The process of etching in the tooth surface leads to demineralization of enamel in tooth. This leads to increase in porosity in tooth; this can aid in more water deposition on the surface.

What does etch do to enamel?

Acid etching is the use of an acidic substance to prepare the tooth's natural enamel for the application of an adhesive. The acid roughens the surface microscopically, increasing retention of resin sealant. Etching of dental enamel with acid removes the smear layer and opens enamel tubules.

Does etching remove enamel?

Just as you might sand the varnish off a smooth wooden table before you paint it a new color, the etching process makes a tooth surface rougher, so the attached dental material is more secure. Microscopically, etching dissolves some of the minerals in the enamel and dentin, the two outer layers of your teeth.