Document Classification

Section Type: METHODS

Text: Specimens were randomly assigned to one of the following surface conditioning protocols (n = 10 per group) : group 1, veneer : 4 % hydrofluoric acid (HF) (Porcelain Etch) + core : aluminum trioxide (50-m Al2O3) + core + veneer : silane (ESPE-Sil) ; group 2 : core : Al2O3 (50 m) + veneer : HF + core + veneer : silane ; group 3 : veneer : HF + core : 30 m aluminum trioxide particles coated with silica (30 m SiO2) + core + veneer : silane ; group 4 : core : 30 m SiO2 + veneer : HF + core + veneer : silane.