Acid etching of enamel

Acid etching of the enamel, or enamel conditioning is an important technique in clinical practice.  37% phosphoric acid is used for this procedure. 

Stages in acid etching of enamel

Stage 1: Acid removes plaque and other debris along with thin layer of enamel. 

Stage 2: It inceases the porosity of exposed surfaces through selective dissolution of crystals which provides a better bonding surface for the restorative and adhesive materials.

Patterns in acid etching of enamel

Type I: It is the most common characterized by preferential removal of rods.

Type II: It preferentially removes the interrod enamel and rod remains intact.

Type III: It is irregular and indiscriminate. 

Uses

It is used for 

1. Fissure sealants

2. Bonding of restorative materials to enamel

3. Cementing of orthodontic brackets to the tooth surfaces