Farkli yüzey işlemlerinin iki yüksek translusent monolitik zirkonya CAD/CAM malzemesinin self adeziv simanlarla bağlanma mukavemetine olan etkisinin değerlendirilmesi

Evaluation of shear bond strength of two highly translucent monolithic zirconia CAD/CAM materials to self-adhesive resin cement after different surface pretreatment In-vitro study aimed to assess the effect of different surface treatments on the shear bond strength of self-adhesive resin cement to highly translucent monolithic zirconia-based CAD/CAM materials. 2 brands of highly translucent monolithic CAD/CAM zirconia were evaluated: Zenostar Zr translucent (Wieland Dental; Pforzheim, Germany) and Ceramill zolid fx preshade (Amann Girrbach AG, Koblach, Austria). 152 disc shaped monolithic zirconia sample of two brands were used and prepared from pre-sintered blocks using 5 axis CAD/CAM system (VHF K5 Germany) and then sintered to the final required dimension (10 mm in diameter and 3 mm in height) in a special high-temperature furnace. After those 140 discs were divided into seven groups according to the surface treatment received: no treatment (control), 9.5% HF acid etching, airblasting with 50 μm Al2O3, airblasting with 50 μm Al2O3 + Z Prime Plus, Cojet, Siljet, fiber laser. Composite resin cylinders were bonded to zirconia disc with RelyX U200 self-adhesive resin cement according to manufacturer's instructions. All specimens were thermocycled (5000 cycles at 5oC/55oC). 12 samples were used for surface roughness evaluation using SEM. A shear bond test was performed using the universal testing machine. Failure modes were examined using stereomicroscope and SEM. Data were analyzed statistically by using two-way ANOVA and post hoc Tukey's multiple comparison test. The bond strength was not statistically significantly different between two highly translucent zirconia CAD/CAM materials (p:0.055; p>0.05). The bond strength was significantly affected by the surface treatment (p:0.000; p<0.05). The highest shear bond strength for Zenostar was reported as fiber laser (17,81±2 MPa). The highest shear bond strength for Ceramill was reported as fiber laser (21,7±3,55 MPa). There was no statistically significant difference between bond strength of Tribochemical silica coating (Cojet, Siljet) and air blasting plus Z Prime Plus for both monolithic zirconia groups. The predominant failure mode was cohesive failure for fiber laser groups and mixed failure for Cojet, Siljet, and blasting+ Z Prime Plus groups. HF acid surface treatment for one hour is not effective for bond of monolithic zirconia. Cojet, Siljet, and alumina blasting with Z Prime Plus is the best available cementation protocol for highly translucent monolithic zirconia. Fiber laser enhanced shear bond strength of two highly translucent monolithic zirconia CAD/CAM blocks, however it led to discoloration of zirconia. Fiber laser as surface treatment needs more research for optimization their effect to increase bond strength without damage to highly translucent monolithic zirconia. Key Words: Shear bond strength, CAD/CAM, monolithic zirconia, self-adhesive resin cement, surface treatment, fiber laser.