Seven days prior to the non-surgical periodontal therapy, periapical radiographs will be taken from the whole mouth of all patients. They will be set in an oral hygiene program (OHP) according to their specific needs. In this program, patients will be instructed about an effective self-performed plaque control, including information about the Bass Technique (Bass, 1954) and interproximal cleaning with dental floss and interdental brushes. They will be also motivated to brush the dorsal surface of the tongue once a day and will receive a dentifrice that shall be used throughout the experimental period (Colgate Total®, Anakol Ind. Com Ltda - Brazil's Kolynos - Colgate Palmolive Co., Sao Bernardo do Campo, SP, Brazil). After the OHP, subjects will undergo the assessment of clinical periodontal parameters previously described and the collection of subgingival plaque and GCF in selected sites (baseline) will be performed. Shortly, patients will receive supragingival scaling and coronal polishing with prophy cup on all the teeth present in the oral cavity. The non-surgical periodontal therapy will initiate 7 days after the OHP and initial supragingival scaling. Within 24 hours, a specialist in Periodontics will perform supra and subgingival scaling and root planing of all teeth with periodontal involvement, using hand (Gracey Curettes, Hu-Friedy, Chicago, IL, USA) and ultrasonic instruments. The instrumentation will be performed on each quadrant until achievement of an adequate cleaning and root planing, which will be verified with a dental explorer. Individuals will receive professional prophylaxis biweekly during three months after the end of the nonsurgical periodontal therapy. On biweekly follow-up visits, patient's cooperation will be monitored by verifying the status of oral hygiene.