Decellularized Apple-Derived Scaffolds for Bone Tissue Engineering In Vitro and In Vivo.

Plant-derived cellulose biomaterials have been employed in various tissue engineering applications. In vivo studies have shown the remarkable biocompatibility of scaffolds made of cellulose derived from natural sources. Additionally, these scaffolds possess structural characteristics that are relevant for multiple tissues, and they promote the invasion and proliferation of mammalian cells. Recent research using decellularized apple hypanthium tissue has demonstrated the similarity of its pore size to that of trabecular bone as well as its ability to effectively support osteogenic differentiation. The present study further examined the potential of apple-derived cellulose scaffolds for bone tissue engineering (BTE) applications and evaluated their in vitro and in vivo mechanical properties. MC3T3-E1 preosteoblasts were seeded in apple-derived cellulose scaffolds that were then assessed for their osteogenic potential and mechanical properties. Alkaline phosphatase and alizarin red S staining confirmed osteogenic differentiation in scaffolds cultured in differentiation medium. Histological examination demonstrated widespread cell invasion and mineralization across the scaffolds. Scanning electron microscopy (SEM) revealed mineral aggregates on the surface of the scaffolds, and energy-dispersive spectroscopy (EDS) confirmed the presence of phosphate and calcium elements. However, despite a significant increase in the Young's modulus following cell differentiation, it remained lower than that of healthy bone tissue. In vivo studies showed cell infiltration and deposition of extracellular matrix within the decellularized apple-derived scaffolds after 8 weeks of implantation in rat calvaria. In addition, the force required to remove the scaffolds from the bone defect was similar to the previously reported fracture load of native calvarial bone. Overall, this study confirms that apple-derived cellulose is a promising candidate for BTE applications. However, the dissimilarity between its mechanical properties and those of healthy bone tissue may restrict its application to low load-bearing scenarios. Additional structural re-engineering and optimization may be necessary to enhance the mechanical properties of apple-derived cellulose scaffolds for load-bearing applications.

Optimized reamer geometry for controlled reaming of the proximal femur.

Preparation of the femoral proximal medullary cavity by reaming is essential for intramedullary nail osteosynthesis and hip revision arthroplasty. The use of reamers sometimes exerts high torsional forces on the bone. Design and direction of rotation of the reamer are potential influencing factors. The aim of this biomechanical study is to evaluate the best combination of a right- or left-cutting reamer with a clockwise- or counterclockwise-rotating insert in terms of preparation and safety. Right- and left-cutting reamers with conical design were each introduced into five synthetic femurs in both clockwise and counterclockwise rotation with constant feed force. A specially constructed test system was used for this series of tests, with which the respective intramedullary channel were reamed step by step. This was then used to determine the required torque. In addition, the feed rate measurement was analyzed using a modified digital caliper. The feed rates of the reamers with rotation in the same direction as the cutting direction were significantly increased compared to rotation in the opposite cutting direction (CCRLC vs. CCRRC 76.8 ± 9.0 mm/s vs. 25.2 ± 8.3 mm/s and CRRC vs. CRLC 54.3 ± 12.3 mm/s vs. 19.3 ± 0.6 mm/s; p < 0.01). In contrast, the mean torque during the reaming process was identical in all four groups. When preparing the proximal femoral medullary cavity, especially in cases with fragile bone structure, the available reamers should be introduced in opposite rotation to the cutting direction to achieve a more controllable feed of the reamer. Left-cutting reamers represent an alternative, using them in the usual clockwise-rotating technique to reduce the risk of complications during reaming.

Enthesis repair - State of play.

The fibrocartilaginous enthesis is a highly specialised tissue interface that ensures a smooth mechanical transfer between tendon or ligament and bone through a fibrocartilage area. This tissue is prone to injury and often does not heal, even after surgical intervention. Enthesis augmentation approaches are challenging due to the complexity of the tissue that is characterised by the coexistence of a range of cellular and extracellular components, architectural features and mechanical properties within only hundreds of micrometres. Herein, we discuss enthesis repair and regeneration strategies, with particular focus on elegant interfacial and functionalised scaffold-based designs.

Biomaterials for bone defect repair: Types, mechanisms and effects.

Bone defects or bone discontinuities caused by trauma, infection, tumours and other diseases have led to an increasing demand for bone grafts and biomaterials. Autologous bone grafts, bone grafts with vascular tips, anastomosed vascular bone grafts and autologous bone marrow components are all commonly used in clinical practice, while oversized bone defects require the use of bone tissue engineering-related biomaterials to repair bone defects and promote bone regeneration. Currently, inorganic components such as polysaccharides and bioceramics, as well as a variety of bioactive proteins, metal ions and stem cells can be loaded into hydrogels or 3D printed scaffold materials to achieve better therapeutic results. In this review, we provide an overview of the types of materials, applications, potential mechanisms and current developments in the repair of bone defects.

How to remove a well-fixed metaphyseal sleeve in revision knee arthroplasty: A step-by-step surgical procedure.

BACKGROUND: The rising incidence and complexity of revision knee arthroplasty has led to an increase in the use of metaphyseal reconstruction systems. One of the most widely used systems are metaphyseal sleeves as they have demonstrated excellent long-term survival. However, there is concern about the possible difficulty of extracting a sleeve if it were necessary, as no known procedures have yet been validated. METHODS: We examined the outcomes of removing 23 well-integrated metaphyseal sleeves using the same systematized technique. RESULTS: All sleeves were extracted without any intraoperative complications. Four subjects required an osteotomy to complete the extraction, while 62% of the sample were found to have an AORI IIB defect. All cases were successfully reconstructed with a new metaphyseal fixation, implanting a new sleeve in 38% of subjects compared with cones in the remaining 62%. CONCLUSIONS: The technique described here produced successful, reproducible outcomes for the removal of integrated metaphyseal sleeves with minimal bone loss and no intraoperative complications.

Advances in 3D Printing of Highly Bioadaptive Bone Tissue Engineering Scaffolds.

The number of patients with bone defects caused by trauma, bone tumors, and osteoporosis has increased considerably. The repair of irregular, recurring, and large bone defects poses a great challenge to clinicians. Bone tissue engineering is emerging as an appropriate strategy to replace autologous bone grafting in the repair of critically sized bone defects. However, the suitability of bone tissue engineering scaffolds in terms of structure, mechanics, degradation, and the microenvironment is inadequate. Three-dimensional (3D) printing is an advanced additive-manufacturing technology widely used for bone repair. 3D printing constructs personalized structurally adapted scaffolds based on 3D models reconstructed from CT images. The contradiction between the mechanics and degradation is resolved by altering the stacking structure. The local microenvironment of the implant is improved by designing an internal pore structure and a spatiotemporal factor release system. Therefore, there has been a boom in the 3D printing of personalized bone repair scaffolds. In this review, successful research on the preparation of highly bioadaptive bone tissue engineering scaffolds using 3D printing is presented. The mechanisms of structural, mechanical, degradation, and microenvironmental adaptations of bone prostheses and their interactions were elucidated to provide a feasible strategy for constructing highly bioadaptive bone tissue engineering scaffolds.

A novel pneumatic drill for bone biopsy under MRI imaging.

PURPOSE: Bone biopsies are currently conducted under computed tomography (CT) guidance using a battery-powered drill to obtain tissue samples for diagnosis of suspicious bone lesions. However, this procedure is suboptimal as images produced under CT lack soft tissue discrimination and involve ionizing radiation. Therefore, our team developed an MRI-safe pneumatic drill to translate this clinical workflow into the MR environment, which can improve target visualization and eliminate radiation exposure. We compare drill times and quality of samples between the 2 drills using animal bones. METHODS: Five porcine spare rib bones were obtained from a butcher shop. Each bone was drilled twice using the Arrow OnControl battery-powered drill and twice using our pneumatically actuated drill. For this study, we used an 11-gauge bone biopsy needle set with an internal core capturing thread. A stopwatch recorded the overall time of drilling for each specimen obtained. RESULTS: All 20 samples collected contained a high-quality inner core and cortex. The total average time for drilling with the pneumatic drill was 8.5 s (+ / - 2.5 s) and 7.1 s (+ / - 1.4 s) with the standard battery-powered drill. CONCLUSION: Both drills worked well and were able to obtain comparable specimens. The pneumatic drill took slightly longer, 1.39 s on average, but this extra time would not be significant in clinical practice. We plan to use the pneumatic drill to enable MRI-safe bone biopsy for musculoskeletal lesions. Biopsy under MRI would provide excellent lesion visualization with no ionizing radiation.

Anchoring flap suture technique to repair a wound with exposed bone after hip disarticulation: a case report and brief review of the literature.

BACKGROUND: In specific clinical scenarios characterized by poor tissue conditions surrounding a wound, achieving stable flap fixation with standard sutures can be challenging. The anchoring flap suture technique, which is commonly used for soft tissue-to-bone attachment in cases of injury, may be an alternative and effective approach. CASE REPORT: This report describes the successful application of the anchoring flap suture technique to repair a wound with exposed bone in a 39-year-old female patient. She presented with a 7% TBSA wound of the left trunk following hip disarticulation. After 4 operations, a wound with exposed iliac bone remained. Given the compromised condition of the tissues surrounding the exposed bone, the authors opted to anchor a local flap directly to the exposed bone. Steady flap fixation was achieved using the anchoring flap suture method, resulting in complete healing of that wound. Remarkably, no short- or long-term complications associated with the flap were observed. Three months after hospital discharge, the patient regained mobility, walking on 1 leg with the assistance of a 4-legged walker. CONCLUSION: The anchoring flap suture technique seems to be a reliable and effective treatment option, particularly in cases in which inadequate soft tissue precludes the use of traditional flap fixation using standard sutures.

Segmenting/Pre-Processing Data from Bone Screw Thread-Stripping Tests.

Bone screws must be appropriately tightened to achieve optimal patient outcomes. If over-torqued, the threads formed in the bone may break, compromising the strength of the fixation; and, if under-torqued, the screw may loosen over time, compromising the stability. Previous work has proposed a model-based system to automatically determine the optimal insertion torque. This system consists of a reverse-modelling step to determine strength, and a forward modelling step to determine maximum torque. These have previously been tested in isolation, however future work must test the combined system. To do so, the data must be segmented and pre-processed. This was done based on specific features of the recorded data. The methodology was tested on 50 screw-insertion data sets across 5 different materials. With the parameters used, all data sets were correctly segmented. This will form a basis for the further processing of the data and validating the combined systemClinical relevance: The system for torque limit determination must be tested in its entirety to properly asses its performance. This paper discusses some of the steps required to pre-process the data to make this assessment. If successful, this system may improve patient outcomes in orthopaedic surgery.

Prospective evaluation of clinical and radiographic 10-year results of Fitmore short-stem total hip arthroplasty.

BACKGROUND: Short stems were introduced into total hip arthroplasty (THA) to preserve bone stock, to transmit more load to the proximal femur, and to enable minimal invasive approaches. This study is the first long-term study (with a follow-up of 10 years) of the survival as well as the clinical and radiographic outcomes of the Fitmore hip stem, a short curved uncemented stem. METHODS: In total, 123 Fitmore hip stems were prospectively evaluated. At the final 10-year follow-up, 80 Fitmore stems (78 patients: 30 female, 48 male) were eligible for evaluation. Clinical parameters were thigh pain, EQ-5D, Harris Hip Score (HHS) and Oxford Hip Score. Radiographic parameters were cortical hypertrophy (CH), bone condensation, cortical thinning, radiolucency, reactive lines, calcar rounding, calcar resorption, subsidence and varus/valgus position. RESULTS: After 10 years, there was a survival rate of 99% (1 revision because of aseptic stem loosening). HHS had improved from 59 to 94 and Oxford Hip Score from 22 to 43. CH rate after 1 year was 69% and after 10 years 74%. In the first year, radiolucency was found in 58% and in 17.5% after 10 years. Subsidence after 1 year was 1.6 ± 1.6 mm and 5.0 ± 3.1 mm after 10 years. CONCLUSIONS: The Fitmore hip stem showed a survival rate of 99% as well as good clinical and radiographic outcomes in the long-term follow-up of 10 years.

Evaluating and Comparing the Effectiveness of Nano-HA and HA + ß-TCP with A-PRF Clinically and Radiographically in the Treatment of Human Infrabony Defects.

AIM: To evaluate and compare the effectiveness of nanocrystalline hydroxyapatite (NcHA) with advanced platelet-rich fibrin (A-PRF) and hydroxyapatite-reinforced beta tricalcium phosphate (HA + ß-TCP) with A-PRF in the treatment of human infrabony defects clinically and radiographically using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: There were a total of 28 defects, with 14 defects in the test and control groups, respectively. There were total 28 patients were involved in the study. The test group (group A) was treated with NHA and A-PRF, while the control group (group B) was treated with HA + ß-TCP and A-PRF. Bone defect fill was the primary result of the investigation. Periodontal pocket depth (PPD), R-CAL, papillary bleeding index (PBI), and PI were the secondary outcome. Clinical and radiographic measurements were recorded at baseline and 6 months postoperatively. RESULTS: No significant difference was observed between the two groups in terms of PPD reduction (4.64 ± 0.74 mm vs 4.07 ± 0.99 mm), clinical attachment loss (CAL) gain (4.64 ± 0.74 mm vs 3.92 ± 0.99 mm) and radiographic defect depth reduction (2.41 ± 0.32 mm vs 2.40 ± 0.27 mm) for test and control groups, respectively. CONCLUSION: At 6-month post-surgery, both treatment modalities demonstrated statistically significant improvements with regard to CAL gains, PPD reduction, and reduction in radiographic defect depth. CLINICAL RELEVANCE: The NcHA and HA + ß-TCP with A-PRF is a novel material used in the treatment of infrabony defect for periodontal regeneration. The NcHA and HA + ß-TCP with A-PRF need to consider biomaterials for bone defect fill.

Design and manufacturing of biomimetic scaffolds for bone repair inspired by bone trabeculae.

Porous scaffold (PorS) implants, particularly those that mimic the structural features of natural cancellous bone (NCanB), are increasingly essential for the treatment of large-area bone defects. However, the mechanical properties of NCanB-based bionic bone scaffold (BioS) and its performance as a bone repair material have not been fully explored. This study investigates the effect of bionic structure parameters on the mechanical properties and bone reconstruction performance of BioS. Using laser powder bed fusion (L-PBF) technology, different BioS with various structural parameters were created and evaluated using Micro-CT, compression testing, Finite Element (FE) Simulation, and computational fluid dynamics (CFD), and compared to commonly used clinical PorS. Assess the capacity of the BioS scaffold to support and enhance bone reconstruction following implantation through the evaluation of its mechanical properties, permeability, and fluid shear stress (FSS). BioS-85-90 and BioS-80-50 showed suitable mechanical properties, performed well in FE simulation of implantation, demonstrated outstanding abilities for osteoinductive ingrowth and bone tissue differentiation, and proved to be reliable materials for the reconstruction of bone defects. Therefore, BioS shows significant potential for clinical application as a bone reconstruction material, providing a solid foundation for the integration of tissue engineering and bionic design.

Noninvasive and Microinvasive Nanoscale Drug Delivery Platforms for Hard Tissue Engineering.

Bone tissue plays a crucial role in protecting internal organs and providing structural support and locomotion of the body. Treatment of hard tissue defects and medical conditions due to physical injuries, genetic disorders, aging, metabolic syndromes, and infections is more often a complex and drawn out process. Presently, dealing with hard-tissue-based clinical problems is still mostly conducted via surgical interventions. However, advances in nanotechnology over the last decades have led to shifting trends in clinical practice toward noninvasive and microinvasive methods. In this review article, recent advances in the development of nanoscale platforms for bone tissue engineering have been reviewed and critically discussed to provide a comprehensive understanding of the advantages and disadvantages of noninvasive and microinvasive methods for treating medical conditions related to hard tissue regeneration and repair.

Supracondylar Apophysis of the Humerus: Rare Cause of High Compression of the Median Nerve / Apófise supracondilar do úmero: Causa rara de compressão alta do nervo mediano

Abstract Supracondylar apophysis (SA) is a bony prominence that originates from the anteromedial aspect of the distal humerus with a lower projection and which, although usually asymptomatic, due to the relationship with adjacent structures can cause symptoms. We describe the case of a 42-year-old woman with pain complaints radiating from her elbow to her hand, with 6 months of evolution. On objective examination, the patient had a sensory deficit in the median nerve territory and decreased grip strength. Radiographs of the distal humerus were performed, in which a bone spike was visible, and magnetic resonance imaging showed thickening of the median nerve epineurium. Electromyography showed severe axonal demyelination of the median nerve proximal to the elbow. A median nerve compression caused by a SA was diagnosed. The patient underwent surgery and, 1 year after the operation, she had a complete clinical recovery. Supracondylar apophysis is a rare, but possible and treatable cause of high median nerve compression.

Resumo A apófise supracondilar (ASC) é uma proeminência óssea que tem origem na face anteromedial do úmero distal com projeção inferior e que, apesar de habitualmente assintomática, pela relação com as estruturas adjacentes pode causar sintomatologia. Descrevemos o caso de uma mulher de 42 anos, com queixas álgicas irradiadas do cotovelo à mão, com 6 meses de evolução. Ao exame objetivo, a paciente apresentava um déficit sensorial no território do nervo mediano e diminuição da força de preensão. Foram realizadas radiografias do úmero distal nas quais era visível uma espícula óssea, e na ressonância magnética era evidente o espessamento do epineuro do nervo mediano. A eletromiografia apresentou uma desmielinização axonal grave do nervo mediano proximal ao cotovelo. Foi diagnosticada uma compressão do nervo mediano por uma ASC. A paciente foi submetida à cirurgia e 1 ano pós-operatório apresentou recuperação clínica total. A ASC é uma causa rara, mas possível e tratável da compressão alta do nervo mediano.

New strategy for osseodensification during osteotomy in low-density bone: an in vitro experimental study.

The goal of this in vitro study was to evaluate and propose a new strategy for osseodensification technique using a drill counterclockwise to densification of bone of low density. Synthetic bone blocks of two different low densities (type III and IV) were used for the tests. The conventional drilling group (CD group) used Turbo-drill in a clockwise direction, and the osseodensification group (OD group) applied Turbo-drill in a counterclockwise direction. The applied tests were: (i) measurement of the temperature variation (ΔT) and (ii) measurement of the torque during the osteotomies, comparing the new strategy with the conventional drilling. Both groups were tested without (condition c1) and with (condition c2) irrigation, generating four subgroups: CDc1, CDc2, ODc1, and ODc2. Twenty osteotomies were made for each subgroup with a thermocouple positioned intra-bone (1 mm distant from the osteotomy) to measure the temperature produced. Other 20 samples/group were used to measure the torque value during each osteotomy in both synthetic bone density blocks. The mean of the ΔT during the osteotomies in type III bone was: 6.8 ± 1.26 °C for the CDc1 group, 9.5 ± 1.84 °C for the ODc1, 1.5 ± 1.35 °C for the CDc2, and 4.5 ± 1.43 °C for ODc2. Whereas, in the type IV bone, the ΔT was: 5.2 ± 1.30 °C for the CDc1 group, 7.0 ± 1.99 °C for the ODc1, 0.9 ± 1.05 °C for the CDc2, and 2.7 ± 1.30 °C for ODc2. The maximum torque during the osteotomies was: 8.8 ± 0.97 Ncm for CD samples and 11.6 ± 1.08 Ncm for OD samples in the type III bone; and 5.9 ± 0.99 Ncm for CD samples and 9.6 ± 1.29 Ncm for OD samples in the type IV bone. Statistical differences between the groups were detected in tests and conditions analyzed (p < 0.05). Using the drill counterclockwise for osseodensification in low-density bone generated a significantly greater torque of a drill than in CD and temperature variation during osteotomies. However, the temperature range displayed by the OD group was below critical levels that can cause damage to bone tissue.

Progress in the application of 3D-printed sodium alginate-based hydrogel scaffolds in bone tissue repair.

In recent years, hydrogels have been widely used in the biomedical field as materials with excellent bionic structures and biological properties. Among them, the excellent comprehensive properties of natural polymer hydrogels represented by sodium alginate have attracted the great attention of researchers. At the same time, by physically blending sodium alginate with other materials, the problems of poor cell adhesion and mechanical properties of sodium alginate hydrogels were directly improved without chemical modification of sodium alginate. The composite blending of multiple materials can also improve the functionality of sodium alginate hydrogels, and the prepared composite hydrogel also has a larger application field. In addition, based on the adjustable viscosity of sodium alginate-based hydrogels, sodium alginate-based hydrogels can be loaded with cells to prepare biological ink, and the scaffold can be printed out by 3D printing technology for the repair of bone defects. This paper first summarizes the improvement of the properties of sodium alginate and other materials after physical blending. Then, it summarizes the application progress of sodium alginate-based hydrogel scaffolds for bone tissue repair based on 3D printing technology in recent years. Moreover, we provide relevant opinions and comments to provide a theoretical basis for follow-up research.

VISTA Approach in Conjunction with Enamel Matrix Derivative, Corticocancellous Bone, and Connective Tissue Graft for Periodontal Defect Surgery: A Case Series.

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.

Fibrocartilage extracellular matrix augmented demineralized bone matrix graft repairs tendon-to-bone interface in a rabbit tendon reconstruction model.

Current tendon/ligament reconstructions integrate via scar tissue rather than proper bone-tendon interface regeneration, which affects graft longevity, changes in bone tunnel size, and functional outcomes. The purpose of this study was to develop a functional demineralized bone matrix (DBM) + fibrocartilage extracellular matrix (FCECM) composite scaffold, characterize its physicochemical properties, and evaluate its efficacy in repairing tendon-bone interface in a rabbit tendon reconstruction model. Solubilized FCECM was loaded and crosslinked on to DBM scaffolds via gamma-irradiation to create DBM + FCECM scaffolds. The resulting scaffold showed interconnected pores coated with FCECM and protein cargo similar to FCECM. The addition of FCECM modified the physicochemical properties of the DBM scaffold, including microstructure, biochemical composition, mechanical strength, thermodynamic properties, and degradation period. The DBM + FCECM scaffold was biocompatible for mesenchymal stem cells (MSCs) and resulted in elevation of fibrochondrogenic gene markers compared to DBM scaffolds in vitro. In vivo implantation of DBM + FCECM scaffold resulted in neofibrocartilage formation, better pullout strength, and less bone tunnel widening compared to DBM only group in a rabbit tendon reconstruction model. In conclusion, the FCECM augmented DBM scaffold repairs the tendon-bone interface with osseous-fibrocartilage tissue, which may be utilized to improve current tendon reconstruction surgeries.

The Diamond Concept Enigma: Recent Trends of Its Implementation in Cross-linked Chitosan-Based Scaffolds for Bone Tissue Engineering.

An increasing number of publications over the past ten years have focused on the development of chitosan-based cross-linked scaffolds to regenerate bone tissue. The design of biomaterials for bone tissue engineering applications relies heavily on the ideals set forth by a polytherapy approach called the "Diamond Concept". This methodology takes into consideration the mechanical environment, scaffold properties, osteogenic and angiogenic potential of cells, and benefits of osteoinductive mediator encapsulation. The following review presents a comprehensive summarization of recent trends in chitosan-based cross-linked scaffold development within the scope of the Diamond Concept, particularly for nonload-bearing bone repair. A standardized methodology for material characterization, along with assessment of in vitro and in vivo potential for bone regeneration, is presented based on approaches in the literature, and future directions of the field are discussed.

[Evaluation of the effect of cattle calcined bone grafting material to repair alveolar bone defect after tooth extraction].

PURPOSE: To verify the efficacy and safety of calcined cattle bone grafting material in filling alveolar bone defect after tooth extraction. METHODS: A randomized, bind, parallel, positive-control multicenter clinical trial was conducted. A total of 280 subjects were randomly assigned to either the experimental group (calcined cattle bone group) or control group (Bio-Oss group) equally. The main efficacy indicator was the imaging changes 24 weeks after material implantation. Secondary efficacy indicators were wound healing, rejection, bone metabolism, post-filling symptoms and signs of bone infection. The safety of material was assessed by the incidence of adverse events and serious adverse events. SAS 8.2 software package was used for statistical analysis. RESULTS: A total of 280 cases were included, of them 267 cases completed the study while 13 cases fell off. The effective rate of FAS(PPS) was 90.58%(97.46%) in the experimental group and 87.05% (95.04%) in the control group. The difference of effective rate between the experimental group and control group (95%CI) was 3.53% (-3.88%, 10.94%) of FAS, 2.42% (-2.38%, 7.22%) of PPS, and there was no significant difference between the two groups. The incision healing of the two groups was good, and the incidence of rejection, bone infection signs, post-filling symptoms and bone metabolic changes was very low. The incidence of adverse events was similar in the two groups, and no serious adverse events related to the study materials occurred. CONCLUSIONS: The efficacy of calcined cattle bone grafting material in filling alveolar bone defect after tooth extraction is not inferior to that of Bio-Oss, and it is safe and effective for alveolar bone defect repair.