Shear Strength Between Adhesive Cement and Yttria-Stabilized-Zirconia and Cobalt-Chrome Alloy With and Without Retentive Holes - an in vitro study

ABSTRACT De-bonding is the most common failure of resin-bonded fixed partial dentures. The aim was to determine if the shear bond strength (SBS) differed between a dental adhesive and a Co-Cr alloy and an yttria-stabilized zirconia (Y-TZP). Furthermore, to determine whether retention holes in the two materials and storage for 21 days in water affected the results. The hypothesis was that there are no significant differences between the compared groups. 10 embedded discs of Co-Cr alloy without and 10 with retentive holes, and 10 discs of Y-TZP without and 17 with retentive holes were sand- and steam blasted. A pillar of adhesive cement was bonded to the surface of the discs and stored in water at 37 °C for 24 hr and / or 21 days. An UltraTest machine with a crosshead speed of 1 mm/ min was used for SBS. The mean SBS after 24 hr / 21 days in water were recorded. The SBS of Co-Cr alloy without retentive hole was 16.3 MPa after 24 hr and 11.4 MPa after 21 days, the SBS of Y-TZP without retentive hole was 18.5 MPa after 24 hr and 12.6 MPa after 21 days. The SBS of Co-Cr alloy with retentive hole 13.9 MPa after 21 days and Y-TZP with retentive hole 16.9 MPa after 21 days. No statistically significant differences were found between the groups with or without retentive holes and after 24 hr or 21 days in water, p> 0.05