Bond strength durability of self-adhesive resin cements to zirconia ceramic: An in vitro study

Statement of problem. How contamination, cleaning, and artificial aging affect the bond strength of self-adhesive resin cements to zirconia ceramics is unclear. Purpose. The purpose of this in vitro study was to assess the durability and bond strength of different self-adhesive resin cements to zirconia ceramics subjected to contamination, cleaning, and aging. Material and methods. A total 192 zirconia ceramic squares were airborne-particle abraded with 50 mu m Al2O3 at a pressure of 100 kPa. The specimens were then divided into 4 main experimental groups (n=48) according to the type of self-adhesive resin. Specimens in the subgroups (n=16) were exposed to 3 different treatment methods: alcohol bath cleaning only, contamination with saliva and alcohol bath cleaning, and contamination with saliva and cleaning with Ivoclean followed by alcohol bath cleaning. Bonded specimens were stored in distilled water (37 degrees C), either for 3 days with no thermocycling or for 150 days interrupted by 37 500 thermocycles between 5 degrees C and 55 degrees C. After storage, the bond strength was determined using a universal testing machine. Results were analyzed statistically, using nonparametric tests. Results. After saliva contamination, the tensile bond strength for all specimens decreased significantly (P<.001). Furthermore, after saliva contamination and during 150 days of water storage with thermocycling, all specimens debonded spontaneously. However, use of the cleaning medium (Ivoclean) significantly increased the tensile bond strength for almost all specimens (P<.05). Conclusions. Saliva contamination significantly negatively influenced the bond strength and durability to zirconia ceramic. Ceramic cleaning using Ivoclean significantly improved the bond strength to saliva contaminated zirconia ceramics.