Connective Tissue Graft Versus Mucograft Collagen Matrix for Coverage of Multiple Gingival Recession Defects

Objectives The main objective of this study is to assess if the Mucograft Collagen Matrix reduces morbidity, shortens time to recovery and improves patient based outcomes with respect to the use of autologous connective tissue graft harvested from the patient own palate when used to obtain root coverage of multiple adjacent gingival recessions.

The secondary objective is to assess the non-inferiority - in terms of complete root coverage, percentage of root coverage and professional evaluation of aesthetics - of the use of Mucograft Collagen Matrix and autologous connective tissue harvested from the patient's own palate.

Design and Outcomes This will be a parallel group, standard of care-controlled, assessor-blind, randomized, multicenter, multinational, clinical trial.

The statistical design will be a superiority trial in terms of the primary outcomes (patient based outcomes) and non-inferiority trial in terms of the professional outcomes measuring root coverage and aesthetics.

Sample size has been estimated in 140 subjects per treatment arm using a pilot case series analyzed with a multilevel statistical approach and a non inferiority margin of 0.25 mm in recession coverage.

Randomization will be performed by computer generated random codes, using random permuted blocks with a block size of 4 to avoid uneven splits and minimization for the key prognostic factor cigarette smoking. Allocation will be concealed to the surgeons until completion of preparation of the recipient bed by opaque envelopes. A central study registrar will perform patient registration.

Study locations will include academic centers and a practice-based research network in Italy, Switzerland, Germany, Belgium, France, Spain and Greece.

A single examiner, blind with respect to the treatment assignment, will perform all measurements at each center. Trained personnel not involved with the surgical intervention will: i) administer patient questionnaires, ii) provide instructions and collect patient diaries. A single calibrated investigator with specific experience in using the specific score will centrally perform assessment of esthetic scores on standardized digital images.

A biostatistician blind with respect to treatment assignment will perform the analysis.

Interventions and Duration The two intervention groups will consist of surgery with connective tissue graft (standard of care control) and surgery with the application of Mucograft Collagen Matrix (MCM, Test group). Experienced clinicians will deliver treatment consisting of root coverage surgery using coronally advanced flaps, the most utilized procedure for coverage of multiple recessions. Surgery will be standardized and the same procedures/materials will be employed to ensure consistency.

Follow-up of individual patients will be 6 months (to be extended to 3 years if funding will be available)

Inclusion criteria

• 2-4 adjacent gingival recession (one at least 3 mm deep)

Exclusion criteria

• Interdental attachment loss greater than 1 mm at recession sites