Principal Component Analysis results on individual samples. Principal Component Analysis (PCA) results on all individual samples at the level of OTUs clustering sequences at a 3% difference: A) the plot of the PCA axis 1 (accounting for 29.7% of intersample variation) and the axis 2 (12.3% of intersample variation); B) the plot of the PCA axis 1 and the axis 3 (9.1% of intersample variation). Blue dots - samples from individual S1, green dots - samples from individual S2, red dots - individual S3. A - approximal, B - buccal, L - lingual surface of i - incisor or m - molar tooth, respectively. Data were normalized to an equal number of reads per sample and log2 transformed.