TAGS PENETRATING DENTIN OF A NEW ADHESIVE RESIN

抄録

The change of the dentinal tubules by acid-etching and the morphology and the adhering state of new adhesive composite resin tags penetrating the tubules were obse1ved by SEM, comparing with the representative conventional composite resin. When the fractured surfaces of the unetched floor dentin were observed, all tubule entrances were closed by blocking with cutting debris up to 10 to 20 µm depth. Etching opened them by dissolving the debris and further widened the tubule entrances up to 10 to 20 µm depth by dissolving the peritubular dentin near the apertures. Resin tags penetrated 10 to 20 µm in vital teeth, 60 to 100 µm in freshly extracted teeth and several hundred µm in old extracted teeth. The tags of the new resin penetrating the tubules copied exactly the shape of the tubule walls, producing hollow depressions at the ends, indicating that the resin polymerized, adhering tightly to the walls, while those of the conventional resin produced highly tapered side walls with pointed ends, indicating that the resin shrank separating from the tubule walls on polymerization. The new resin did not produce any gap at the resin-dentin interface unlike the conventional resm.