Thin layer of enamel is removed; debris, tooth pellicle & chemically inert crystallites are removed. Which term describes this?

Thin layer of enamel is removed; debris, tooth pellicle & chemically inert crystallites are removed. Which term describes this?

• A. Etched zone
• B. Dentin layer
• C. Pellicle layer
• D. Sealed zone

Answer: (A)

The key idea is that acid etching creates an etched zone on enamel. When enamel is prepared for bonding, a thin surface layer is dissolved by acid, removing debris, the acquired pellicle, and inert crystallites as the outer enamel is demineralized. This removes the smear and creates a rough, porous surface—the etched zone—that allows resin to penetrate and form micromechanical bonds. The other terms don’t describe this surface result: a dentin layer would refer to dentin tissue; the pellicle layer is the film that is removed, not the surface after etching; a sealed zone implies a surface that has been sealed, not the demineralized, porous layer created by etching.

The key idea is that acid etching creates an etched zone on enamel. When enamel is prepared for bonding, a thin surface layer is dissolved by acid, removing debris, the acquired pellicle, and inert crystallites as the outer enamel is demineralized. This removes the smear and creates a rough, porous surface—the etched zone—that allows resin to penetrate and form micromechanical bonds. The other terms don’t describe this surface result: a dentin layer would refer to dentin tissue; the pellicle layer is the film that is removed, not the surface after etching; a sealed zone implies a surface that has been sealed, not the demineralized, porous layer created by etching.