Purpose: This invitro study investigated the effect of lithium disilicate surface treatment methods and thermocycling condition on the bond strength to resin cement.
Material and methods: 12 Lithium disilicate ceramic blocks (7x9x6 mm) were fabricated from IPS e.max CAD blocs. Specimens were allocated in 3 groups (n=4), according to type of surface treatment: Group HFI: etched with 5 % HF acid followed by Monobond plus, Group HFP: etched with 9% HF acid followed by Monobond plus and Group MEP: treated using self-etch primer (Monobond Etch & Prime). Composite blocks of equal size were fabricated and bonded to ceramic blocs using self-adhesive resin cement. Specimens were embedded in acrylic resin blocks then sectioned into beam-shaped specimens (1x1mm). Each group was further subdivided into two subgroups according to aging by thermocycling Subgroup Immediate (I): stored in distilled water at 37o C For 24 hours then tested immediately and Subgroup Thermocycled (TC): stored then subjected to 5000 thermocycles. The μTBS were presented in MPa and failure mode of debonded specimens were examined by stereomicroscope and SEM to investigate surface characterization.
Results: The μTBS mean values ranged between (20.19 and 23.09 Mpa) for (I) subgroups and (14.93 and 15.45 Mpa) for (TC) subgroups. HFP-I showed the highest μTBS (23.09MPa). Thermocycling significantly affected the bond strength results (p=0.001) of all groups.
Conclusion: HF Etching of Lithium disilicate with increased concentration followed by silane application is optimal for ceramic/resin bonding. Moreover, Single-bottle self-etch ceramic primer proved to be a good alternative protocol