The purpose of this study is to analyze the percentage of root coverage in Miller class I and II gingival recessions using connective tissue graft and collagen matrix with a two years follow-up.

A sample calculation using a mean of 2.92 mm of the quantity of keratinized mucosa obtained after six months in the most recent study (McGUIRE; SCHEYER, 2014) using the same collagen matrix with a standard deviation of ± 0.88 mm, a difference of 0.4 mm being chosen as statistically significant. In addition, a 95% bilateral confidence interval and 80% power were used. A sample of 38 individuals per group was obtained. In addition, a 20% loss is expected during follow-up, a total of 46 individuals should be evaluated.

Periapical radiographic examinations should be performed before the collection of data to confirm the absence of bone loss. The following clinical parameters should be evaluated in both test and control groups: visible plaque index, gingival bleeding index, gingival recession, keratinized mucosa width and thickness, probing depth, bleeding on probing and periodontal biotype for each teeth with a North Carolina periodontal probe. The periodontal biotype for each teeth should be rated as thin or thick, according to probe transparency during probing depth. For statistical purposes, percentages of faces with gingival recession should be calculated. These parameters should be evaluated at baseline and at one, three and six months, one and two years post-therapy.

Clinical parameters should be collected by two operators, calibrated by the Kappa test for the keratinized mucosa width and thickness, periodontal biotype, probing depth and gingival recession.

After the inclusion of the patients, anamnesis and initial examination were performed. The subjects should be divided randomly, using a simple draw, in the following two groups: test - (collagen matrix) and control - (connective tissue graft) placebo associated with basic periodontal therapy). The data should be analyzed using descriptive and inferential statistics, with parametric tests, through the software package Social Sciences (SPSS), version 17.0 (free version).

Inclusion Criteria:

• Gingival recessions of class I or II types according to Miller (1985), in contralateral, superior or inferior premolars and / or canines;
• Fine periodontal biotype characterized by the transparency of the North Carolina probe when introduced into the periodontal sulcus (KAN et al., 2003);
• The teeth with gingival recession should not be restored in their cervical portion;
• Periodontal health characterized by absence of bleeding at probing, depth of probing less than 3 mm;
• Visible Plaque Index and Gingival Bleeding Index less than or equal to 30%.

Exclusion Criteria:

• Orthodontic appliances;
• Fixed or removable prostheses involving the premolar teeth with gingival recession;
• Being a smoker;
• Pregnancy or lactation;
• Systemic diseases that may interfere with healing or periodontal health (diabetes, leukemia, hypertension, among others).