Effect of parallel surface cuts on bonding to dentine

The strength of adhesive joints has been found to result from combinations of micromechanical, chemical and diffusion components depending on the system 1. The development of adhesives that bond dental restorative materials to human dentine has been a major advance in the science of dental materials. The purpose of this investigation was to study the contribution of parallel surface cuts on the joint strength of dentine adhesives. Half of the specimens were finished with 60 grit SiC paper as a control. The other half were polished with 600 grit SiC paper and then finished with an instrument that produced a series of parallel surface cuts. A two-way analysis of variance showed that both the surface preparation and the adhesive system had a significant effect on shear bond strength (p < 0.0001). In general, the samples finished with 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 at the tooth/adhesive interface. The majority of samples with parallel surface cuts failed cohesively within the adhesive system. The experimental instrument is designed to produce retentive grooves or undercuts in the dentine surface which enhance micromechanical adhesion.