Inclusion Criteria:  good condition of general health a minimum of 2 teeth for each quadrant with Pocket Depth (PD) ranging from 4-6 mm no involvement of the furcation a minimum of a six teeth per quadrant, respectively  Exclusion Criteria:  periodontal therapy during the last 12 months assumption of antibiotics during the last 6 months pregnancy any systemic condition which might affect the effects of the study treatment previous or current radiation or immunosuppressive therapies use of mouthwash containing antimicrobials during the previous 3 months no use of hormonal contraceptives medication by anti-inflammatory and immunosuppressive drugs previous history of hard drinking smoking class II and III tooth mobility