The influence of surface treatment and luting cement on in vitro behavior of two-unit cantilever resin-bonded bridges

Objectives. The purpose of this study was to find the optimal combination of surface pretreatment and luting cement for two-unit CoCr cantilever resin-bonded bridges. Methods. Tensile peel, load and torque strength tests were performed using flat ground bovine teeth as substrate, four different commercially available luting cements, and CoCr beams as simulated cantilever resin-bonded bridges. The CoCr beams were pretreated with sandblasting or Rocatec. Tensile peel, load and torque strengths were determined 72 h after cementation. The effects of sandblasting and Rocatec pretreatments on the morphology of the CoCr surface was investigated with SEM and EDAX analysis. Results. The average strengths of the three tests showed that Rely X ARC, Resiment and Panavia were the same and significantly lower than UniFix. Rocatec showed a significantly higher average bond strength than sandblasting considering all tests. The peel test, which showed the lowest failure values, is clinically the most relevant test. This test showed that only UniFix as luting cement with sandblasting as pretreatment generates a significantly higher bond strength compared with the other cements and pretreatments. Significance. Based on the results of this study the use of Unifix with sandblasting as metal surface pretreatment, is preferred for cementation of two-unit CoCr cantilever resin-bonded bridges.