Fig. 6.

Interkingdom assemblage-mediated biofilm and tooth decay on human enamel. (A) On human enamel surfaces, biofilms derived from interkingdom assemblages (Assembl) or from aggregated S. mutans (Agg S.m.) were imaged using confocal microscopy. Insets with dotted lines show high-resolution view of magnified areas. Green, S. mutans; cyan, C. albicans; red, EPS matrix. (B) Multiscale analyses of the tooth-enamel underneath the biofilms. (Left) Macroscopic demineralized lesions (brighter, chalky areas) developed on the enamel surface when biofilms derived from interkingdom assemblages are present; (Right) corresponding surface topography analysis showing microcavities formed on the enamel surface. The surface topography is color-coded to visualize the microcavities. (C) Transverse microradiography of the human enamel surface underneath the biofilm derived from aggregated S. mutans (Upper) or biofilms derived from interkingdom assemblages (Lower). White arrowheads indicate area of enamel demineralization caused by biofilms derived from assemblages. (D) Quantitative analysis of biofilm surface coverage on human tooth-enamel, tooth surface topography, and tooth mineral analysis (mean ± SD of n = 4 independent replicates. *P < 0.05 by Student’s t test.