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Additive manufacturing has emerged as a transformative tool in biomedical engineering, offering precise control over scaffold design for bone tissue engineering and regenerative medicine. While much attention has been focused on optimizing pore-based scaffold architectures, filament-based microarchitectures remain relatively understudied, despite the fact that the majority of 3D-printers generate filament-based structures. Here, we investigated the influence of filament characteristics on bone regeneration outcomes using a lithography-based additive manufacturing approach. Three distinct filament-based scaffolds (Fil050, Fil083, and Fil125) identical in macroporosity and transparency, crafted from tri-calcium phosphate (TCP) with varying filament thicknesses and distance, were evaluated in a rabbit model of bone augmentation and non-critical calvarial defect. Additionally, two scaffold types differing in filament directionality (Fil and FilG) were compared to elucidate optimal design parameters. Distance of bone ingrowth and percentage of regenerated area within scaffolds were measured by histomorphometric analysis. Our findings reveal filaments of 0.50 mm as the most effective filament-based scaffold, demonstrating superior bone ingrowth and bony regenerated area compared to larger size filament (i.e., 0.83 mm and 1.25 mm scaffolds). Optimized directionality of filaments can overcome the reduced performance of larger filaments. This study advances our understanding of microarchitecture's role in bone tissue engineering and holds significant implications for clinical practice, paving the way for the development of highly tailored, patient-specific bone substitutes with enhanced efficacy.

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Bisphosphonates (BP) are anti-resorptive drugs that are widely used to prevent bone loss in osteoporosis. Since inhibition of bone resorption will cause a decrease in bone formation through a process called coupling, it is hypothesized that extended treatment protocols may impair bone healing. In this study, ß-tri­calcium-phosphate (ßTCP) ceramics were inserted into critical-size long bone defects in estrogen-deficient mice under BP therapy. The study assessed the benefits of coating the ceramics with Bone Morphogenetic Protein-2 (BMP2) and an engineered BMP2 analogue (L51P) that inactivates BMP antagonists on the healing process, implant resorption, and bone formation. Female NMRI mice (11-12 weeks of age) were ovariectomized (OVX) or sham operated. Eight weeks later, after the manifestation of ovariectomy-induced osteoporotic bone changes, BP therapy with Alendronate (ALN) was commenced. After another five weeks, a femoral critical-size defect was generated, rigidly fixed, and ßTCP-cylinders loaded with 0.25 µg or 2.5 µg BMP2, 2.5 µg L51P, and 0.25 µg BMP2/2.5 µg L51P, respectively, were inserted. Unloaded ßTCP-cylinders were used as controls. Femora were collected six and twelve weeks post-implantation. Histological and micro-computer tomography (MicroCT) evaluation revealed that insertion of cylinders coated with 2.5 µg BMP2 accelerated fracture repair and induced significant bone formation compared to controls (unloaded cylinders or coated with 2.5 µg L51P, 0.25 µg BMP2) already six weeks post-implantation, independent of estrogen-deficiency and BP therapy. The simultaneous administration of BMP2 and L51P (0.25 µg BMP2/2.5 µg L51P) did not promote fracture healing six and twelve weeks post-implantation. Moreover, new bone formation within the critical-size defect was directly linked to the removal of the ßTCP-implant in all experimental groups. No evidence was found that long-term therapy with ALN impaired the resorption of the implanted graft. However, osteoclast transcriptome signature was elevated in sham and OVX animals upon treatment with BP, with transcript levels being higher at six weeks than at twelve weeks post-surgery. Furthermore, the transcriptome profile of the developing repair tissue confirmed an accelerated repair process in animals treated with 2.5 µg BMP2 implants. L51P did not increase the bioefficacy of BMP2 in the applied defect model. The present study provides evidence that continuous administration of BP does not inhibit implant resorption and does not alter the kinetics of the healing process of critical-size long bone defects. Furthermore, the BMP2 variant L51P did not enhance the bioefficacy of BMP2 when applied simultaneously to the femoral critical-size defect in sham and OVX mice.

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Aim: The study aimed to assess the remineralizing potential of four different commercially available agents using a Scanning Electron Microscope (SEM), energy dispersive X-ray (EDX) analysis, and Vickers Microhardness (VMH) Test. Materials and Methods: Forty-four specimens (n = 11 per group) were prepared from extracted teeth. A window of 6 mm × 4 mm was made on all the specimens that represented three zones, namely, sound enamel, demineralized enamel, and remineralized enamel. The zone for demineralized enamel was subjected to four different remineralizing agents; casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF), tricalcium phosphate fluoride (TCP-F), calcium sucrose phosphate (CSP), and self-assembling peptide (P11-4). Remineralization (REM) was assessed using VMH; the structural changes were assessed using SEM that was analyzed using EDX analysis. The specimens were subjected to a newer regimen of demineralization. One-way ANOVA followed by post hoc Tukey test was used with a level of significance at P ≤ 0.05. Results: There were no significant differences in VMH between the groups for sound enamel (P = 0.472) and demineralized enamel (P = 0.116). VMH was statistically significantly more for P11-4 and the least for CPP-ACPF (P = 0.011). A post hoc analysis revealed higher VMH for P11-4 compared to CPP-ACPF (P = 0.014) and TCP-F (P = 0.035). SEM showed a homogeneous layer of minerals for all groups except CPP-ACPF. TCP-F reported a higher degree of REM, followed by P11-4 as assessed using EDX analysis. Conclusion: Self-assembling peptide (P11-4) exhibited a higher degree of REM than other remineralizing agents followed by CSP.

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BACKGROUND: This study was aimed to investigate whether the application of platelet-rich plasma (PRP) combined with ß-tri-calcium phosphate (ß-TCP) grafts after core decompression (CD) could improve the clinical outcomes of early stage of avascular necrosis of femoral head. METHODS: Forty-five (54 hips) patients with Ficat-Arlet classification stage I-II treated by CD with ß-TCP grafts with or without the application of PRP from July 2015 to October 2020 were reviewed. Group A (CD + ß-TCP grafts) included 24 patients (29 hips), while group B (CD + ß-TCP grafts + PRP) included 21 patients (25 hips). Visual analogue scale (VAS) score, Harris hip score (HHS), change in modified Kerboul angle and the hip joint survival were evaluated and compared between the groups. Patients had a mean follow-up period of 62.1 ± 17.2 months and 59.3 ± 14.8 months in group A and group B, respectively. RESULTS: The mean VAS scores in group A was significantly higher than group B at the 6 months (2.9 ± 0.7 vs 1.9 ± 0.6, p < 0.01) and final follow up postoperative (2.8 ± 1.2 vs 2.2 ± 0.7, p = 0.04). The mean HHS in group A was significantly lower than group B at the 6 months (80.5 ± 13.8 vs 89.8 ± 12.8, p = 0.02). However, at the final follow up, there is no significant difference between the groups (77.0 ± 12.4 vs 83.1 ± 9.3, p = 0.07). The mean change in modified Kerboul angle was -7.4 ± 10.6 in group A and -19.9 ± 13.9 in group B which is statistically significant (p < 0.01). Survivorship from total hip arthroplasty were 86.2%/84% (p = 0.86) at the final follow up, which was not statistically significant. No serious complications were found in both groups. CONCLUSIONS: A single dose of PRP combined with CD and ß-TCP grafts provided significant pain relief, better functional outcomes, and delayed progression in the short term compared to CD combined with ß-TCP grafts. However, the prognosis of the femoral head did not improve significantly in the long term. In the future, designing new implants to achieve multiple PRP injections may improve the hip preservation rate.

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There is a significant unmet clinical need to prevent amputations due to large bone loss injuries. We are addressing this problem by developing a novel, cost-effective osseointegrated prosthetic solution based on the use of modular pieces, bone bricks, made with biocompatible and biodegradable materials that fit together in a Lego-like way to form the prosthesis. This paper investigates the anatomical designed bone bricks with different architectures, pore size gradients, and material compositions. Polymer and polymer-composite 3D printed bone bricks are extensively morphological, mechanical, and biological characterized. Composite bone bricks were produced by mixing polycaprolactone (PCL) with different levels of hydroxyapatite (HA) and ß-tri-calcium phosphate (TCP). Results allowed to establish a correlation between bone bricks architecture and material composition and bone bricks performance. Reinforced bone bricks showed improved mechanical and biological results. Best mechanical properties were obtained with PCL/TCP bone bricks with 38 double zig-zag filaments and 14 spiral-like pattern filaments, while the best biological results were obtained with PCL/HA bone bricks based on 25 double zig-zag filaments and 14 spiral-like pattern filaments.

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OBJECTIVES: This study aimed to assess and compare the effectiveness of three different remineralizing agents (Tricalcium phosphate paste, Fluoride varnish, and Nano-hydroxyapatite gel) using the DIAGNOdent device. MATERIAL AND METHODS: The present clinical study was carried out on 90 initial carious lesions detected by ICDAS caries diagnostic criteria and then take the baseline record by DIAGNOdent device. The selected initial carious lesions were randomly classified into three groups according to treatment modalities (30 lesions in each group) according to remineralizing agents: group A (TCP), group B (fluoride varnish) and group C (nano-hydroxyapatite gel). The remineralizing agents were applied for four minutes once weekly for four weeks. At the fifth week, the DIAGNOdent scores of initial carious lesions were recorded to evaluate the effect of remineralizing agents. A paired t-test was used to compare between baseline date and follow up of DIAGNOdent scores. A one-way ANOVA test was used to compare DIAGNOdent scores among the three groups. Post- Hoc Tukey test was used to determine the significant difference between every two groups. RESULTS: There were statistically significant differences among the three groups at follow up (p = 0.001). Within each group, there was a significant difference between baseline and follow up scores (p = 0.000 for the three groups). Multiple comparisons between every two groups showed a highly statistically significant difference at follow up records between nano-hydroxyapatite versus TCP and fluoride varnish on pit and fissure caries (p = 0.039 and p = 0.007 respectively) and the nano-hydroxyapatite was the best of them. CONCLUSION: The present study concluded that the three remineralizing agents were effective in the treatment of initial carious lesion and the most effective remineralizing agent was nano-hydroxyapatite.

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3D printed scaffolds composed of gelatin and ß-tri-calcium phosphate (ß-TCP) as a biomimetic bone material are fabricated, thereby providing an environment appropriate for bone regeneration. The Ca2+ in ß-TCP and COO- in gelatin form a stable electrostatic interaction, and the composite scaffold shows suitable rheological properties for bioprinting. The gelatin/ß-TCP scaffold is crosslinked with glutaraldehyde vapor and unreacted aldehyde groups which can cause toxicity to cells is removed by a glycine washing. The stable binding of the hydrogel is revealed as a result of FTIR and degradation rate. It is confirmed that the composite scaffold has compressive strength similar to that of cancellous bone and 60 wt% ß-TCP groups containing 40 wt% gelatin have good cellular activity with preosteoblasts. Also, in the animal experiments, the gelatin/ß-TCP scaffold confirms to induce bone formation without any inflammatory responses. This study suggests that these fabricated scaffolds can serve as a potential bone substitute for bone regeneration.

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One of the most common prophylactic techniques to solve prosthetic joint infection (PJI) is incorporation of antibiotics into acrylic bone cement to prevent bacterial colonization and proliferation by providing local antibiotic delivery directly at the implant site. Further, there has been a significant concern over the efficacy of commonly used antibiotics within bone cement due to the rise in multi-drug resistant (MDR) microorganisms. Selenium is an essential trace element that has multiple beneficial effects for human health and its chemotherapeutic action is well known. It was reported that nanostructured selenium enhanced bone cell adhesion and has an increased osteoblast function. In this context, we used the selenium nanoparticles (SeNPs) to improve antibacterial and antioxidant properties of poly (methyl methacrylate) (PMMA) and tri calcium phosphate (TCP)-based bone cements, and to reduce of the infection risk caused by orthopedic implants. As another novelty of this study, we proposed phosphatidylcholine (PC) as a unique and natural stabilizer in the synthesis of selenium nanoparticles. After the structural analysis of the prepared bone cements was performed, in vitro osteointegration and antibacterial efficiency were tested using MC3T-E1 (mouse osteoblastic cell line) and SaOS-2 (human primary osteogenic sarcoma) cell lines, and S. aureus (Gram positive) and E.coli (Gram negative) strains, respectively. More importantly, PC-SeNPs-reinforced bone cements exhibited significant effect against E. coli, compared to S. aureus and a dose-dependent antibacterial activity against both bacterial strains tested. Meanwhile, these bone cements induced the apoptosis of SaOS-2 through increased reactive oxygen species without negatively influencing the viability of the healthy cell line. Furthermore, the obtained confocal images revealed that PC-SeNPs (103.7 ± 0.56 nm) altered the cytoskeletal structure of SaOS-2 owing to SeNPs-induced apoptosis, when MC3T3-E1 cells showed a typical spindle-shaped morphology. Taken together, these results highlighted the potential of PC-SeNPs-doped bone cements as an effective graft material in bone applications.

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BACKGROUND: Polymethylmethacrylate bone cement has a variety of applications in orthopedic surgery, but it also has some shortcomings such as high heat generation during polymerization and poor integration with bone tissue. In this study, a bio-composite bone cement composed of tri-calcium phosphate and chitosan as additives to acrylic bone cement was developed. Our hypothesis is that this new bio-composite bone cement has a better osteo-integration than pure polymethyl methacrylate cement. METHODS: Physiological composition, i.e., 65 wt% inorganic and 35 wt% organic components, of tri-calcium phosphate and chitosan contents was selected as degradable additives to replace acrylic bone cement. A series of properties such as exothermic temperature changes, setting time, bio-mechanical characteristics, degradation behaviors, and in vitro cytotoxicity were examined. Preliminary in vivo animal study was also performed. RESULTS: The results showed that the bio-composite bone cement exhibited lower curing temperature, longer setting time, higher weight loss and porosity after degradation, lower compressive Young's modulus, and ultimate compressive strength as compared with those of pure polymethyl methacrylate cement. Cell proliferation tests demonstrated that the bio-composite bone cement was non-cytotoxic, and the in vivo tests revealed that was more osteo-conductive. CONCLUSIONS: The results indicated that the modified chitosan/tri-calcium phosphate/polymethyl methacrylate bio-composites bone cement could be degraded gradually and create rougher surfaces that would be beneficial to cell adherence and growth. This new bio-composite bone cement has potential in clinical application. Our future studies will focus on long-term implantation to investigate the stability of the bio-composite bone cement in long-term implantation.

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BACKGROUND: Filling bone defect after debridement of infected nonunion is an orthopedic challenge. Since the volume of autologous bone graft available is limited, allograft, demineralized bone matrix, and calcium phosphate ceramic-based bone graft substitutes have come up as potential autograft expanders. This study was conducted to analyze the use of beta tri-calcium phosphate (B-TCP)-based composite ceramic as autologous bone-graft expander in the management of postinfective segmental gap nonunion of long bones managed with two-stage Masquelet's technique. MATERIALS AND METHODS: 42 consecutive patients with postinfective segmental long bone defects of 4-12 cm managed with Masquelet's-induced membrane technique, operated between February 2012 and June 2015, were included in this prospective case series. During the second stage bone-grafting procedure, iliac crest autograft alone or mixed with B-TCP granules (ratio not exceeding >1:1) was used along with appropriate internal-fixation. Bony union (defined clinicoradiologically as ability to painlessly bear weight on affected limb without support along with bridging of 3 cortices on X-rays) was evaluated. RESULTS: Union was achieved in 80.9% patients (34/42) with index bone grafting. 100% union rate was achieved in patients where only autograft was used (15/15) and in nonsmoker femoral nonunion patients with the use of B-TCP (13/13). The use of B-TCP was associated with higher rate of nonunion in smokers (6/8, 75%) and in tibial nonunions (4/9, 55.5%). All, but one, of 8 patients with nonunion, united after the second-bone grafting procedure. CONCLUSION: B-TCP is an efficacious and safe autologous bone graft expander in Masquelet's two-stage management of post infective segmental gap nonunion of long bones. Patients should be counseled regarding increased risk of nonunion and need for repeat grafting with its use, especially if they are smokers or site of involvement is tibia.

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Five highly efficient phosphate solubilizing bacteria, viz., Pantoea sp. A3, Pantoea sp. A34, Kosakonia sp. A37, Kosakonia sp. B7 and Bacillus sp. AH9 were isolated from termitorial soils of Sanjivani island of southern Maharashtra, India. These isolates were characterized and explored for phosphate solubilization and plant growth promotion. Among these, Bacillus sp. AH9 showed highest phosphate solubilization index (3.5) and solubilization efficiency (250%) on Pikovskaya agar. Interestingly, Pantoea sp. A34 displayed maximum mineral phosphate solubilization (1072.35 mg/L) in liquid medium and during this period the pH dropped to 3.13. All five isolates had highest P solubilization at 48 h after inoculation. During mineral phosphate solubilization, both gluconic acid and 2-keto gluconic acid were produced by Kosakonia and Bacillus isolates, while only 2-keto gluconic acid was detected in Pantoea isolates. Highest organic acid (39.07 ± 0.04 g/L) production was envisaged in Bacillus sp. AH9, while Pantoea sp. A34 produced the least amount (13.00 ± 0.01 g/L) of organic acid. Seed bacterization with Pantoea sp. A3 and Kosakonia sp. A37 resulted in ~ 37% and ~ 53% increase in root length of tomato seedlings, respectively, while Pantoea sp. A34 and Kosakonia sp. B7 had deleterious effects on root length as well as overall growth of the seedlings. To our knowledge, this is the first report of plant growth promoting potential of microorganisms isolated from termitorial soil of Sanjivani island, which is a drought-prone area. Therefore, such efficient growth promoting P solubilizers can offer an effective solution for sustainable agriculture in arid, dryland farming and drought-prone regions.

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The design of bioactive scaffolds with improved mechanical and biological properties is an important topic of research. This paper investigates the use of polymer-ceramic composite scaffolds for bone tissue engineering. Different ceramic materials (hydroxyapatite (HA) and ß-tri-calcium phosphate (TCP)) were mixed with poly-ε-caprolactone (PCL). Scaffolds with different material compositions were produced using an extrusion-based additive manufacturing system. The produced scaffolds were physically and chemically assessed, considering mechanical, wettability, scanning electron microscopy and thermal gravimetric tests. Cell viability, attachment and proliferation tests were performed using human adipose derived stem cells (hADSCs). Results show that scaffolds containing HA present better biological properties and TCP scaffolds present improved mechanical properties. It was also possible to observe that the addition of ceramic particles had no effect on the wettability of the scaffolds.

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Reconstruction of bone defects prior to implant placement now involves synthetic substitutes such as ß-TCP because of its ability to promote bone remodeling. Its capacity to be progressively substituted by the patient's bone allows to regenerate a dense bone volume. In addition, its availability in large quantities, avoiding the morbidity observed with harvesting autogenous bone, widens the operative indications. In this paper, the main indications of ß-TCP in maxillofacial surgery (dentistry, parodontology and dental implant surgery) are reviewed. They include periodontal bone disease, bone disjunction, pre-implant surgery (sinus floor elevation and lateralization of the inferior alveolar nerve).

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Bone is a plastic tissue with a large healing capability. However, extensive bone loss due to disease or trauma requires extreme therapy such as bone grafting or tissue-engineering applications. Presently, bone grafting is the gold standard for bone repair, but presents serious limitations including donor site morbidity, rejection, and limited tissue regeneration. The use of stem cells appears to be a means to overcome such limitations. Bone marrow mesenchymal stem cells (BMSC) have been the choice thus far for stem cell therapy for bone regeneration. However, adipose-derived stem cells (ASC) have similar immunophenotype, morphology, multilineage potential, and transcriptome compared to BMSC, and both types have demonstrated extensive osteogenic capacity both in vitro and in vivo in several species. The use of scaffolds in combination with stem cells and growth factors provides a valuable tool for guided bone regeneration, especially for complex anatomic defects. Before translation to human medicine, regenerative strategies must be developed in animal models to improve effectiveness and efficiency. The pig presents as a useful model due to similar macro- and microanatomy and favorable logistics of use. This review examines data that provides strong support for the clinical translation of the pig model for bone regeneration.

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The aim of this study was to evaluate the indicators of osteogenesis, cytotoxicity and genotoxicity of an experimental beta tri-calcium phosphate (experimental ß-TCP) compared with two other bone substitutes: bovine hydroxyapatite (HA) (Bio-Oss® - Geistlich) and beta tri-calcium phosphate (ß-TCP - Bionnovation). The cell viability and genotoxicity were measured by MTT and MNT assay, respectively. The indicators of osteogenesis were analyzed by alkaline phosphatase activity, total protein content, and calcium deposition. The MTT and MNT assay showed that none of the tested materials was cytotoxic nor genotoxic. Concerning the indicators of osteogenesis, it was observed that cells in contact with all the materials were able to induce the osteogenesis and this process was influenced by the period of the cell culture in contact with bone substitutes. Based on the results of this study, it was concluded that this experimental ß-TCP appears to be a promising material as a bone substitute.

O objetivo deste estudo foi avaliar os indicadores da osteogênese, citotoxicidade e genotoxicidade de um beta-tricálcio fosfato (ß-TCP experimental) comparado com dois outros substitutos ósseos : Hidroxiapatita Bovina (HA) (Bio-Oss® - Geistlich) e beta-tricálcio fosfato (ß-TCP - Bionnovation). A viabilidade celular e genotoxicidade foram mensuradas pelos ensaios MTT e MNT, respectivamente. Os indicadores da osteogênese foram analisados pela atividade de fosfatase alcalina (ALP), conteúdo de proteína total, e deposição de cálcio. Os ensaios MTT e MNT mostraram que nenhum dos materiais testados foi citotóxico ou genotóxico. Em relação aos indicadores da osteogênese, foi observado que as células em contato com todos os materiais foram capazes de induzir a osteogênese, e que esse processo foi influenciado pelo período da cultura celular em contato com os substitutos ósseos. Baseado nos resultados desse estudo, conclui-se que este ß-TCP experimental parece ser um material promissor para ser utilizado como substituto ósseo.

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Bone defects resulting from trauma or infection need timely and effective treatments to restore damaged bone. Using specialized three-dimensional (3D) printing technology we have created custom 3D scaffolds of hydroxyapatite (HA)/beta-tri-calcium phosphate (ß-TCP) to promote bone repair. To further enhance bone regeneration we have coated the scaffolds with dipyridamole, an agent that increases local adenosine levels by blocking cellular uptake of adenosine. Nearly 15% HA:85% ß-TCP scaffolds were designed using Robocad software, fabricated using a 3D Robocasting system, and sintered at 1100°C for 4 h. Scaffolds were coated with BMP-2 (200 ng mL-1 ), dypiridamole 100 µM or saline and implanted in C57B6 and adenosine A2A receptor knockout (A2AKO) mice with 3 mm cranial critical bone defects for 2-8 weeks. Dipyridamole release from scaffold was assayed spectrophotometrically. MicroCT and histological analysis were performed. Micro-computed tomography (microCT) showed significant bone formation and remodeling in HA/ß-TCP-dipyridamole and HA/ß-TCP-BMP-2 scaffolds when compared to scaffolds immersed in vehicle at 2, 4, and 8 weeks (n = 5 per group; p ≤ 0.05, p ≤ 0.05, and p ≤ 0.01, respectively). Histological analysis showed increased bone formation and a trend toward increased remodeling in HA/ß-TCP- dipyridamole and HA/ß-TCP-BMP-2 scaffolds. Coating scaffolds with dipyridamole did not enhance bone regeneration in A2AKO mice. In conclusion, scaffolds printed with HA/ß-TCP promote bone regeneration in critical bone defects and coating these scaffolds with agents that stimulate A2A receptors and growth factors can further enhance bone regeneration. These coated scaffolds may be very useful for treating critical bone defects due to trauma, infection or other causes. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 366-375, 2017.

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OBJECTIVES: To compare CPP-ACP, Tri-calcium phosphate and Hydroxyapatite on remineralization of artificial caries like lesions on primary enamel. STUDY DESIGN: Ten extracted Primary molars coated with nail varnish, leaving a window of 2×4 mm on buccal and lingual surface were immersed in demineralizing solution for 96 hours and sectioned longitudinally to obtain 40 sections (4 sections per tooth) and were randomly divided into 4 groups (A to D) n=10; Group A: negative control, Group B: CPP-ACP, Group C: Tri-calcium phosphate, Group D: Hydroxyapatite. Sections were subjected to pH cycling for 10 days and were evaluated by polarized light microscope before and after treatment. RESULTS: Intra group comparison of demineralization and remineralization was done by paired t-test. One way ANOVA was used for multiple group comparisons followed by post HOC TUKEY'S Test for group wise comparisons. Remineralization was found more with Group D followed by Group B, C and A. CONCLUSION: Hydroxyapatite showed better remineralization when compared to CPP-ACP and Tri-calcium phosphate.

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Biphasic mixtures of either Mg(2+) or combined Mg(2+) and Sr(2+) cation substituted ß-tricalcium phosphate (ß-TCP) and amorphous calcium phosphate (ACP) were prepared using a low temperature chemical phosphatizing and hydrolysis reaction approach. Scaffolds prepared using the cation substituted calcium phosphates were capable of supporting similar levels of human mesenchymal stem cell proliferation in comparison to commercially available ß-TCP. The concentrations of Mg(2+), Sr(2+), and PO4(3-) released from these scaffolds were also within the ranges desired from previous reports to support both hMSC proliferation and osteogenic differentiation. Interestingly, hMSCs cultured directly on scaffolds prepared with only Mg(2+) substituted ß-TCP were capable of supporting statistically significantly increased alkaline phosphatase activity, osteopontin, and osteoprotegerin expression in comparison to all compositions containing both Mg(2+) and Sr(2+), and commercially available ß-TCP. hMSCs cultured in the presence of scaffold extracts also exhibited similar trends in the expression of osteogenic markers as was observed during direct culture. Therefore, it was concluded that the enhanced differentiation observed was due to the release of bioactive ions rather than the surface microstructure. The role of these ions on transforming growth factor-ß and bone morphogenic protein signaling was also evaluated using a PCR array. It was concluded that the release of these ions may support enhanced differentiation through SMAD dependent TGF-ß and BMP signaling.

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The purpose of this study is to evaluate the dentinal tubule occlusion potential and penetration of Clinpro® White Varnish (5% sodium fluoride + tri-calcium phosphate) in the presence or absence of Nd:YAG laser. Seventy-five dentin samples collected from 38 freshly extracted human molars were randomly divided into five groups (n = 15). Groups A, B, D, and E were varnished with Clinpro, whereas group C (no treatment) served as the control group. Groups B and E were further irradiated with Nd:YAG laser (1.5 W, 10 Hz, 1 min). All study groups were subjected to pH cycling (kept in 0.3% citric acid 5 min/day for 5 days). Groups A, B, and C were evaluated for tubule occlusion using scanning electron microscopy. Groups D and E were evaluated for penetration with confocal laser scanning microscopy (SEM). Non-parametric Kruskall-Wallis and Dunn's statistical tests were used for analysis of SEM results. The penetration depths were analyzed with one-way ANOVA followed by Fisher's Least Significant Difference tests. Tubular occlusion of groups A and B were significantly greater than group C (p < 0.05). Tubular occlusion of group B were significantly greater than group A (p < 0.05). Penetration depth for group D was significantly greater than group E (p < 0.05). Laser application improved the tubular occlusion capacity of Clinpro. Contrary, laser reduced the penetration of Clinpro. SCANNING 38:619-624, 2016. © 2016 Wiley Periodicals, Inc.

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OBJECTIVE: To assess the healing outcomes at buccal dehiscence defects after 4 months following implant placement immediately into extraction sockets (IPIES) and filled with a mixture of synthetic hydroxyl apatite (HA) 60% and ß-tri-calcium phosphate (ß-TCP) 40% in comparison with leaving a blood clot. MATERIAL AND METHODS: Eight Labrador dogs were used, and an implant was placed immediately following tooth extraction into the distal alveolus of the third premolars, bilaterally. Standardized buccal defects, 8 mm in depth and 4 mm in width at the coronal and 2 mm in width at the apical outlines were created. A mixture of synthetic HA 60% and ß-TCP 40% was used to fill the defects at the test sites, while the control sites were left unfilled. Collagen membranes were used to cover the defects at both sides, and a non-submerged healing was allowed. After 4 months of healing, biopsies were obtained and processed for morphometric analysis. RESULTS: A vertical gain in the extent of the bony crest and of osseointegration levels of 4.2 ± 2.4 and 3.3 ± 2.1 mm at the test sites and of 5.0 ± 0.8 and 4.6 ± 1.0 mm at the control sites, respectively, were observed. BIC% within the buccal defects reached similar levels (37-42%) both at test and control sites. None of the means of the variables differed significantly between the two groups. New bone formation within the defects was higher, and the percentage of the connective tissue was lower at the control (65.7 ± 11.7% and 2.5 ± 3.3%, respectively) compared to the test sites (16.8 ± 11.3% and 48.9 ± 29.5%, respectively). These differences were statistically significant. CONCLUSIONS: The use of a mixture of synthetic HA 60% and ß-TCP 40% to fill surgically created buccal dehiscence defects at IPIES sites covered with a collagen membrane did not improve osseointegration in the defect area.

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