that a slightly staged approach for full-arch rehabilitation in both jaws using immediate implant loading protocols is a realistic treatment option. Furthermore, RFA follow-up indicates that immediately occlusally loaded implants placed in reduced bone quality and quantity are more prone to loose stability in the early healing period compared with implants placed in dense bone quality. [source] Minimally Invasive Flapless Implant Surgery: A Prospective Multicenter StudyCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2005ODhc, William Becker DDS ABSTRACT Background: Placement of implants with a minimally invasive flapless approach has the potential to minimize crestal bone loss, soft tissue inflammation, and probing depth adjacent to implants and to minimize surgical time. Purpose: The aim of this multicenter study was to evaluate implant placement using a minimally invasive one-stage flapless technique up to 2 years. Materials and Methods: Fifty-seven patients ranging in age from 24 to 86 years were recruited from three clinical centers (Tucson, AZ, USA; Tel Aviv, Israel; Göteborg, Sweden). Seventy-nine implants were placed. A small, sharp-tipped guiding drill was used to create a precise, minimally invasive initial penetration through the mucosa and into bone (Nobel Biocare, Yorba, Linda, CA, USA). Implants were placed according to the manufacturer's instructions, with minimal countersinking. The parameters evaluated were total surgical time, implant survival, bone quality and quantity, implant position by tooth type, depth from mucosal margin to bone crest, implant length, probing depth, inflammation, and crestal bone changes. At 2 years, for 79 implants placed in 57 patients, the cumulative success rate using a minimally invasive flapless method was 98.7%, indicating the loss of 1 implant. Changes in crestal bone for 77 baseline and follow-up measurements were insignificant (radiograph 1: mean 0.7 mm, SD 0.5 mm, range 2.8 mm, minimum 0.2 mm, maximum 3.0 mm; radiograph 2: mean 0.8 mm, SD 0.5 mm, range 3.4 mm, minimum 0.12 mm, maximum 3.5 mm). Using descriptive statistics for 78 patients (one implant lost), mean changes for probing depth and inflammation were clinically insignificant. The average time for implant placement was 28 minutes (minimum 10 minutes, maximum 60 minutes, SD 13.1 minutes). Average depth from mucosal margin to bone was 3.3 mm (SD 0.7 mm, minimum 2 mm, maximum 5 mm, range 3 mm). Thirty-two implants were placed in maxillae and 47 in mandibles. Conclusions: The results of this study demonstrate that following diagnostic treatment planning criteria, flapless surgery using a minimally invasive technique is a predictable procedure. The benefits of this procedure are lessened surgical time; minimal changes in crestal bone levels, probing depth, and inflammation; perceived minimized bleeding; and lessened postoperative discomfort. [source] Cutting Torque Measurements in Conjunction with Implant Placement in Grafted and Nongrafted Maxillas as an Objective Evaluation of Bone Density: A Possible Method for Identifying Early Implant Failures?CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 1 2004Björn Johansson DDS ABSTRACT Background: Bone grafts are frequently used to enable the placement of dental implants in atrophied jaws. The biomechanical properties of bone grafts used in one- or two-stage implant procedures (in comparison with the use of nongrafted bone) are not well known. Purpose: The purpose of this study was (1) to measure cutting torques during the placement of self-tapping dental implants in nongrafted bone and in bone grafts, either as blocks or in a milled particulate form, in patients undergoing implant treatment in an edentulous maxilla and (2) to identify implants with reduced initial stability and to correlate these findings with a clinical classification of jawbone quality. Materials and Methods: The study included 40 consecutive patients with edentulous maxillas, 27 of whom were subjected to bone grafting prior to or in conjunction with implant placement (grafting group) and 13 of whom received implants without grafting (nongrafted group). Grafted bone from the iliac crest bone was used (1) as onlay blocks, (2) as maxillary sinus inlay blocks, or (3) in particulate form in the maxillary sinus. Implants were placed after 6 to 7 months of healing, except in the maxillary sinus inlay blocks, where implants were placed simultaneously. Cutting torque values were obtained from 113 grafted implant sites and from 109 nongrafted implant sites. Results: Significantly lower cutting torque values were assessed in grafted regions than in nongrafted regions, irrespective of grafting technique. Lower values were also seen for implants placed in block grafts after 6 months when compared to other grafting techniques used. The cutting torque values revealed an inverse linear relation to the Lekholm and Zarb bone quality index. Conclusion: The cutting torque values correlated well with the Lekholm and Zarb index of bone quality. Significantly lower cutting torque values were seen in grafted bone than in nongrafted bone. [source] | |||||||||||||||||||||||||