Fig. 8.

405-nm images of (top) a 6 h specimen (a) prior to application of transparent viscoelastic pressure sensitive adhesive, and (b) after application of adhesive. The measured contrast for this specimen is 0.6 prior and 0.45 after application of adhesive. 405-nm images of (bottom) a 4 h occlusal specimen (c) prior to application of sensitive adhesive, and (d) after application of adhesive. The measured contrast for this specimen is 0.42 prior and 0.32 after application of adhesive. The white boxes in (b) and (d) represent the region where the adhesive was applied. No reversal in contrast between eroded and sound enamel is seen, indicating that the adhesive did not fill subsurface voids.