Bone Matrix Research Articles

Implant Stability and Histomorphometric Analysis Comparing Two Different Implant Macrogeometries Placed in Fresh Sockets: An Experimental Study in Sheep.

The aim of the present animal study was to examine the impact of two implant designs that promote different insertion torque values on implant stability and evaluate, histomorphometrically, the bone healing for immediate implant placement in fresh sockets. Twelve female sheep (35.0±5.0kg) and 48 conical Morse-taper dental implants divided into two groups (n = 24 per group): G1 group, where the implants present a design that can provide high insertion torque values; and G2 group, where the implants present a design that can provide low insertion torque values. Both had the same surface treatment, and dimensions (4.0 mm in diameter and 10 mm in length). The first two posterior teeth (both sides) were extracted carefully. Sequentially, there were osteotomies in the mesial socket of each molar tooth. The final implant position was 2 mm below the buccal bone crest level. On the right side, implants of the G1 were placed anteriorly, followed by implants of the G2; and, on the left side, it was the reverse. A digital torquemeter was used to measure the maximum final insertion torque value (f-IT). The initial implant stability quotient (ISQ) was measured immediately after the implant insertion (T0) and immediately after the euthanasia and removing the mandibles with the implants. The animals were euthanized (n=6 animals/ time) at 21 days (T1) and 35 days (T2). The t-test was used to compare statistical differences for each intragroup parameter analyzed. Pearson's correlation was used to analyze possible correlations: f-IT and BIC%, f-IT and ISQ, and ISQ and %BIC. Regarding the insertion torque, the G1 presented higher values than the G2, with a statistically significant difference (p<0.0001). The ISQ mean values were higher in the B-L direction than those obtained for M-D for both groups. %BIC measurements showed higher values in samples from G2 than G1 at both times and in both directions. New bone, medullary spaces, and collagen matrix had statistical differences between the groups at each evaluation time. Using implants with a modified macrogeometry plays a significant role in implant stability and the healing process of bone tissue around the implant. It is important for clinicians to carefully consider implant macrogeometry when planning dental implant surgery to achieve optimal implant stability and successful osseointegration, mainly in cases of immediate implant placement.

Unique Spatial Transcriptomic Profiling of the Murine Femoral Fracture Callus: A Preliminary Report.

Fracture callus formation is a dynamic stage of bone activity and repair with precise, spatially localized gene expression. Metastatic breast cancer impairs fracture healing by disrupting bone homeostasis and imparting an altered genomic profile. Previous sequencing techniques such as single-cell RNA and in situ hybridization are limited by missing spatial context and low throughput, respectively. We present a preliminary approach using the Visium CytAssist spatial transcriptomics platform to provide the first spatially intact characterization of genetic expression changes within an orthopedic model of impaired fracture healing. Tissue slides prepared from BALB/c mice with or without MDA-MB-231 metastatic breast cancer cells were used. Both unsupervised clustering and histology-based annotations were performed to identify the hard callus, soft callus, and interzone for differential gene expression between the wild-type and pathological fracture model. The spatial transcriptomics platform successfully localized validated genes of the hard (Dmp1, Sost) and soft callus (Acan, Col2a1). The fibrous interzone was identified as a region of extensive genomic heterogeneity. MDA-MB-231 samples demonstrated downregulation of the critical bone matrix and structural regulators that may explain the weakened bone structure of pathological fractures. Spatial transcriptomics may represent a valuable tool in orthopedic research by providing temporal and spatial context.

Computational modeling of cracking in cortical bone microstructure using the mesh fragmentation technique

The cortical bone is a hierarchical composite material that, at the microscale, is segmented in an interstitial matrix, cement line, osteons, and Haversian canals. The cracking of the structure at this scale directly influences the macro behavior, and, in this context, the cement line has a protagonist role. In this sense, this work aims to simulate the crack initiation and propagation processes via cortical bone microstructure modeling with a two-dimensional mesh fragmentation technique that captures the mechanical relevance of its constituents. In this approach, high aspect ratio elements are inserted between the regular constant strain triangle finite elements to define potential crack paths a priori. The crack behavior is described using a composed damage model with two scalar damage variables, which is integrated by an implicit-explicit (Impl-Ex) scheme to avoid convergence problems usually found in numerical simulations involving multiple cracks. The approach’s capability of modeling the failure process in cortical bone microstructure is investigated by simulating four conceptual problems and one example based on a digital image of an experimental test. The results obtained in terms of crack pattern and failure mechanisms agree with those described in the literature, demonstrating that the numerical tool is promising to simulate the complex failure mechanisms in cortical bone, considering the properties of its distinct phases.

Variability of BMP-2 content in DBM products derived from different long bone.

Demineralized bone matrix (DBM) has been regarded as an ideal bone substitute as a native carrier of bone morphogenetic proteins (BMPs) and other growth factors. However, the osteoinductive properties diverse in different DBM products. We speculate that the harvest origin further contributing to variability of BMPs contents in DBM products besides the process technology. In the study, the cortical bone of femur, tibia, humerus, and ulna from a signal donor were prepared and followed demineralizd into DBM products. Proteins in bone martix were extracted using guanidine-HCl and collagenase, respectively, and BMP-2 content was detected by sandwich enzyme-linked immunosorbent assay (ELISA). Variability of BMP-2 content was found in 4 different DBM products. By guanidine-HCl extraction, the average concentration in DBMs harvested from ulna, humerus, tibia, and femur were 0.613 ± 0.053, 0.848 ± 0.051, 3.293 ± 0.268, and 21.763 ± 0.344, respectively (p < 0.05), while using collagenase, the levels were 0.089 ± 0.004, 0.097 ± 0.004, 0.330 ± 0.012, and 1.562 ± 0.008, respectively (p < 0.05). In general, the content of BMP-2 in long bones of Lower limb was higher than that in long bones of upper limb, and GuHCl had remarkably superior extracted efficiency for BMP-2 compared to collagenase. The results suggest that the origin of cortical bones harvested to fabricate DBM products contribute to the variability of native BMP-2 content, while the protein extracted method only changes the measured values of BMP-2.

Characterization of additively manufactured lumbar interbody fusion cages based on triply periodic minimal surfaces

The advent of laser powder bed fusion (LPBF) allows the fabrication of open-porous bone implants such as lumbar interbody fusion (LIF) cages. However, common LIF cages feature massive support structures and cavities for bone substitute material to meet regulatory requirements with respect to mechanical and biological properties. Since the use of autologous bone substitutes involves significant costs and risks, research is being conducted into alternative designs. This is where the present study comes in by exploring the potential of triply periodic minimal surfaces (TPMS) for metallic LIF cages without supports and cavities in a holistic approach. Specifically, various homogeneous and graded scaffolds with pore size of 400–1100μm and volume fraction of ≤0.25 are designed before being produced from Ti-6Al-4V ELI powder using LPBF. Morphological characterization demonstrates a high process fidelity with a maximum of 8.7% target/actual deviation for the volume fraction. This promotes structural integrity so that the compressive strength of 69MPa or 20.6kN complies with the minimum requirements of ASTM F2077. Based on in vitro cell tests, a mineralization process including bone matrix formation is observed in all variants, with the homogeneous scaffold with 1100μm pore size proving to be particularly beneficial. In conclusion, the results encourage the further development of TPMS based LIF cages without support structures and cavities.

3D-printed polycaprolactone/tricalcium silicate scaffolds modified with decellularized bone ECM-oxidized alginate for bone tissue engineering

The treatment of large craniofacial bone defects requires more advanced and effective strategies than bone grafts since such defects are challenging and cannot heal without intervention. In this regard, 3D printing offers promising solutions through the fabrication of scaffolds with the required shape, porosity, and various biomaterials suitable for specific tissues. In this study, 3D-printed polycaprolactone (PCL)-based scaffolds containing up to 30 % tricalcium silicate (TCS) were fabricated and then modified by incorporation of decellularized bone matrix- oxidized sodium alginate (DBM-OA). The results showed that the addition of 20 % TCS increased compressive modulus by 4.5-fold, yield strength by 12-fold, and toughness by 15-fold compared to pure PCL. In addition, the samples containing TCS revealed the formation of crystalline phases with a Ca/P ratio near that of hydroxyapatite (1.67). Cellular experiment results demonstrated that TCS have improved the biocompatibility of PCL-based scaffolds. On day 7, the scaffolds modified with DBM and 20 % TCS exhibited 8-fold enhancement of ALP activity of placenta-derived mesenchymal stem/stromal cells (P-MSCs) compared to pure PCL scaffolds. The present study's results suggest that the incorporation of TCS and DBM-OA into the PCL-based scaffold improves its mechanical behavior, bioactivity, biocompatibility, and promotes mineralization and early osteogenic activity.

Numerical calculation of streaming potential around osteocytes under human gait loading

Streaming potential is a type of stress-generated potential in bone that affects the electrical environment of osteocytes and may play a role in bone remodeling. Because the electrical environment around osteocytes has been difficult to measure experimentally until now, a numerical solid-liquid-streaming potential coupling method was proposed to analyze the streaming potential generated by bone deformation in the lacunae and canaliculus network (LCN) of the bone. Using this method, the cellular shear stress caused by liquid flow on the osteocyte surface was first calculated, and the results were consistent with those reported in the literature. Subsequently, the streaming potentials in the LCN caused by bone matrix deformation under an external gait load were calculated numerically. The results showed that the streaming potential increased slowly in the lacuna and relatively rapidly in the canaliculus and that the streaming potential increased with a decrease in the radius or an increase in the length of the canaliculus. The results also showed that relatively large gaps between the lacunae and osteocytes could induce higher streaming potentials under the same loading.

A photoresponsive recombinant human amelogenin-loaded hyaluronic acid hydrogel promotes bone regeneration.

In order to evaluate the effect of methacrylated hyaluronic acid (HAMA) hydrogels containing the recombinant human amelogenin (rhAm) invitro and invivo. The ultimate goal in treating periodontal disease is to control inflammation and achieve regeneration of periodontal tissues. In recent years, methacrylated hyaluronic acid (HAMA) containing recombinant human amyloid protein (rhAm) has been widely used as a new type of biomaterial in tissue engineering and regenerative medicine. However, there is a lack of comprehensive research on the periodontal regeneration effects of this hydrogel. This experiment aims to explore the application of photoresponsive recombinant human amelogenin-loaded hyaluronic acid hydrogel for periodontal tissue regeneration and provide valuable insights into its potential use in this field. The effects of rhAm-HAMA hydrogel on the proliferation of human periodontal ligament cells (hPDLCs) were assessed using the CCK-8 kit. The osteogenic differentiation of hPDLCs was evaluated through ALP staining and real-time PCR. Calvarial parietal defects were created in 4-week-old Sprague Dawley rats and implanted with deproteinized bovine bone matrix in different treatment groups. The animals were euthanized after 4 and 8 weeks of healing. The bone volume of the defect was observed by micro-CT and histological analysis. Stimulating hPDLCs with rhAm-HAMA hydrogel did not significantly affect their proliferation (p > .05). ALP staining and real-time PCR results demonstrated that the rhAm-HAMA group exhibited a significant upregulation of osteoclastic gene expression (p < .05). Micro-CT results revealed a significant increase in mineralized tissue volume fraction (MTV/TV%), trabecular bone number (Tb.N), and mineralized tissue density (MTD) of the bone defect area in the rhAm-HAMA group compared to the other groups (p < .05). The results of hematoxylin and eosin staining and Masson staining at 8 weeks post-surgery further supported the results of the micro-CT. The results of this study indicate that rhAm-HAMA hydrogel could effectively promote the osteogenic differentiation of hPDLCs and stabilize bone substitutes in the defects that enhance the bone regeneration invivo.

Mechanical insights into jawbone characteristics under chronic kidney disease: A comprehensive nanoindentation approach

The mechanical properties of the jawbone play a critical role in determining the successful integration of dental prostheses. Chronic kidney disease (CKD) has been identified to abnormally accelerate bone turnover rates. However, the impact of CKD on the mechanical characteristics of the jawbone has not been extensively studied. This study sought to evaluate the time-dependent viscoelastic behaviors of rat jawbones, particularly in the scenarios both with and without CKD. We hypothesized that CKD might compromise the bone's innate toughening mechanisms, potentially owing to the time-dependent viscoelasticity of the bone matrix proteins. The maxillary and mandibular bones of Wistar rats were subjected to nanoindentation and Raman micro-spectroscopy. Load-hold-displacement curves from the cortical regions were obtained via nanoindentation and were mathematically characterized using a suitable viscoelastic constitutive model. Raman micro-spectroscopy was employed to identify nuanced vibrational changes in local molecular structures induced by CKD. The time course of indenter penetration onto cortical bones during the holding stage (creep behavior) can be mathematically represented by a series arrangement of the Kelvin–Voigt bodies. This configuration dictates the overall viscoelastic response observed during nanoindentation tests. The CKD model exhibited a reduced extent of viscoelastic contributions, especially during the initial ramp loading phase in both the maxillary and mandibular cortical bones. The generalized Kelvin–Voigt model comprises 2 K–Voigt elements that signify an immediate short retardation time (τ1) and a subsequent prolonged retardation time (τ2), respectively. Notably, the mandibular CKD model led to an increase in the delayed τ2 alongside an increase in non-enzymatic collagen cross-linking. These suggest that, over time, CKD diminishes the bone's capability for supplementary energy absorption and dimensional recovery, thus heightening their susceptibility to fractures.

Composite demineralized bone matrix nanofiber scaffolds with hierarchical interconnected networks via eruptive inorganic catalytic decomposition for osteoporotic bone regeneration

Demineralized bone matrix (DBM) is one of the standard biomaterials used to fill surgical bone defects in general orthopedic procedures. However, current DBM products come in the form of powder or viscous solutions that fail to mimic the natural hierarchical structure of bone while also using large amounts of valuable material. To overcome this, compact fibrous DBM/polymer (fDBM) composites were prepared via electrospinning. Then, by exploiting the catalytic decomposition of hydrogen peroxide, oxygen pockets are formed in the scaffold imparting it with a hierarchical porous structure similar to bone (Op-fDBM). These pockets created by bubbles of oxygen help give the scaffold a mechanically stable shape while the incorporated DBM supports cell adhesion and growth. In vivo evaluations reveal that fDBM increased bone volume by 41.7 % while Op-fDBM increased bone volume by 68.6 %. Significant increases in regenerated bone volume with the use of minimal amounts of DBM in fiber form go to show the great potential of this work in the field of bone regeneration.

TGF-β1-triggered BMI1 and SMAD2 cooperatively regulate miR-191 to modulate bone formation

Transforming growth factor beta 1 (TGF-β1), as the most abundant signaling molecule in bone matrix, is essential for bone homeostasis. However, the signaling transduction of TGF-β1 in bone-forming microenvironment remains unknown. Here, we showed that microRNA-191 (miR-191) was downregulated during osteogenesis and further decreased by osteo-favoring TGF-β1 in bone marrow mesenchymal stem cells (BMSCs). MiR-191 was lower in bone tissues from children than in those from middle-aged individuals and it was negatively correlated with collagen type I alpha 1 chain (COL1A1). MiR-191 depletion significantly increased osteogenesis and bone formation in vivo. Hydrogels embedded with miR-191-low BMSCs displayed a powerful bone repair effect. Mechanistically, transcription factors BMI1 and SMAD2 coordinately controlled miR-191 level. In detail, BMI1 and pSMAD2 were both upregulated by TGF-β1 under osteogenic condition. SMAD2 activated miR-191 transcription, while BMI1 competed with SMAD2 for binding to miR-191 promoter region, thus disturbing the activation of SMAD2 on miR-191 and reducing miR-191 level. Altogether, our findings reveal that miR-191 regulated by TGF-β1-induced BMI1 and SMAD2 negatively modulated bone formation and regeneration, and inhibition of miR-191 might be therapeutically useful to enhance bone repair in clinic.

Preventing septic implant failures in osteoporotic hip fractures using antibiotic-loaded functionalized nanocement

Osteoporosis is a prevalent skeletal disorder and the most common cause of debilitating hip fractures, primarily affecting post-menopausal women and elderly people. Implants used to stabilize osteoporotic fragility fractures are susceptible to bacterial infections, which further deteriorate the implantationsite. In the current study, we developed a nanocement-based treatment for tackling hip implant infection in an osteoporotic rat model. The development of osteoporosis was confirmed by an 80% decrease in serum estradiol levels and a further reduced T-score value of −4.170 ± 0.411 for femur neck canal. Further, an infected K-wire was implanted in femoral neck canal to induce implant-associated osteomyelitis. In order to combat infection and promote bone healing, it was followed by debridement and implantation of rifampicin-loaded nanocement functionalized with various combinations of bone marrow MSCs (bMSC) exosomes, bone morphogenetic protein-2 (BMP-2) and zoledronic acid (ZA). The findings of this study demonstrated the potential of exosomes as an alternative for reducingBMP-2 dosage, and the treatment promoted successful bone regeneration withenhanced mechanical strength, and a significant decrease in bacterial load. Improved bone remodeling and matrix deposition at the implantation site were confirmed by DXA, micro-CT, and histology. Further, immunohistochemical staining showed increased expression of collagen I and CD31, which indicated bone matrix deposition and vascularization, respectively, while reduced expression of α-SMA and NOS2 confirmed a reduction in fibrosis and inflammation, respectively. Overall, our one-step treatment strategy has the potential to prevent implant-associated bone infection in osteoporotic hip fractures, promote bone formation, and enhance the mechanical strength of osteoporotic bone, thereby preventing subsequent secondary fractures.

Using different methods to measure ultrasonic attenuation in cortical bone: A comparison

The assessment of bone mineral density (BMD) and bone microstructure is important in screening for various bone diseases. Dual x-ray absorptiometry is the most commonly used technique for evaluating BMD; however, alternatives are necessary due to the use of ionizing radiation and low resolution, the latter of which prevents obtaining information on bone microstructure. Quantitative ultrasound presents a potentially attractive alternative. The microstructure of porous media, such as cortical bone, influences the attenuation of ultrasound; as such, ultrasound attenuation can be used to obtain information about the microstructure of cortical bone. Different models and measurement methods may be used to estimate ultrasonic attenuation in a cortical bone. In this study, three different methods of measuring ultrasonic attenuation were used. Finite-difference time-domain simulations were conducted in maps mimicking cortical bone. Pore densities and pore size distributions in the bone matrix, as well as absorptive properties of the bone and porous matrices, were specified for all simulations. Attenuation was measured within the pulse bandwidth as a function of frequency using the independent scattering approximation (ISA), a cortical backscatter method (CortBS), and the reflections from the two surfaces of the cortical bone map. Excellent agreement was found between these three methods.

Induction of mineralized matrix production by recombinant human BMP-2 Immobilized in TEMPO-Oxidized Cellulose Hydrogel: a novel target for tissue repair

Bone morphogenetic proteins (BMPs) are potent promoters of osteogenesis, especially BMP-2, which has been highlighted for acting as a growth and differentiation factor that promotes new bone formation. There are several biomaterials that can be used to release bioactive substances, such as natural polymers. Cellulose has stood out for the possibility of its chemical modification using the reagent 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) to obtain a cellulose derivative (TEMPO oxidized cellulose nanofibers - ToCNF), which is shown to be a promising material for biological application. The objective of this work was to evaluate TEMPO cellulose immobilized with rhBMP-2 against the activity of inducing bone cell proliferation and differentiation in vitro, evaluating the ability to form bone matrix in pre-osteoblastic cell lineage of rats - MC3T3. Cell viability assays using resazurin were performed and for detection of mineralized matrix, Alizarin Red solution was used. The results reveal the good capacity of TEMPO cellulose functionalized with rhBM-2 in inducing the synthesis of mineralized bone matrix.

Heterogeneous ultrasonic wave properties in leg cortical bones of Thoroughbreds

Safe and inexpensive diagnosis of leg bone disease in the field is very important for Thoroughbreds and large animals, because large animals are difficult to transport, and prompt diagnosis is required. The quantitative ultrasound (QUS) is attracting attention for the evaluation of leg bones because it can give us information of elasticity, which is related to the bone quality. For the development of a QUS system of animal leg bones, understanding of characteristic ultrasonic wave properties (velocity and attenuation) is a key issue. Therefore, wave properties in Thoroughbreds’ leg bones were obtained experimentally using an ultrasonic pulse technique. Precise measurements showed clear heterogeneity of ultrasonic wave properties due to the location. Opposed to the other large animals like bovines, high wave velocities were found in the medial and lateral parts, which possibly tells the effects of hard training in the fields. From a clinical perspective, the medial and lateral parts are less prone to diseases such as periostitis. The attenuation was greater in the posterior part, especially in the porous area near the trabecular bone. We also found that attenuation depended on bone matrix. Further investigation is necessary to discuss on the heterogeneity of wave properties in detail.

Arthroscopic-Assisted Core Decompression of Humeral Head Osteonecrosis With Bone Marrow Aspirate Concentrate Augmentation

Background: The proximal humerus is the second-most common anatomic site for osteonecrosis, a condition of disrupted blood supply leading to death of bone tissue, with resultant shoulder pain and dysfunction. Core decompression is a viable joint-preserving surgical intervention that aims to improve local blood supply and restore bone health prior to bony collapse. Indications: Humeral head osteonecrosis has numerous underlying causes, most commonly the sequelae of prior trauma, chronic use of systemic corticosteroids, sickle cell disease, and alcohol abuse. Core decompression may be indicated in the early, pre-collapse stages of osteonecrosis, whereas more advanced stages of disease are commonly indicated for joint reconstruction procedures, such as bone grafting or arthroplasty. Technique Description: With the patient in the beach chair position, bone marrow aspirate concentrate (BMAC) is harvested through a percutaneous incision along the anterolateral proximal humerus. While viewing through a standard posterior portal, a transtibial anterior cruciate ligament (ACL) guide is placed through an anterior portal at a site on the humeral head surface, centered at the area of greatest humeral head bone edema as identified on preoperative magnetic resonance imaging. A guide pin is placed through a lateral portal within the ACL guide, to the subchondral bone. A 7.0-mm reamer is applied over the guidewire, followed by administration of demineralized bone matrix soaked in BMAC into the reamed channel within the proximal humerus. Results: In patients with early stages of humeral head osteonecrosis, core decompression confers superior clinical outcomes with reduced rates of subsequent surgical procedures compared with nonoperative treatment. Core decompression has shown to reduce the radiographic progression of osteonecrosis. Further research is necessary to determine the additional clinical benefits of augmentation with orthobiologic agents, such as BMAC. Conclusion: Arthroscopic-assisted core decompression is a valuable, minimally invasive surgical treatment for early-stage proximal humerus osteonecrosis. Adjunctive treatment with BMAC and demineralized bone matrix may enhance clinical outcomes. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Variables Influencing Bone Formation After Transcrestal Sinus Floor Elevation: Radiographic and Tomographic Evaluations.

To evaluate the influence of initial implant protrusion within the subantral space on hard tissue gain for implants placed simultaneously with transcrestal sinus floor elevation (TSFE) with a biomaterial. A total of 50 implants were placed after TSFE in 44 patients using either a human demineralized bone matrix or a deproteinized bone mineral matrix. Intraoral radiographs were obtained before and immediately after surgery. CBCT scans were obtained at the last follow-up (mean: 6.6 years). The initial bone crest height was 4.6 ± 1.4 mm, and the initial protrusion of the implants above the sinus floor was 3.5 ± 1.4 mm. At the follow-up assessments, the hard tissue mean gain was 2.5 ± 1.5 mm, resulting in a mean residual protrusion of 1.1 ± 1.3 mm. Only 10 implants did not protrude above the apical level of hard tissue. Positive correlations were found between hard tissue gain and initial protrusion (r = 0.55; 95% CI: 0.32 to 0.72; P = .0001), between the initial and final protrusions (r = 0.38; 95% CI: 0.10 to 0.60; P = .007), and between the follow-up period and final protrusion (r = 0.35; 95% CI: 0.07 to 0.58; P = .012). The higher the initial protrusion was, the higher were the hard tissue gain and the final protrusion of the implant above the apical level of the hard tissue.

Quantitative and qualitative evaluation of three MSCT for high resolution bone imaging

IntroductionStrategies for achieving high resolution varies between manufacturers. In CT, the helical mode with narrow collimation has long been considered as the gold standard for high-resolution imaging. More recently, incremental modes with small dexels and focal spot, have been developed but have not been compared with helical acquisitions under optimal conditions. The aim of this work is to compare the high-resolution acquisition strategies currently proposed by recent MSCT. MethodsThree CT systems were compared. A phantom was used to evaluate geometric accuracy, uniformity, scan slice geometry, and spatial resolution. Human dry bones were used to test different protocols on real bone architecture. A blind visual analysis was conducted by trained CT users for classifying the different acquisitions (p-values). ResultsAll systems give satisfactory results in terms of geometric accuracy and uniformity. The in-plane MTF at 5% were respectively 13.4, 15.9 and 18.1 lp/cm. Dry-bones evaluation confirms that acquisition#3 is considered as the best. ConclusionsThe incremental acquisition coupled with à small focal spot, and a high-sampling detector, overpasses the reference of low-pitch helical acquisitions for high-resolution imaging. Cortical bone, bony vessels, and tumoral matrix analysis are the very next challenges that will have to be managed to improve normal and pathologic bone imaging thanks to the availability UHR-CT systems.

Surgical management of severe cherubism persisting into early adulthood: a case report and literature review.

Cherubism is a rare fibro-osseous condition characterized by bilateral expansion of the mandible and maxilla. Due to its rarity, treatment guidelines for cherubism have not been clearly established. Observation without surgical intervention is typically recommended, as cherubism often regresses spontaneously after puberty. However, a surgical intervention may be necessary if aggressive lesions lead to severe complications. In this report, we present a case involving surgical management of cherubism that did not spontaneously regress until early adulthood. An 18-year-old man was diagnosed with cherubism, presenting characteristic upward-looking eyes and a swollen face. He strongly desired surgical management. Gross contouring of the mandible was performed using an osteotome. Subsequently, delicate contouring was performed by bone burring and curettage. The remaining multiple locular bony defects were filled with demineralized bone matrix. No major complications, including infection and hematoma, occurred during the 8-month follow-up period. The facial contour remained stable without the aggravation of cherubism. The patient was satisfied with the cosmetic results. Considering that cherubism is a rare disease globally, with few reported cases in Korea, and that treatment guidelines are not clearly established, we anticipate that the results of this case will contribute to the development of future protocols for treating cherubism.

The effect of caponization on tibia bone histomorphometric properties of crossbred roosters

The negative effect of caponization on the structural, geometric and mechanical parameters of femur and tibia has been shown in a few studies. Nevertheless, its influence on tibia bone microarchitecture is still largely unknown. Therefore, this study aimed to assess the effect of castration on the microstructural parameters of the trabecular and compact bone of tibia bone in crossbred chickens. The experiment involved 96 roosters derived from crossing Yellowleg Partridge hens (Z˙\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\dot{\ ext{Z}}}$$\\end{document}-33) and Rhode Island Red cockerels (R-11) fattened until the 16th, 20th and 24th week of life. Animals were randomly divided into 2 groups of 48 each. Group I (control) consisted of intact roosters and group II (experimental) consisted of birds subjected to caponization at the 8th week of age. The castration surgery had no influence on some properties within compact bone such as osteon diameter On.Dm, osteon perimeter On.Pm, osteon area On.Ar, osteocyte lacunar number Ot.Lc.N, osteon bone area On.B.Ar, osteon wall thickness On.W.Th as well as thick-mature collagen content in all analyzed age groups of animals. Nevertheless, our results demonstrate that castration caused a decrease of Haversian canal area Hc.Ar, osteocyte lacunar area Ot.Lc.Ar and osteocyte lacunar porosity Ot.Lc.Po among the 16-week-old birds, decrease of Haversian canal perimeter Hc.Pm and increase of fraction of bone area On.B.Ar/On.Ar among 16- and 24-week-old individuals and also an increase of osteocyte lacunar density Ot.Lc.Dn in the osteons of the oldest roosters. Additionally, some microstructural parameters of trabecular bone show the negative effect of caponization. The youngest 16-week-old capons were characterized by thinnin the trabecular in the epiphysis part of tibia. Moreover, in the case of 24-week-old, there is an increase in the trabecular separation Tb.Sp with simultaneous decrease of trabecular number Tb.N compared to roosters, which may suggest the increase of the bone resorption among the oldest individuals. The increased bone turnover in the epiphysis part of the tibia bone also indicates changes in the collagen fibers distribution, where among 20-week-old animals there is a decrease in the content of immature thin collagen fibers with simultaneous increase in the content of mature thick collagen fibers. Furthermore, among the oldest 24-week-old individuals we can observe the increased thick-to-thin collagen ratio, which may be a sign of slowing down in bone formation.