The study compared ion release from resin-based materials containing calcium orthophosphates. Amorphous calcium phosphate (ACP), dicalcium phosphate anhydrous (DCPA), dicalcium phosphate dihydrate (DCPD), and tricalcium phosphate (β-TCP) nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and surface area (nitrogen adsorption isotherms, BET method). Nanoparticles were added to a dimethacrylate-based resin and materials were tested for degree of conversion (DC) and calcium/phosphate release up to 28 days under pH 5.5 and 7.0. Data were analyzed by ANOVA/Tukey test (alpha: 0.05).The crystallinity of DCPA, DCPD, and β-TCP were confirmed, as well as the ACP amorphous nature. DCPD and β-TCP presented larger agglomerates than DCPA and ACP. The surface area of ACP was 5-11 times higher than those of the other nanoparticles. Materials showed similar DC. The material containing ACP released significantly more ions than the others, which released similar amounts of calcium and, in most cases, phosphate. Ion release was not affected by pH. Calcium release decreased between 7 and 21 days, while phosphate levels remained constant after 14 days. In conclusion, ACP higher ion release can be ascribed to its high surface area. DCPA, DCPD, and β-TCP had similar performances as ion-releasing fillers.
ResumoOs objetivos desse estudo foram: desenvolver e caracterizar membranas poliméricas de ácido poli-L-láctico (PLLA) associado à dexametasona (DX) e vitamina D (VD) e avaliar a citotoxicidade e capacidade de osteoindução desses materiais na presença PLLA, PLLA/DX ou PLLA/VD, e as concentrações de DX e VD foram 1, 5 ou 10% em peso. A morfologia das malhas foi avaliada por microscopia eletrônica de varredura (MEV). As membranas foram armazenadas por 14 dias em meio de cultura e o meio condicionado coletado foi adicionado sobre cultura de PDLSC para análise da citotoxicidade por meio de ensaio de redução do MTT em 24 e 72h. Diferenciação óssea foi determinada por meio de ensaio de vermelho de alizarina após 21 dias de cultura das PDLSC em todos materiais. Não houve diferenças estatísticas quanto à viabilidade celular, de forma que todas as membranas produzidas foram atóxicas às PDLSCs em 24 e 72h (88±10% e 95±10%). Os materiais com 1 e 5% de vitamina D e 1% de dexametasona promoveram maior diferenciação celular, com absorbância de 0,7 ± 0,1 e 0,8 ± 0,1 e 0,5± 0,1, respectivamente, e diferiram do controle de PLLA (0,28 ± 0,01). Desta forma, podemos concluir que as membranas desenvolvidas foram biocompatíveis em PDLSC e propiciaram aumento na osteodiferenciação quando 1% de dexametasona ou 1 e 5% de vitamina D foram associados ao PLLA.
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