Bond strength evaluation of the veneering-ceramics bonds

OBJECTIVE: The purpose of this study was to determine whether the bond of veneering porcelain to a ceramic core in bilayered ceramics was similar to that of the metal ceramic control of well known behaviour. STUDY DESIGN: Six groups of nine specimens each were fabricated, whose dimensions were 15 mm long and 8 mm in diameter at the core, and 2 mm long and 8 mm in diameter for the veneer. The groups were GR. 1 (control group): CrNi alloy/d.SIGN (Ivoclar), GR. 2: IPS e.maxPress/IPS e.maxCeram (Ivoclar), GR. 3: IPS e.maxZirCad/IPS e.maxZirPress (Ivoclar), GR. 4: IPS e.maxZirCad/IPS e.maxCeram (Ivoclar), GR. 5: Lava Frame (3M ESPE)/Lava Ceram (3M ESPE) and GR. 6: Lava Frame (3M ESPE)/IPS e.maxCeram (Ivoclar). A shear strength test was used in all samples with a universal testing machine. The chosen crosshead speed was of 0.50 mm/min. The obtained results were analyzed using a one way analysis of variance test (ANOVA) to determine whether significant differences existed between the groups (p<0.05). A Student Newman-Keuls multiple comparisons test was used. RESULTS: GR. 1: 13.45 MPa, GR. 2: 24.20 MPa, GR. 3: 12.70 MPa, GR. 4: 7.86 MPa, GR. 5: 10.20 Mpa and GR. 6: 4.62 Mpa. CONCLUSIONS: The bond strength of group 1 (control) was similar to groups 3 and 5. Group 2, whose core and veneer are both porcelains with a similar chemical composition, with silica as their main component, achieved the best adhesive results between both porcelains. The technique on zirconia cores that showed the higher results was the pressed technique. The lowest results were for the group using porcelains from different manufacturers.