Work of adhesion of resin on treated lithia disilicate-based ceramic

Objective. This study is to test the hypothesis that chemical etching and silane coating of a ceramic surface will influence the work of adhesion (WA) of adhesive resin to dental ceramic. Methods. A hot-pressed lithia disilicate-based ceramic was used as a model material to investigate the influence of probing media and surface treatments on WA using a dynamic contact angle analyzer. Eighty ceramic specimens were randomly divided into eight experimental groups and treated as follows: (1 and 3) as polished; (2 and 4) etched with 9.5% hydrofluoric acid (HF) for 1 min; (5) etched with 4% acidulated phosphate fluoride (APF) for 2 min; (6) silane coated; (7) etched with HF for 1 min and silane coated; (8) etched with APF for 2 min and silane coated. Advancing and receding contact angles (θa and θr) were measured using high purity water (γ=72.6 mN/m) for groups 1 and 2, and a liquid resin (γ=39.7 mN/m) for groups 3–8 as probing liquids. Results. The liquid resin medium yielded a lower WA than water. Silanization produced a significantly lower WA (p<0.001) than non-silanated surfaces. Etching alone consistently yielded a greater WA for all surface treatments (p<0.001). Significance. The silanated ceramic surface exhibited a lower surface energy and did not enhance bonding to the liquid resin by work of adhesion.