DOI: 10.36347/sjds.2019.v06i04.002

Pages: 213-218

The objective of this study is (i) to compare the shear strength of lithium disilicate IPS e.max® Press color A1 (Ivoclar Vivadent, Baden-Württemberg, Ellwangen, Germany) laminate disks to bovine incisive enamel using four cementation protocols; and (ii) to assess the failure mode, classified as adhesive (enamel or ceramics), cohesive or mixed, and its possible association with the technique used for cementation. To this end, 40 bovine incisives and 80 laminate disks measuring 0.5mm of thickness and 3mm of diameter were used. The test specimens were divided in four groups (n=10): G1 and G2 cemented with photopolymering resin cement RelyX® Venner (3M ESPE, St. Paul-MN, USA), using a vertical shaft in G1 and ultrasound for 5s in G2; G3 and G4 cemented with compound resin Filtek® Z350XT (3M ESPE, St. Paul-MN, USA) pre-heated at 50ºC, using vertical shaft in G3 and ultrasound for 5s in G4. Two laminate disks were cemented on each tooth, one at the mesial region, another at the incisal region with constant pressure of 500g. Shearing was performed using a chisel knife in a universal testing machine (EMIC DL2000) with load of 500Kgf at 0.5mm/s. Results for failure mode were obtained using a stereo microscope. There is no significant difference between the groups regarding shear strength or region of cementation, both within or between groups. Failure is predominantly adhesive. There is no correlation between cementation protocol and failure mode, whether at the mesial or incisal region. It is possible to conclude that all cementation protocols assessed here are indicated for clinical use since they present similar shear strength. Longitudinal clinical studies are necessary.