The purpose of this study is to compare the clinical outcomes after coronally advanced flap technique (CAF) associated or not to a porcine collagen matrix graft (CM) in the treatment of single gingival recessions. For this blinded randomized controlled clinical trial, 40 patients with Miller Class I or II gingival recession ≥ 2 mm in canines or premolars will selected and randomly assigned to receive either CAF or CAF+CM. The clinical parameters evaluated will be probing depth, clinical attachment level, gingival recession height, height and thickness of keratinized tissue. Clinical measurements will be taken at baseline and 45 days, 2, 3 and 6 months after surgery.

Inclusion Criteria:

• Age ≥ 18 years.
• Presence of at least one Class I or II Miller gingival recession ≥ 2 mm in maxillary canines or premolars with identifiable cementum-enamel junction (CEJ) and without deep non-carious cervical lesions (< 0.5 mm): A + (Pini-Prato et al. 2010).
• Aesthetic complaint and/or presence of dentin hypersensitivity to air stimulus.
• Full-mouth visible plaque index ≤ 20% (Ainamo & Bay 1975).
• Full-mouth sulcus bleeding index ≤ 20% (Mühlemann & Son 1971).

Exclusion Criteria:

• Smoking.
• Pregnancy.
• Presence of systemic disorders (diabetes, hypertension, heart disease or any other condition that could contraindicate periodontal surgery).
• Use of medications (immunosuppressants, phenytoin or anything else that might affect mucosal healing and repair).
• Previous periodontal surgery in the area.