Objective

Materials for pulp protection should have therapeutic properties in order to stimulate remineralization and pulp reparative processes. The aim of this study was to evaluate the mechanical properties, biocompatibility, cell differentiation and bioactivity of experimental light-curable resin-based materials containing bioactive micro-fillers.

Methods

Four calcium-phosphosilicate micro-fillers were prepared and incorporated into a resin blend: 1) Bioglass 45S5 (BAG); 2) zinc-doped bioglass (BAG-Zn); 3) βTCP-modified calcium silicate (β-CS); 4) zinc-doped β-CS (β-CS-Zn). These experimental resins were tested for flexural strength (FS) and fracture toughness (FT) after 24 h and 30-day storage in simulated body fluid (SBF). Cytotoxicity was evaluated using MTT assay, while bioactivity was evaluated using mineralization and gene expression assays (Runx-2 & ALP).

Results

The lowest FS and FT at 24 h was attained with β-CS resin, while all the other tested materials exhibited a decrease in FS after prolonged storage in SBF. β-CS-Zn maintained a stable FT after 30-day SBF aging. Incorporation of bioactive micro-fillers had no negative effect on the biocompatibility of the experimental materials tested in this study. The inclusion of zinc-doped fillers significantly increased the cellular remineralization potential and expression of the osteogenic genes Runx2 and ALP (p < 0.05).

Significance

The innovative materials tested in this study, in particular those containing β-CS-Zn and BAG-Zn may promote cell differentiation and mineralization. Thus, these materials might represent suitable therapeutic pulp protection materials for minimally invasive and atraumatic restorative treatments.

中文翻译：

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实验性光固化纸浆保护材料的细胞分化，生物活性和机械性能

客观的

用于保护纸浆的材料应具有治疗特性，以刺激再矿化和纸浆修复过程。这项研究的目的是评估含有生物活性微填料的实验性光固化树脂基材料的机械性能，生物相容性，细胞分化和生物活性。

方法

制备了四种磷酸钙硅酸盐微填料并将其掺入到树脂共混物中：1）Bioglass 45S5（BAG）; 2）掺锌生物玻璃（BAG-Zn）；3）βTCP改性的硅酸钙（β-CS）；4）掺杂锌的β-CS（β-CS-Zn）。在模拟体液（SBF）中储存24小时和30天后，测试了这些实验树脂的挠曲强度（FS）和断裂韧性（FT）。使用MTT分析评估细胞毒性，同时使用矿化和基因表达分析（Runx-2＆ALP）评估生物活性。

结果

β-CS树脂在24 h时具有最低的FS和FT，而所有其他测试材料在SBF中长期保存后，其FS降低。SBF老化30天后，β-CS-Zn保持稳定的FT值。掺入生物活性微填料对本研究中测试的实验材料的生物相容性没有负面影响。掺锌的填料的加入显着提高了细胞再矿化的潜力，并增强了成骨基因Runx2和ALP的表达（p <0.05）。

意义

在这项研究中测试的创新材料，特别是那些包含β-CS-Zn和BAG-Zn的材料可能会促进细胞分化和矿化。因此，这些材料可能代表用于微创和无创伤修复治疗的合适的治疗性牙髓保护材料。