The gingival thickness (GT) and keratinized tissue width (KTW) constitute the gingival phenotype, a concept that has received a great deal of appreciation in recent years. Gingival phenotype modification has been achieved via different surgical techniques and grafting materials. Despite the superiority of autogenous grafts, their increased patient morbidity and limited recourse has led to the development of graft substitutes. The human dermal matrix is a notable example that, depending on its processing method, can become freeze-dried or solvent-dehydrated acellular dermal matrix (FDADM and SDADM, respectively). This article reports the 9-year outcomes of a randomized clinical trial regarding gingival phenotype modification following root coverage with FDADM and SDADM. Twelve of the original 20 patients were available at the 9-year follow-up. Overall, the outcomes of gingival phenotype modification were maintained in both groups and at all sites after 9 years. For KTW, an incremental increase was observed over time in both groups, and minimal or no changes were noted in GT from the 1-year recall to the 9-year recall. However, the gingival margin level showed an apical shift for both groups.