At baseline and +14 and +30 and +90 days after the non-surgical periodontal therapy, GCF samples will be obtained from eight interproximal sites of each patient. The supragingival plaque from selected teeth will be removed and the sites will be carefully dried with air jets, and subsequently isolated with sterile cotton rolls. Samples of GCF will be obtained with papers strips (Periopaper® -Oralflow Inc., Amityville, NY, USA). The papers strips will be gently inserted into the orifice of the periodontal pocket, remaining 30 seconds subgingivally. The amount of GCF absorbed will be determined by an electronic measurer of humid mass (Periotron® -Oralflow Inc., Amityville, NY, USA). Samples will be placed in sterile Eppendorf tubes stored at - 80°C for cytokines (IL-1β, IL-10 and TNF-a) quantification (pg/μl) at Genese Laboratory (Genese Produtos Diagnosticos LTDA, Sao Paulo, SP, Brazil). Cytokines levels will be determined using a three-plex Millipore kit (Millipore Corporation, Billerica, MA, USA) and the Luminex 100TM system (Luminex, MiraiBio, Alameda, CA, USA).