School of Dentistry, Department of Biomaterials and Oral Biology, University of São Paulo, São Paulo, Brazil.
J Dent Res. 2024 Apr;103(4):427-433. doi: 10.1177/00220345231225459. Epub 2024 Jan 29.
The phosphate ester monomer 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) is capable of bonding to hydroxyapatite and, for this reason, is a key component of several self-etch adhesives. In this study, dicalcium phosphate dihydrate particles (DCPD; CaHPO.2HO) were functionalized with 10-MDP and used to formulate an experimental composite with 50 vol% inorganic content (3:1 DCPD:silanated barium glass ratio) dispersed in a BisGMA/TEGDMA matrix. The tested hypothesis was that DCPD functionalization would improve the composite's mechanical performance without compromising Ca release. Composites containing nonfunctionalized DCPD or only reinforcing glass (in both cases, with or without 10-MDP mixed in the resin phase) were used as controls. Materials were tested for degree of conversion (DC; by Fourier transform infrared spectroscopy), water sorption (WS) and solubility (SL; according to ISO 4049), biaxial flexural strength (BFS)/modulus (FM) after 24 h and 5 mo in water, and 28-d Ca release in water (by plasma-coupled optical emission spectroscopy). Data were analyzed using analysis of variance/Tukey test (alpha: 5%). DCPD functionalization did not interfere with DC. The composite containing functionalized DCPD showed significantly lower WS and SL in comparison with the material formulated with nonfunctionalized particles. The presence of 10-MDP (as a functionalizing agent or dispersed in the resin phase) reduced the composite's initial BFS and FM. After 5 mo in water, the composite with functionalized DCPD and both glass-only composites were able to maintain their mechanical properties at levels statistically similar to what was observed after 24 h. Ca release was significantly reduced in both formulations containing 10-MDP. In conclusion, DCPD functionalization with 10-MDP increased the composite's resistance to hydrolytic degradation, improving its mechanical stability after prolonged water storage. However, the impaired water transit at the particle-matrix interface led to a reduction in Ca release.
磷酸酯单体 10-甲基丙烯酰氧癸基二氢磷酸酯 (10-MDP) 能够与羟磷灰石结合，因此是几种自酸蚀胶粘剂的关键成分。在这项研究中，二水磷酸氢钙颗粒 (DCPD; CaHPO.2HO) 用 10-MDP 进行功能化，并用于配制一种具有 50 体积%无机含量的实验性复合材料（3:1 DCPD：硅烷化钡玻璃比）分散在 BisGMA/TEGDMA 基质中。测试的假设是 DCPD 的功能化不会损害 Ca 释放，而提高复合材料的机械性能。含有未功能化 DCPD 或仅增强玻璃的复合材料（在这两种情况下，树脂相都含有或不含有 10-MDP）用作对照。通过傅里叶变换红外光谱法 (FTIR) 测试材料的转化率 (DC)，根据 ISO 4049 测试吸水率 (WS) 和溶解度 (SL)，24 h 和 5 个月在水中的双轴弯曲强度 (BFS)/模量 (FM)，以及 28 天水中的 Ca 释放量 (通过等离子体耦合发射光谱法)。使用方差分析/ Tukey 检验 (alpha: 5%) 分析数据。DCPD 的功能化不影响 DC。与用非功能化颗粒配制的材料相比，含有功能化 DCPD 的复合材料具有明显更低的 WS 和 SL。10-MDP 的存在（作为功能化剂或分散在树脂相中）降低了复合材料的初始 BFS 和 FM。在水中放置 5 个月后，具有功能化 DCPD 的复合材料和仅含玻璃的两种复合材料都能够保持其机械性能，与在 24 小时后观察到的性能在统计学上相似。两种含有 10-MDP 的配方中的 Ca 释放量均显著降低。总之，用 10-MDP 对 DCPD 进行功能化提高了复合材料对水解降解的抵抗力，在长时间水储存后提高了其机械稳定性。然而，颗粒-基质界面处水的迁移受阻导致 Ca 释放减少。
