Abstract:

Objective To observe the two- dimensional morphology of microleakage between dentin and adhesives. Methods The occlusal 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 °C）. 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.

Key words: adhesion interface, microleakage, adhesive, dentin