EFFECT OF PARALLEL SURFACE CUTS ON BONDING TO DENTIN

The strength of adhesive joints has been found to result from combinat ions of micromechanical, chemical and diffusion components depending o n the system(1). The development of adhesives that bond dental restora tive materials to human dentine has been a major advance in the scienc e of dental materials. The purpose of this investigation was to study the contribution of parallel surface cuts on the joint strength of den tine adhesives. Half of the specimens were finished with 60 grit SIC p aper as a control. The other half were polished with 600 grit SIC pape r and then finished with an instrument that produced a series of paral lel surface cuts. A two-way analysis of variance showed that both the surface preparation and the adhesive system had a significant effect o n shear bond strength (p < 0.0001). In general, the samples finished w ith parallel surface cuts gave shear bond strength values about double those finished with silicon carbide alone. For those control samples prepared with a 60 grit surface, the predominant type of failure was a t the tooth/adhesive interface. The majority of samples with parallel surface cuts failed cohesively within the adhesive system. The experim ental instrument is designed to produce retentive grooves or undercuts in the dentine surface which enhance micromechanical adhesion.