Table 4.

The 3 silane layers formed after silane application and methods of elimination of the two undesirable outermost layers.

Layers	Composition	Method of Elimination	First Alternative Method of Elimination	Second Alternative Method of Elimination
Outermost layer [67]	Small oligomers	Washed away by organic solvents or water at room temperature	Apply the silane followed by hot air drying (50 ± 5 °C) for 15 s for proper solvent evaporation. Then rinse with hot water (80 °C) for 15 s followed by another hot air drying for 15 s.	Try-in step performed following the silanation
Middle layer [76,77,78]	Hydrolyzable oligomers could compromise the coupling of the cement	Removed with hot water
Inner layer [76,77,78]	Monolayer covalently bonded to the silica phase of the ceramic and is hydrolytically stable	Not to be removed	N.A	N.A