Adult patients showing Miller's class I or II recession defects requiring root coverage were recruited to participate in the study. All patients were submitted to non surgical periodontal therapy consisting of scaling and root planing, prophylaxis, and oral hygiene instruction in order to reduce/eliminate gingival inflammation. After that, patients were randomly allocated to three different treatment groups based on root conditioning: G0- no conditioning; G90- root conditioning for 90 seconds; G180- root conditioning for 180 seconds. Allocation was defined by a software. Root coverage was performed by subepithelial connective tissue graft (SCTG) in all treated sites by the same operator, who performed the indicated root treatment. Periodontal parameters were investigated at baseline and at 1, 3, 6 and 12 months post-operatively by a blinded trained expertise different from operator and included: pocket depth, recession height, clinical attachment level, width of keratinized gingiva, sulcular bleeding index and plaque index. Hypersensitivity at recession sites was also investigated at baseline and at 7 days, 14 days, 1, 3, 6 and 12 months after treatment according to visual analogic scale (VAS).