To evaluate, histometrically, the healing of gingival recessions treated by coronally positioned flaps associated with enamel matrix protein derivative (EMD-Group) and to compare it to that obtained with coronally positioned flaps alone (CPF-Group). Five mongrel dogs were used. Gingival recessions were surgically created on the buccal aspect of the upper cuspids. The defects (5 x 7 mm) were exposed to plaque accumulation for 3 months. After a preparation period, the contralateral defects were randomly assigned to each group. After 3 months of healing, the dogs were sacrificed and the blocks were processed. The histometric parameters evaluated included: gingival recession, length of epithelium, new connective tissue attachment and new bone. The gingival recession was -0.1 +/- 0.2 mm for the EMD-Group and -0.8 +/- 1.3 mm for the CPF-Group (P = 0.17). The extension of the epithelium was 1.2 +/- 1.0 mm for the EMD-Group and 1.3 +/- 0.7 mm for the CPF-Group (P = 0.89). The new connective tissue attachment was 4.8 +/- 0.7 in the EMD-Group and 4.0 +/- 1.4 in the CPF-Group (P = 0.22). The new bone was 0.1 +/- 1.8 mm and -0.5 +/- 1.4 mm in the EMD-Group and CPF-Group, respectively (P = 0.50). Histologically, the defect coverage observed was 98.2% for the EMD-Group and 85.8% for the CPF-Group.16287-9