Study of physicochemical properties and effects on bonding to zirconia ceramics of five resin cements

The aim of this study was to investigate the physicochemical properties of five resin cements and their effects on bonding to zirconia ceramics. The degree of conversion (DC) and water contact angle of five resin cements were measured. Fifty zirconia blocks were randomly divided into five groups according to resin cements (RelyX Ultimate [RUL]; Panavia F [PF]; Clearfil SA Luing [CSA]; Multilink Speed [MS]; RelyX Unicem [RUN]) and bonded to the prepared dentin. After storage for 24 h and 5000 thermal cycles, the micro-tensile bond strength (µTBS) was tested, the failure modes and bond interface morphology were observed. The results were subjected to statistical analysis. The DC of CSA and the contact angle of RUL was the largest. At 24 h, the µTBS was MS > RUL > CSA ≈ PF > RUN (p < 0.05). After 5000 cycles, the µTBS was MS > CSA > RUL > PF ≈ RUN (p < 0.05). The failure modes were determined to mixed and interface failures. The resin tags of RUL were thicker, longer, more uniform and numerous. In conclusion, the bond strength of resin cement is affected by many factors, such as DC and wettability. The Clearfil SA showed the lower reduction on bonding effect after 5000 cycles, while Multilink Speed presented the highest µTBS before and after 5000 cycles.