Different surgical techniques have been used to treat gingival recessions. This preliminary study compared clinical findings for the treatment of isolated gingival defects using a coronally positioned flap associated with a subepithelial connective tissue graft or an acellular dermal matrix graft. Ten subjects with bilateral and comparable Miller Class I or II defects were selected. The defects were > or =3.0 mm deep and were assigned randomly to the test group, which was treated with a coronally positioned flap associated with an acellular dermal matrix, or to the control group, which was treated with a coronally positioned flap associated with a subepithelial connective tissue graft. Probing depth (PD), clinical attachment level (CAL), gingival recession depth (GRD), and width (KT) and thickness (GT) of the keratinized tissue were assessed at baseline and 6 months after the surgery. Mean root coverage was 50% in the test group (representing a gingival margin shift of 2.1 +/- 0.99 mm) and 79.5% in the control group (representing a gingival margin shift of 3.5 +/- 1.20 mm). These results were statistically different on intra- and intergroup comparisons (P <0.05). Between-group comparisons revealed statistically significantly greater gains in CAL, GRD, and GT in the control group (P < or =0.05); no differences were found for PD or KT (P > or =0.05). The coronally positioned flap associated with a subepithelial connective tissue graft or an acellular dermal matrix graft was effective in root coverage. However, the coronally positioned flap associated with a connective tissue graft provided a more favorable clinical outcome. More expanded studies are needed to confirm the present findings.