Influence of Micromechanical and Chemical Conditioning on Bonding to Machinable Composite

Purpose: To evaluate the influence of micromechanical and chemical conditioning on bonding to hybrid ceramic (machinable composite MZ100 blocks). Materials and methods: A total of 64 machinable composite discs (MZ100 paradigm) were fabricated using CAD/CAM technology according to the desired dimensions (10 mm width and 4 mm thickness). The discs were divided in two main groups (n=32): as milled group (AM) and sandblast group (SB) used Al2O3 (50-μm). Each main group was subdivided into two subgroups (n=16) according to method of chemical conditioning: conventional silane (SI) and multipurpose primer (MP). Composite resin discs were fabricated according to desired dimensions (4.5 mm width x 3.5 mm thickness). Surface treated MZ100 discs were bonded to the composite resin discs according to the types of adhesive resin cements, multistep adhesive resin cements or self-adhesive resin cements. One hour after bonding, all specimens were stored in water bath at 37°C for 5 months followed by thermocycling for 10,000 cycles. Following artificial aging all bonded specimens underwent shear bond strength testing using universal Instron testing machine. Assessment of the debonding failure mode was done by Binocular optical microscope and SEM. Statistical analysis was performed using a 3-Way ANOVAs.Results: In Three-Way ANOVAs test revealed statistically significant different in SBS between (SB) and (AM) groups {p=0.000} and between different resin cements used {p=0.006}. While there, was no statistically significant different when used different chemical conditioning methods {p=0.132}. Conclusions: Sandblasting of the MZ100 paradigm block surface is recommended when luting with the self-adhesive or multistep adhesive resin cements. The self-adhesive performed SBS values compared to multistep adhesive resin cement in all groups. The combination between micromechanical and chemical conditioning of MZ100 paradigm block surface are recommended over the chemical conditioning alone.