Abstract
The aim of the study was to investigate the adhesive bond and compressive strength of novel bulk fill resin composite with zirconia (Zr) nano-hybrid filler. Sixty molars were mounted in acrylic resin with flat occlusal surface. Half of the specimen (n=30) were bonded using total etch (TE) and the other half with self-etch (SE) technique. Specimens treated with SE (n=30) and TE (n=30) bonding protocol were divided into three groups, based on the type of bulk fill build-up materials (ZC-ZirconCore, MC-MulticCore Flow and LC-Luxacore Dual), resulting in six study groups [MC-TE, MC-SE, LC-TE, LC-SE, ZC-TE, ZC-SE]. Cylindrical (3 x 3mm) build-ups were performed followed by shear bond strength testing (crosshead speed-1mm/min). Ten specimens for each bulk fill build-up material (MC, LC and ZC) were prepared for compressive strength testing. All specimens were tested for maximum failure loads (crosshead speed-0.5cm/min). Analysis of variance and paired t-test were performed to statistically analyze the data. TE technique showed significantly higher bond strength values as compared to SE technique (p<0.001) for all three materials (MC, LC and ZC). Shear bond strength for MC [TE,17.88(2.00)-SE,9.43(0.98)] and LC [TE,18.91(2.57)-SE,6.35(1.12)] groups were significantly higher than ZC group [TE,13.99(1.09)-SE,4.61(0.84)]. Specimens in ZC group (266.73 +/- 9.76) showed significantly higher compressive strength in comparison to MC (247.66 +/- 9.72) (p=0.004) and LC (249.87 +/- 13.17) (p<0.001) groups. Zirconia nano-hybrid filler resin bulk fill material has comparatively high compressive strength and low bond strength making them suitable for clinical applications in the posterior region with favorable conditions for adhesive bonding.