A varnish to prevent etching unrestored enamel.

The prognosis of acid-etched enamel was investigated in both laboratory and clinical experiments. Acid etching produced irregularities even on the prismless layer that covers prism enamel. The irregularities produced by etching are not remineralized in vivo but are filled with organic debris. Brushing reduced the depth of the irregularities but did not eliminate them. A protective varnish against acid etching was developed. The varnish also serves as a guide to facilitate removal of excess resin beyond the cavosurface margin.