Xenogenic Collagen Matrix and Subepithelial Connective Tissue Graft in the Treatment of Gingival Recession

this study is a Clinical evaluation of using Xenogenic collagen matrix (XCM) plus coronally advanced flap (CAF) compared to subepithelial connective tissue graft (SCTG) plus coronally advanced flap to treat Miller class I gingival recession. A split-full-split thickness flap will be elevated in the (XCM+CAF) group while it will be an only partial thickness flap in the (SCTG+CAF) group. The sample size will be 15 patients. Each patient has bilateral Miller Class I gingival recessions; and as a split-mouth study design one side will be treated with (SCTG+CAF), while the other will be treated with (XCM+CAF).