牙本质粘接界面微渗漏的二维形态

Two-dimensional morphology of microleakage between dentin and adhesives

目的观察牙本质粘接界面微渗漏的二维形态。方法去除磨牙面釉质,暴露牙本质,分别用3种粘接剂(Prime&Bond NT、Contax和Adper Prompt)粘接牙本质,其上制作复合树脂冠。顺牙齿长轴,在相互垂直的两个方向片切牙齿,制备条状试样。每个牙齿制备的试样为两组,一组进行冷热循环10000次,另一组不冷热循环,之后相继浸泡于氨化硝酸银溶液及显影液中,然后测定微拉伸粘接强度。最后在扫描电镜下观察界面破坏和混合破坏试样的断面。结果粘接界面微渗漏的二维形态呈各种不同的树枝状,从边缘伸向中心,冷热循环后的微渗漏程度明显加重。结论牙本质粘接界面的微渗漏并非是从外到里齐头并进,而是呈树枝状,其程度与粘接剂种类和是否进行冷热循环有关。

Objective To observe the two-dimensional morphology of microleakage between dentin and adhesives. Methods The ecclusal enamel of human third molar was cut out and the dentin exposed, followed by the application of dental adhesive （.Prime ＆ Bond NT, Contax and Adper Prompt）, then a composite resin crown was built up. After storage in water（37 ℃） for 24 h, all teeth were vertically serially sectioned into matchstick-shaped specimens through the bond interfaces. Half of the specimens from one tooth were subjected to thermal cycling and another half was stored in water（37 ℃）. All specimens were then immersed in ammoniacal silver nitrate solution, followed by developing solution. At last all specimens were subjected to microtensile test at a cross-head speed of 1.0 mm/min and their fractured surfaces were observed under scanning electron microscope. Results The planar contour of all the silver leakage was various branching, treelike shape, spreading from the border of section to the center. Conclusion The planar contour of microleakage is treelike shape and its extent is influenced by adhesives and thermal cycling.