Influence of Dentin on Bonding of Composite Resin

Part 1 Effect of fresh dentin and storing conditions

Abstract

The effects of preserving conditions and time after extraction of human teeth, as specimens for bond strength of composite resin to the dentin, were investigated by the tensile test method and scanning electron microscopy (SEM).
When the teeth were stored in physiologic saline solution, bond strength at 15 minutes after extraction showed the lowest value (13kg/cm²), and at 1 to 12 weeks it was elevated to about 35kg/cm². However pretreatment with citric acid-FeCl₃ solution of dentin surface increased the bond strength 3-fold. The teeth stored in formalin for 6 months had the highest bond strength (80kg/cm²). On SEM observation of the dentin and resin surfaces following the tensile test, a clear correlation was found between range of bond strength and appearance of resin tags.