Supragingival dental plaque pooled samples were collected at the 14th postoperative day from both interproximal tooth surfaces respectively to the interdental papilla with the highest EHI value, using curettes. Pooled samples were individually collected in 150μl TE buffer solution. Samples were stored at -80 until processing, which was performed at the Laboratory of Cell and Matrix Pathobiology at the Institute of Biosciences and Applications, National Center for Scientific Research (N.C.S.R.), Athens, Greece. Bacterial genomic DNA was isolated and purified using the PureLink® Genomic DNA Μini Kit, following the Gram (+) bacterial cell lysis manufacturer's protocol. Purified DNA concentrations were determined spectrophotometrically (NanoDrop 1000). Specimens were analyzed using quantitative real time PCR (qPCR) in order to evaluate the total bacterial count in each pooled sample. qPCR was conducted with application of a set of universal primers (forward primer: 5' TCCTACGGGAGGCAGCAGT 3' and reverse primer: 5' GGACTACCAGGGTATCTAATCCTGTT 3', with an amplicon size of 466 base pairs), reported to detect DNA sequences of gene encoding for 16S ribosomal subunit of at least 50 different bacterial species (aerobic and anaerobic Gram positive and Gram negative) and SYBR Green Ι fluorescent probe. Serial dilutions of DNA extract of pure bacterial cultures of Escherichia coli were performed in order to generate a standard curve for the qPCR. Reactions were performed for 40 cycles at 94 °C for 30 sec, 58 °C for 45 sec and 72 °C for 10 min in a Light Cycler 96 qPCR Device. Results were analyzed using the Light Cycler 96 1.1 Software. Total bacterial count of each sample is expressed as total bacterial DNA mass (ng) and bacterial copy numbers (x106).