Bonding of restorative materials to dentine

The potential advantages of bonding a filling material to dentine have long been recognized by the dental profession. Such bonding would prevent recurrent decay and would provide a long-lasting restoration. Bonding of suitable filling materials to enamel can be easily accomplished by first etching the enamel with acid. This opens up areas in the enamel and permits filling materials to flow into the openings and form mechanical locks. It is not possible to do this with dentine since the acid used to etch enamel would harm the pulp when applied to dentine. The present status of dentine bonding is that a small number of products are now being marketed with claims of bonding to dentine. In addition, research is being conducted on some experimental products. Results in the laboratory show that the bond strengths achieved by composite resins, using the commercially available materials on dentine, do not reach those obtained with acid etched enamel. The correlation of these results with clinical performance is unknown. Therefore, the amount of available information is at present insufficient to make recommendations on the effectiveness or ineffectiveness of commercially available dentine bonding systems. However, it appears that caution should be employed when using any product requiring an etchant or acidic cleansing agent. There is a need for further research to gain better understanding of the biological safety and effectiveness of both the present commercial and experimental dentine bonding systems.