Abstract
Today, direct composite fillings have reached a satisfactory level, aesthetically and functionally, to replace decayed or lost tooth tissue. However, as the bond degrades with time, the restoration lifetime is limited, depending largely on the type of adhesive used. This review examines the processes involved in the adhesion of biomaterials to enamel and dentin. Contemporary adhesives are categorized upon ultra-morphological, chemical and mechanical features, as well as clinical parameters. Apart from these properties, special attention is given to one-step (self-etch) adhesives, as they are aggressively marketed as the most user-friendly adhesives. Nevertheless, in-vitro research has revealed considerable shortcomings related to many of these simplified adhesives. Notwithstanding the amount of n-vitro data available, non-carious class-V clinical trials remain the ultimate test method to assess clinical success. In combination with the prior in-vitro assessment, the following conclusions were drawn : 1) At present, the three-step etch&rinse approach remains the ‘golden standard’ in terms of bonding effectiveness ; 2) Any kind of simplification in the application procedure results in loss of bonding effectiveness ; 3) The today most acceptable trade-off between bonding effectiveness and ease-of-use is a ‘mild’ two-step self-etch approach that combines micro-mechanical interlocking with additional chemical interaction, the latter definitely contributing to the bond stability on the long term.
