Bovine Hydroxyapatite Research Articles

Tomographic and Electron Microscopy Description of Two Bone-Substitute Xenografts for the Preservation of Dental Alveoli.

After tooth extraction, bone levels in the alveoli decrease. Using a bone substitute can help minimize this bone loss. The substitute can be sourced from a human or animal donor or synthetically prepared. In this study, we aimed to address the following PICOS question: In patients needing dental alveolar preservation for implant placement, how does alveolar preservation using a bovine hydroxyapatite bone xenograft with collagen compare to a xenograft without collagen in terms of changes in alveolar height and width, bone density, and the characteristics of the bone tissue observed in biopsies taken at 6 months? We evaluated two xenograft-type bone substitutes for preserving post-extraction dental sockets using tomography and microscopy to answer that question. A total of 18 dental alveoli were studied: 11 preserved with a xenograft composed of apatite (InterOss) and 7 with a xenograft composed of apatite-collagen (InterOss Collagen). Tomographic controls were performed at 1 and 6 months, and microscopic studies were performed on 13 samples. The biopsies were examined with scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). A Multivariate Analysis of Variance (MANOVA) was conducted in the statistical analysis, revealing a significant increase in bone density over time (p = 0.04). Specifically, bone density increased from an average of 526.14 HU at 30 days to 721.96 HU at 60 days in collagen-free samples. However, no statistically significant differences in height or width were found between groups. The MANOVA results indicated that the overall model had a low predictive ability for height, width, and density variables (R-squared values were low), likely due to sample size limitations and the complexity of bone tissue dynamics. On the other hand, FTIR analysis revealed the presence of phosphate groups, carbonates, and amides I, II, and III, indicative of inorganic (hydroxyapatite) and organic (type I collagen) materials in the xenografts. TGA and DSC showed high thermal stability, with minimal mass loss below 150 °C. Finally, both xenografts were influential in alveolar bone regeneration after extraction without significant differences. The trend of increasing collagen density suggests an effect that requires further investigation. However, it is recommended that the sample size be increased to enhance the validity of the results.

Effect of pH on hydroxyapatite coatings obtained by spray pyrolysis and their use as matrices for antibiotic adsorption by spin coating and release properties.

Calcium phosphate materials, particularly hydroxyapatite (HA), are extensively used in biomedical applications because of their prominence as primary inorganic constituents of human hard tissues. This study investigates the synthesis of HA coatings via spray pyrolysis using various precursors, including HA derived from bovine bone. The effects of pH on the formation and properties of HA coatings were systematically examined. Samples exposed to acidic conditions or left without pH adjustment led to the formation of HA, contrasting with the outcomes observed through dissolution methods. Different characterization techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD), were employed to evaluate the quality and crystallinity of the coatings. Among the samples, those exhibiting superior crystallinity and nanostructured features, including bovine HA, were selected for further surface functionalization with the antibiotic enrofloxacin using spin coating. As expected, the antibiotic loading on each material's surface depended on the amount of HA deposited on the substrate. However, the desorption results indicated that, in all cases, desorption persisted beyond 38 h, implying that HA-loaded matrices could be effective systems for controlled and prolonged drug release, which could be useful in dental or orthopedic implants for inhibiting the growth of bacterial biofilms.

Effect of bovine hydroxyapatite composite with secretome under normoxia and hypoxia conditions on inflammatory parameters in massive bone defect of rabbit radius bone.

Hydroxyapatite as a scaffold is capable of producing good bone regeneration formation. Incorporating secretome into scaffolds optimizes the bone healing process. The increase in proinflammatory, anti-inflammatory, and growth factors is one of the key factors in bone healing. In this study, we measured the levels of IL-6, IL-10, and FGF-2 to determine the effectiveness of bovine hydroxyapatite with secretome from normoxia and hypoxia on bone healing. This animal study employed a pure experimental research design, utilizing a post-test-only control group design. Bone marrow mesenchymal stem cells from rabbit thigh bones were used to derive secretomes under hypoxic and normoxic conditions. Bovine bone-derived hydroxyapatite (BHA) was treated with secretomes under both conditions. Rabbits' radius bones were implanted with BHA alone, BHA with normoxic secretome, and BHA with hypoxic secretome, then observed for 30 and 60 days. Levels of IL-6, IL-10, and FGF-2 were examined on days 30 and 60. On the 30th day, there was a significant increase in the levels of FGF-2, IL-6, and IL-10, with a dominance of strongly positive levels in BHA alone. However, on the 60th day, the levels of FGF-2, IL-6, and IL-10 started to decrease in all groups, with a dominance of moderately positive levels. Statistical tests showed significant results in all groups on days 30 and 60 (p < .05). Among the three groups, the best levels of growth factors and pro-inflammatory factors, and the lowest levels of anti-inflammatory factors were found in the BHA alone group on evaluation day 30.

Are we approaching the development of a novel calcium phosphate-based bioceramic dental material?

ObjectivesDevelop a sustainable bovine hydroxyapatite dental ceramic with the addition of titanium dioxide (TiO2) nanoparticles (5 % and 8 % by weight), analyzing the outcome of this addition to the microstructure, as well as its mechanical and chemical properties, in order to evaluate whether they satisfy the International Organization for Standardization (ISO) 6872:2015 for dental ceramics or not. MethodsDisks were obtained through uniaxial followed by isostatic pressing from bovine hydroxyapatite powder and TiO2 nanoparticles and sintered at 1300ºC for 2 h. Three experimental groups were developed (HA, HA+5 %TiO2 and HA+8 %TiO2) and subjected to X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), indentation fracture (IF), biaxial flexural strength (BFS) and chemical solubility test. ResultsXRD revealed, for HA group, the appearance of a peak corresponding to b-tricalcium phosphate (ß-TCP). For HA+ 5 %TiO2 and HA+ 8 %TiO2, the entire composition was converted into ß-TCP and calcium titanate (CaTiO3). The SEM images showed a dense ceramic matrix and a uniform distribution of another phase in groups with TiO2 nanoparticles. HA+ 5 %TiO2 (1.40 ± 0.18 MPa.m1/2) and HA+ 8 %TiO2 (1.32 ± 0.18 MPa.m1/2) showed significantly higher fracture toughness values than HA (0.67 ± 0.09 MPa.m1/2). HA showed significantly higher characteristic stress (295.8 MPa) in comparison to groups with 5 % (235.1 MPa) and 8 % (214.4 MPa) TiO2 nanoparticles. Differences were not observed between the Weibull modulus values. The solubility results indicated that all experimental ceramics were above the 2000 ug/cm2 limit set by the ISO 6872:2015. SignificanceThis study proposed the development and characterization of a new ceramic for dental prosthesis made from HA extracted from bovine bones, with the intention of reusing these solids waste and transforming them into a sustainable and low-cost material. Although the experimental calcium phosphate ceramic with additions of 5 % and 8 % of TiO2 achieved desirable mechanical properties, the chemical solubility values were very high.

The effect of green mussel (Perna viridis) shells’ hydroxyapatite application on alkaline phosphatase levels in rabbit femur bone defect

Background Non-union fractures can be prevented with bone grafts, such as hydroxyapatite made from green mussel shells. Green mussel shells contain a high percentage of HA, making them a promising alternative for bone healing. This research aims to reveal the effectiveness of green mussel shell HA as a bone substitute material and to provide knowledge for further research. Methods This research was conducted for four months using a true experimental research method with a post-test-only control group design. This study used 36 New Zealand rabbits (Oryctolagus cuniculus) which were divided into 9 groups: positive control, negative control, and intervention at weeks 2, 4 and 6 after the intervention. All groups were subjected to three general procedures: pre-surgery, surgery, and post-surgery. This study utilized histological evaluation and biochemical assessment, specifically measuring serum alkaline phosphatase (ALP) levels, to investigate the effects of hydroxyapatite (HA) from green mussel shells on bone healing in rabbits. Results The findings demonstrated that green mussel shell HA hashad efficacy in accelerating bone healing, better than HA bovine HA i.e. green mussel shell hydroxyapatite showed superior efficacy compared to bovine hydroxyapatite in accelerating and maximizing fracture healing, as compared to the 6-week negative control group and demonstrated a significant difference (p &lt; 0.05). Conclusions Green mussel hydroxyapatite is proven to be able to fasten and maximize the bone healing process as fast as bovine HA, and even has higher efficacy than bovine HA.

Comprehensive clinical and histological evaluation of bovine hydroxyapatite bone graft with polypropylene membrane versus leukocyte- and platelet-rich fibrin for alveolar preservation after tooth extraction.

Osseointegrated implant placement in the ideal prosthetic position necessitates a sufficient residual alveolar ridge. Tooth extraction and the subsequent healing process often lead to bony deformities, characterized by a reduction in alveolar ridge height and width, resulting in unfavorable ridge architecture for dental implant placement. Several materials, including allografts, alloplastics, xenografts, and autogenous bone, are commonly used to address these concerns. In this context, leucocyte- and platelet-rich fibrin (L-PRF) emerges as a promising solution. This case report aims to compare the clinical and histological efficacy of bovine hydroxyapatite bone graft covered with polypropylene membrane (BHAG-PM) and leucocyte- and platelet-rich fibrin (L-PRF) in preserving dental alveoli following tooth extraction. Extraction, graft placement in the alveoli, and the anterior border between extracted elements were performed for both treatment groups. Up to 24 months of follow-up revealed satisfactory and comparable clinical and histological outcomes. These results suggest that both BHAG-PM and L-PRF effectively promote alveolar preservation, paving the way for ideal implant placement. In general, bone-substitute materials are effective in reducing alveolar changes after tooth extraction. Xenograft materials should be considered as among the best of the available grafting materials for alveolar preservation after tooth extraction. Both techniques effectively preserve the alveolar bone and facilitate the placement of osseointegrated implants in ideal positions, paving the way for successful oral rehabilitation.

Effect of Applying 1% Metformin on Guided Bone Regeneration Processes with Bovine-Derived Xenografts.

Background: Although xenografts have shown successful results in GBR procedures due to their osteoconductive properties, many authors have opted to add co-adjuvant drugs to favor osteogenesis and differentiate cells into an osteoblastic lineage. Metformin has been shown to have bone-protective properties, regulating osteoclast differentiation, as well as the ability to promote osteoblast mineralization and differentiation. The present study aimed to evaluate the effect of the local application of a 1% metformin solution on bone neoformation in the treatment of an experimental bone defect in a guided bone regeneration animal model with a particulated bovine hydroxyapatite xenograft with hyaluronate. Methods: With this purpose in mind, two critical defects with 8 mm diameter and 0.5 mm depth were created in eight male New Zealand rabbit calvarias. Titanium cylinders were fixed in each defect and filled with particulate hydroxyapatite of bovine origin and sodium hyaluronate, with sterile injectable saline added to the control group and sterile 1% metformin solution added to the test group. At 6 weeks, the animals were euthanized, and samples were obtained and prepared for histomorphometric analysis. Results: A higher percentage of new bone formation was observed in the metformin samples than in the control samples, both in the region closest to the animal's calvaria and in the most distal region analyzed. A higher average bone-biomaterial contact percentage was observed in the samples, with metformin in both the proximal and distal regions. There was no statistically significant difference in the mean value in either region in both parameters. Conclusion: The local application of a 1% metformin solution in an animal model of guided bone regeneration with particulate bovine hydroxyapatite and hyaluronate resulted in greater bone neoformation and xenograft osseointegration than in the control group.

Bovine hydroxyapatite/3Y-TZP bioceramic: Aligning 3Y-TZP content with sintering parameters

This study aimed to produces and characterize bovine hydroxyapatite (HA) bioceramic with 3Y-TZP addition and analyze different sintering curves. HA was extracted from bovine bones and nanoparticulated. HA discs (0, 1, 5 and 10 wt% 3Y-TZP) were subjected to uniaxial and isostatic pressing. Dilatometry analysis was performed and the groups were sintered using 3 different firing curves (conventional, 1300 °C; 2-step, 1292 °C; 2-step, 1420 °C). The samples were analyzed by X-ray diffraction (XRD), biaxial flexural strength (BFS), Vickers microhardness (VH) and Field emission scanning electron microscopy (FE-SEM). The dilatometry results signaled the need for sintering optimization in groups added with 3Y-TZP. XRD demonstrated the characteristic crystallographic peaks of HA in the pure groups and with 1% 3Y-TZP, and decomposition of HA into β-TCP and formation of calcium zirconate in the groups with 5 and 10% 3Y-TZP. Considering each composition, the groups of pure HA (131.3 ± 13.5 MPa; 401 ± 12.7 GPa) sintered by the conventional curve and HA+1%3Y-TZP (145 ± 8.6 MPa; 507 ± 47.9 GPa), HA+5%3Y-TZP (68.1 ± 14.2 MPa; 183 ± 9.8 GPa) and HA+10%3Y-TZP (55.6 ± 5.1 MPa; 96.1 ± 7.64 GPa) sintered by the 2-step curve at 1420 °C, combined the best BFS and VH results. The addition of 1 wt% 3Y-TZP and optimization in the sintering process improved the mechanical and microstructural properties of HA bioceramics and maintenance of its crystalline characteristics. Refinement in material processing is necessary for the future use of this bioceramic in dentistry.

In vitro immersion study and characterization of biomimetic bovine hydroxyapatite scaffolds: Influence of calcination temperature (600 and 1000 °C) on apatite formation

This work reports on the properties of natural bovine hydroxyapatite (HAp) scaffolds calcined at temperatures of 600 and 1000 °C and on the effects of apatite formation on these calcined scaffolds during immersion experiments in Hank's Balanced Salt Solution (HBSS) from 0 to 28 days. The study systematically identifies different mechanisms that determine the formation of the apatite layer. First, compositional analysis of the scaffolds by inductively couple plasma (ICP) reveals significant differences in macromineral content, which includes calcium, phosphorus, magnesium, and sodium. Subsequent X-ray diffraction (XRD) analysis reveals the presence of hydroxyapatite in both scaffolds, while the 1000 °C sample has additional β-whitlockite due to the higher calcination temperature. Further investigation by Fourier Transform Infrared Spectroscopy (FTIR) and Raman analyzes revealed carbonated HAp in the 600 °C scaffolds and characteristic bands of HAp in the 1000 °C scaffolds. Morphological changes during immersion, documented by Scanning Electron Microscopy (SEM) images, display leaf-like and cauliflower-like structures in the 600 °C sample and rash-like features leading to leaf-type apatite formation in the 1000 °C sample. High-Resolution Transmission Electron Microscopy (HR-TEM) showed elongated crystals in both samples, confirming exclusive HAp presence in the 600 °C sample and the coexistence of HAp and β-whitlockite phases in the 1000 °C sample. After 28 days of immersion, TEM images at 600 °C reveal ordered apatite particles, while the 1000 °C images exhibit random apatite formation, confirmed by Energy Dispersive X-ray Spectroscopy in TEM (EDS-TEM). In addition, both scaffolds calcined at 600 and 1000 °C showed biocompatibility, as cytotoxicity tests confirmed a remarkable 100 % cell viability, underlining their non-toxicity. The scaffolds calcined at 600 and 1000 °C therefore exhibit high bioactivity and viability, supporting their suitability for bone tissue engineering applications.

Mechanical characterisation of polylactic acid-alendronate bioscrew in different concentrations of glutaraldehyde

Background: Bioscrew is a developing innovation as a substitute to avoid re-surgery for screw removal; one of the bioscrew materials is polylactic acid (PLA). Alendronate plays a role in reducing osteoclastic activity, causing a decrease in osteoclast-mediated bone resorption, thereby accelerating the process of bone union. Objective: This study determines adding various glutaraldehyde concentrations to the bioscrew mechanical characteristics. Method: This study used the PLA bioscrew immersed into bovine hydroxyapatite (BHA)-gelatin (GEL)-alendronate (ALE) solution, then added with 0% (F1), 1% (F2), and 1,5% (F3) glutaraldehyde (GTA) as cross-link agent. Result: The pore diameter for F1, F2, and F3 were: 38.90±15.34; 29.01±8.94; and 30.58±7.40 μm, respectively. The flexural strength for F1, F2, and F3 were: 1.00±0.22, 1.18±0.13, and 1.11±0.16 MPa, respectively. The pull-out strength for F1, F2, and F3 were: 4.88 ± 0.79; 7.87 ± 0.24; and 7.65±1.02 N, respectively. The degradation rate for F1, F2, and F3 were: 14.40±2.08; 3.81±0.67; and 4.97±0.58 %, respectively. This study has found that glutaraldehyde concentrations significantly affect pull-out strength and degradation rate. The highest mechanical strength and slowest degradation rate for % weight loss was F2. Conclusion: Adding glutaraldehyde may enhance the mechanical characteristics of the bioscrew.

Effectiveness of Bilayer Scaffold Containing Chitosan/Gelatin/Diclofenac and Bovine Hydroxyapatite on Cartilage/Subchondral Regeneration in Rabbit Joint Defect Models.

Subchondral defects are often caused by trauma involving cartilage damage, leading to subsequent damage to the underlying bone, specifically the subchondral region. Bilayer scaffolds made from biomaterials, such as bovine hydroxyapatite, possess biocompatible and biodegradable properties that mimic the natural environmental conditions of target tissues so that they can support the formation of new tissues. On the other side, diclofenac as an anti-inflammatory drug potentiates to inhibit the inflammatory excess regarding the damage. This study aims to study the effectiveness of diclofenac scaffold to rabbit joint defect model. The scaffold was implanted in the rabbit femoral trochlear bone hole, which had a diameter of 5 mm and a depth of 4 mm. After 28 days of intervention, the animals were examined using macroscopic evaluation, hematoxylin-eosin (HE) staining, and immunohistochemistry (IHC) for type I collagen and type II collagen. Subsequently, the cartilage was evaluated using the International Cartilage Repair Society (ICRS) scoring system. The macroscopic ICRS scores were significantly higher (p < 0.05) in the bilayer scaffold implantation group compared to the monolayer scaffold and control groups. Histological ICRS scores were also significantly higher (p < 0.05) in the bilayer scaffold group compared to the control group. Type II collagen expression was higher (p < 0.05) in the bilayer scaffold group compared to the monolayer scaffold and control groups, although type I collagen expression was lower in comparison. In conclusion, this research suggests that the diclofenac-loaded bilayer scaffold effectively enhances cartilage and subchondral bone regeneration.

Histomorphometric Comparison of Bio-Oss vs. Osteodens in Maxillary Sinus Floor Elevation Procedures

Introduction: The loss of dental elements can lead to excessive bone loss in the posterior maxillary segments, which can limit the placement of dental implants in that area, the pneumatization of the maxillary sinus and the absence of dental elements to keep the bone active are some of the main causes. Among the wide range of available grafting materials, bovine hydroxyapatite has been extensively studied and has shown excellent clinical and histological results. Materials and methods: A total of 17 maxillary sinus floor elevations were performed (n = 8 Osteodens, n = 9 Bio-Oss). After a healing period of 6 to 8 months, a block of the grafted area was obtained using trephines and analyzed by histomorphometry. Results: The percentage of neoformed bone tissue was higher for Bio-Oss (39.0% ± 11.1) compared to Osteodens (33.4% ± 8.3), while the remaining graft values were slightly lower in Bio-Oss compared to Osteodens (16.3% ± 11.2 and 20.8% ± 12.1, respectively). The proportion of connective tissue was similar in both groups (44.7% Bio-Oss and 45.8% Osteodens). Age, gender, and residual height of the sinus floor did not show statistically significant differences. Conclusions: In this study, both graft materials (Bio-Oss and Osteodens) showed no statistically significant differences in their ability to regenerate suitable bone tissue for implant placement after 6 months of healing. Further studies with a larger sample size are needed to validate these results.

Decontamination and Repair Protocol Promotes Positive Outcomes in Implants Affected by Peri-implantitis: A Human Case Series.

This study assessed the effectiveness and predictability of a readily available protocol to treat peri-implantitis utilizing mechanical debridement, chemical antiseptic surface detoxification, and osseous grafting. Nine patients (7 women, 2 men; mean age: 56.5 years) with 15 implants with peri-implantitis were included. Pocket probing depth (PPD), bleeding on probing (BOP), and standardized digital periapical radiographic measurements were taken. Surgical flaps were elevated, and the implant threads were cleaned with a plastic curette. Chemical decontamination was performed by scrubbing solutions of 0.25% sodium hypochlorite (NaClO) and 1.5% hydrogen peroxide (H2O2) around the exposed implant using cotton pellets. Bony defects were filled with a 50/50 mixture of bovine hydroxyapatite and nanocrystalline calcium sulfate (CaSO4). A porcine collagen membrane was placed over the grafted bony defect. Follow-up appointments were scheduled 1 week, 2 weeks, 3 months, 6 months, 9 months, and 1 year posttreatment. Clinical and radiographic parameters were assessed and compared. At baseline, PPD ranged from 5 to 7.5 mm (mean: 6 ± 0.7 mm). At 12 months, PPD ranged from 1.5 to 4.2 mm (mean: 2.5 ± 0.8 mm). The mean PPD reduction of 3.6 mm (59.2%) was statistically significant (P < .001). The number of bleeding sites around each test implant decreased significantly from 4 to 0.4 sites between baseline and 12 months (P < .001). Mean radiographic bone loss decreased from 4.8 ± 1.3 mm to 2.7 ± 1.2 mm (P < .001). The proposed method of mechanical decontamination, chemical detoxification, and bone regeneration is clinically effective and reproducible. Clinical peri-implant parameters and radiographic bone levels were improved and maintained their stability for 1 year using this peri-implantitis treatment protocol.

Application of green mussel (Perna viridis) shells hydroxyapatite on osteocalcin levels and osteoblast cells in rabbit femur bone defect.

Bovine hydroxyapatite (HA) used for bone grafts is relatively expensive, necessitating the development of alternative sources. Alternative HA materials derived from green mussel shells with smaller molecular sizes are inexpensive and abundantly available throughout Indonesian waters. The purpose of this study is to investigate the effect of green mussel shells HA on bone healing. This post-test-only experimental research used male rabbits with femoral defects divided into three groups randomly: K (no treatment), P1 (bovine HA treatment), and P2 (green mussel shell HA treatment). The osteocalcin level was assessed biochemically while osteoblast cells were histopathologically at the second, fourth, and sixth weeks. Statistic tests were used to assess differences between groups and periods with statistical significance P<0.05. Nine rabbits in each group showed significant differences between groups K, P1, and P2 in term osteocalcin levels at week 2 (2.60, 4.53±0.12, 4.47±0.23; P=0.046), week 4 (5.13±0.12, 8.53±0.12, 7.47±0.12; P=0.025), and week 6 (8.20, 11.93±0.23, 10.93±0.31, P=0.023), while in term osteoblast cells only at week 6 (16.33±3.46, 26.10±3.52, 30.40±3.29; P=0.006). The osteocalcin level and osteoblast increased significantly between groups K and P1/P2 from the initial trial until the last week. Osteoblast cells in the groups P1/P2 increased significantly, especially at week 6. Green mussel shell HA has the biochemical effectiveness of osteocalcin and can increase osteoblast cells comparable to bovine HA, which can enhance bone healing.

Biological performance of a novel bovine hydroxyapatite in a guided bone regeneration model: A preclinical study in a mandibular defect in dogs.

This preclinical model study aims to evaluate the performance and safety of a novel hydroxyapatite biomaterial (Wishbone Hydroxyapatite, WHA) on guided bone regeneration compared to a commercially available deproteinized bovine bone mineral (Bio-Oss, BO). Twenty-four beagle dogs were allocated to three timepoint cohorts (4, 12, and 26 weeks) of eight animals each. In all animals, four critical-sized, independent wall mandibular defects were created (32 defects/cohort). Each animal received all four treatments, allocated randomly to separated defects: WHA + collagen membrane (M), BO + M, no treatment (Sham, Sh), and Sh + M. At each timepoint, the specimens were harvested for histologic and histomorphometric analyses to determine the newly formed bone and osteoconductivity. At 4 weeks, bone regeneration was significantly higher for WHA + M (46.8%) when compared to BO + M (21.4%), Sh (15.1%), and Sh + M (23.1%) (p < 0.05); at 12 and 26 weeks, regeneration was similar for WHA and BO. Bone-to-material contact increased over time similarly for WHA + M and BO + M. From a safety point of view, inflammation attributed to WHA + M or BO + M was minimal; necrosis or fatty infiltrate was absent. WHA + M resulted in higher bone regeneration rate than BO + M at 4 weeks. Both BO + M and WHA + M were more efficient than both Sh groups at all timepoints. Safety and biocompatibility of WHA was favorable and comparable to that of BO.

Bone samples' behavior in sunlight, IR light, and temperature increase with FEM simulation.

Biological and environmental factors produce biochemical processes that modify the bone structure. A few studies have attempted to show the adverse biological effects of sun radiation. The bone tissue exposures to infrared and sunlight radiation are analyzed by using focused sound, characterization spectroscopy techniques, and image processing. The study is complemented with a finite element method simulation on temperature behaviors. The crystal morphology on the bone hydroxyapatite and functional groups was characterized by X-ray diffraction and infrared spectroscopy. The infrared spectra confirmed the hydroxyl group of bovine hydroxyapatite, amines, and lipids are also correlated with modifications of the hydroxyapatite. The diffractograms showed the characteristic peaks of hydroxyapatite, with the main intensity at 2θ = 32.02°. Bone samples exposed to sun radiation presented a peak at 2θ = 27.5°, evidencing the possible formation of β-TCP y α-TCP. The analysis with the spectroscopy techniques about the structural changes in the samples suggests interpreting an increase of sound obtained by expanding the exposure time. It is possible to verify that there are some structural changes in the bone samples due to exposure to non-ionizing radiation. These results show an increase in the registered intensity sound correlated with the interpretation of the structural changes of bone. Thanks to the different novel analysis techniques established in the present study, it could establish the changes that experienced the bone structure under different sources of radiation, which will help to better detect scenarios of bone deficiency.

The administration of bovine hydroxyapatite: Alendronate implant accelerates bone defect healing in an osteoporotic rat.

Bone fracture is the main consequence of osteoporosis, which may become a neglected disease. This study aims to fabricate bovine hydroxyapatite-gelatine (BHA-GEL) based bone-implant with alendronate (ALE) in vivo. Wistar rats were used for an osteoporotic animal model induced by ovariectomy. There were three groups: negative control, BHA-GEL implant, and BHA-GEL-ALE implant. Each group performed a defect by drilling the femur (diameter of 2.2mm and depth of 2mm). Observations on the closure of bone defects were performed by X-ray radiography at the second and sixth week after surgery. The mechanism of bone healing was observed by using hematoxylin-eosin (HE) staining and immunohistochemical technique with anti-vascular endothelial growth factor (VEGF) and anti-alkaline phosphatase (ALP) antibodies. The radiograph examination showed the implanted group had accelerated bone growth. In addition, the osteoblast, osteoclast and osteocyte had accelerated migration to the defect area. Moreover, the immunoreactive score (IRS) of VEGF at the sixth week in the BHA-GEL-ALE group was lower than the other groups. Meanwhile, the IRS of ALP in BHA-GEL-ALE was higher compared to other groups. The BHA-GEL-ALE implant accelerates the healing of bone defect in the osteoporotic rat by increasing the ALP expression and the total number of cells.

Vertical Bone Augmentation Using Two Bioactive Glasses in a Rabbit Tibia Model: A Comparative Study with Literature Review

Background: Recently, synthetic materials based on bioactive glasses have been in special demand in dental implantology, which, according to the mechanism of their action, are not only osteo-conductors, but also osteo-inductors. Of even greater interest is the fact that the biological degradation of these materials causes alkalization of the area and inhibits the growth of many pathogens. Considering the unique properties of this group of osteoplastic fillers and the problems associated with healing after guided bone regeneration, this study aimed to compare the effectiveness of using bioactive glasses S53P4 and 45S5 when performing vertical bone augmentation in an experiment applying a rabbit tibia model. Methods and Results: Six adult outbred rabbits aged from 1.5 to 2 years and weighing from 2.5 kg to 3.2 kg were used in the study. A titanium mesh was used to perform a true vertical guided bone regeneration technique. In each animal, two titanium tents were placed: one on the left tibia and one on the right tibia. On the left limb, empty spaces were filled with bioactive synthetic bone filler NovaBone® Morsels (USA); on the right limb, we used a mixture of bioactive glass Bonalive® granules CMF (Finland) and mineralized bone MedPark Bone-D XB (Bovine Xenograft, South Korea) in a ratio of 1:1. The quantity and quality of regenerated tissues were assessed after 8-10 weeks. The NovaBone application has allowed a gain of 2.6±2.67 mm in extra-skeletal hard tissue growth. No signs of guided bone regeneration were observed in all cases of application of an osteoplastic mixture of Bonalive and Bone-D XB granules. Conclusion: Within the limits of this study, it was found that the use of a mixture of bioactive glass Bonalive (S53P4) with bovine hydroxyapatite in a 1:1 ratio was not effective in vertically guided bone regeneration, but the application of NovaBone (45S5) could promote a new bone formation.

Characteristics of freeze-dried bovine hydroxyapatite (BHA)—secretome composites as bone graft candidates

Characteristics of freeze-dried bovine hydroxyapatite (BHA)—secretome composites as bone graft candidates

The effect of temperature on the physical-chemical properties of bovine hydroxyapatite biomimetic scaffolds for bone tissue engineering

This work focuses on the changes in hydroxyapatite (HAp) scaffolds obtained from bovine trabecular bone after heat treatments ranging from 400 to 1100 °C. The main objective is to gain a comprehensive understanding of the thermal behavior and structural modifications of these HAp scaffolds and evaluate their suitability for specific applications.Thermal analysis using thermogravimetry and differential scanning calorimetry revealed distinct thermal events associated with HAp crystallite coalescence, carbonate elimination, and Mg out-diffusion. Fourier transform infrared spectroscopy demonstrates the presence of organics in samples annealed at temperatures below 500 °C and the elimination of carbonates in samples annealed at temperatures above 700 °C.Raman spectroscopy indicated a transition from nano-to-micro-sized HAp crystallites in both the raw and samples annealed at 400 and 500 °C. X-ray diffraction analysis shows changes in the full width at half maximum (FWHM) of the (002) peak for the annealed samples. Crystalline parameters were determined using Rietveld refinement. Scanning electron microscopy images revealed the phenomenon of HAp crystallite coalescence during heat treatment. The growth of the crystallites and the transition from nano to micro size occurred at approximately 600 °C.Importantly, the macroporosity of the HAp scaffolds remained unchanged regardless of the calcination temperature, while mesoporosity was observed only in scaffolds calcined at lower temperatures (400, 500, and 600 °C). Furthermore, the raw, 400, and 500 °C scaffolds retained organic materials, resulting in improved mechanical properties.These findings provide valuable insights into the thermal behavior and structural changes of HAp scaffolds derived from bovine trabecular bone. The study suggests that scaffolds calcined at 600 °C exhibit suitable properties for bone tissue engineering applications, predominantly consisting of carbonated HAp nanocrystals, featuring three types of porosity, and are free of organic material.