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 ß-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.

Storage protocol of dental pulp cells from human exfoliated deciduous teeth / Protocolo de armazenamento de células pulpares de dentes decíduos humanos

Objetivo: O objetivo deste estudo foi isolar células do tecido pulpar de dentes decíduos humanos, avaliar a capacidade de proliferação, caracterizá-las e normatizar as técnicas de cultivo e expansão celular destas para a criação de um banco de células. Material e métodos: Dentes decíduos sem cárie e com indicação ortodôntica de para extração foram utilizados como doadores de tecido para a pesquisa. As células foram extraídas de tecidos pulpares, isoladas e cultivadas em condições ideais até alcançarem confluência. Resultados: Após consecutivas passagens, as células cultivadas foram caracterizadas por meio de técnicas de imunofluorescência e congeladas entre a 2ª e a 6ª passagem, criando-se um biorrepositório de células da polpa de dentes decíduos humanos. Conclusão: A criação de bancos de células pulpares de dentes decíduos humanos permite uma aplicação mais ágil nas pesquisas laboratoriais, reduzindo o tempo e o custo da obtenção de novas amostras. Evita necessidade de triagem e obtenção de novos doadores de dentes e tecidos, e permite maior rapidez nas repetições de protocolos de pesquisas. (AU)

Objective: This study aimed to isolate the cells from the dental pulp tissue of human primary teeth, study the capacity of proliferation, characterize the cells and standardize the technique of culture and expansion to create a cell banking. Material and Methods: Primary teeth with no caries and orthodontic reasons were extracted for pulp tissue obtainment. The cells were extracted from the pulp cells, isolated and cultured under ideal conditions until full expansion. Results: After consecutive passages, the cultured cells were characterized using immunofluorescence technique and frozen between the 2nd and 6th passage, thus creating a biorepository of dental pulp cells from human primary teeth. Conclusion: The creation of a cell banking from dental pulp cells from human primary teeth enables the easy application of cells in laboratorial studies, reducing the cost and time for obtaining the samples, avoid the involvement of new subjects and allow a fast reproducibility of the researches. (AU)