Division of Applied Materials Science, Department of Materials Science and Engineering, Uppsala University, Uppsala, Sweden, 75121.
ACS Biomater Sci Eng. 2020 Jun 8;6(6):3599-3607. doi: 10.1021/acsbiomaterials.0c00262. Epub 2020 May 4.
Occlusion of exposed dentin tubules may eliminate or reduce dentin hypersensitivity by hindering fluid movements within the tubules. In this study, the mode of action of spherical particles of amorphous calcium magnesium phosphate (180-440 nm in diameter) was studied. A degradation study of the particles in Tris-HCl buffer showed that the particles continuously released Ca, Mg, and phosphate, and XRD analysis revealed the formation of hydroxyapatite (HA) after 1 week. The occluding effect and efficacy of the spherical particles as an occluding agent were evaluated in an study. The ACMP particles were incorporated in a gel intended for at-home use and tested on extracted human molars. Application of the particles followed by incubation in artificial saliva resulted in occlusion of exposed tubules, and examination with SEM showed that the particles could penetrate the tubules down to 100 μm from the dentin surface. Transformation of the particles into nanocrystalline HA-structures (nanoHA) was initiated at the dentin surface within 12 h of application, and tubule penetration of the particles, accompanied by further ion release and diffusion of ions, resulted in deep intratubular occlusion in the majority of the tubules within 3 days from application. NanoHA was tightly adhered to the tubule walls, filling the entire tubule volume after 7 days. The results of this study demonstrate the mode of action of the amorphous calcium magnesium phosphate particles in occluding exposed dentin tubules. Interaction with saliva and transformation of the particles within the tubules inducing further mineralization indicate that the particles may be used as an effective treatment to reduce dentin hypersensitivity.
暴露的牙本质小管的闭塞可能通过阻碍小管内的流体运动来消除或减少牙本质敏感。在这项研究中，研究了无定形磷酸钙镁（直径 180-440nm）球形颗粒的作用方式。在 Tris-HCl 缓冲液中的颗粒降解研究表明，颗粒不断释放 Ca、Mg 和磷酸盐，并且 XRD 分析显示在 1 周后形成了羟基磷灰石（HA）。在一项研究中评估了球形颗粒作为封闭剂的封闭效果和功效。将 ACMP 颗粒掺入用于家庭使用的凝胶中，并在提取的人磨牙上进行了测试。颗粒的应用随后在人工唾液中孵育导致暴露的小管闭塞，SEM 检查表明颗粒可以穿透小管，从牙本质表面向下穿透 100μm。在应用后的 12 小时内，颗粒在牙本质表面开始转化为纳米晶 HA 结构（nanoHA），颗粒的穿透，伴随着进一步的离子释放和离子扩散，导致在应用后 3 天内，大多数小管中的管内闭塞很深。纳米 HA 紧密附着在小管壁上，在 7 天后填充整个小管体积。这项研究的结果表明了无定形磷酸钙镁颗粒在闭塞暴露的牙本质小管中的作用方式。与唾液的相互作用以及颗粒在小管内的转化诱导进一步的矿化表明，这些颗粒可用作减少牙本质敏感的有效治疗方法。
