University of São Paulo, Department of Biomaterials and Oral Biology, School of Dentistry, São Paulo, Brazil.
Santo Amaro University, São Paulo, Brazil.
J Mech Behav Biomed Mater. 2018 Aug;84:161-167. doi: 10.1016/j.jmbbm.2018.05.022. Epub 2018 May 26.
to verify the effect of the addition of dicalcium phosphate dihydrate (DCPD) particles functionalized with di- or triethylene glycol dimethacrylate (DEGDMA or TEGDMA) on the degree of conversion (DC), post-gel shrinkage (PS), mechanical properties, and ion release of experimental composites.
Four composites were prepared containing a BisGMA/TEGDMA matrix and 60 vol% of fillers. The positive control contained only barium glass fillers, while in the other composites 15 vol% of the barium was replaced by DCPD. Besides the functionalized particles, non-functionalized DCPD was also tested. DC after 24 h (n = 3) was determined by FTIR spectroscopy. The strain gage method was used to obtain PS 5 min after photoactivation (n = 5). Flexural strength and modulus (n = 10) were calculated based on the biaxial flexural test results, after specimen storage for 24 h or 60 days in water. The same storage times were used for fracture toughness testing (FT, n = 10). Calcium and phosphate release up to 60 days was quantified by ICP-OES (n = 3). Data were analyzed by ANOVA/Tukey test (alpha: 5%).
Composites containing functionalized DCPD presented higher DC than the control (p < 0.001). The material containing DEGDMA-functionalized particles showed higher PS than the other composites (p < 0.001). After 60 days, only the composite with DEGDMA-functionalized DCPD presented fracture strength similar to the control, while for flexural modulus only the composite with TEGDMA-functionalized particles was lower than the control (p < 0.001). FT of all composites containing DCPD was higher than the control after 60 days (p < 0.005). Calcium release was higher for the composite with non-functionalized DCPD at 15 days and no significant reductions were observed for composites with functionalized DCPD during the observation period (p < 0.001). For all the tested composites, phosphate release was higher at 15 days than in the subsequent periods, and no difference among them was recorded at 45 and 60 days (p < 0.001).
DCPD functionalization affected all the studied variables. The composite with DEGDMA-functionalized particles was the only material with strength similar to the control after 60 days in water; however, it also presented the highest shrinkage. The presence of DCPD improved FT, regardless of functionalization. DCPD functionalization reduced ion release only during the first 15 days.
验证二水合磷酸二钙（DCPD）颗粒与二甘醇二甲基丙烯酸酯（DEGDMA 或 TEGDMA）的二或三乙二醇功能化对实验性复合材料的转化率（DC）、凝胶后收缩（PS）、机械性能和离子释放的影响。
制备了四种含有 BisGMA/TEGDMA 基质和 60vol%填料的复合材料。阳性对照物仅含有钡玻璃填料，而在其他复合材料中，15vol%的钡被 DCPD 取代。除了功能化颗粒外，还测试了非功能化的 DCPD。24 小时后通过傅里叶变换红外光谱法（FTIR）测定 DC（n=3）。光激活后 5 分钟使用应变计法（n=5）获得 PS。在水中储存 24 小时或 60 天后，根据双轴弯曲试验结果计算弯曲强度和模量（n=10）。在相同的储存时间下（n=10）进行断裂韧性测试（FT）。通过电感耦合等离子体发射光谱法（ICP-OES）定量测量钙和磷的释放量（n=3）。使用方差分析/图基检验（alpha：5%）分析数据。
含有功能化 DCPD 的复合材料的 DC 高于对照组（p<0.001）。含有 DEGDMA 功能化颗粒的材料的 PS 高于其他复合材料（p<0.001）。60 天后，只有含有 DEGDMA 功能化 DCPD 的复合材料的断裂强度与对照组相似，而对于弯曲模量，只有含有 TEGDMA 功能化颗粒的复合材料低于对照组（p<0.001）。60 天后，所有含有 DCPD 的复合材料的 FT 均高于对照组（p<0.005）。15 天时，含有非功能化 DCPD 的复合材料的钙释放较高，而在观察期间，含有功能化 DCPD 的复合材料的钙释放没有明显减少（p<0.001）。对于所有测试的复合材料，在 15 天时磷酸盐释放高于随后的时间段，并且在 45 天和 60 天之间没有记录到它们之间的差异（p<0.001）。
DCPD 功能化影响了所有研究的变量。60 天后在水中，只有含有 DEGDMA 功能化颗粒的材料的强度与对照组相似；然而，它也表现出最高的收缩率。DCPD 的存在提高了 FT，而与功能化无关。DCPD 功能化仅在最初的 15 天内降低了离子释放。
