Influence of bonding surface and bonding methods on the fracture resistance and survival rate of full-coverage occlusal veneers made from lithium disilicate ceramic after cyclic loading

Abstract

ObjectivesThe purpose of this laboratory study was to evaluate the influence of bonding method and type of dental bonding surface on fracture resistance and survival rate of resin bonded occlusal veneers made from lithium disilicate ceramic after cyclic loading. MethodsFourty-eight extracted molars were divided into three groups (N=16) depending on the preparation: within enamel, within dentin/enamel or within enamel/composite resin filling. Lithium disilicate occlussal veneers were fabricated with a fissure-cusp thickness of 0.3–0.6mm. Restorations were etched (5% HF), silanated and adhesively luted using a dual-curing luting composite resin. Test groups were divided into two subgroups, one using a only a self-etching primer, the other additionally etching the enamel with phosphoric acid. After water storage (37°C; 21d) and thermocycling (7500 cycles; 5–55°C), specimens were subjected to dynamic loading in a chewing simulator (600,000 cycles; 10kg/2Hz). Surviving specimens were loaded until fracture using a universal testing machine. ResultsAll specimens survived artificial aging, several specimens showed some damage. ANOVA revealed that enamel etching provided statistically significantly (p≤0.05) higher fracture resistance than self-etching when bonding to enamel and dentin. Self-etching provided statistically significant (p≤0.05) higher fracture resistance for the enamel-composite group than for the enamel group. Enamel etching provided statistically significant (p≤0.05) higher fracture resistance for the enamel and dentin group than for groups enamel and enamel-composite. SignificanceEtching enamel improved the fracture resistance of occlusal veneers when bonding to dentin and enamel and increased the survival rate when bonding to enamel.