Relationship between amounts of total bacteria and F. nucleatum in tongue coating. Scatter plots of the amounts of total bacteria (X-axes) and F. nucleatum (Y-axes) in whole collected tongue coating samples expressed as logarithm values of the genome weight (A) in case with tongue cleaning and (B) without tongue cleaning. Closed circles, open circles, and triangles show values obtained at baseline, and days 3 and 10, respectively. Solid, dotted, and broken lines indicate approximate straight lines for baseline, and days 3 and 10, respectively. Correlation coefficients in subjects with tongue cleaning were 0.746, 0.837, and 0.928 at baseline, and on days 3 and 10, respectively, while those in subjects without tongue cleaning were 0.884, 0.844, and 0.896, respectively.