In vivo resin impregnation of dentinal tubules

This study investigated the in vivo resin impregnation of dentinal tubules on exposed dentin surfaces with transversely cut tubules and examined the effect of different pretreatment on impregnation of the dentin. The results have lead to the following conclusions: 1. There is no sound reason to routinely etch and impregnate the dentin with resin on cavity walls. 2. It is possible to impregnate flat areas of exposed dentin which are not close to the pulp and which have transversely sectioned dentinal tubules. This may block dentin sensitivity, preventing infection and irritation of the pulp. 3. The etching time with 37% phosphoric acid should be limited to 5 seconds. This is sufficient to open and enlarge the dentinal tubules at the surface. 4. The desiccation should be performed with the air nozzle near, and almost parallel to, a flat surface for at least 15 seconds. An uneven surface results in uneven impregnation of the dentinal tubules due to incomplete desiccation. Therefore, the compressed air should be applied from different directions. Better results are obtained if the dentin surface is smooth. This may be achieved by planing with a smooth fissure bur. 5. To obtain satisfactory desiccation of dentin walls in cavities, an air nozzle should be reduced in diameter enough to allow it to enter the cavity. It should be kept in motion while continuously air drying the cavity surface.