KU Leuven BIOMAT, Department of Oral Health Research, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Belgium.
Dent Mater. 2013 Aug;29(8):888-97. doi: 10.1016/j.dental.2013.05.006. Epub 2013 Jun 13.
The functional monomer 10-methacryloxydecyl dihydrogen phosphate (10-MDP), recently used in more self-etch adhesives, chemically bonds to hydroxyapatite (HAp) and thus tooth tissue. Although the interfacial interaction of the phosphoric-acid functional group of 10-MDP with HAp-based substrates has well been documented, the effect of the long carbon-chain spacer of 10-MDP on the bonding effectiveness is far from understood.
We investigated three phosphoric-acid monomers, 2-methacryloyloxyethyl dihydrogen phosphate (2-MEP), 6-methacryloyloxyhexyl dihydrogen phosphate (6-MHP) and 10-MDP, that only differed for the length of the carbon chain, on their chemical interaction potential with HAp and dentin, this correlatively using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Commercial 6-MHP and 10-MDP containing adhesives were investigated as well.
XRD revealed that on HAp only 10-MDP produced monomer-calcium salts in the form of 'nano-layering', while on dentin all monomers produced 'nano-layering', but with a varying intensity in the order of 10-MDP>6-MHP>2-MEP. TEM confirmed that 10-MDP formed the thickest hybrid and adhesive layer. XRD and TEM revealed 'nano-layering' for all commercial adhesives on dentin, though less intensively for the 6-MHP containing adhesive than for the 10-MDP ones.
It is concluded that not only the phosphoric-acid group but also the spacer group, and its length, affect the chemical interaction potential with HAp and dentin. In addition, the relatively strong 'etching' effect of 10-MDP forms more stable monomer-Ca salts, or 'nano-layering', than the two shorter carbon-chain monomers tested, thereby explaining, at least in part, the better bond durability documented with 10-MDP containing adhesives.
最近在更多自酸蚀粘结剂中使用的功能单体 10-甲氧基癸基二氢磷酸酯（10-MDP）通过化学键与羟基磷灰石（HAp）和牙本质结合。尽管 10-MDP 的磷酸基团与 HAp 基基底的界面相互作用已经得到很好的证明，但 10-MDP 的长碳链间隔基对粘结效果的影响还远未被理解。
我们研究了三种磷酸单体，即 2-甲基丙烯酰氧基乙基二氢磷酸酯（2-MEP）、6-甲基丙烯酰氧基己基二氢磷酸酯（6-MHP）和 10-MDP，它们仅在碳链长度上有所不同，研究了它们与 HAp 和牙本质的化学相互作用潜力，这通过 X 射线衍射（XRD）和透射电子显微镜（TEM）进行了相关研究。同时还研究了商业的含有 6-MHP 和 10-MDP 的粘结剂。
XRD 表明，在 HAp 上，只有 10-MDP 以“纳米层状”的形式产生单体-钙盐，而在牙本质上，所有单体都产生“纳米层状”，但强度顺序为 10-MDP>6-MHP>2-MEP。TEM 证实 10-MDP 形成了最厚的混合层和粘结层。XRD 和 TEM 表明，所有商业粘结剂在牙本质上都存在“纳米层状”，但含有 6-MHP 的粘结剂的强度不及含有 10-MDP 的粘结剂。
研究结论认为，不仅是磷酸基团，而且是间隔基及其长度，都会影响与 HAp 和牙本质的化学相互作用潜力。此外，10-MDP 的相对较强的“蚀刻”效应形成了比测试的两种较短碳链单体更稳定的单体-Ca 盐，或“纳米层状”，这至少部分解释了含有 10-MDP 的粘结剂具有更好的粘结耐久性。
