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Purpose: To investigate the relationship between the structural parameters of trabecular bone obtained from CBCT imaging and the primary stability of dental implants. Materials and Methods: Sixty patients underwent implant placement followed by primary stability evaluation via measurement of the insertion torque (IT) and the implant stability quotient (ISQ). Gray values (GV) and the fractal dimension (FD) were also measured using pretreatment CBCT images. Results: FD values showed a positive and significant relationship with ISQ and IT values (P = .017 and P = .004, respectively). Additionally, there was a positive and significant correlation between GV and IT (P = .004) as well as between GV and ISQ (P = .010). FD and GV showed a considerable difference between the maxillary and mandibular jaws and were higher in the mandible. Only FD was significantly different between men and women and was higher in men. In the two age groups (older and younger than 45 years), only GV was considerably higher in people older than 45 (P < .05). Conclusions: Both fractal dimension and gray values obtained from CBCT are efficient methods for predicting the primary stability of the implant due to their relationship with ISQ and IT values. [ABSTRACT FROM AUTHOR]

Purpose: To assess whether a recently introduced implant placement micromotor that provides site-specific, operatorindependent cancellous bone density measurements can detect the presence of a cortical bone layer and measure its thickness and density. Materials and Methods: An in vitro experiment was performed on six double-layer polyurethane foam blocks mimicking the jawbone with different cortical thickness/cancellous density combinations. The densities were measured using the micromotor after either removing the cortical layer or leaving it intact, both with and without irrigation. Results: The results were compared by means of nonparametric statistical tests. Independent of irrigation, the micromotor detected the cortical layer when it was left intact and accurately estimated its thickness. The micromotor did not discriminate between blocks when they were considered separately, but it did when they were grouped into four or three classes. Conclusions: The present study suggests that the micromotor may represent a valid device to quantitatively assess bone quality and density. If the micromotor can quantitatively distinguish different cortical/cancellous bone combinations in humans, it may be a helpful tool for performing finely tuned, patient-tailored preparations of the implant seat, making tooth rehabilitation in challenging clinical conditions more predictable. [ABSTRACT FROM AUTHOR]

Objectives: Fractal analysis is a numerical method that indicates the structural patterns and complexity of the trabecular bone on radiographs. The aim of this cross-sectional study was to evaluate the trabecular bone structure in systemically healthy patients and diabetes mellitus patients with periodontitis using fractal analysis. Method and materials: The study included 125 mandibular first molars of nonsmoker patients. The subjects were divided into five subgroups: diabetes mellitus patients with mild-moderate periodontitis, diabetes mellitus patients with advanced periodontitis, systemically healthy individuals with mild-moderate periodontitis, systemically healthy individuals with advanced periodontitis, and systemically healthy individuals with gingivitis (control group). Clinical periodontal parameters (pocket depth, bleeding on probing, clinical attachment loss, and bone loss) were recorded. Two specific sites located in the mesial-distal regions (n = 250) of the mandibular first molars were identified using periapical radiographs captured with a parallel technique. Fractal analysis values were calculated using the box-counting method. One-way analysis of variance (ANOVA), and Pearson correlation analysis were used forstatistical evaluation. Results: The highest fractal analysis values were observed in systemically healthy with gingivitis patients (mesial fractal analysis: 1.86 ± 0.01; distal fractal analysis: 1.85 ±0.01). Patients with periodontitis (mesial fractal analysis: 1.78 ±0.02; distal fractal analysis: 1.79 ± 0.01) exhibited lower fractal analysis values compared to the control group. There was no significant difference in mesial and distal fractal analysis values between all periodontitis groups. No correlation was found between age, sex, clinical attachment loss, bone loss, and fractal analysis (P>.05). Conclusions: Although fractal analysis values were lower in the periodontitis groups compared to the control group, fractal analysis did not demonstrate any periodontitis-associated changes of bone tra-beculationin diabetes at any stage of periodontitis. Furthermore, there was no significant association between fractal analysis values and age, sex, clinical attachment, and bone loss. [ABSTRACT FROM AUTHOR]

The biggest challenge during periodontal regeneration in the anterior region is the prevention of soft tissue recession. Minimally invasive surgeries, particularly papilla preservation techniques and soft tissue augmentation, may significantly reduce such postoperative soft tissue recession. This article presents the vestibular incision subperiosteal tunnel access (VISTA) approach for periodontal regeneration in the anterior region. A subperiosteal tunnel prepared from a single vertical vestibular incision adjacent to the defect is used for debridement, application of enamel matrix derivative, defect grafting with corticocancellous tuberosity bone, and insertion of the connective tissue graft. Evaluation of six cases with up to 6 years of follow-up showed improvements in all clinical parameters. The probing pocket depth improved from 8.2 ± 0.75 mm initially to 2.7 ± 0.52 mm at follow-up, clinical attachment level improved from 8.5 ± 0.83 mm initially to 2.7 ± 0.52 mm at follow-up, and midfacial gingival recession of 1 mm at two sites was corrected. The papillae were stable at all sites, with an average distance of 4.8 mm from the incisal edge to the papilla tip. This technique seems to be a promising approach for achieving both esthetic and functional goals of periodontal regenerative surgery. However, experience in performing microsurgeries and harvesting tuberosity tissues may be a limitation. [ABSTRACT FROM AUTHOR]

Purpose: To examine the stresses caused by different All-on-4 surgical techniques—conventional, a combination of monocortical and bicortical, bicortical, and nasal floor elevation—on the implant and the surrounding bone using 3D finite element analysis (FEA). Materials and Methods: A 3D bone model of the atrophic maxilla was created based on CT imaging of the fully edentulous adult patient. All implants used in the models were 4 mm in diameter, and the length was 13 mm in the anterior and 15 mm in the posterior. Implants were applied to four different atrophic maxillary models with the All-on-4 technique: anterior and posterior monocortical implants in the first model, anterior monocortical and posterior bicortical in the second model, anterior and posterior bicortical in the third model, and anterior and posterior bicortical with nasal floor elevation in the fourth model. Eight linear analyses were performed by applying force from both vertical and 45-degree oblique directions to the four models prepared in our study. Results: When the cortical and cancellous bone around the anterior implants was examined, it was observed that the oblique and vertical loading conditions and the stresses around the implant were similar in all models. When the posterior implants were examined, model 1 (ie, anterior and posterior monocortical implants) showed the greatest oblique compression, vertical compression, and vertical tension forces. According to the Von Mises stress (VMS) analysis results for anterior and posterior implants, higher values were observed in model 1 compared to models 3 and 4 under oblique and vertical forces. It was observed that bicortical placement of the implants reduced the stresses on the bone and implant-abutment system but had no significant effect on the stress on the bar. Conclusions: According to the results of our study, in the All-on-4 technique, bicortical placement of the implants reduced the stresses on the bone and implant when the anatomical limitations allowed. In addition, nasal floor elevation can be applied in the atrophic maxilla in appropriate indications. [ABSTRACT FROM AUTHOR]

Lead-free piezoelectric ceramics can generate electrical signals to promote bone defect repair, but they suffer from low bioreactivity. In this study, K 0.48 Na 0.52 NbO 3 & akermanite composite ceramic (KNN & AK) was prepared using digital light processing (DLP). The influence of sintering temperature and AK content was investigated. With the increase of sintering temperature, the piezoelectric coefficient d 33 of the composite ceramics first increased and then decreased, reaching a maximum of 7.80 pC/N at 1070 °C. The doping of AK would lead to a significant decrease in the piezoelectric property, and the AK content should not exceed 10 wt% to achieve the piezoelectric coefficient of human bone. After immersion in Tris-HCl solution for 28 days, the weight loss rate of the composite ceramics doped with 15 wt% AK could reach 8.36 %. The combination of KNN and AK promotes the application of piezoelectric bone scaffolds in the field of bone repair. [ABSTRACT FROM AUTHOR]

[Display omitted] Stone-built cultural heritage faces threats from natural forces and anthropogenic pollutants, including local climate, acid rain, and outdoor conditions like temperature fluctuations and wind exposure, all of which impact their structural integrity and lead to their degradation. The development of a water-based, environmentally-friendly protective coatings that meet a combination of requirements posed by the diversity of the substrates, different environmental conditions, and structures with complex geometries remains a formidable challenge, given the numerous obstacles faced by current conservation strategies. Here we report the structural, electrical, and mechanical characterization, along with performance testing, of a nanostructured hydrophilic and self-healing hybrid coating based on hydroxyapatite (HAp) nanocrystals and polyelectrolyte multilayers (PEM), formed in-situ on Greek marble through a simple spray layer-by-layer surface functionalization technique. The polyelectrolyte-hydroxyapatite multilayer (PHM) structure resembled the design of naturally forming trabecular bone, attained at a short procedural time. It exhibited chemical affinity, aesthetical compatibility and resistance to weathering while offering reversibility. The proposed method is able to generate micron-sized coatings with controlled properties, such as adhesion and self-healing, leading to less weathered surfaces. Our results show that the PHM is a highly effective protective material that can be applied for stone protection and other similar applications. [ABSTRACT FROM AUTHOR]

Early fusion is crucial in interbody procedures to minimize mechanical complications resulting from delayed union, especially for patients with osteoporosis. Bone morphogenetic proteins (BMPs) are used in spinal fusion procedures; however, limited evaluation exists regarding time-to-fusion for BMP use, particularly in patients with osteoporosis. To evaluate the difference in time-to-fusion after single-level transforaminal lumbar interbody fusion (TLIF) surgery between recombinant human bone morphogenetic protein-2 (rhBMP-2) usage and nonusage groups according to bone density. Retrospective single-center cohort study. This study enrolled 132 patients (mean age, 65.25±8.66; male patients, 40.9%) who underwent single-level TLIF for degenerative disorders between February 2012 and December 2021, with pre- and postoperative computed tomography (CT). The interbody fusion mass and bone graft status on postoperative CT scans was obtained annually, and time-to-fusion was recorded for each patient. The patients were divided into 2 groups based on rhBMP-2 use during the interbody fusion procedure. Patients were further divided into osteoporosis, osteopenia, and normal groups based on preoperative L1 vertebral body attenuation values, using cutoffs of 90 and 120 Hounsfield units. It was strictly defined that fusion is considered complete when a trabecular bone bridge was formed, and therefore, the time-to-fusion was measured in years. Time-to-fusion was statistically compared between BMP group and non-BMP groups, followed by further comparison according to bone density. The time-to-fusion differed significantly between BMP and non-BMP groups, with half of the patients achieving fusion within 2.5 years in the BMP group compared with 4 years in the non-BMP group (p<.001). The fusion rate varied based on bone density, with the maximum difference observed in the osteoporosis group, when half of the patients achieved fusion within 3 years in the BMP group compared to 5 years in the non-BMP group (p<.001). Subgroup analysis was conducted, revealing no significant associations between time-to-fusion and factors known to influence the fusion process, including age, gender, medical history, smoking and alcohol use, and medication history, except for rh-BMP2 use and bone density. RhBMP-2 usage significantly reduced time-to-fusion in single-level TLIF, especially in patients with osteoporosis. Level III. [ABSTRACT FROM AUTHOR]

Objective: It is known that fracture risk is increased in patients with psoriatic arthritis (PsA); however, there is no consensus on the association with osteoporosis. The purpose of this study was to elicit the rate of osteoporosis and the risk factors of osteoporosis in patients with PsA at our institution. Methods: The data in this study were extracted from 163 patients with PsA. Osteoporosis and osteopenia were defined based on the WHO definition. Osteoporosis was also diagnosed when a fragility vertebral compression fracture was observed. Results: The osteoporosis and osteopenia rates for PsA patients were 11.7% and 33.1%, respectively. The rates of osteoporosis and osteopenia in males were particularly high compared to previous reports, at 9.3% and 34.3%, respectively. Trabecular bone score was considered age-appropriate for both males and females. Body mass index and Trabecular bone score were significantly lower in patients with osteoporosis. Conclusions: In patients with PsA, males are at elevated risk of osteoporosis and associated fragility fractures even if they are under 50 years. Body mass index was significantly lower in osteoporotic cases, suggesting the importance of bone mineral density testing and treatment in such cases. [ABSTRACT FROM AUTHOR]

Resonance frequency analysis (RFA) is valuable for assessing implant status. In a previous investigation, acetabular cup fixation was assessed using laser RFA and the pull‐down force was predicted in an in vitro setting. While the pull‐down force alone is sufficient for initial fixation evaluation, it is desirable to evaluate the bone strength of the foundation for subsequent fixation. Diminished bone quality causes micromotion, migration, and protracted osseointegration, consequently elevating susceptibility to periprosthetic fractures and failure of ingrained trabecular bone. Limited research exists on the evaluation of bone mineral density (BMD) around the cup using RFA. For in vivo application of laser RFA, we implemented the sweep pulse excitation method and engineered an innovative laser RFA device having low laser energy and small dimensions. We focused on a specific frequency range (2500–4500 Hz), where the peak frequency was presumed to be influenced by foundational density. Quantitative computed tomography with a phantom was employed to assess periprosthetic BMD. Correlation between the resonance frequency within the designated range and the density around the cup was evaluated both in the laboratory and in vivo using the novel laser RFA device. The Kruskal–Wallis test showed robust correlations in both experiments (laboratory study: R = 0.728, p < 0.001; in vivo study: R = 0.619, p < 0.001). Our laser RFA system can assess the quality of bone surrounding the cup. Laser RFA holds promise in predicting the risk of loosening and might aid in the decision‐making process for additional fixation through screw insertion. [ABSTRACT FROM AUTHOR]

• FN is expressed early during mouse limb development at distinct regions within the growth plate and bone. • Cartilage-specific cFN and circulating pFN are distributed distinctly during embryonic and postnatal bone development. • Deletion of cFN and pFN leads to reduced bone growth and bone formation during early and adult postnatal development. • Absence of both FN isoforms in FN double knockout mice leads to altered chondrogenesis. • Ablation of both FN isoforms in developing long bones is associated with reduced TGFβ1 and phospho-AKT. Fibronectin (FN) is a ubiquitous extracellular matrix glycoprotein essential for the development of various tissues. Mutations in FN cause a unique form of spondylometaphyseal dysplasia, emphasizing its importance in cartilage and bone development. However, the relevance and functional role of FN during skeletal development has remained elusive. To address these aspects, we have generated conditional knockout mouse models targeting the cellular FN isoform in cartilage (cFNKO), the plasma FN isoform in hepatocytes (pFNKO), and both isoforms together in a double knockout (FNdKO). We used these mice to determine the relevance of the two principal FN isoforms in skeletal development from postnatal day one to the adult stage at two months. We identified a distinct topological FN deposition pattern in the mouse limb during different gestational and postnatal skeletal development phases, with prominent levels at the resting and hypertrophic chondrocyte zones and in the trabecular bone. Cartilage-specific cFN emerged as the predominant isoform in the growth plate, whereas circulating pFN remained excluded from the growth plate and confined to the primary and secondary ossification centers. Deleting either isoform independently (cFNKO or pFNKO) yielded only relatively subtle changes in the analyzed skeletal parameters. However, the double knockout of cFN in the growth plate and pFN in the circulation of the FNdKO mice significantly reduced postnatal body weight, body length, and bone length. Micro-CT analysis of the adult bone microarchitecture in FNdKO mice exposed substantial reductions in trabecular bone parameters and bone mineral density. The mice also showed elevated bone marrow adiposity. Analysis of chondrogenesis in FNdKO mice demonstrated changes in the resting, proliferating and hypertrophic growth plate zones, consistent alterations in chondrogenic markers such as collagen type II and X, decreased apoptosis of hypertrophic chondrocytes, and downregulation of bone formation markers. Transforming growth factor-β1 and downstream phospho-AKT levels were significantly lower in the FNdKO than in the control mice, revealing a crucial FN-mediated regulatory pathway in chondrogenesis and bone formation. In conclusion, the data demonstrate that FN is essential for chondrogenesis and bone development. Even though cFN and pFN act in different regions of the bone, both FN isoforms are required for the regulation of chondrogenesis, cartilage maturation, trabecular bone formation, and overall skeletal growth. [ABSTRACT FROM AUTHOR]

Previous studies have shown that Wnt7b potently stimulates bone formation by promoting osteoblast differentiation and activity. As high-fat feeding leads to obesity and systemic metabolic dysregulation, here we investigate the potential benefit of Wnt7b overexpression in osteoblasts on both bone and whole-body metabolism in mice fed with a high-fat diet (HFD). Wnt7b overexpression elicited massive overgrowth of trabecular and cortical bone but seemed to ameliorate body fat accumulation in mice with prolonged HFD feeding. In addition, Wnt7b overexpression modestly improved glucose tolerance in male mice on HFD. Collectively, the results indicate that targeted overexpression of Wnt7b in osteoblasts not only stimulates bone formation but also improves certain aspects of global metabolism in overnourished mice. Lay Summary: Emerging evidence indicates that increased healthy bone tissue may improve general energy metabolism of the body. Here we test the hypothesis that mice containing excess bone mass may be healthier than usual when overnourished with a high-fat diet. We found that mice with excess bone did not gain as much body fat as the normal mice did. In addition, the male mice with extra bone exhibited better tolerance to glucose injection than their normal counterparts. Thus, the data support the notion that increased bone formation may improve global energy metabolism. [ABSTRACT FROM AUTHOR]

Thalassemic osteopathy includes low bone mass and impaired bone microarchitecture. We aimed to evaluate the prevalence and determinants of bone quantity (osteoporosis) and quality (microarchitecture) in a cohort of adult patients with transfusion-dependent thalassemia (TDT). Patients with TDT (n = 63) and age- and BMI-matched controls (n = 63) were recruited in the study. Areal bone mineral density (BMD) was measured using DXA Hologic scanner. P1NP and β-CTX were estimated by electrochemiluminescence assay. Bone geometry and volumetric BMD (vBMD) were estimated by second-generation high-resolution peripheral quantitative computed tomography. Bone turnover marker β-CTX was significantly lower in the TDT group, but there was no difference in P1NP levels. Low bone mass (Z ≤ −2) was present in greater proportion of patients both at lumbar spine (LS) (54 vs 0%; p = .001) and femoral neck (FN) (33 vs 8%; p = .001). Hypogonadism was associated with low BMD at FN (OR 10.0; 95% CI, 1.2–86; p = .01) and low hemoglobin with low BMD at LS (OR 1.58; 95% CI, 0.96–2.60; p = .07). The mean trabecular bone score was also significantly lower in patients compared with controls (1.261 ± 0.072 vs 1.389 ± 0.058). Total, cortical and trabecular vBMD were significantly lower in cases than controls. The trabecular number and cortical thickness were significantly lower and trabecular separation higher in cases than controls. Adults with TDT have significantly lower areal, cortical and trabecular vBMD. The bone microarchitecture is also significantly impaired in terms of lower number and wider spacing of trabeculae as well as lower cortical thickness and area at both radius and tibia. Graphical Abstract Lay Summary: Bone quantity and quality are likely to be affected in patients with thalassemia who are dependent on regular blood transfusions. This study evaluated bone health in adults with transfusion-dependent thalassemia (TDT) by comparing bone density and microarchitecture with age- and BMI-matched controls. Adults with TDT had significantly lower bone mineral density (both areal and volumetric), suggesting low bone quantity compared to healthy controls. Trabecular and cortical microarchitecture were also adversely affected, suggesting impaired bone quality. Overall, the study highlights that adults with TDT have significantly compromised bone quantity and quality, increasing their risk for osteoporosis and related fractures. [ABSTRACT FROM AUTHOR]

Background: One of the primary concerns in the paediatric emergencies is traumatic dental injuries. Objective: This study aimed to create trauma in primary teeth and reveal its effects finite element analysis. Design: Three‐dimensional models were created using cone‐beam computed tomography images, representing a maxillary primary central incisor. An impact force moving at a speed of 10 m/s was simulated on the labial tooth surface in two directions: buccal and incisal. Results: The stress and deformation experienced in the adjacent tooth due to the primary tooth were higher than those generated in the permanent tooth. Forces applied in the incisal direction resulted in higher levels of stress and deformation in the permanent tooth germ. The difference between the stress and deformation values in primary teeth in the forces applied in the buccal and incisal directions is 21% and 75%, respectively; in the permanent tooth germ, this difference was 233% and 100%, respectively. Conclusions: Based on the findings of this study, it is crucial to thoroughly evaluate not only the affected primary tooth but also the adjacent teeth and the permanent tooth germ in traumatic dental injuries. This comprehensive examination allows for the anticipation and management of potential long‐term problems. [ABSTRACT FROM AUTHOR]

Arthropathies are common in past populations and can be categorized into two groups: those with predominant bone production (e.g., osteoarthritis) and those with significant bone loss (e.g., erosive arthropathies). The former is frequent in the archaeological record, whereas the latter are uncommon. We present a Post‐Medieval male individual, recovered in the Convent of the Holy Spirit (Loures, Portugal), with multiple articular and entheseal bone changes, particularly extensive periarticular, marginal, and subchondral erosive processes, often exposing trabecular bone. Proliferative lesions and extensive ankylosis are also observed in the synovial joints. These pathological changes affect both the axial and peripheral skeleton in a polyarticular, bilateral, and asymmetric pattern. Given that the appendicular skeleton, particularly the hands and feet, are the most affected areas, the most probable diagnosis is a peripheral spondyloarthropathy such as psoriatic arthritis or reactive arthritis. This case study is the first archaeological instance of psoriatic arthritis or reactive arthritis described in Portugal, highlighting the importance of a differential diagnosis and the need for reflection when pathological changes characteristics overlap, advocating for a broader diagnostic approach. [ABSTRACT FROM AUTHOR]

Objective: Anorexia Nervosa (AN) is characterized by a distortion of body image, very low body weight, malnutrition and hormonal dysregulations, resulting in reduced bone mineral density (BMD) and impaired bone microarchitecture. The updated Trabecular Bone Score (TBS) algorithm accounts for soft tissue thickness (TBSTT) instead of BMI (TBSBMI). The aim of the study was to assess both TBS algorithms in adult AN patients compared to normal-weight controls(CTRL). Method: This retrospective cross-sectional study investigated 34 adult female anorexia nervosa (AN) patients and 26 healthy normal-weighted age- and sex-matched controls (CTRL). Bone texture analysis was assessed by TBSTT and TBSBMI (TBS iNsight® V4.0 and V3.1), bone mineral density (BMD; lumbar spine LS, femoral neck, total hip) and body composition by DXA (GE Lunar iDXATM). Laboratory analyses included bone turnover markers (CTX; P1NP; sclerostin). Data analysis was performed using parametric (t-test) or non-parametric test (Mann-Whitney-U-Test) depending on normality, one-way ANCOVA and correlation analysis (Perason's or Spearman's). Results: AN patients (BMI 14.7(1.6)) and CTRL (BMI 22.4(4.0)) were of comparable age (22.8(7.1) vs.25.0(4.0)years, p = 0.145). TBSTT(1.319±0.09 vs.1.502±0.07, p<0.001) and TBSBMI(1.317±0.10 vs.1.548±0.09, p<0.001) were significantly lower in AN patients compared to CTRL. Soft tissue thickness was lower in AN (p<0.001). Within the CTRL group, but not in AN, TBSTT and TBSBMI were significantly different (p<0.001). BMD was lower at all sites in AN patients (p<0.001 for all), being lowest at LS. Bone Mineral Content, Lean Body mass and Fat Mass were lower in AN (p<0.001). AN patients had lower P1NP (p = 0.05), but higher CTX (p = 0.001) and sclerostin (p = 0.003) levels. Conclusion: Adult AN patients have lower TBSTT and TBSBMI, reduced BMD and an uncoupling of bone turnover. In AN both TBS algorithms show similar reduced trabecular bone microarchitecture. The observed difference of TBSTT and TBSBMI in CTRL with normal body composition highlight the importance of the new algorithm. [ABSTRACT FROM AUTHOR]

Simple Summary: Bone defects present significant challenges in orthopedics, with alternatives to autografts commonly required owing to issues such as donor-site morbidity. Allogeneic demineralized bone matrix (DBM) is one viable option; however, handling difficulties and low mechanical strength necessitate effective carriers. Currently, DBM formulations are usually a paste or putty. This study evaluated hydroxyethyl cellulose (HEC) as a novel DBM carrier to improve clinical outcomes in a canine tibial defect model. We aimed to enhance the mechanical strength and osteogenic properties of DBM by incorporating cancellous bone or calcium phosphate. Our results suggest that combining DBM with HEC effectively promotes bone regeneration. Demineralized bone matrix (DBM) is a widely used allograft material for bone repair, but its handling properties and retention at defect sites can be challenging. Hydroxyethyl cellulose (HEC) has shown promise as a biocompatible carrier for bone graft materials. This study aimed to evaluate the efficacy of DBM combined with cancellous bone putty formed using HEC as an allograft material for bone regeneration in a canine tibial defect model. Experiments were conducted using dogs with proximal tibial defects. Four groups were compared: empty (control group), DBM + HEC (DH), DBM + cancellous bone + HEC (DCH), and DBM + cancellous bone + calcium phosphate + HEC (DCCH). Radiographic, micro-computed tomography (CT), and histomorphometric evaluations were performed 4 and 8 weeks postoperatively to assess bone regeneration. The Empty group consistently exhibited the lowest levels of bone regeneration throughout the study period, indicating that DBM and cancellous bone with HEC significantly enhanced bone regeneration. At week 4, the DCCH group showed the fastest bone regeneration on radiography and micro-computed tomography. By week 8, the DCH group showed the highest area ratio of new bone among all experimental areas, followed by the DH and DCCH groups. This study demonstrated that HEC significantly enhances the handling, mechanical properties, and osteogenic potential of DBM and cancellous bone grafts, making it a promising carrier for clinical applications in canine allograft models. When mixed with allograft cancellous bone, which has high porosity and mechanical strength, it becomes a promising material offering a more effective and reliable option for bone repair and regeneration. [ABSTRACT FROM AUTHOR]

Myeloid cells are pivotal in the inflammatory and remodeling phases of fracture repair. Here, we investigate the effect of periostin expressed by myeloid cells on bone regeneration in a monocortical tibial defect (MTD) model. In this study, we show that periostin is expressed by periosteal myeloid cells, primarily the M2 macrophages during bone regeneration. Knockout of periostin in myeloid cells reduces cortical bone thickness, disrupts trabecular bone connectivity, impairs repair impairment, and hinders M2 macrophage polarization. Mechanical stimulation is a regulator of periostin in macrophages. By activating transforming growth factor-β (TGF-β), it increases periostin expression in macrophages and induces M2 polarization. This mechanosensitive effect also reverses the delayed bone repair induced by periostin deficiency in myeloid cells by strengthening the angiogenesis-osteogenesis coupling. In addition, transplantation of mechanically conditioned macrophages into the periosteum over a bone defect results in substantially enhanced repair, confirming the critical role of macrophage-secreted periostin in bone repair. In summary, our findings suggest that mechanical stimulation regulates periostin expression and promotes M2 macrophage polarization, highlighting the potential of mechanically conditioned macrophages as a therapeutic strategy for enhancing bone repair. [ABSTRACT FROM AUTHOR]

Type-H capillary endothelial cells control bone formation during embryogenesis and postnatal growth but few signalling mechanisms underpinning this influence have been characterised. Here, we identify a highly expressed type-H endothelial cell protein, Clec14a, and explore its role in coordinating osteoblast activity. Expression of Clec14a and its ligand, Mmrn2 are high in murine type-H endothelial cells but absent from osteoblasts. Clec14a−/− mice have premature condensation of the type-H vasculature and expanded distribution of osteoblasts and bone matrix, increased long-bone length and bone density indicative of accelerated skeletal development, and enhanced osteoblast maturation. Antibody-mediated blockade of the Clec14a-Mmrn2 interaction recapitulates the Clec14a−/− phenotype. Endothelial cell expression of Clec14a regulates osteoblast maturation and mineralisation activity during postnatal bone development in mice. This finding underscores the importance of type-H capillary control of osteoblast activity in bone formation and identifies a novel mechanism that mediates this vital cellular crosstalk. The receptor Clec14a and its ligand Mmrn2, which are highly expressed in Type-H capillary endothelial cells, regulate osteoblast maturation and mineralisation activity during postnatal bone development in mice. [ABSTRACT FROM AUTHOR]

Chronic kidney disease (CKD) is a significant global health issue and often involves CKD-mineral and bone disorder (MBD) and sarcopenia. Plasminogen activator inhibitor-1 (PAI-1) is an inhibitor of fibrinolysis. PAI-1 has been implicated in the pathogenesis of osteoporosis and muscle wasting induced by inflammatory conditions. However, the roles of PAI-1 in CKD-MBD and sarcopenia remain unknown. Therefore, the present study investigated the roles of PAI-1 in bone loss and muscle wasting induced by adenine in PAI-1-deficient mice. CKD was induced in PAI-1+/+ and PAI-1-/- mice by administration of adenine for ten weeks. Muscle wasting was assessed by grip strength test, quantitative computed tomography (CT) analysis and muscle weight measurement. Osteoporosis was assessed by micro-CT analysis of femoral microstructural parameters. PAI-1 deficiency did not affect adenine-induced decreases in body weight and food intake or renal dysfunction in male or female mice. PAI-1 deficiency also did not affect adenine-induced decreases in grip strength, muscle mass in the lower limbs, or the tissue weights of the gastrocnemius, soleus, and tibialis anterior muscles in male or female mice. PAI-1 deficiency aggravated trabecular bone loss in CKD-induced male mice, but significantly increased trabecular bone in CKD-induced female mice. On the other hand, PAI-1 deficiency did not affect cortical bone loss in CKD-induced mice. In conclusion, PAI-1 is not critical for the pathophysiology of CKD-MBD or CKD-induced sarcopenia in mice. However, PAI-1 may be partly related to bone metabolism in trabecular bone in the CKD state with sex differences. [ABSTRACT FROM AUTHOR]

Purpose: The difference of Hounsfield Unit (HU) value in different regions of L3 vertebra in middle-aged and elderly patients with lumbar degeneration diseases (LDD) was analyzed. To investigate the influence of proliferative tissue on HU value of cancellous bone and its correlation with bone mineral density (BMD). Methods: The medical records of middle-aged and elderly patients with LDD in our hospital from December 2020 to December 2023 were retrospectively analyzed. The patients were divided into osteophyte group and no-osteophyte group according to the presence or absence of osteophyte formation on lumbar spine X-ray. In osteophyte group, cancellous bone HU value, containing cortical bone overall HU value and containing osteophyte overall HU value in L3 vertebra were measured on the lumbar CT cross-section. In no-osteophyte group, only the cancellous bone HU value and the containing cortical bone overall HU value were measured. Differences in HU value in different regions of the L3 vertebral body were compared within and between groups of middle-aged and elderly patients with LDD, respectively. To investigate its effect on cancellous bone HU measurements and to do a correlation analysis with patients' BMD. Results: A total of 115 patients with LDD were included in this study, including 65 males and 50 females, with an average age of 67.83 ± 6.59 years. The results of the study showed no statistical differences in age (P = 0.15), gender (P = 0.57), smoking (P = 0.88), drinking history (P = 0.76), medical history (P > 0.05) and BMI(P = 0.29) between the two groups. In osteophyte group, the mean cancellous bone HU value was 98.00 ± 25.50 HU, the containing cortical bone overall HU value was 189.02 ± 46.18 HU, and the containing osteophyte overall HU value was 232.69 ± 56.01 HU. The overall HU values containing cortical bone and containing osteophyte were significantly higher than cancellous bone HU value (P < 0.001). In no-osteophyte group, the mean cancellous bone HU value was 102.04 ± 19.64 HU, and the containing cortical bone overall HU value was 175.00 ± 28.97 HU, which was statistically significantly different (P < 0.001). There was no significant difference in cancellous bone HU value and the containing cortical bone overall HU value between the two groups (P > 0.05). The results of the Pearson correlation analysis showed a significant correlation between the cancellous bone HU value of the L3 vertebrae and the QCT BMD value of the patients (r = 0.95, P < 0.001). However, there was no significant correlation between containing cortical bone overall HU value and containing osteophyte overall HU value and the patient's QCT BMD value (P > 0.05). Conclusions: Vertebral HU value is an alternative measurement that effectively reflects the patient's BMD. In middle-aged and elderly LDD patients, HU values in different areas of L3 vertebra are significantly different, and hyperplastic tissues such as cortical bone and osteophytes may exponentially lead to higher HU value in patients. Compared with other measurement areas, vertebral cancellous bone HU value have the advantage of accurately assessing patients' BMD. [ABSTRACT FROM AUTHOR]

This study explores the fabrication and characterisation of 3D-printed polylactic acid (PLA) scaffolds reinforced with calcium hydroxyapatite (cHAP) for bone tissue engineering applications. By varying the cHAP content, we aimed to enhance PLA scaffolds' mechanical and thermal properties, making them suitable for load-bearing biomedical applications. The results indicate that increasing cHAP content improves the tensile and compressive strength of the scaffolds, although it also increases brittleness. Notably, incorporating cHAP at 7.5% and 10% significantly enhances thermal stability and mechanical performance, with properties comparable to or exceeding those of human cancellous bone. Furthermore, this study integrates machine learning techniques to predict the mechanical properties of these composites, employing algorithms such as XGBoost and AdaBoost. The models demonstrated high predictive accuracy, with R2 scores of 0.9173 and 0.8772 for compressive and tensile strength, respectively. These findings highlight the potential of using data-driven approaches to optimise material properties autonomously, offering significant implications for developing custom-tailored scaffolds in bone tissue engineering and regenerative medicine. The study underscores the promise of PLA/cHAP composites as viable candidates for advanced biomedical applications, particularly in creating patient-specific implants with improved mechanical and thermal characteristics. [ABSTRACT FROM AUTHOR]

This study aims to introduce a robust numerical approach to simulate complex small‐scale mediums such as trabecular bone tissue in form of a cylindrical specimen taken from human vertebra. Consideration of previous related studies indicates that there are several challenges in utilizing standard finite element (FE) techniques for the analysis of such biomechanical structures. This is mainly due to their time‐consuming procedure required for generating geometry conforming meshes. In this regard, the finite cell method (FCM) is an interesting alternative because it is based on the concept of the fictitious domain technique in which underlying meshes do not need to conform to the boundary of the domain. Since the considered trabecular bone tissue consists of a complex small‐scale internal morphology, generating a FE mesh is rather complicated. So, the application of the FCM can be justified by overcoming the mentioned shortcomings of FE methods for this problem. Using FCM, it is possible to simulate the mentioned trabecular cylinder from vertebral body using higher order cells of regular shapes where the geometry is taken care of through the numerical integration. The input for the present numerical tool corresponding to the complex internal morphology of the proposed tissue is given by a high‐resolution microCT scan. The outcome of the FCM will be compared to results obtained by mechanical testing of the specimen. [ABSTRACT FROM AUTHOR]

Modern shoulder arthroplasties with stemless implants help to preserve the original bone substance of the proximal humerus and to reduce potential risks of conventional implants. Their shape allows newly formed bone to grow directly through the implant. However, it is not fully explained how an optimal fixation of the implant by formation of new bone can be achieved or stimulated. In this context, we develop a method to simulate the mechanical loading of the proximal humerus during the surgery using the finite element method to investigate whether one or more mechanical stress variables can be correlated with measurement data of cell activity in the bone, which is available in the form of SPECT/CT data. This contribution presents measurements with n=12$n=12$ explanted humeral heads from patients undergoing planned total shoulder arthroplasties in order to parameterize a material model for trabecular bone to be used in the finite element simulation. The raw data of these measurements were published and can be accessed for further investigations. [ABSTRACT FROM AUTHOR]

Introduction Traditional open mastoidectomy is performed through a retro-auricular incision to expose the mastoid cortex. Few have addressed the possibility of performing an endoscopic minimally invasive mastoidectomy. Objective Our objective was to test the feasibility of performing an endoscopic mastoidectomy through a 1 cm incision and burr hole. Methods Ten cadaver heads (20 mastoids) were used for this morphometric study. We performed an endoscopic mastoidectomy through a 1 cm burr hole located over the antrum. The goals were to reach predetermined landmarks and maximize the drilling of cancellous mastoid bone. Computed tomography (CT) imaging was acquired at baseline, after endoscopic approach and after traditional open mastoidectomy. The scans were then analyzed with volumetric measurements of each mastoid. Results Endoscopic mastoidectomy facilitated access to most anatomical landmarks. While open mastoidectomy enabled greater extents of mastoidectomy and tegmen exposure, the endoscopic approach exposed 76% of mastoid and 69.9% of the tegmen achievable by the open approach. Additionally, baseline mastoid volume and tegmen surface area positively correlated with the extent of mastoidectomy and tegmen exposure, respectively. Baseline mastoid volume negatively correlated with the percentage of mastoid drilled and tegmen exposed. Conclusion We demonstrated the feasibility of an endoscopic mastoidectomy through a standardized postauricular burr hole. This approach reduces the incision size and the need for soft tissue dissection. Burr hole mastoidectomy is facilitated using angled scopes which are not reliant on 0-degree line-of-sight. Although the endoscopic approach afforded slightly less exposure, the location and burr hole size can be adjusted depending on the clinical indications. [ABSTRACT FROM AUTHOR]

The Trabecular Bone Score (TBS), a gray-level textural assessment derived from dual-energy X-ray absorptiometry images, serves as a validated index of trabecular bone microarchitecture. Over the past decade, significant evidence has highlighted the usefulness of TBS in primary and secondary osteoporosis, leading to its integration with the Fracture Risk Assessment Tool (FRAX) and bone mineral density (BMD) T-score adjustments. This review explores the role of TBS in fracture prediction, treatment initiation, and monitoring. Studies confirm that TBS enhances fracture risk prediction in both primary and secondary osteoporosis when combined with BMD and clinical risk factors. Evidence also suggests that including TBS alongside BMD and FRAX offers significant potential for treatment stratification, considering the overall skeletal profile, such as bone mass, bone quality, and clinical risk factors. Consequently, TBS has become a standard part of clinical care worldwide. Future enhancements hope to adjust for soft tissue thickness, broadening the applicability of TBS across diverse body types and pediatric populations. [ABSTRACT FROM AUTHOR]

Metabolic bone diseases (MBDs) are a diverse group of diseases, affecting the mass or structure of bones and leading to reduced bone quality. Parameters representing different aspects of bone health can be obtained from various magnetic resonance imaging (MRI) methods such as proton MR spectroscopy, as well as chemical shift encoding-based water-fat imaging, that have been frequently applied to study bone marrow in particular. Furthermore, T2* mapping and high-resolution trabecular bone imaging have been implemented to study bone microstructure. In addition, quantitative susceptibility mapping and ultrashort echo time imaging are used for trabecular and cortical bone assessment. This review offers an overview of technical aspects, as well as major clinical applications and derived main findings, for MRI-based assessment of bone quality in MBDs. It focuses on osteoporosis as the most common MBD. [ABSTRACT FROM AUTHOR]

Since its introduction in 1987, dual-energy X-ray absorptiometry (DXA) has revolutionized bone assessment, becoming the gold standard for measuring bone mineral density (BMD). Its low radiation exposure and high accuracy have made it indispensable in diagnosing osteoporosis, aligning with World Health Organization criteria. However, DXA evolution extends beyond BMD measurement, with emerging tools like the Trabecular Bone Score (TBS) and the DXA-based Bone Strain Index (BSI). TBS provides insights into trabecular bone architecture, enhancing the prediction of fracture risk. Despite limitations like body mass index correlation, TBS aids in evaluating patients with conditions such as diabetes and glucocorticoid exposure. BSI, introduced in 2019, evaluates bone strength using finite element analysis, complementing BMD and TBS by assessing bone fatigue. Advancements in DXA-based tools extend to Hip Structural Analysis and three-dimensional DXA software, offering valuable insights into hip fracture risk. Moreover, DXA serves beyond bone assessment, aiding in abdominal aortic calcification assessment, enhancing cardiovascular risk stratification. In summary, the expanding capabilities of DXA promise comprehensive skeletal and cardiovascular health evaluation, contributing significantly to clinical management and prevention strategies. [ABSTRACT FROM AUTHOR]

Objectives: To assess the impact of the presence or position (buccal/palatal) of impacted canines on trabecular bone density using fractal analysis (FA) on cone-beam computed tomography (CBCT) images, and to compare the results with a control group without impacted canines. Methods: This retrospective study included 41 patients with unilateral impacted canines (30 palatal, 11 buccal) and a control group of 39 patients who underwent surgically assisted rapid maxillary expansion. All patients had CBCT images recorded for diagnostic and treatment purposes. Cross-sectional CBCT images were obtained between the first and second premolars on both sides of the patients' maxilla. From these images, fractal dimension (FD) was measured in a 20 × 20 pixel region of interest in the trabecular bone using the ImageJ software. Results: The FD values were significantly higher on the impacted side in the impacted canine group (p = 0.02). Within the impacted canine group, a significant increase in FD was observed on the impacted side in the buccal-impacted subgroup (p = 0.02), while no significant difference was observed in the palatal-impacted subgroup (p > 0.05). Conclusions: According to the results of our study, there is an association between the position of the impacted canine and trabecular bone density. An increased trabecular bone density may play a role in the etiology of buccally impacted canines. Clinicians should consider anchorage planning, and appropriate force level, during the forced eruption of buccally impacted canines with high surrounding bone density, to minimize undesirable movements and achieve optimal treatment outcomes. [ABSTRACT FROM AUTHOR]

Introduction We previously showed that a 3-week oral metformin (MET) treatment enhances the osteogenic potential of bone marrow stromal cells (BMSCs) and improves several bone histomorphometric parameters in Wistar rats with metabolic syndrome (MetS). However, the skeletal effects of extended periods of MET need to be completely elucidated. Hence, in this study, the impact of a prolonged (3-month) MET treatment was investigated on bone architecture, histomorphometric and biomechanics variables, and osteogenic potential of BMSCs in Wistar rats with or without MetS. Materials and Methods Young male Wistar rats (n=36) were randomized into four groups (n=9) that received either 20% fructose (F), MET (MET), F plus MET treatments (FMET), or drinking water alone (Veh). Rats were euthanized, blood was collected, and bones were dissected and processed for peripheral quantitative computed tomography (pQCT) analysis, static and dynamic histomorphometry, and bone biomechanics. In addition, BMSCs were isolated to determine their osteogenic potential. Results MET affected trabecular and cortical bone, altering bone architecture and biomechanics. Furthermore, MET increased the pro-resorptive profile of BMSCs. In addition, fructose-induced MetS practically did not affect the the structural or mechanical variables of the skeleton. Conclusion A 3-month treatment with MET (with or without MetS) affects bone architecture and biomechanical variables in Wistar rats. [ABSTRACT FROM AUTHOR]

Objective: In addition to the surface hemorrhage of cancellous bone after large‐area osteotomy, the intramedullary hemorrhage after the reamed knee joint is also a major cause of postoperative bleeding after total knee arthroplasty (TKA). This study evaluated the efficacy and safety of bone wax application at different time points of prone hemorrhage to reduce perioperative blood loss. Methods: From August 2023 to December 2023, 150 patients undergoing primary unilateral TKA were included in this prospective, randomized controlled trial, patients were randomly divided into three groups: group A, after autogenous osteotomy plug was used to fill the femoral medullary cavity, the residual space was sealed with bone wax and the exposed cancellous bone surface around the prosthesis was coated with bone wax after the prosthesis adhesion; group B, only the exposed cancellous bone surface around the prosthesis was coated with bone wax; and group C, no bone wax was used. The primary outcome was total perioperative blood loss. Secondary outcomes included occult blood loss, postoperative hemoglobin reduction, blood transfusion rate, lower limb diameter, and knee function, while length of hospital stay was recorded. Tertiary outcomes included the incidence of postoperative related adverse events. Results: The total blood loss in group A (551.5 ± 224.5 mL) and group B (656.3 ± 267.7 mL) was significantly lower than that in group C (755.3 ± 248.3 ml, p < 0.001), and the total blood loss in group A was also lower than that in group B (p < 0.05). There were also significant differences in the reduction of hemoglobin level and hidden blood loss among the three groups (p < 0.05). However, there was no significant improvement in postoperative lower limb swelling, knee joint activity and hospitalization time; there was no significant difference in the incidence of complications such as thromboembolism. Conclusion: The use of bone wax in TKA can safely and effectively reduce perioperative blood loss and hemoglobin drop rate, and multiple use at time points during the operation when blood loss is prone to occur can produce more significant hemostatic effect. [ABSTRACT FROM AUTHOR]

Evidence acquired in the past years highlighted the high complexity of Neanderthal subsistence strategies in terms of the spectrum of exploited species (mammals, birds, aquatic resources). However, in many sites diet was mainly focused on the acquisition and processing of large and medium-sized ungulates. In these cases, the evaluation of killing profiles and skeletal frequencies has allowed to highlight behavioural variability among Mousterian populations living in different geographical areas. In the frame of these studies, zooarchaeology and taphonomy of the Middle Palaeolithic phases (MIS 4/MIS 3) from the external deposit of Grotta di Santa Croce (Apulia, southern Italy) are presented in this paper. Faunal assemblage is almost exclusively composed of horse and aurochs remains. The sample, which is not altered by carnivore activities, mainly consists of intensively fractured limb bone shafts and isolated teeth. Epiphyses, tarsal/carpal bones, and phalanges are quite rare, as well as unidentified spongy bone fragments. Analysis of tooth eruption and wear points to the exploitation of adult individuals, rather than juveniles and sub-adults. Body part profiles, as well as mortality ones point to a specific hunting behaviour that may reflect particular nutritional needs. The hypothesis of an intense exploitation of fats is discussed. [ABSTRACT FROM AUTHOR]

Bone formation is tightly modulated by genetically encoded molecular proteins that interact to regulate cellular differentiation and secretion of bony matrix. Many transcription factors are known to coordinate these events by controlling gene transcription within networks. However, not all factors involved are known. Here, we identified a novel function for Zinc Finger Homeobox 3 (Zfhx3), a gene encoding a transcription factor, as a regulator of bone metabolism. We knocked out Zfhx3 conditionally in mice in either chondrocytes or osteoblasts and characterized their bones by micro-CT in 12-week-old mice. We observed a negative effect in linear bone growth in both knockout mice but reduced bone mass only in mice with Zfhx3 deleted in osteoblasts. Loss of Zfhx3 expression in osteoblasts affected trabecular bone mass in femurs and vertebrae in both sexes but influenced cortical bone volume fraction only in females. Moreover, transcriptional analysis of femoral bones in osteoblast Zfhx3 conditional knockout mice revealed a reduced expression of osteoblast genes, and histological evaluation of trabecular bones suggests that Zfhx3 causes changes in bone formation and not resorption. The loss of Zfhx3 causes reductions in trabecular bone area and osteoid volume, but no changes in the expression of osteoclast differentiation markers or number of TRAP stained osteoclasts. These studies introduce Zfhx3 as a relevant factor toward understanding gene regulatory networks that control bone formation and development of peak bone mass. [ABSTRACT FROM AUTHOR]

A bone bruise is generated by a bony collision that could occur when the anterior cruciate ligament (ACL) is injured, and its pattern reflects the injury mechanism and skeletal maturity. Thus, the bone bruise pattern is useful to predict a subject-specific injury mechanism, although the sensitivity and/or effect of the material property and the knee position at injury is still unclear. The objective of the present study was to determine the effect of the material property and knee position on the bone bruise pattern in skeletally mature and immature subjects using finite element analysis. Finite element models were created from a magnetic resonance (MR) image in the sagittal plane of a skeletally mature (25 y. o.) and immature (9 y. o.) male subject. The femur and tibia were collided at 2 m/s to simulate the impact trauma and determine the maximum principal stress. The analysis was performed at 15, 30, and 45 deg of knee flexion, and neutral, 10 mm anterior and posterior translated position at each knee flexion angle. Although high stress was distributed toward the metaphysis area in the mature model, the stress did not cross the growth plate in the immature model. The size of the stress area was larger in the mature model than those in the immature model. The location of the stress area changed depending on the joint position. Young's modulus of cartilage and trabecular bone also affected the location of the stress area. The Young's modulus for the cartilage affected peak stress during impact, while the size of the stress area had almost no change. These results indicate that the bone bruise pattern is strongly associated with subject-specific parameters. In addition, the bone bruise pattern was affected not only by knee position but also by tissue qualities. In conclusion, although the bone bruise distribution was generally called footprint of the injury, the combined evaluation of the quality of the structure and the bone bruise distribution is necessary for properly diagnosing tissue injury based on the MR imaging. [ABSTRACT FROM AUTHOR]

In the past decade, the transfibular approach to Total Ankle Replacement (TAR) has emerged as an alternative to anterior approach with reduced bone resection. The purpose of this systematic review is to report survival, complications, and reoperation rates of transfibular TAR. We conducted a systematic search of studies that evaluated complications, reoperations, and survival of transfibular TAR following PRISMA guidelines across PubMed, Scopus and Web of Science. Our review included data from 12 cohorts, comprising 919 patients across 7 countries, with an average age of 62 years (59% posttraumatic). Over an average follow-up period of 3 years, adverse events occurred in 23% of cases, with 18% requiring surgical reintervention, mostly due to hardware removal. The survival rate of the transfibular TAR metal components was 97% at the final follow-up. Transfibular TAR demonstrates a 97% survival rate at a 3-year follow-up. Level II [ABSTRACT FROM AUTHOR]

The primary component of natural bone minerals, hydroxyapatite (HA), has been the subject of research on materials for bone implants. Sintered HA scaffolds, on the other hand, degrade slowly after implantation and exhibit a high degree of crystallization at high temperatures, making it challenging to match the rate at which new bone grows. In this study, the benefit of self-curing calcium phosphate bone cement was employed to create porous apatite scaffolds without sintering. The lamellar pore structure was created by directional freeze-casting, and the enhanced specific surface area aided the in-situ hydration process. The crystallinity of sinterless porous apatite scaffolds diminishes when the TTCP and DCPD molar ratios drop. When the molar ratio is adjusted to 1:2.25, the crystallinity of the fabricated scaffold is reduced to 63.99 %, and 10.21 % can be degraded in 30 days. The degradation of porous scaffolds in simulated body fluids mainly depends on the rapid dissolution and transformation of solid phase powders in the early hydration reaction and the slow diffusion of the apatite in the later stage. The compressive strength of the porous scaffold is 5.3 MPa and its elastic modulus is 0.68 GPa. After 14 days of degradation, the compressive strength was 4.0 MPa and the elastic modulus was 0.64 GPa, which was still within the applicable range of cancellous bone repair. It has a promising application prospect as a substitute scaffold for absorbable cancellous bone. [ABSTRACT FROM AUTHOR]

Highly porous titanium foams are great candidates for replacing bone structures with a low elastic modulus owing to their ability to avoid the stress shielding effect. However, the production of highly porous foams (>70 vol.%) with well-distributed, stable, and predictable porous architectures using powder compaction and space holders is challenging. In this study, pure titanium powder and mechanically alloyed Ti-13Ta-6Sn were mixed with 50, 70, and 80 vol.% KCl powders as a space holder, cold-compacted, and sintered in a plasma-assisted sintering reactor to produce highly porous foams. The space holder was completely removed using heat and plasma species collisions prior to sintering. A Ti-13Ta-6Sn alloy powder with α, β, and metastable FCC-γ phases was synthesized. The characteristics of the alloyed powder, mixing step, and the resulting sintered samples were compared to those of CP-Ti. After sintering, the alloy exhibited α and β phases and a reduced elastic modulus. Foams with an elastic modulus in the range of the cortical and trabecular bones were obtained. The results showed the effects of the space holder volume fractions on the volume fraction, size, distribution, interconnectivity, and shape of the pores. The Ti-13Ta-6Sn foams exhibited a uniform open-celled porous architecture, lower elastic modulus, higher yield strength, and higher passivation resistance than CP-Ti. Ti-13Ta-6Sn exhibited a nontoxic effect for the mouse fibroblast cell line. [ABSTRACT FROM AUTHOR]

Background/Objectives: Dental implants have emerged as a modern solution for edentulous jaws, showing high success rates. However, the implant's success often hinges on the patient's bone quality and quantity, leading to higher failure rates in poor bone sites. To address this issue, short implants have become a viable alternative to traditional approaches like bone sinus lifting. Among these, Bicon® short implants with a plateau design are popular for their increased surface area, offering potential advantages over threaded implants. Despite their promise, the variability in patient-specific bone quality remains a critical factor influencing implant success and bone turnover regulated by bone strains. Excessive strains can lead to bone loss and implant failure according to Frost's "Mechanostat" theory. To better understand the implant biomechanical environment, numerical simulation (FEA) is invaluable for correlating implant and bone parameters with strain fields in adjacent bone. The goal was to establish key relationships between short implant geometry, bone quality and quantity, and strain levels in the adjacent bone of patient-dependent elasticity to mitigate the risk of implant failure by avoiding pathological strains. Methods: Nine Bicon Integra-CP™ implants were chosen. Using CT scans, three-dimensional models of the posterior maxilla were created in Solidworks 2022 software to represent the most challenging scenario with minimal available bone, and the implant models were positioned in the jaw with the implant apex supported by the sinus cortical bone. Outer dimensions of the maxilla segment models were determined based on a prior convergence test. Implants and abutments were considered as a single unit made of titanium alloy. The bone segments simulated types III/IV bone by different cancellous bone elasticities and by variable cortical bone elasticity moduli selected based on an experimental data range. Both implants and bone were treated as linearly elastic and isotropic materials. Boundary conditions were restraining the disto-mesial and cranial surfaces of the bone segments. The bone–implant assemblies were subjected to oblique loads, and the bone's first principal strain fields were analyzed. Maximum strain values were compared with the "minimum effective strain pathological" threshold of 3000 microstrain to assess the implant prognosis. Results: Physiological strains ranging from 490 to 3000 microstrain were observed in the crestal cortical bone, with no excessive strains detected at the implant neck area across different implant dimensions and cortical bone elasticity. In cancellous bone, maximum strains were observed at the first fin tip and were influenced by the implant diameter and length, as well as bone quality and cortical bone elasticity. In the spectrum of modeled bone elasticity and implant dimensions, increasing implant diameter from 4.5 to 6.0 mm resulted in a reduction in maximum strains by 34% to 52%, depending on bone type and cortical bone elasticity. Similarly, increasing implant length from 5.0 to 8.0 mm led to a reduction in maximum strains by 15% to 37%. Additionally, a two-fold reduction in cancellous bone elasticity modulus (type IV vs. III) corresponded to an increase in maximum strains by 16% to 59%. Also, maximum strains increased by 86% to 129% due to a decrease in patient-dependent cortical bone elasticity from the softest to the most rigid bone. Conclusions: The findings have practical implications for dental practitioners planning short finned implants in the posterior maxilla. In cases where the quality of cortical bone is uncertain and bone height is insufficient, wider 6.0 mm diameter implants should be preferred to mitigate the risk of pathological strains. Further investigations of cortical bone architecture and elasticity in the posterior maxilla are recommended to develop comprehensive clinical recommendations considering bone volume and quality limitations. Such research can potentially enable the placement of narrower implants in cases of insufficient bone. [ABSTRACT FROM AUTHOR]

Background: The calcaneal enthesis, an osseous footprint where the Achilles tendon seamlessly integrates with the bone, represents a complex interface crucial for effective force transmission. Bone adapts to mechanical stress and remodels based on the applied internal and external forces. This study explores the relationship between the elasticity of the Achilles tendon enthesis and the bone microstructure in the calcaneal crescent. Methods: In total, 19 calcaneal-enthesis sections, harvested from 10 fresh-frozen human cadaveric foot-ankle specimens (73.8 ± 6.0 years old, seven female), were used in this study. Indentation tests were performed at the enthesis region, and Hayes' elastic modulus was calculated for each specimen. Micro-CT scanning was performed at 50-micron voxel size to assess trabecular bone microstructure within six regions of interest (ROIs) and the cortical bone thickness along the calcaneal crescent. Results: Significant Spearman correlations were observed between the enthesis elastic modulus and trabecular bone thickness in the distal entheseal (ROI 3) and proximal plantar (ROI 4) regions (R = 0.786 and 0.518, respectively). Conclusion: This study highlights the potential impacts of Achilles tendon enthesis on calcaneal bone microstructure, which was pronounced in the distal calcaneal enthesis, suggesting regional differences in load transfer mechanism that require further investigation. [ABSTRACT FROM AUTHOR]

Background and Objectives: Periodontal therapy aims to arrest the progression of periodontal diseases and possibly to regenerate the periodontal apparatus. To shift healing from repair to regeneration, the blood clot that fills the periodontal defect and remains in contact with structures such as tooth root, mucosa and bone needs to be stable, which is a reason why the treatment of non-containing periodontal bone defects, in which the clot may undergo displacement, is challenging. The gingival soft tissue, properly sutured, may act as a wall for blood clot stabilization. Knowledge on the response of the blood clot to stress and how it might vary according to the characteristics of the tissues it gets in contact with might be deepened. The aim of this study was to investigate in vitro, by means of a micro-loading device, the response of the complex formed by a blood clot and diverse tissues, simulating those involved in periodontal regeneration, to a displacing tensile test. Materials and Methods: Experimental samples made of two layers of either hard dental tissues, cancellous bone or oral mucosa, between which fresh blood was interposed, underwent a debonding experiment by means of a micro-loading device that measured their response to uniaxial tensile stress. Results: The peak of tensile stress and the overall work needed for the complete rupture of the clot's fibrin filaments were significantly higher for hard dental tissues than for other tissues. However, mucosa sustained the highest maximal strain in terms of relative displacement between the plates of the micro-loading device to accomplish the complete rupture of the fibrin filaments compared to the other tissues, suggesting that the mucosa might act as a stable interface with the clot and be able to sustain tensile stresses. Conclusions: This in vitro study seems to support the use of mucosa to act as a wall for regenerative procedures of suprabony periodontal defects given its capability to form a stable interface with the clot. [ABSTRACT FROM AUTHOR]

Objectives: Inaccurate design, insertion or loading of mini-implant may lead to disturbed bone turnover and subsequent implant failure. This study assesses the two commonly used types of implants and their bone stress pattern and determines which type of implant may be more patient-compatible. Method: The samples were categorized into four groups and analyzed by scanning electron microscopy to assess the surface morphology. Stress distribution was estimated using finite element method for which three-dimensional (3D) models of the maxilla and mini-screws were prepared. The implant was then inserted 5 mm from the alveolar crest onto the buccal cortical plate of maxilla between the second premolar and first molar within the platform of Ansys Workbench software. Two loads were applied: 5 Ncm and 2 N. Evaluation of von Mises stresses in the bone was estimated. Results: The study concluded that tapered stainless steel screws exerted greater stress on the bone than titanium screws in both situations. As the diameter increased from 1.3 mm to 1.5 mm, the mini-screw displacement and stress were less. Under 2 N force, the stress was distributed around the head and neck of the mini-implant and the cortical bone. Conclusion: The assessment of von Mises stress distributed around an orthodontic mini-implant under a constant load revealed that stainless steel mini-screws generated more stress than titanium mini-screws. It was observed that the majority of the stress and strain is tolerated by the cortical bone, not the cancellous bone. The diameter of mini-screw is more significant irrespective of material composition. [ABSTRACT FROM AUTHOR]

Osteoporosis and other metabolic bone diseases are prevalent in the aging population. While bone has the capacity to regenerate throughout life, bone formation rates decline with age and contribute to reduced bone density and strength. Identifying mechanisms and pathways that increase bone accrual in adults could prevent fractures and accelerate healing. G protein-gated inwardly rectifying K+ (GIRK) channels are key effectors of G protein-coupled receptor signaling. Girk3 was recently shown to regulate endochondral ossification. Here, we demonstrate that deletion of Girk3 increases bone mass after 18 weeks of age. Male 24-week-old Girk3-/- mice have greater trabecular bone mineral density and bone volume fraction than wildtype (WT) mice. Osteoblast activity is moderately increased in 24-week-old Girk3-/- mice compared to WT mice. In vitro, Girk3-/- bone marrow stromal cells (BMSCs) are more proliferative than WT BMSCs. Calvarial osteoblasts and BMSCs from Girk3-/- mice are also more osteogenic than WT cells, with altered expression of genes that regulate the wingless-related integration site (Wnt) family. Wnt inhibition via Dickkopf-1 (Dkk1) or β-catenin inhibition via XAV939 prevents enhanced mineralization, but not proliferation, in Girk3-/- BMSCs and slows these processes in WT cells. Finally, selective ablation of Girk3 from cells expressing Cre recombinase from the 2.3 kb-Col1a1 promoter, including osteoblasts and osteocytes, is sufficient to increase bone mass and bone strength in male mice at 24 weeks of age. Taken together, these data demonstrate that Girk3 regulates progenitor cell proliferation, osteoblast differentiation, and bone mass accrual in adult male mice. Lay Summary: Osteoporosis is a prevalent, debilitating disease characterized by low bone mass. Identifying pathways that enhance bone formation could lead to therapies that prevent fractures and increase bone mass. In this study, we show that whole-body or osteoblast-specific deletion of G protein-gated inwardly rectifying K+ channel 3 (Girk3) increases bone mass in male adult mice. Osteoblast progenitor cells from Girk3-/- animals are more proliferative and differentiate more quickly into mature osteoblasts. Taken together, we show that Girk3 is a novel regulator of bone mass in adult mice. Graphical Abstract [ABSTRACT FROM AUTHOR]

Objectives: Osteoporosis is widely regarded as a typical aged-related disease caused by impaired bone remodeling. This research was designed to explore the protective effects of electroacupuncture (EA) on senile osteoporosis in a rat model and investigate the underlying mechanisms. Methods: Three-month-old rats were randomly selected as the youth group, and 24-month-old rats were randomly assigned to the elderly and EA groups. Rats in the EA group received 30 min of EA at bilateral SP10, ST36, K13 and GB34 daily, 5 days a week for 8 weeks. Bone mineral density (BMD), microstructure of the bone tissue, bone turnover biomarkers and expression level of autophagy-related proteins were detected. Results: Compared with the elderly group, EA treatment significantly increased BMD of the femur and ameliorated the microstructure. EA treatment increased trabecular bone volume ratio (= bone volume / total volume [BV/TV]) and trabecular number (Tb.N) and decreased trabecular separation (Tb.Sp) in senile osteoporosis rats. Compared with the elderly group, the serum N-terminal telopeptide of type I collagen (NTX1) level in the EA group was lower, and the serum procollagen type I N-terminal propeptide (PINP) concentration was higher. In addition, the expression of Beclin 1, microtubule-associated protein I light chain 3 (LC3B) and P62 was inhibited in the senile osteoporosis rats after EA treatment. Conclusions: EA can effectively alleviate aging-related bone loss and improve the microstructure of bone tissue in senile osteoporosis rats, and the regulation of autophagy might be one of the important mechanisms. [ABSTRACT FROM AUTHOR]

Hydrogels have emerged as potential materials for bone grafting, thanks to their biocompatibility, biodegradation, and flexibility in filling irregular bone defects. In this study, we fabricated a novel NAH hydrogel system, composed of N,O‐carboxymethyl chitosan (NOCC), aldehyde hyaluronic acid (AHA), and hydroxyapatite (HAp). To improve the mechanical strength of the fabricated hydrogel, a porous polycaprolactone (PCL) matrix was synthesized and used as a three‐dimensional (3D) support template for NAH hydrogel loading, forming a novel PCL/NAH hybrid scaffold. A mixture of monosodium glutamate (M) and sucrose (S) at varied weight ratios (5M:5S, 7M:3S, and 9M:1S) was used for the fabrication of 3D PCL matrices. The morphology, interconnectivity, and water resistance of the porous PCL scaffolds were investigated for optimal hydrogel loading efficiency. The results demonstrated that PCL scaffolds with porogen ratios of 7M:3S and 9M:1S possessed better interconnectivity than 5M:5S ratio. The compressive strength of the PCL/NAH hybrid scaffolds with 9M:1S (561.6 ± 6.1 kPa) and 7M:3S (623.8 ± 6.8 kPa) ratios are similar to cancellous bone and all hybrid scaffolds were biocompatible. Rabbit models with tibial defects were implanted with the PCL/NAH scaffolds to assess the wound healing capability. The results suggest that the PCL/NAH hybrid scaffolds, specifically those with porogen ratio of 7M:3S, exhibit promising bone healing effects. [ABSTRACT FROM AUTHOR]

Osteoporosis is a disease characterized by abnormal bone metabolism, where bone resorption outpaces bone formation. In this study, we investigated the key functional components of Lactobacillus plantarum AR495 in mitigating ovariectomy (OVX)-induced osteoporosis in mice. The results indicated that both Lactobacillus plantarum AR495 and its fermentation broth significantly reduced urinary calcium and deoxypyridinoline (DPD) levels in the mice. These interventions inhibited bone resorption and improved trabecular bone architecture by modulating the nuclear factor κB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) signaling pathway. Additionally, the L. plantarum AR495 and fermentation broth groups inhibited the RANKL/TRAF-6 and TLR4/MYD88 pathways, leading to enhanced bone metabolism, improved intestinal barrier function, and reduced intestinal inflammation. In vitro experiments revealed that AR495 fermentation supernatant fractions larger than 100 kDa and those between 50–100 kDa significantly decreased the activity of the osteoclast marker TRAP, regulated the expression of the TLR4/MYD88 pathway, and inhibited osteoclast formation, thereby alleviating the OVX-induced osteoporosis phenotype. These findings suggest that these components may be primary functional elements of L. plantarum AR495 in the treatment of osteoporosis. [ABSTRACT FROM AUTHOR]

Background: The adult human skeleton is composed of cortical and cancellous bone. The proportions of these two types of bone tissue differ in various parts of the skeleton. The aim of this cross-sectional study was to quantify the determinants of bone mineral density (BMD) and bone mineral content in various regions of interest (ROIs) in smokers and never-smokers. Methods: In this study, 4,332 bone scans of three regions of interest (ROIs) were analyzed: the forearm (distal and proximal), femur, and lumbar spine. Body composition and bone parameters were measured using dual-energy X-ray absorptiometry. Smoking was measured using the Global Adult Tobacco Survey questionnaire. Body mass index (BMI) was calculated, and physical activity (PA) was characterized by the metabolic equivalent of task (MET). Results: Among women, the interaction between PA (positive ß coefficient) and smoking (negative ß coefficient) was a significant predictor of BMD in the distal and proximal forearm (adj. R2 = 0.40 and R2 = 0.58; p < 0.001). The interaction of three variables--age, smoking (negative ß), and MET (positive ß)--was significant for total hip BMD (adj. R2 = 0.54; p < 0.001). The interaction between BMI and MET (positive ß) and smoking (negative ß) was significant for BMD in the lumbar spine (adj. R2 = 0.62; p < 0.001). In men, the interaction between MET (positive ß) and smoking (negative ß) was significant for BMD in the forearm and lumbar spine (adj. R2 = 0.44, R2 = 0.46, and R2 = 0.49; p < 0.01). Smoking alone was a significant negative predictor of total hip BMD (adj. R2 = 0.34; p < 0.001). Conclusion: Among both women and men, never-smokers had significantly better bone parameters than smokers. Smoking was a significant negative predictor for BMD in the various ROIs in both women and men. Physical activity was a significant positive predictor of BMD, with a strong association with bone parameters. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of the All-on-4 design and 4 alternative implant-supported fixed prosthesis designs on stress distribution in implants, peri-implant bone, and prosthetic framework in the edentulous mandible under different loading conditions using three-dimensional finite element analysis (3D-FEA).Five different experimental finite element models (Model A (unsplinted 6), Model B (splinted 6), Model C (All-on-4), Model D (axial; 2 anterior, 2 posterior), and Model E (4 interforaminal)) were created. Three different loading conditions were applied (canine loading, unilateral I-loading, and unilateral II-loading). The highest minimum (Pmin) and the maximum (Pmax) principal stress values were acquired for cortical and trabecular bones; the highest von Mises (mvM) stress values were obtained for implants and metal frameworks. Model B and Model D showed the most favorable stress distribution. The All-on-4 design (Model C) also showed acceptable stress values close to those of Model B and Model D in the cortical and trabecular bones. In accordance with the stress values in the bone structure, the lowest stress values were measured in the implants and Co-Cr framework in Model B and Model D. The highest stress values in all structures were measured for unilateral loading- II, while the lowest values were found for canine loading. It was concluded that Model B and Model D experimental models showed better biomechanical performance in all structures. Furthermore, the use of a splinted framework, avoiding cantilevers, results in lower stress transmission. On the other hand, canine loading and unilateral loading-I exhibited the best loading conditions. [ABSTRACT FROM AUTHOR]

Appropriate regeneration of jawbone after dental or surgical procedures relies on the recruitment of osteoprogenitor cells able to differentiate into matrix-producing osteoblasts. In this context, photobiomodulation (PBM) has emerged as promising therapy to improve tissue regeneration and to facilitate wound healing processes. The aim of this study was to determine the effect of PBM on human osteoprogenitor cells isolated from mandibular trabecular bone. Bone marrow stromal cell cultures were established from 4 donors and induced toward osteogenic differentiation for 14 days in a standard osteogenic assay. Cells were irradiated with a combined red/near-infrared (NIR) laser following different schedules and expression of osteogenic, matrix-related, osteoclastogenic and inflammatory genes was analyzed by quantitative PCR. Gene expression analysis revealed no overall effects of PBM on osteogenic differentiation. However, a statistically significant reduction was observed in the transcripts of COL1A1 and MMP13, two important genes involved in the bone matrix homeostasis. Most important, PBM significantly downregulated the expression of RANKL, IL6 and IL1B, three genes that are involved in both osteoclastogenesis and inflammation. In conclusion, PBM with a red/NIR laser did not modulate the osteogenic phenotype of mandibular osteoprogenitors but markedly reduced their expression of matrix-related genes and their pro-osteoclastogenic and pro-inflammatory profile. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is a prevalent aging disorder of synovial joints and recent work suggests that a parental high‐fat diet increases OA severity following joint injury in offspring. We hypothesized that a maternal high‐fat high‐sugar (HFHS) diet would promote spontaneous osteoarthritis‐related cartilage and bone changes in 1‐year‐old offspring. Female C57BL/6 J mice were placed on either a chow control or HFHS diet for 6 weeks before mating to a chow‐fed C57BL/6 J male and maintained on their assigned diets throughout pregnancy and lactation. Male and female offspring were weaned onto a chow diet, raised to 1 year of age, and evaluated for cartilage and bone changes indicative of OA. However, offspring did not show early signs of OA as measured by histological Mankin scoring, mechanical testing of the pericellular matrix, histological synovitis scoring, or subchondral bone thickening as measured by microcomputed Tomography. On the other hand, male offspring from HFHS‐fed dams had reduced trabecular bone quality in the tibial metaphysis and decreased cortical thickness. Although maternal HFHS diet did not impact trabecular or cortical bone quality in tibias of female offspring, the radii of these animals had decreased cortical thickness, increased medullary area, and impaired breaking strength compared to those of control‐fed dams. Finally, we evaluated bone quality and strength in male and female F2 offspring and found that the grandmaternal diet modestly impacted radial bone geometry but not strength. Together these results suggest that maternal HFHS diet impairs F1 offspring skeletal integrity in a sex and bone site‐specific manner. [ABSTRACT FROM AUTHOR]

Background: Osteoporosis is a major health concern for postmenopausal women, and the effect of simvastatin (Sim) on bone metabolism is controversial. This study aimed to investigate the effect of simvastatin on the bone microstructure and bone mechanical properties in ovariectomized (OVX) mice. Methods: 24 female C57BL/6J mice (8-week-old) were randomly allocated into three groups including the OVX + Sim group, the OVX group and the control group. At 8 weeks after operation, the L4 vertebral bones were dissected completely for micro-Computed Tomography (micro-CT) scanning and micro-finite element analysis (µFEA). The differences between three groups were compared using ANOVA with a LSD correction, and the relationship between bone microstructure and mechanical properties was analyzed using linear regression. Results: Bone volume fraction, trabecular number, connectivity density and trabecular tissue mineral density in the OVX + Sim group were significantly higher than those in the OVX group (P < 0.05). For the mechanical properties detected via µFEA, the OVX + Sim group had lower total deformation, equivalent elastic strain and equivalent stress compared to the OVX group (P < 0.05). In the three groups, the mechanical parameters were significantly correlated with bone volume fraction and trabecular bone mineral density. Conclusions: The findings suggested that simvastatin had a potential role in the treatment of osteoporosis. The results of this study could guide future research on simvastatin and support the development of simvastatin-based treatments to improve bone health. [ABSTRACT FROM AUTHOR]