Hashimoto Masanori, Ohno Hiroki, Sano Hidehiko, Kaga Masayuki, Oguchi Haruhisa
Division of Pediatric Dentistry, Graduate School of Dental Medicine, Hokkaido University, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Hokkaido, Japan.
Biomaterials. 2003 Sep;24(21):3795-803. doi: 10.1016/s0142-9612(03)00262-x.
Our knowledge of the mechanisms responsible for the degradation of resin-dentin bonds are poorly understood. This study investigated the degradation of resin-dentin bonds after 1 year immersion in water. Resin-dentin beams (adhesive area: 0.9mm(2)) were made by bonding using a resin adhesive, to extracted human teeth. The experimental beams were stored in water for 1 year. Beams that had been stored in water for 24h were used as controls. After water storage, the beams were subjected to microtensile bond testing. The dentin side of the fractured surface was observed using FE-SEM. Subsequently, these fractured beams were embedded in epoxy resin and examined by TEM. The bond strength of the control specimens (40.3+/-15.1MPa) decreased significantly (p<0.01) after 1 year of water exposure (13.3+/-5.6MPa). Loss of resin was observed within fractured hybrid layers in the 1 year specimens but not in the controls. Transmission electron microscopic examination revealed the presence of micromorphological alterations in the collagen fibrils after 1 year of water storage. These micromorphological changes (resin elution and alteration of the collagen fibrils) seem to be responsible for the bond degradation leading to bond strength reduction.
我们对导致树脂-牙本质粘结降解的机制了解甚少。本研究调查了树脂-牙本质粘结在水中浸泡1年后的降解情况。使用树脂粘合剂将树脂-牙本质梁（粘结面积：0.9mm²）粘结到拔除的人牙上制成。实验梁在水中储存1年。在水中储存24小时的梁用作对照。水储存后，对梁进行微拉伸粘结测试。使用场发射扫描电子显微镜观察断裂表面的牙本质侧。随后，将这些断裂的梁嵌入环氧树脂中并通过透射电子显微镜检查。对照样本的粘结强度（40.3±15.1MPa）在水暴露1年后显著降低（p<0.01）（13.3±5.6MPa）。在储存1年的样本的断裂混合层中观察到树脂损失，而对照样本中未观察到。透射电子显微镜检查显示，水储存1年后胶原纤维存在微观形态改变。这些微观形态变化（树脂洗脱和胶原纤维改变）似乎是导致粘结降解从而导致粘结强度降低的原因。
