Cariogenic bacterial microbiota
The bacterial microbiota associated with the 120 teeth was
analyzed by the denaturing gradient gel electrophoresis (PCR-
DGGE) technique, using primers and conditions previously pub-
lished [9]. Positive 16S-rDNA amplicons were separated in 8%
vertical electrophoresis polyacrylamide gels at 60 8C; with a urea-
formamide denaturating gel gradient of 30–50% at 130 V during
16 h. Bands were excised, re-amplified with the same primers,
sequenced and results were compared with those from the GenBank
NCBI database to assign the corresponding genera and species.