1. Following the baseline examination each of the 20 randomly selected patients will be informed about the cause of periodontal disease.
2. The 10 deepest interproximal sites in each quadrant will be selected and exposed to microbial sampling. Two sterilized paper points will be inserted into the pocket of each site and will be keep in place for 60 s. The twin paper points will be remove and distributed in two vials and transfer for microbiological processing.
3. The study participants will undergo SCALE AND ROOT PLANING (SRP). SRP will be performed two quadrants at a time under local anaesthesia at approximately weekly intervals.
4. The adjunctive antibiotics selected by 'the exCELLingence' system will be started at the second SRP visit.

1. Following the baseline examination each of the 20 randomly selected patients will be informed about the cause of periodontal disease.
2. The 10 deepest interproximal sites in each quadrant will be selected and exposed to microbial sampling. Two sterilized paper points will be inserted into the pocket of each site and will be keep in place for 60 s. The twin paper points will be remove and distributed in two vials and transfer for microbiological processing.
3. The study participants will undergo SCALE AND ROOT PLANING (SRP). SRP will be performed two quadrants at a time under local anaesthesia at approximately weekly intervals.
4. The adjunctive antibiotics agents selected by 'Origen' laboratories analysis will be started at the second SRP visit.

1. Following the baseline examination each of the 20 randomly selected patients will be informed about the cause of periodontal disease.
2. The 10 deepest interproximal sites in each quadrant will be selected and exposed to microbial sampling. Two sterilized paper points will be inserted into the pocket of each site and will be keep in place for 60 s. The twin paper points will be remove and distributed in two vials and transfer for microbiological processing.
3. The study participants will undergo SCALE AND ROOT PLANING (SRP). SRP will be performed two quadrants at a time under local anaesthesia at approximately weekly intervals.
4. The adjunctive antibiotics agents selected by 'Echevarne' laboratories analysis will be started at the second SRP visit.

SRP will be performed two quadrants at a time under local anaesthesia at approximately weekly intervals.

Each session will be carried out with the following materials: - Ultrasound device (SONICflex 2003 / L) and curettes (Hu-Friedy Manufacturing, Illinois, USA).

It is defined as the distance in millimeters between CEJ and the end of the periodontal pocket. The calculation of the depth of the pocket + gingival recession or pocket depth - gingival hyperplasia will be carried out.

The probing depth will be measured in six areas (disto-buccal, mediate-vestibular, mesio-buccal, disto-palatal, mid-palatal, and mesio-palatal) of each tooth with Williams PQ-OW 208 396 probe. It will be use with a pressure of 20 grams that is equivalent to the pressure of dropping the weight of the probe without exerting additional pressure.

The "Full mouth bleeding score" (FMBS) will be calculated based on scores of 0 (no bleeding) or 1 (bleeding) after probing depths are checked. Four surfaces per tooth are evaluated: mesial, distal, vestibular and lingual.

The percentage of gingival surfaces with presence of plaque in the dentogingival junction of the teeth is found. Four surfaces per tooth are evaluated: mesial, distal, vestibular and lingual.