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Objectives: To implement a dentin slice model of mesenchymal stem cells derived from dental tissues in a fibrin-agarose construct for dental pulp regeneration. Material and Methods: MSCs derived from different oral cavity tissues were combined with a fibrin-agarose construct at standard culture conditions. Cell viability and proliferation tests were assayed using a fluorescent cell dye Calcein/Am and WST-1 kit. The proliferation assay was evaluated at 24, 48, 72, and 96 hours. Also, we assessed the dental pulp stem cells (DPSCs) cell morphology inside the construct with histological stains such as Hematoxylin and Eosin, Masson's trichrome, and Periodic acid­Schiff. In addition, we elaborated a tooth dentin slice model using a culture of DPSC in the fibrin­agarose constructs co-adhered to dentin walls. Results: The fibrin-agarose construct was a biocompatible material for MSCs derived from dental tissues. It provided good conditions for MSCs' viability and proliferation. DPSCs proliferated better than the other MSCs, but the data did not show significant differences. The morphology of DPSCs inside the construct was like free cells. The dentin slice model was suitable for DPSCs in the fibrin-agarose construct. Conclusion: Our findings support the dentin slice model for future biological use of fibrin-agarose matrix in combination with DPSCs and their potential use in dental regeneration. The multipotency, high proliferation rates, and easy obtaining of the DPSCs make them an attractive source of MSCs for tissue regeneration.

Objetivos: Implementar un modelo de dentina con células madre mesenquimales derivadas de tejidos dentales en una constructo de fibrina-agarosa para la regeneración de la pulpa dental. Material y Métodos: Las MSC derivadas de diferentes tejidos de la cavidad oral se combinaron con una construcción de fibrina-agarosa en condiciones de cultivo estándar. Las pruebas de viabilidad y proliferación celular se ensayaron utilizando un kit de colorante celular fluorescente Calcein/Am y WST-1. El ensayo de proliferación se evaluó a las 24, 48, 72 y 96 horas. Además, evaluamos la morfología celular de las células madre de la pulpa dental (DPSC) dentro de la construcción con tinciones histológicas como hematoxilina y eosina, tricrómico de Masson y ácido peryódico de Schiff. Además, elaboramos un modelo de rebanadas de dentina dental utilizando un cultivo de DPSC en las construcciones de fibrina-agarosa coadheridas a las paredes de la dentina. Resultados: La construcción de fibrina-agarosa fue un material biocompatible para las MSC derivadas de tejidos dentales. Proporcionó buenas condiciones para la viabilidad y proliferación de las MSC. Las DPSC proliferaron mejor que las otras MSC, pero los datos no mostraron diferencias significativas. La morfología de las DPSC dentro de la construcción era como la de las células libres. El modelo de corte de dentina fue adecuado para DPSC en la construcción de fibrina-agarosa.Conclusión: Nuestros hallazgos respaldan el modelo de corte de dentina para el futuro uso biológico de la matriz de fibrina-agarosa en combinación con DPSC y su uso potencial en la regeneración dental. El multipotencial, las altas tasas de proliferación y la fácil obtención de las DPSC las convierten en una fuente atractiva de MSC para la regeneración de tejidos.

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OBJECTIVE: To evaluate the healing response of critical defects in rat calvaria with recombinant cementum protein 1 (hrCEMP-1) combined with human dental pulp stem cells (hDPSC) and polylactide-co-glycolide/hydroxyapatite (PLGA/HA) scaffold. METHODS: The effect of hrCEMP-1 on proliferation and differentiation of human dental stem cells (hDPSCs) toward a mineralizing-like phenotype was evaluated in monolayer and PLGA/HA scaffold by qPCR. 5 mm calvarial defects were created in Wistar rats and filled with: 1) PLGA/HA scaffold; 2) hDPSCs-PLGA/HA scaffold; 3) hrCEMP-1-hDPSc-PLGA/HA scaffold; 4) control (without scaffold). Bone formation was evaluated by histological-histomorphometric analysis, scanning electron microscopy (SEM) and radiographic evaluation. Comparisons between groups were made with a one-way analysis of variance ANOVA and Bonferroni post-hoc test. RESULTS: In vitro results showed that the PLGA/HA scaffold loaded with hrCEMP-1 improved the proliferation and differentiation of hDPSCs towards a mineralization phenotype by inducing mRNA expression of ALP, OSX, RUNX2, OP, and COL-I genes. The hrCEMP-1/hDPSCs/-PLGA/HA scaffold resulted only in connective tissue formed after ten weeks of healing, larger central radiolucency, and a low peripheral density. We showed superior bone growth and repair with a PLGA/HA matrix scaffold alone and containing hDPSCs compared to the hrCEMP/cells group. CONCLUSIONS: PLGA/HA scaffold with hrCEMP-1 induces hDPSC commitment to mineralizing phenotype in vitro, but does not promote critical size osseous defect repair in vivo when it is included in a substitute biomaterial with hDPSc-PLGA/HA scaffold.

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Silk fibroin is a protein with intrinsic characteristics that make it a good candidate as a scaffold for tissue engineering. Recent works have enhanced its benefits by adding inorganic phases that interact with silk fibroin in different ways. A systematic review was performed in four databases to study the physicochemical and biological performance of silk fibroin nanocomposites. In the last decade, only 51 articles contained either in vitro cell culture models or in vivo tests. The analysis of such works resulted in their classification into the following scaffold types: particles, mats and textiles, films, hydrogels, sponge-like structures, and mixed conformations. From the physicochemical perspective, the inorganic phase imbued in silk fibroin nanocomposites resulted in better stability and mechanical performance. This review revealed that the inorganic phase may be associated with specific biological responses, such as neovascularisation, cell differentiation, cell proliferation, and antimicrobial and immunomodulatory activity. The study of nanocomposites as tissue engineering scaffolds is a highly active area mostly focused on bone and cartilage regeneration with promising results. Nonetheless, there are still many challenges related to their application in other tissues, a better understanding of the interaction between the inorganic and organic phases, and the associated biological response.

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Osteochondritis dissecans (OCD) is a condition that corresponds to an idiopathic focal lesion affecting the subchondral bone with possible compromise of the stability of the adjacent cartilage. Treatment depends on the size of the lesion, cartilage stability, and the physeal status. The case reported is about an 18-year-old male patient who complained of suffering from knee pain for a period of ten months. Magnetic resonance imaging (MRI) revealed a lesion of 2 cm2 in the medial femoral condyle that compromised the subchondral bone, compatible with OCD. He underwent surgery that consisted of filling the subchonral defect with an iliac crest autograft and sealing the defect with a hyaluronic acid scaffold. At the 12-month follow-up, the MRI shows complete healing and the patient has resumed sports activities. Management with autologous iliac crest graft and hyaluronic acid scaffold represents an effective alternative treatment for OCD.

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Our aim was to compare the wound healing of autogenous bone grafts with that of fresh-frozen allogeneic block bone in rabbits. We used 25 animals. One was killed before the experiment to provide the allogeneic bone, and the remainder were killed at four time points (n=6 in each group). On histometrical analysis there was a significant difference between the two groups only at 45days and between 15 and 45days in the intergroup analysis. However, there was significantly more revascularisation (p<0.05), resorption (p<0.05), and bony replacement (p<0.05) in the autogenous group in the immunohistochemical analysis. In later periods, the autogenous bone was replaced by newly-formed bone in all samples, whereas it was always possible to find regions of devitalised bone in the fresh-frozen allogeneic bone grafts. Autogenous grafts were completely replaced whereas, in the fresh- frozen allogeneic grafts, we found acellular tissue that had been incorporated into the receptor bed interface during the later evaluation times.

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