“…[ 10 32 , 35 ] To measure the penetration depth, most of the articles used confocal laser scanning microscopies (CLSM) (18 studies),[ 8 10 , 17 18 , 20 21 22 25 , 27 28 29 31 32 33 34 35 36 37 ] followed by polarized light microscopy (one study),[ 23 ] scanning electron microscopy (SEM) (one study),[ 30 ] stereomicroscope (two studies)[ 19 26 ] and optical profilometer (one study). [ 24 ] Adhesive,[ 18 19 , 30 32 , 36 ] fissure sealant,[ 22 23 24 32 ] flowable composite resin,[ 8 33 ] fluoride,[ 33 ] CPP-ACP,[ 19 ] MFIR[ 8 ] and colloid silica[ 25 ] were the materials investigated and compared with resin infiltration. In most studies, the artificial WSL was produced by a demineralizing solution,[ 10 19 , 22 23 24 25 26 31 , 35 ] followed by phosphoric acid,[ 17 18 ] pH cycling,[ 10 ] HCL,[ 32 ] acetate buffer,[ 37 ] deionized water[ 36 ] or lactic acid.…”