Non-Inferiority of Fibroguide Collagen Membrane Compared to Autologous Connective Tissue Graft for Coverage of Multiple Adjacent Recession. Multicenter Trial.

Inclusion Criteria: * Male and female, 18 to 70 years of age, with a minimum of two adjacent teeth with gingival recession (at least one with a depth ≥ 3 mm - RT1 or RT2 with 2 mm or less of interdental periodontal attachment loss) in anterior and premolar teeth in the maxilla and requiring surgical intervention, without medical contraindications to elective surgery. In case of recessions on five or more adjacent teeth, the teeth at the external sides will not be included in the study. * At least 2 mm marginal keratinized tissue width and irrespective of soft tissue thickness prior therapy. The study should involve treatment naïve patients in terms of root coverage procedures. Prior therapy should include treatment of gingival inflammation, if present, instructions in non-traumatic oral hygiene, and reconstruction of the cemento-enamel junction with adhesive dental materials in case of cervical abrasion or erosion involving this structure * Evidence of subject ability to achieve good oral hygiene and control gingivitis in the whole of the dentition (FMPS\<25% and FMBS\<25%) * Ability to understand study procedures and to comply with them for the entire length of the study. Ability and willingness to give written informed consent. Exclusion Criteria: * Presence of untreated periodontitis * Persistence of uncorrected gingival trauma from tooth brushing * Interdental attachment loss greater than 2 mm or furcation involvement in the experimental teeth * Presence of less than 2 mm of keratinized tissue width * Presence of severe tooth malposition, rotation or clinically significant super-eruption * Self reported current smoking exceeding 10 cigarettes/day or pipe or cigar smoking * Rheumatoid arthritis or known sensitization to collagen based medical products. * Presence of medical contraindications to elective surgery * Participation in another interventional clinical trial * Current drug or alcohol use or dependence that, in the opinion of the site investigator, would interfere with adherence to study requirements. * Inability or unwillingness of individual to give written informed consent. * Uncontrolled diabetes mellitus * Allergy to collagen * Pregnancy or lactation or sexually active female subjects who are of childbearing potential and who are not using hormonal or barrier methods of birth control (e.g., oral or parenteral contraceptives, diaphragm plus spermicide, condoms). * Radiotherapy * immunosuppressive therapy * chronic steroid therapy (inhaler or systemic).