Total-etch

The total-etch system completely removes the smear layer using an acidic gel (usually phosphate acid) and demineralizes hydroxyapatite under the smear layer of the dentin.

With the classic total-etch technique, both the enamel and dentin are etched with phosphoric acid.

As illustrated in Figure 12-1, dentin etching did not gain wide acceptance until Fusayama introduced the total-etch concept in 1979.