Search Results (94)

Although publications have documented the osteo-inductive effects of various bioactive materials on tissue sections, the associated morphologic patterns of tissue remodeling pathways at the cellular level have not been detailed. Therefore, we present a comparative histopathological follow-up evaluation of bone defect repair mediated by silica aerogels and methacrylate hydrogels over a 6-month period, which is the widely accepted time course for complete resolution. Time-dependent microscopic analysis was conducted using the “critical size model”. In untreated rat calvaria bone defects (control), re-ossification exclusively started at the lateral regions from the edges of the remaining bone. At the 6th month, only a few new bones were formed, which were independent of the lateral ossification. The overall ossification resulted in a 57% osseous encroachment of the defect. In contrast, aerogels (AE), hydrogels (H), and their β-tricalcium-phosphate (βTCP)-containing counterparts, which were used to fill the bone defects, characteristically induced rapid early ossification starting from the 1st month. This was accompanied by fibrous granulomatous inflammation with multinucleated giant macrophages, which persisted in decreasing intensity throughout the observational time. In addition to lateral ossification, multiple and intense intralesional osseous foci developed as early as the 1st month, and grew progressively thereafter, reflecting the osteo-inductive effects of all compounds. However, both βTCP-containing bone substituents generated larger amounts and more mature new bones inside the defects. Nevertheless, only 72.8–76.9% of the bone defects treated with AE and H and 80.5–82.9% of those treated with βTCP-containing counterparts were re-ossified by the 6th month. Remarkably, by this time, some intra-osseous hydrogels were found, and traces of silica from AE were still detectable, indicating these as the causative agents for the persistent osseous–fibrous granulomatous inflammation. When silica or methacrylate-based bone substituents are used, chronic ossifying fibrous granulomatous inflammation develops. Although 100% re-ossification takes more than 6 months, by this time, the degree of osteo-fibrous solidification provides functionally well-suited bone repair. Full article

Aim: to evaluate the bone regeneration capacity of two alloplastic biomaterials in a critical-size rat calvarial defect model. Methods: A total of 80 rats were randomized into 8 groups of 10 animals each. An Ø8 mm, critical-size calvarial defect was created, and the following treatments were randomly allocated: sham surgery, deproteinized bovine bone mineral (DBBM) + collagen membrane (CM), poly-(lactic-co-glycolic-acid) (PLGA)-coated pure phase β-tricalcium phosphate (β-TCP), or PLGA-coated 60% hydroxyapatite (HA):40%β-TCP. Animals were allowed to heal for 2 and 6 weeks. Microcomputed tomography (μCT) was used to evaluate mineralized tissue and biomaterial displacement. Histological samples were used to evaluate new bone formation. Results: μCT analysis showed no significant differences among groups for total volume of mineralized tissue or residual biomaterials. DBBM + CM showed significantly increased horizontal biomaterial displacement at 2 weeks but not at 6 weeks. Histological analysis showed that sham surgery had a significantly higher percentage of bone area fraction than the DBBM + CM and PLGA + β-TCP at 2 weeks, but not at 6 weeks. Residual biomaterial area fraction showed no significant differences among experimental groups at any healing time. Conclusions: The alloplastic biomaterials showed suitable construct integrity and retention in the defect. All biomaterials were associated with limited new bone formation comparable to the sham surgery control. Full article

(1) Background: Alveolar bone regeneration in dentistry has become important with the evolution of implantology. Biomaterials used for bone grafting are increasingly used to provide resistant bone support that is favorable for the insertion of dental implants. The aim of the study was to analyze the degree of biocompatibility and bone neoformation of two biomaterials compared to natural healing. (2) Methods: Bone defects of 3 mm diameter were created in the calvaria of 15 adult male Wistar rats. Three groups were created: group A, in which natural healing was achieved; group B, in which porcine xenograft was added; and group C, in which experimental synthetic bone based on hydroxyapatite reinforced with titanium particles was added. Samples were collected at 2 and 4 months postoperatively and analyzed microscopically and histologically. (3) Results: Data were obtained on the healing pattern of the created cavities, as well as the degree of their filling with newly formed bone tissue. Following the results obtained from the stereomicroscope analysis and histological analysis, statistically significant differences were observed between the two biomaterials regarding the time required for the transformation process of the graft particles into bone. Thus, the porcine xenograft was incorporated more quickly into the native bone, while the synthetic bone required a longer period of time. (4) Conclusions: The bone graft materials used acted as scaffolds for the newly formed bone, but each biomaterial required a different amount of time for the particles to be incorporated into the native bone. Full article

Background: Osseointegrated implants are essential for rehabilitating edentulous patients, but critical bone defects remain challenging. Guided bone regeneration (GBR) with barrier membranes is an effective approach. This study evaluated a 3D printed membrane made from acrylated epoxidized soybean oil (AESO) combined with a xenogeneic graft for GBR in critical-size defects. Methods: Forty-eight male Sprague Dawley rats (150 g) were assigned to four groups: a negative control group (NC, blood clot only), a positive control group (PC, biomaterial without membrane), a negative test group (NT, blood clot with membrane), and a positive test group (PT, biomaterial with membrane). Results: The PT group showed the highest bone volume and superior bone maturation compared to the other groups. Bone quality parameters (Tb.N, Tb.Th) indicated enhanced maturation in the groups using the membrane. A histological analysis confirmed centripetal bone formation. Conclusion: The AESO-based membrane provided mechanical support and controlled resorption, addressing collagen membrane limitations. Its combination with the GTO^® graft material enhanced osteoconduction, bone formation, and bone quality, highlighting its potential for complex bone defect reconstructions. Full article

Bone substitutes are commonly used in bone regeneration, and their functionalization with bioactive molecules can significantly enhance bone regeneration by directly influencing bone cells. This study aimed to evaluate the potential of raloxifene-functionalized Cerabone^® (CB) for promoting bone repair and to highlight the implications in bone regeneration. The effectiveness of Cerabone^® functionalized with raloxifene via sonication or gel delivery in promoting bone repair in rat calvaria defects was assessed. Ninety-six male rats with critical-sized calvarial defects were divided into six treatment groups (n = 16): COAG (spontaneous blood clot), CB (Cerabone^®), CBS (Cerabone^® sonicated alone), CBRS (Cerabone^® with raloxifene sonicated), CBG (Cerabone^® with gel vehicle), and CBRG (Cerabone^® with 20% raloxifene gel). After 14 and 28 days, samples were analyzed using microtomography, histomorphometry, immunohistochemistry, and fluorescence techniques. Quantitative data were statistically analyzed, comparing each group to the control CB group with significance set at p < 0.05. Micro-CT analysis demonstrated a significant increase in bone volume in the CBRS, CBRG, and CBS groups at 28 days compared to the CB group (p < 0.05). Specifically, the mean bone volume percentages for the CBRS, CBRG, CBS, and CB groups were 21.18%, 17.51%, 13.18%, and 7.8%, respectively. Histomorphometry showed increased new bone formation in the CBRS and CBRG groups at both 14 and 28 days. Fluorescence analysis revealed a significantly higher daily mineral apposition rate in the CBRS and CBRG groups at 28 days. These findings suggest that raloxifene-functionalized CB, delivered via sonication or gel, significantly enhances bone repair by improving bone volume and mineralization, highlighting its potential as an effective strategy for bone regeneration. Full article

This study evaluated the osteogenic potential of the bioactive glasses SinGlass (45S5) and SinGlass High (F18) in regenerating critical bone defects in rat calvaria. Both biomaterials promoted new bone formation around the particles, with the SinGlass High (F18) group exhibiting a higher rate of bone maturation. Histomorphological and birefringence analyses revealed better organization of the newly formed bone in the biomaterial-treated groups, and immunohistochemistry indicated the expression of osteogenic markers such as osteocalcin, immunostaining for bone morphogenetic protein 2 (BMP 2), and immunostaining for bone morphogenetic protein 4 (BMP 4). Microtomography computadorized (Micro-CT) revealed centripetal bone formation in both groups, with greater integration of the particles into the surrounding bone tissue. The superior performance of SinGlass High (F18) was attributed to its higher potassium and magnesium content, which enhance osteoconductivity. After 42 days, the SinGlass High (F18) group showed the highest percentage of new bone formation, in line with previous studies. Although our results are promising, the limited follow-up period and use of a single animal model highlight the need for further research to validate clinical applicability. SinGlass High (F18) appears to be a viable alternative to autografts in bone repair, with potential to improve tissue integration and accelerate recovery. Full article

Background: The use of ex vivo assays associated with biomaterials may allow the short-term visualization of a specific cell type response inserted in a local microenvironment. Blood is the first component to come into contact with biomaterials, providing blood clot formation, being substantial in new tissue formation. Thus, this research investigated the physiological blood clot (PhC) patterns formed in 3D scaffolds (SCAs), based on chitosan and 20% beta-tricalcium phosphate and its effect on osteogenesis. Initially, SCA were inserted for 16 h in rats calvaria defects, and, after that, osteoblasts cells (OSB; UMR-106 lineage) were seeded on the substrate formed. The groups tested were SCA + OSB and SCA + PhC + OSB. Cell viability was checked by MTT and mineralized matrix formation in OSB using alizarin red (ARS). The alkaline phosphatase (ALP) and bone sialoprotein (BSP) expression in OSB was investigated by indirect immunofluorescence (IF). The OSB and PhC morphology was verified by scanning electron microscopy (SEM). Results: The SCA + PhC + OSB group showed greater cell viability (p = 0.0169). After 10 days, there was more mineralized matrix deposition (p = 0.0365) and high ALP immunostaining (p = 0.0021) in the SCA + OSB group. In contrast, BSP was more expressed in OSB seeded on SCA with PhC (p = 0.0033). Conclusions: These findings show the feasibility of using PhC in ex vivo assays. Additionally, its inclusion in the experiments resulted in a change in OSB behavior when compared to in vitro assays. This “closer to nature” environment can completely change the scenario of a study. Full article

Bone regeneration is a highly dynamic and complex process that involves hematopoietic stem cells and mesenchymal cells, collagen fibers, non-collagenous proteins and biomolecules from extracellular matrices, and different cytokines and immune cells, as well as growth factors and hormones. Some phytochemicals due to antioxidant and anti-inflammatory effects can modulate the bone signaling pathways and improve bone healing and thus can be a good candidate for osteoregeneration. The aim of this study was to analyze the impact of Juglans regia L. extract compared to ellagic acid on bone neoformation in rats. The animals with a 5 mm calvaria defect were divided into four groups (n = 10): group 1 was treated with ellagic acid 1% (EA), group 2 was treated with Juglans regia L. extract 10% (JR), group 3 was treated with a biphasic mix of hydroxyapatite and tricalcium phosphate (Ceraform), and group 4 was treated with vehicle inert gel with carboxymethylcellulose (CMC). After 3 weeks of treatment, blood samples were collected for oxidative stress and inflammation assessment. Additionally, the receptor activator of nuclear factor kappa-Β ligand (RANKL) and hydroxyproline levels were quantified in blood. The skull samples were analyzed by scanning electron microscopy in order to detect the modifications in the four groups. The results suggested that JR extract had relevant anti-oxidant effect and bone protective activity and generated the accumulation of Ca and P, demonstrating the potential therapeutic abilities in bone regeneration. Full article

The aim of this study was to evaluate the efficacy of autologous dentin (AD), bovine xenograft (BX) and magnesium-enriched bovine xenograft (BX + Mg) in the healing of critical cranial bone defects (CCBDs) in rats. Eighty male Wistar rats were divided into four groups: BX, BX + Mg, AD and the control group (no intervention). Eight mm CCBDs were created and treated with the respective biomaterials. Healing was assessed 7, 15, 21 and 30 days after surgery by micro-computed tomography (micro-CT), real-time polymerase chain reaction (RT-PCR) and immunohistochemical analysis. Micro-CT analysis showed that AD had the highest bone volume and the least amount of residual biomaterial at day 30, indicating robust bone formation and efficient resorption. BX + Mg showed significant bone volume but had more residual biomaterial compared to AD. RT-PCR showed that the expression of osteocalcin (OC), the receptor activator of nuclear factor κB (RANK) and sclerostin (SOST), was highest in the AD group at day 21 and vascular endothelial growth factor (VEGF) at day 15, indicating increased osteogenesis and angiogenesis in the AD group. Immunohistochemical staining confirmed intense BMP-2/4 and SMAD-1/5/8 expression in the AD group, indicating osteoinductive properties. The favorable gene expression profile and biocompatibility of AD and BX + Mg make them promising candidates for clinical applications in bone tissue engineering. Further research is required to fully exploit their potential in regenerative surgery. Full article

Biomaterials and biopharmaceuticals for correcting large bone defects are a potential area of translational science. A new bioproduct, purified from snake venom and fibrinogen from buffalo blood, aroused interest in the repair of venous ulcers. Expanding potential uses, it has also been used to form biocomplexes in combination with bone grafts, associated with physical therapies or used alone. The aim of this preclinical study was to evaluate low-level laser photobiomodulation (PBM) in critical defects in the calvaria of rats filled with nanohydroxyapatite (NH) associated with the heterologous fibrin biopolymer (HFB). Sixty animals were used, divided into six groups (n = 10 each): G1 (NH); G2 (HFB); G3 (NH + HFB); G4 (NH + PBM); G5 (HFB + PBM); G6 (NH + HFB + PBM). PBM simultaneously used red (R) and infrared (IR) light emission, applied intraoperatively and twice a week, until the end of the experiment at 42 days. Microtomography, bone formation can be seen initially at the margins of the defect, more evident in G5. Microscopically, bone formation demonstrated immature and disorganized trabeculation at 14 days, with remnants of grafting materials. At 42 days, the percentage of new bone formed was higher in all groups, especially in G5 (HFB, 45.4 ± 3.82), with collagen fibers at a higher degree of maturation and yellowish-green color in the birefringence analysis with Picrosirius-red. Therefore, it is concluded that the HFB + PBM combination showed greater effectiveness in the repair process and presents potential for future clinical studies. Full article

Background: Tissue engineering represents a promising field in regenerative medicine, with bioresorbable polymers such as polycaprolactone (PCL) playing a crucial role as scaffolds. These scaffolds support the growth and repair of tissues by mimicking the extracellular matrix. Objective: This study aimed to assess the in vivo performance of three-dimensional PCL scaffolds by evaluating their effects on bone repair in rat calvaria and the tissue reaction in subcutaneous implant sites, as well as their impact on major organs such as the kidneys, lungs, and liver. Methods: Three-dimensional scaffolds made of PCL were implanted in the subcutaneous tissue of rats’ backs and calvaria. Histological analyses were conducted to observe the bone repair process in calvaria and the tissue response in subcutaneous implant sites. Additionally, the kidneys, lungs, and livers of the animals were examined for any adverse tissue alterations. Results: The histological analysis of the bone repair in calvaria revealed newly formed bone growing towards the center of the defects. In subcutaneous tissues, a thin fibrous capsule with collagenous fibers enveloping the implant was observed in all animals, indicating a positive tissue response. Importantly, no harmful alterations or signs of inflammation, hyperplasia, metaplasia, dysplasia, or hemorrhage were detected in the kidneys, lungs, and liver. Conclusions: The findings demonstrate that PCL scaffolds produced through additive manufacturing are biocompatible, non-cytotoxic, and bioresorbable, promoting osteoconduction without adverse effects on major organs. Hence, PCL is confirmed as a suitable biomaterial for further studies in tissue engineering and regenerative medicine. Full article

Osteoporotic vertebral compression fractures (OVCFs) are the most prevalent fractures among patients with osteoporosis, leading to severe pain, deformities, and even death. This study explored the use of ectopic embryonic calvaria derived mesenchymal stem cells (EE-cMSCs), which are known for their superior differentiation and proliferation capabilities, as a potential treatment for bone regeneration in OVCFs. We evaluated the impact of EE-cMSCs on osteoclastogenesis in a RAW264.7 cell environment, which was induced by the receptor activator of nuclear factor kappa-beta ligand (RANKL), using cytochemical staining and quantitative real-time PCR. The osteogenic potential of EE-cMSCs was evaluated under various hydrogel conditions. An osteoporotic vertebral body bone defect model was established by inducing osteoporosis in rats through bilateral ovariectomy and creating defects in their coccygeal vertebral bodies. The effects of EE-cMSCs were examined using micro-computed tomography (μCT) and histology, including immunohistochemical analyses. In vitro, EE-cMSCs inhibited osteoclast differentiation and promoted osteogenesis in a 3D cell culture environment using fibrin hydrogel. Moreover, μCT and histological staining demonstrated increased new bone formation in the group treated with EE-cMSCs and fibrin. Immunostaining showed reduced osteoclast activity and bone resorption, alongside increased angiogenesis. Thus, EE-cMSCs can effectively promote bone regeneration and may represent a promising therapeutic approach for treating OVCFs. Full article

Background: Guided bone regeneration (GBR) has become a necessary practice in implantology. Absorbable membranes have shown advantages over non-absorbable membranes, such as blood support of bone tissue. This study aimed to evaluate five collagen membranes in rat calvaria critical-size defects through a histomorphometric analysis of the inflammatory profile during the initial phase of bone repair. Materials and methods: A total of 72 Albinus Wistar rats were used for the study, divided into six groups, with 12 animals per group, and two experimental periods, 7 and 15 days. The groups were as follows: the CG (clot), BG (Bio-Gide^®), JS (Jason^®), CS (Collprotect^®), GD (GemDerm^®), and GDF (GemDerm Flex^®). Results: Data showed that the BG group demonstrated an inflammatory profile with an ideal number of inflammatory cells and blood vessels, indicating a statistically significant difference between the JS and CS groups and the BG group in terms of the number of inflammatory cells and a statistically significant difference between the JS and CS groups and the GD group in terms of angiogenesis (p < 0.05). Conclusions: We conclude that different origins and ways of obtaining them, as well as the thickness of the membrane, can interfere with the biological response of the material. Full article

The aim of this study was to evaluate the effect of local administration of melatonin (MLT) on molecular biomarkers and calvaria bone critical defects in female rats with or without osteoporosis, associated or not with a xenogeneic biomaterial. Forty-eight female rats were randomly divided into two groups: (O) ovariectomized and (S) placebo groups. After 45 days of osteoporosis induction, two critical-size defects (5 mm diameter) were created on the calvaria. The groups were subdivided according to the following treatment: (C) Clot, MLT, MLT associated with Bio-Oss^® (MLTBO), and Bio-Oss^® (BO). After 45 days, the defect samples were collected and processed for microtomography, histomorphometry, and biomolecular analysis (Col-I, BMP-2, and OPN). All animals had one femur harvested to confirm the osteoporosis. Microtomography analysis demonstrated a bone mineral density reduction in the O group. Regarding bone healing, the S group presented greater filling of the defects than the O group; however, in the O group, the defects treated with MLT showed higher mineral filling than the other treatments. There was no difference between the treatments performed in the S group (p = 0.05). Otherwise, O-MLT had neoformed bone higher than in the other groups (p = 0.05). The groups that did not receive biomaterial demonstrated lower levels of Col-I secretion; S-MLT and S-MLTBO presented higher levels of OPN, while O-C presented statistically lower results (p < 0.05); O-BO showed greater BMP-2 secretion (p < 0.05). In the presence of ovariectomy-induced osteoporosis, MLT treatment increased the newly formed bone area, regulated the inflammatory response, and increased OPN expression. Full article

The purpose of this study was to evaluate the repair process in rat calvaria filled with synthetic biphasic bioceramics (Plenum^® Osshp-70:30, HA:βTCP) or autogenous bone, covered with a polydioxanone membrane (PDO). A total of 48 rats were divided into two groups (n = 24): particulate autogenous bone + Plenum^® Guide (AUTOPT+PG) or Plenum^® Osshp + Plenum^® Guide (PO+PG). A defect was created in the calvaria, filled with the grafts, and covered with a PDO membrane, and euthanasia took place at 7, 30, and 60 days. Micro-CT showed no statistical difference between the groups, but there was an increase in bone volume (56.26%), the number of trabeculae (2.76 mm), and intersection surface (26.76 mm²) and a decrease in total porosity (43.79%) in the PO+PG group, as well as higher values for the daily mineral apposition rate (7.16 µm/day). Histometric analysis presented material replacement and increased bone formation at 30 days compared to 7 days in both groups. Immunostaining showed a similar pattern between the groups, with an increase in proteins related to bone remodeling and formation. In conclusion, Plenum^® Osshp + Plenum^® Guide showed similar and sometimes superior results when compared to autogenous bone, making it a competent option as a bone substitute. Full article