Bone Material Research Articles

Fabrication of magnesium-doped biphasic calcium phosphate granules with sea urchin spine-derived porous structure

In bone regeneration, synthetic materials are required to replace autogenous bone grafts. The shape, composition, surface, and porous structure of the material are key factors in bone formation and material resorption. In this study, we describe the fabrication of Mg-doped biphasic calcium phosphate (Mg-BCP) granules comprising hydroxyapatite (HAp) and beta-tricalcium phosphate (β-TCP) by exploiting the structural and chemical characteristics of sea urchin spines. The Mg-BCP granules were cylinders with a 1.2–1.8 mm diameter and height of 1.4–1.7 mm. The β-TCP/HAp ratio and Mg content in the Mg-BCP granules were controlled within the ranges of 0.36–0.45 and 2.40–6.21 mol%, respectively. Controlling the β-TCP/HAp ratio and Mg content may contribute to controlling the material resorption rate and promoting osteogenesis and angiogenesis. The Mg-BCP granules maintained the structural characteristics of the sea urchin spines. The granules comprised radial wedges termed septa, and a meshwork termed stereom. The interseptal gaps, or micropores, decreased from the granular exterior (24–29 μm) to the interior (14–28 μm). The septa in the outermost layer provide concavities on the sides of the cylindrical granules. The stereom meshworks in the core and outer layers involved micropores in the ranges of 3–15 and 3–10 μm, respectively. These multiscale pores and surface undulations may improve cell penetration and attachment, bodily fluid permeability, and protein adsorption. The compressive strengths of the Mg-BCP granules were in the range of 45.2–46.1 MPa, which are useful as bone grafts. Due to their rounded shapes, the Mg-BCP granules filled a mold more densely than the clinically used and irregularly shaped granules. These findings demonstrated that Mg-BCP granules are promising materials for bone regeneration.

Circadian Regulation of Bone Remodeling.

Adult bones are continuously remodeled by the balance between bone resorption by osteoclasts and subsequent bone formation by osteoblasts. Many studies have provided molecular evidence that bone remodeling is under the control of circadian rhythms. Circadian fluctuations have been reported in the serum and urine levels of bone turnover markers, such as digested collagen fragments and bone alkaline phosphatase. Additionally, the expressions of over a quarter of all transcripts in bones show circadian rhythmicity, including the genes encoding master transcription factors for osteoblastogenesis and osteoclastogenesis, osteogenic cytokines, and signaling pathway proteins. Serum levels of calcium, phosphate, parathyroid hormone, and calcitonin also display circadian rhythmicity. Finally, osteoblast- and osteoclast-specific knockout mice targeting the core circadian regulator gene Bmal1 show disrupted bone remodeling, although the results have not always been consistent. Despite these studies, however, establishing a direct link between circadian rhythms and bone remodeling in vivo remains a major challenge. It is nearly impossible to repeatedly collect bone materials from human subjects while following circadian changes. In addition, the differences in circadian gene regulation between diurnal humans and nocturnal mice, the main model organism, remain unclear. Filling the knowledge gap in the circadian regulation of bone remodeling could reveal novel regulatory mechanisms underlying many bone disorders including osteoporosis, genetic diseases, and fracture healing. This is also an important question for the basic understanding of how cell differentiation progresses under the influence of cyclically fluctuating environments.

Histologic evaluation of edentulous alveolar ridge horizontal bone augmentations using a xenogeneic bone substitute and autologous platelet concentrates: a case series.

This case series aimed to assess the efficacy of a novel horizontal ridge augmentation modality using histology. Combinations of "sticky bone" and tenting screws without autologous bone were used as augmentative materials. Five individuals presenting healed, atrophic, partially edentulous sites that required horizontal bone augmentation before implant placement were enrolled. Patients underwent the same augmentation type and 5 months of postoperative reentry procedures. The first surgery served as implant site development, whereas the biopsy and corresponding implant placement were performed during reentry. The bone was qualitatively analyzed using histology and histomorphometry and quantitatively evaluated using CBCT. Four individuals healed uneventfully. Early wound dehiscence occurred in one case. Histology showed favorable bone substitute incorporation into the newly formed bone and intimate contact between de novo bone and graft material in most cases. Histomorphometry revealed an average of 48 ± 28% newly formed bone, 19 ± 13% graft material, and 33 ± 26% soft tissue components. The CBCT-based mean alveolar ridge horizontal increase was 3.9 ± 0.6 mm at 5 months postoperatively. The described augmentation method appears suitable for implant site development resulting in favorable bone quality according to histology. However, clinicians must accommodate 1 to 2 mm of resorption in augmentative material width at the buccal aspect.

Validation process of automatic DNA extraction from bone material using a new advanced protocol for the EZ2 Connect instrument

Identification of human remains using genetic methods is an important task of forensic science. DNA markers are proving essential in the identification of unknown human remains. However, environmental factors can lead to poor preservation of DNA, including in bone material. The aim of this study was therefore to compare two methods of DNA isolation from bone material: the traditional organic method and the new protocol using the EZ2 Connect instrument. The study involved three types of bone material, namely molars/premolars, petrous parts of the temporal bone and femurs, all with an estimated PMI of 70–80 years. Importantly, the biological material was obtained from three different environments, categorized as preserving, neutral and degrading, based on basic physico-chemical tests and the potential impact on the bone.The results obtained show that the DNA was best preserved in the petrous bone, followed by the teeth, and the femur. DNA extraction using the EZ2 Connect instrument with a new protocol gave slightly better results for the petrous bone, comparable results for the teeth and worse results for the femur compared to the organic method. Several protocol modifications were tested and optimal conditions for DNA isolation were proposed for the EZ2 protocol. Furthermore, the use of an automated method facilitated the effective accumulation of isolates and increased the chances of successful identification of unknown human remains.

Gut hormone analogues and skeletal health in diabetes and obesity: Evidence from preclinical models

Diabetes mellitus and obesity are rapidly growing worldwide. Aside from metabolic disturbances, these two disorders also affect bone with a higher prevalence of bone fractures. In the last decade, a growing body of evidence suggested that several gut hormones, including ghrelin, gastrin, glucose-dependent insulinotropic polypeptide (GIP), glucagon, and glucagon-like peptide-1 and 2 (GLP-1 and GLP-2, respectively) may affect bone physiology. Several gut hormone analogues have been developed for the treatment of type 2 diabetes and obesity, and could represent a new alternative in the therapeutic arsenal against bone fragility. In the present review, a summary of the physiological roles of these gut hormones and their analogues is presented at the cellular level but also in several preclinical models of bone fragility disorders including type 2 diabetes mellitus, especially on bone mineral density, microarchitecture and bone material properties. The present review also summarizes the impact of GLP-1 receptor agonists approved for the treatment of type 2 diabetes mellitus and the more recent dual or triple analogue on bone physiology and strength.

Combining anabolic loading and raloxifene improves bone quantity and some quality measures in a mouse model of osteogenesis imperfecta

Osteogenesis imperfecta (OI) increases fracture risk due to changes in bone quantity and quality caused by mutations in collagen and its processing proteins. Current therapeutics improve bone quantity, but do not treat the underlying quality deficiencies. Male and female G610C+/− mice, a murine model of OI, were treated with a combination of raloxifene and in vivo axial tibial compressive loading starting at 10 weeks of age and continuing for 6 weeks to improve bone quantity and quality. Bone geometry and mechanical properties were measured to determine whole bone and tissue-level material properties. A colocalized Raman/nanoindentation system was used to measure chemical composition and nanomechanical properties in newly formed bone compared to old bone to determine if bone formed during the treatment regimen differed in quality compared to bone formed prior to treatment. Lastly, lacunar geometry and osteocyte apoptosis were assessed. OI mice were able to build bone in response to the loading, but this response was less robust than in control mice. Raloxifene improved some bone material properties in female but not male OI mice. Raloxifene did not alter nanomechanical properties, but loading did. Lacunar geometry was largely unchanged with raloxifene and loading. However, osteocyte apoptosis was increased with loading in raloxifene treated female mice. Overall, combination treatment with raloxifene and loading resulted in positive but subtle changes to bone quality.

[Translated article] Mechanical properties variations of immature bone in the earliest stages of development

IntroductionBone as a material varies its composition and mechanical properties throughout life. Although these variations are better understood in adulthood, there is little experimental information on the variation of these properties in early stages of development. The objective of this study is to analyze the mechanical behavior and chemical properties of cortical bone tissue from two animal species in these earliest stages. Material and methodologyTwenty specimens of cortical bone were manufactured from bovine and ovine species that were in different stages of development (feeding exclusively on breast milk, in the transition period to feed or pasture, and young animals but on a solid food diet). The specimens were subjected to tensile tests, recorded with a high-speed camera to obtain deformation maps. Measurements of the tensile force until the specimen broke were also carried out. A fractographic study was carried out with a scanning electron microscope to analyze the fracture surface and an analysis of the amount of calcium in each of the specimens using X-ray dispersion spectroscopy. ResultsA statistically significant and positive correlation was found between the elastic modulus of the specimens and their calcium content. A trend towards more rigid behavior with age was observed. ConclusionsYoung bone tissue tends to stiffen with age as the calcium content increases with an increase in elastic modulus.

3D printing of PEGDA/bioceramic for guiding cell adhesion and migration

The adhesion and migration characteristics of osteocytes on the surface of bone materials are crucial for bone tissue regeneration, which is conducive to the directional repair of bone defects. Herein, the adhesion and migration characteristics of MC3T3-E1 cells on the surface of SLA-3D printed PEGDA/bioceramic materials were analyzed in detail. The results indicated that, in comparison to the cured PEGDA matrix, the pseudopods of cells preferred to adhere to ceramic particles, demonstrating the characteristics of hard drive migration. Furthermore, on a wavy surface with a surface roughness (Ra=2 μm) fabricated by the laser of the SLA-3D printer, MC3T3-E1 cells could grow directionally along the rough channel via contact guidance. Therefore, by controlling the distribution of ceramic particles and adjusting the surface morphology of the printed PEGDA/bioceramic materials, the migration direction of cells can be dominated, which is of great significance for the targeted repair of bone tissue.

Bond Apatite: The natural mineral bone material that doesn't wash away!

Bond Apatite: The natural mineral bone material that doesn't wash away!

Evaluation of Trabecular Bone Microarchitecture and Bone Mineral Density in Young Women, Including Selected Hormonal Parameters.

The absence of non-invasive methods for assessing bone material and structural changes is a significant diagnostic challenge. Dual-energy X-ray absorptiometry (DXA) bone mineral density (BMD) testing is the gold standard for osteoporosis diagnosis. BMD and the trabecular bone score (TBS) have facilitated targeted osteoporosis prevention and treatment in clinical settings. The findings from this study indicate that BMD modulation in young women is influenced by various hormones, potentially compromising the diagnostic precision of BMD for subclinical bone demineralization. A total of 205 women aged 19 to 37 underwent anthropometric measurements and hormonal tests. BMD was determined using DXA, and TBS values were computed from the lumbar spine L1-L4 segment. The multivariate analysis findings suggest that BMD might not be determined by hormones. The relationship between TBS and TSH was statistically significant in the univariate analysis, which indicates the efficacy of further studies to determine the link between TBS and specific hormones. Analyzing the strength of the correlation between TBS and hormones in the univariate analysis shows which factors are worth considering in further analyses. This makes it possible to create better techniques that will help identify young women who are at a higher risk of developing osteoporosis.

Composite or Modified Hydroxyapatite Microspheres as Drug Delivery Carrier for Bone and Tooth Tissue Engineering.

Since hydroxyapatite (HAp) is an important constituent of bone and teeth, it has excellent biocompatibility and bioactivity, good osteoconductive effects and the ability to induce bone formation as a material for bone or tooth repair and replacement. At present, widely used HAp microspheres have some characteristics, such as large specific surface area, light mass, good injection properties, good fluidity, and low aggregation ability, but they are difficult to really meet the biological and clinical needs due to their own mechanical property defects, such as low strength, brittleness, and poor plasticity. Based on the current research status of HAp microspheres, we summarize the research progress of various types of composite microspheres, including inorganic materials, natural polymer materials and synthetic polymer materials, and further analyze the advantages of HAp composite microspheres loaded with drug molecules, proteins and bioactive factors, so as to explore the development prospect of HAp composite microspheres as scaffolds for constructing sustained release systems. It provides a theoretical basis and research direction to prepare HAp composite micro-spheres with superior comprehensive properties so that they can be better applied in bone tissue regeneration and tooth regeneration engineering.

Nanocrystal residual strains and density layers enhance failure resistance in the cleithrum bone of evolutionary advanced pike fish

Failure-resistant designs are particularly crucial for bones subjected to rapid loading, as is the case for the ambush-hunting northern pike (Esox lucius). These fish have slim and low-density osteocyte-lacking bones. As part of the swallowing mechanism, the cleithrum bone opens and closes the jaw. The cleithrum needs sufficient strength and damage tolerance, to withstand years of repetitive rapid gape-and-suck cycles of feeding. The thin wing-shaped bone comprises anisotropic layers of mineralized collagen fibers that exhibit periodic variations in mineral density on the mm and micrometer length scales. Wavy collagen fibrils interconnect these layers yielding a highly anisotropic structure. Hydrated cleithra exhibit Young's moduli spanning 3-9 GPa where the yield stress of ∼40 MPa increases markedly to exceed ∼180 MPa upon drying. This 5x observation of increased strength corresponds to a change to brittle fracture patterns. It matches the emergence of compressive residual strains of ∼0.15% within the mineral crystals due to forces from shrinking collagen layers. Compressive stresses on the nanoscale, combined with the layered anisotropic microstructure on the mm length scale, jointly confer structural stability in the slender and lightweight bones. By employing a range of X-ray, electron and optical imaging and mechanical characterization techniques, we reveal the structure and properties that make the cleithra impressively damage resistant composites. Statement of significanceBy combining structural and mechanical characterization techniques spanning the mm to the sub-nanometer length scales, this work provides insights into the structural organization and properties of a resilient bone found in pike fish. Our observations show how the anosteocytic bone within the pectoral gridle of these fish, lacking any biological (remodeling) repair mechanisms, is adapted to sustain natural repeated loading cycles of abrupt jaw-gaping and swallowing. We find residual strains within the mineral apatite nanocrystals that contribute to forming a remarkably resilient composite material. Such information gleaned from bony structures that are different from the usual bones of mammals showcases how nature incorporates smart features that induce damage tolerance in bone material, an adaptation acquired through natural evolutionary processes.

Clinical evaluation of maxillary sinus floor elevation with or without bone grafts: a systematic review and meta-analysis of randomised controlled trials with trial sequential analysis.

Our goal was to systematically review the current evidence comparing the relative effectiveness of two maxillary sinus floor elevation (MSFE) approaches (internal and external) without bone grafts with that of conventional/grafted MSFE in patients undergoing implantation in the posterior maxilla. Medical databases (PubMed/Medline, Embase, Web of Science, and Cochrane Library) were searched for randomised controlled trials published between January 1980 and May 2023. A manual search of implant-related journals was also performed. Studies published in English that reported the clinical outcomes of MSFE with or without bone material were included. The risk of bias was assessed using the Cochrane Handbook Risk Assessment Tool. Meta-analyses and trial sequence analyses were performed on the included trials. Meta-regression analysis was performed using pre-selected covariates to account for substantial heterogeneity. The certainty of evidence for clinical outcomes was assessed using GRADEpro GDT online (Guideline Development Tool). Seventeen studies, including 547 sinuses and 696 implants, were pooled for the meta-analysis. The meta-analysis showed no statistically significant difference between MSFE without bone grafts and conventional MSFE in terms of the implant survival rate in the short term (n = 11, I2 = 0%, risk difference (RD): 0.03, 95% confidence intervals (CI): -0.01-0.07, p = 0.17, required information size (RIS) = 307). Although conventional MSFE had a higher endo-sinus bone gain (n = 13, I2 = 89%, weighted mean difference (WMD): -1.24, 95% CI: -1.91- -0.57, p = 0.0003, RIS = 461), this was not a determining factor in implant survival. No difference in perforation (n = 13, I2 = 0%, RD = 0.03, 95% CI: -0.02-0.09, p = 0.99, RIS = 223) and marginal bone loss (n = 4, I2 = 0%, WMD = 0.05, 95% CI: -0.14-0.23, p = 0.62, no RIS) was detected between the two groups using meta-analysis. The pooled results of the implant stability quotient between the two groups were not robust on sensitivity analysis. Because of the limited studies reporting on the visual analogue scale, surgical time, treatment costs, and bone density, qualitative analysis was conducted for these outcomes. This systematic review revealed that both non-graft and grafted MSFE had high implant survival rates. Owing to the moderate strength of the evidence and short-term follow-up, the results should be interpreted with caution.

Explaining and predicting the increased thorax injury in aged females: age and subject-specific thorax geometry coupled with improved bone constitutive models and age-specific material properties evaluated in side impact conditions.

Predicting and understanding thorax injury is fundamental for the assessment and development of safety systems to mitigate injury risk to the increasing and vulnerable aged population. While computational human models have contributed to the understanding of injury biomechanics, contemporary human body models have struggled to predict rib fractures and explain the increased incidence of injury in the aged population. The present study enhanced young and aged human body models (HBMs) by integrating a biofidelic cortical bone constitutive model and population-based bone material properties. The HBMs were evaluated using side impact sled tests assessed using chest compression and number of rib fractures. The increase in thoracic kyphosis and the associated change in rib angle with increasing age, led to increased rib torsional moment increasing the rib shear stress. Coupled with and improved cortical bone constitutive model and aged material properties, the higher resulting shear stress led to an increased number of rib fractures in the aged model. The importance of shear stress resulting from torsional load was further investigated using an isolated rib model. In contrast, HBM chest compression, a common thorax injury-associated metric, was insensitive to the aging factors studied. This study proposes an explanation for the increased incidence of thorax injury with increasing age reported in epidemiological data, and provides an enhanced understanding of human rib mechanics that will benefit assessment and design of future safety systems.

Topography of the mandibular canal in male human skulls originating from different time periods.

Dynamic advances in dentistry, especially in implantology has inspired researchers to carry out many studies investigating the topography of the mandibular canal and its ethnic differences. The aim of the study was a comparative analysis of variations in the position and topography of the mandibular canal based on radiographic images of human mandibles originating from modern and medieval skulls. Morphometric examination of 126 radiographs of skulls (92 modern and 34 medieval skulls) was included. The age and sex of individuals were determined based on the morphology of the skull, the obliteration of cranial sutures, and the degree of tooth wear. To define the topography of the mandibular canal on X-ray images, we took 8 anthropometric measurements. We observed significant differences in several parameters. The distance between the base of the mandible and the bottom of the mandibular canal, the distance between the top of the mandibular canal and the crest of the alveolar arch, and the height of the mandibular body. Significant asymmetry was found for two parameters of mandibles from modern skulls: the distance between the top of the mandibular canal and the crest of the alveolar arch at the level of the second molar (p < 0.05), and the distance between the mandibular foramen and the margin of the anterior mandibular ramus (p < 0.007). There were no significant differences between measurements taken on the right and left sides of the medieval skulls. Our study revealed differences in the position of the mandibular canal between modern and medieval skulls, confirming the presence of geographical and chronological differences between populations. Knowledge of variability in the position of the mandibular canal between different local populations is fundamental for the correct interpretation of findings from diagnostic radiological studies used in dental practice and in forensic odontology or analysis of archaeological bone materials.

A Finite Element Model to Investigate the Stability of Osteochondral Grafts Within a Human Tibiofemoral Joint

Osteochondral grafting has demonstrated positive outcomes for treating articular cartilage defects by replacing the damaged region with a cylindrical graft consisting of bone with a layer of cartilage. However, factors that cause graft subsidence are not well understood. The aim of this study was to develop finite element (FE) models of osteochondral grafts within a tibiofemoral joint, suitable for an investigation of parameters affecting graft stability. Cadaveric femurs were used to experimentally calibrate the bone properties and graft-bone frictional forces for use in corresponding image-based FE models, generated from µCT scan data. Effects of cartilage defects and osteochondral graft repair were measured by examining contact pressure changes using further in vitro tests. Here, six defects were created in the femoral condyles, which were subsequently treated with osteochondral autografts or metal pins. Matching image-based FE models were created, and the contact patches were compared. The bone material properties and graft-bone frictional forces were successfully calibrated from the initial tests with good resulting levels of agreement (CCC = 0.87). The tibiofemoral joint experiment provided a range of cases that were accurately described in the resultant pressure maps and were well represented in the FE models. Cartilage defects and repair quality were experimentally measurable with good agreement in the FE model pressure maps. Model confidence was built through extensive validation and sensitivity testing. It was found that specimen-specific properties were required to accurately represent graft behaviour. The final models produced are suitable for a range of parametric testing to investigate immediate graft stability.

Material Selection for Artificial Femur Bone Using PROMETHEE-GAIA Method

Abstract When replacing bones and implants, choosing the right materials for the artificial bone and orthopedic implants is crucial to the procedure’s success. In this work, a thorough assessment of the literature was followed by a thorough and rigorous evaluation of prospective materials for prosthetic femurs using a multicriteria decision-making process known as PROMETHEE-GAIA (Preference Ranking Organization METHod for Enrichment Evaluation and Geometric Analysis for Interactive Assistance). The proposed approach was validated using a total of 12 assessment parameters, including density, tensile strength, and ultimate tensile strength, and 17 candidate materials. The significance of the chosen criteria is well described. These 17 candidate implant materials and the 12 assessment criteria were used to develop a choice matrix. Rankings over the prepared matrix were produced using the PROMETHEE-GAIA program. Ti-6Al-7Nb, Ti-6Al-4V, and ASTM F1537, Standard Specification for Wrought Cobalt-28Chromium-6Molybdenum Alloys for Surgical Implants (UNS R31537, UNS R31538, and UNS R31539), Co-Cr-W emerged as the top contenders and were demonstrated as possible materials for effective artificial femur materials because of the assessment. With a large number of pertinent criteria and a wide range of materials, this study offers a framework for the selection of implant materials. It also emphasizes how choosing materials carefully may increase the durability and efficiency of orthopedic implants.

Analysis of 70 - 300 MeV Proton Energy on Homogeneous and Inhomogeneous Phantoms using PHITS Monte Carlo Package

Proton therapy is a radiotherapy technique using proton particles for reach the target in a straight line and minimize damage to the surrounding tissue. Proton particles that penetrate the body will be deposited at a certain depth and produce a Bragg peak. This study aims to determine the percentage depth dose (PDD) produced by proton radiation in homogeneous and inhomogeneous phantoms. Homogeneous phantom contains water, bone, or lungs material, while inhomogeneous phantom consists of several materials, namely water, bone, and lungs. The interaction of phantom and proton radiation was simulated using the Monte Carlo-based PHITS software. The result indicate that the material density and the proton energy were influencing the dept of Bragg peak. For energy 70 MeV, the Bragg peak position for the water phantom, bone phantom, and lung phantom were 3.80 cm, 2.60 cm, and 15.8 cm. The increase of proton energy causes a deeper Bragg peak position.

Regional variation of the cortical and trabecular bone material properties in the rabbit skull.

The material properties of some bones are known to vary with anatomical location, orientation and position within the bone (e.g., cortical and trabecular bone). Details of the heterogeneity and anisotropy of bone is an important consideration for biomechanical studies that apply techniques such as finite element analysis, as the outcomes will be influenced by the choice of material properties used. Datasets detailing the regional variation of material properties in the bones of the skull are sparse, leaving many finite element analyses of skulls no choice but to employ homogeneous, isotropic material properties, often using data from a different species to the one under investigation. Due to the growing significance of investigating the cranial biomechanics of the rabbit in basic science and clinical research, this study used nanoindentation to measure the elastic modulus of cortical and trabecular bone throughout the skull. The elastic moduli of cortical bone measured in the mediolateral and ventrodorsal direction were found to decrease posteriorly through the skull, while it was evenly distributed when measured in the anteroposterior direction. Furthermore, statistical tests showed that the variation of elastic moduli between separate regions (anterior, middle and posterior) of the skull were significantly different in cortical bone, but was not in trabecular bone. Elastic moduli measured in different orthotropic planes were also significantly different, with the moduli measured in the mediolateral direction consistently lower than that measured in either the anteroposterior or ventrodorsal direction. These findings demonstrate the significance of regional and directional variation in cortical bone elastic modulus, and therefore material properties in finite element models of the skull, particularly those of the rabbit, should consider the heterogeneous and orthotropic properties of skull bone when possible.

Aging impairs the osteocytic regulation of collagen integrity and bone quality

Poor bone quality is a major factor in skeletal fragility in elderly individuals. The molecular mechanisms that establish and maintain bone quality, independent of bone mass, are unknown but are thought to be primarily determined by osteocytes. We hypothesize that the age-related decline in bone quality results from the suppression of osteocyte perilacunar/canalicular remodeling (PLR), which maintains bone material properties. We examined bones from young and aged mice with osteocyte-intrinsic repression of TGFβ signaling (TβRIIocy−/−) that suppresses PLR. The control aged bone displayed decreased TGFβ signaling and PLR, but aging did not worsen the existing PLR suppression in male TβRIIocy−/− bone. This relationship impacted the behavior of collagen material at the nanoscale and tissue scale in macromechanical tests. The effects of age on bone mass, density, and mineral material behavior were independent of osteocytic TGFβ. We determined that the decline in bone quality with age arises from the loss of osteocyte function and the loss of TGFβ-dependent maintenance of collagen integrity.