Bond Strength of Novel Bioactive Resin Modified Luting Agent to Lithium Disilicate Dental Ceramic

The aim was to compare the bond strength of bioactive resin modified, resin based and Self-etch resin modified luting agents in the adhesive bonding of lithium disilicate ceramics with ageing. Twenty-four lithium disilicate ceramic blocks (4x6x8 mm) were fabricated using hot pressing. Blocks were etched (9.5%, HF Acid) for 2 minutes and were exposed to ultrasonic cleaning in a water bath. Silane was applied and allowed to dry for 5 minutes. Bulk fill composite blocks (4x6x8 mm) were used as bonding substrate for lithium disilicate ceramic. Specimen blocks (24) were divided into 6 study groups (1 to 6) based on the type of luting agents [(ACTIVA-Bulkfill, RelyX Unicem, RelyX ARC)] and presence of thermocycling (ageing). The blocks were bonded and light cured for 40 sec with an intensity of 650 mWcm(-2). Specimen sticks of 1 mm(2) cross-section were formed by sectioning and microtensile bond strength (mu-tbs) test was performed by loading bonded sticks (crosshead speed 0.5 mm/min) using a mu-tbs tester. Fractographic analysis was performed using a scanning electron microscope. Means were analyzed with one-way ANOVA and TukeyKramer multiple comparison test. The highest and lowest mu-tbs were shown by Rely-X Unicem [ 22.36 (3.11)] and bioactive (ACTIVA) [ 15.57 (2.04)] luting agents respectively. All cements showed reduction in mu-tbs due to thermocycling. Bioactive (ACTIVA, Bulk-fill) luting agent, showed comparable mu-tbs values to resin-based and Self-etch resin modified cements when bonded to LD ceramics in aged specimen. Bioactive (ACTIVA) luting cement demonstrated durability in bond strength to lithium disilicate ceramics.