A Clinical Trial Testing Root Coverage With Acellular Dermal Matrix in Thin and Thick Gingival Biotypes

Inclusion Criteria: * Subjects must be current patients of Tufts University School of Dental Medicine * Subjects with two Miller class I or class II adjacent recessions with a recession height ≥ 2 mm and \< 4 mm * Affected tooth/teeth are anterior- incisors, canines or premolars (except the mandibular central and lateral incisors) * Healthy subjects with no contraindications to root coverage surgery * Subjects with full-mouth plaque index\<1 and gingival index\<1, calculated as the average value of plaque index and gingival index Exclusion Criteria: * Presence of adjacent defects, whose gingival thickness values place them in a different category other than thick or thin biotype * Areas that have previously been treated with root coverage surgeries * Subjects with a known hypersensitivity to polysorbate 20 (contraindicated with the use of Alloderm®) * Subject smokes more than 5 cigarettes per day * Subjects with systemic conditions which influence wound healing * Subjects that are pregnant or lactating * Subjects with a condition causing immunosuppression, or currently taking immunosuppressant medications * Teeth with severe occlusal interferences, deep cervical lesions, or large restorations whose margins impinge on the cement-enamel junction or make identification of this landmark impossible