Figure 3. Representative transverse microradiography (TMR) pictures (20x) of artificial enamel lesions created using microcosm biofilm after applying the treatments tested. The largest lesions are seen for placebo varnish and untreated groups; while the smallest lesion is seen for TiF₄ followed by NaF varnish groups. The CHX-treated enamel had an intermediate lesion size. The % of lesions with a surface layer was: 40% TiF₄, 61.5% NaF, 68.8% CHX, 50% placebo varnish and 73% control. *CHX=chlorhexidine.