Bonding to dentin: evaluation of three adhesive materials.

Dye penetration was observed in all specimens. SEM demonstrated isolated areas with no gap formation, suggesting a partial bond with dentin. A correlation is evident from the results of both techniques. Since dye-penetration was found to be similar in all the specimens, it was difficult to assess the effect of thermocycling on the amount of dye penetration. The use of posterior composites should be considered as a short-term tested procedure. It should be utilized carefully, following the manufacturer's instructions, and monitored routinely. Undoubtedly, the utilization of posterior composite materials is a very technique-sensitive procedure. Comparing the results of this in vitro study with those previously reported suggests that little improvement has been made in the bonding of the materials tested. Development of new materials and improved techniques are necessary.