Acellular dermal matrix allografts (ADMs) have been hypothesized to create a zone of immobile connective tissue (ICT) extending apical to the mucogingival junction (MGJ). This 12-month prospective randomized trial investigated the presence of ICT after the use of two commercially available ADMs with coronally advanced flaps in the treatment of Miller Class I and II recession defects. This study demonstrated that the use of either type of ADM resulted in predictable root coverage and a zone of ICT extending apical to the MGJ by 1.88 to 2.69 mm. Hence, minimal keratinized gingival width should not preclude the use of ADMs.