Spark erosion as a metal-resin bonding system.

PURPOSE Resin to metal bond strength of two commercial and one experimental metal-resin bonding system for crown and bridge veneer composites was evaluated. MATERIALS AND METHODS All specimens were prepared and tested according to ISO 10477 Amendment 1. A high precious alloy (HPA), a Co/Cr-alloy (Co/Cr) and pure titanium (Ti) were wet-ground to a final surface finish of 800 grit and air-dried. Twenty specimens of each metal were treated with Rocatec (RO), 20 with a Silano-Pen (SP), and 20 with the experimental spark-erosion (SE) bonding system. A light-curing opaque and a crown and bridge veneer composite were applied to each metal specimen. Ten specimens of each metal and bonding system were stored in water for 24h at 37 degrees C, 10 were thermocycled (TC) 5000 times in a water-bath between +5 and +55 degrees C prior to measuring shear bond strength (SBS). Scanning electron microscopy (SEM) was used to examine the treated metal surfaces. RESULTS After 24h SE generated significantly higher SBS values on Ti than RO (p<0.05). SP revealed the highest SBS for Co/Cr. After TC significant decreases occurred for RO on HPA, for SP on Co/Cr and Ti, and for SP on Ti. SE revealed the highest mean bond values for all metals. These results and SEM proved that no sandblasting is required for SE to obtain good bond strength. SIGNIFICANCE The experimental spark-erosion bonding system is an easy and very effective method for surface-treating alloys to obtain high SBS values for crown and bridge veneer composites.