The hydrogel-on-tooth specimens in a CDFF device for biofilm culture. (a) Illustration of a hydrogel-covered tooth lesion shows the ion and amelogenin transportation for remineralization, (b) the tooth specimens on plugs with remineralization hydrogel, (c) the flange with 15 holes where the plugs with O-ring can be inserted with a preset depth of 300 µm to the top, and (d) the sealed glass cylinder to ensure the desired atmosphere for biofilm formation. The Teflon scraper removes excess biofilm keeping a constant thickness of biofilm on the tooth/hydrogel surface.
CDFF: constant-depth film fermenter; AMGN: amelogenin.