Fig. (1) Photographs of non-contact varnish specimens contained in stoppers with varnish applied to acrylic rods before (a) and after (b) each of the three daily inverted immersions in distilled water. In each photograph, the acrylic rods are on the left-hand side, while the dentin specimens are embedded in separate acrylic rods on the right-hand side. The varnished acrylic rods are removed from the stopper during acid challenges and overnight immersions in the artificial saliva mineral mix.