Fig 2. Optical images and shrinkage of dried cross sections exposing the lesion depths.

A) demineralized lesion (DE) with nail varnish shown protecting the unexposed surface; B) shrinkage was greatly decreased when demineralized in the present of PI (DEpi) and and was almost undetectable at C) DE-REM; D) DE-REMpi; and E) DEpi-REMpi. Solid red line = original surface location, black dotted line = lesion depth.