Influence of adhesives containing different photoinitiators and monomeric mixtures on shear bond strength of a resin cement to zirconia

Abstract

Silicatization is a known method for the cementation of polycrystalline ceramics such as zirconia. However, this method must be associated with adhesives for clinical success. Therefore, the type and composition of the adhesive, as well as the photoactivation method/apparatus may influence the bonding stability after the cementation of the prosthetic restoration. The present study will evaluate the stability of bonding to zirconia using experimental adhesives with different monomer mixtures and photoinitiator systems. The adhesives will be prepared with two basic mixtures: Bis-GMA, TEGDMA, HEMA, BHT and ethanol; or Bis-GMA, Bis-EMA, HEMA, BHT and ethanol. The following photoinitiators will be added: CQ/DABE (photoinitiator type II/synergist amine); CQ/DABE/diphenyl iodonium hexafluorophosphate (type II photoinitiator/synergist amine/type I photoinitiator); CQ/TASHFSb (type II photoinitiator/photoinitiator type I); CQ/DABE/TASHFSb (photoinitiator type II / synergist amine / type I photoinitiator). Bonding stability will be evaluated by microshear with a universal machine after storage in water and thermocycling. For this, resin composite cylinders will be cemented over zirconia slices. The surfaces of the slices will be silicatized with Rocatec Plus and will receive a silane coupling agent prior to cementation. The experimental adhesives will then be applied and photoactivated with two light-activating devices: wide-spectrum LED or conventional LED. Resin composite cylinders will be cemented with a dual-cured resin cement and the photoactivation will be carried out through the ceramic, with the light of the apparatus positioned under the ceramic slice, in order to simulate the light attenuation caused by the ceramic during a conventional clinical situation. The data will be analyzed three-way Anova (± = 0.05). (AU)