Yoshihara Kumiko, Nagaoka Noriyuki, Okihara Takumi, Kuroboshi Manabu, Hayakawa Satoshi, Maruo Yukinori, Nishigawa Goro, De Munck Jan, Yoshida Yasuhiro, Van Meerbeek Bart
Center for Innovative Clinical Medicine, Okayama University Hospital, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan.
Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan.
Dent Mater. 2015 Dec;31(12):1493-501. doi: 10.1016/j.dental.2015.09.019. Epub 2015 Oct 28.
The functional monomer 10-MDP has been considered as one of the best performing functional monomers for dental adhesives. Different adhesives containing 10-MDP are commercially available, among which many so-called 'universal' adhesives. We hypothesize that the quality of the functional monomer 10-MDP in terms of purity may affect bonding performance.
We therefore characterized three different 10-MDP versions (10-MDP_KN provided by Kuraray Noritake; 10-MDP_PCM provided by PCM; 10-MDP_DMI provided by DMI) using NMR, and analyzed their ability to form 10-MDP_Ca salts on dentin using XRD. The 'immediate' and 'aged' micro-tensile bond strength (μTBS) to dentin of three experimental 10-MDP primers was measured. The resultant interfacial adhesive-dentin ultra-structure was characterized using TEM.
NMR disclosed impurities and the presence of 10-MDP dimer in 10-MDP_PCM and 10-MDP_DMI. 10-MDP_PCM and 10-MDP_DMI appeared also sensitive to hydrolysis. 10-MDP_KN, on the contrary, contained less impurities and dimer, and did not undergo hydrolysis. XRD revealed more intense 10-MDP_Ca salt deposition on dentin induced by 10-MDP_KN. The adhesive based on the experimental 10-MDP_KN primer resulted in a significantly higher 'immediate' bond strength that remained stable upon aging; the μTBS of the experimental 10-MDP_PCM and 10-MDP_DMI adhesives significantly dropped upon aging. TEM revealed thicker hybridization and more intense nano-layering for 10-MDP_KN.
It was concluded that primer impurities and the presence of 10-MDP dimer affected not only hybridization, but also reduced the formation of 10-MDP_Ca salts and nano-layering. 10-MDP in a high purity grade is essential to achieve durable bonding.
功能性单体10-甲基丙烯酰氧癸基二氢磷酸酯（10-MDP）被认为是牙科粘合剂中性能最佳的功能性单体之一。市面上有多种含10-MDP的粘合剂，其中许多是所谓的“通用型”粘合剂。我们推测，10-MDP在纯度方面的质量可能会影响粘结性能。
因此，我们使用核磁共振（NMR）对三种不同版本的10-MDP（可乐丽诺里塔克公司提供的10-MDP_KN；PCM公司提供的10-MDP_PCM；DMI公司提供的10-MDP_DMI）进行了表征，并使用X射线衍射（XRD）分析了它们在牙本质上形成10-MDP钙盐的能力。测量了三种实验性10-MDP底漆与牙本质的“即时”和“老化后”微拉伸粘结强度（μTBS）。使用透射电子显微镜（TEM）对所得的粘合剂-牙本质界面超微结构进行了表征。
NMR揭示了10-MDP_PCM和10-MDP_DMI中存在杂质以及10-MDP二聚体。10-MDP_PCM和10-MDP_DMI似乎也对水解敏感。相反，10-MDP_KN含有的杂质和二聚体较少，且未发生水解。XRD显示，10-MDP_KN在牙本质上诱导的10-MDP钙盐沉积更强烈。基于实验性10-MDP_KN底漆的粘合剂产生了显著更高的“即时”粘结强度，且老化后保持稳定；实验性10-MDP_PCM和实验性10-MDP_DMI粘合剂的μTBS在老化后显著下降。TEM显示，10-MDP_KN的杂交层更厚，纳米分层更明显。
得出的结论为，底漆杂质和10-MDP二聚体的存在不仅影响杂交，还减少了10-MDP钙盐的形成和纳米分层。高纯度等级的10-MDP对于实现持久粘结至关重要。
