Randomized, controlled, clinical trial to evaluate a xenogeneic collagen matrix as an alternative to free gingival grafting for oral soft tissue augmentation: A 6- to 8-year follow-up.

BACKGROUND: The purpose of this follow up study was to determine if a xenogeneic collagen matrix (CMX) is as effective as free gingival graft (FGG) in preventing further recession 6+ years following vestibuloplasty. METHODS: This study was a single-blind (examiner), randomized, controlled, split-mouth study of 30 subjects with insufficient zones of KT (< 2 mm), associated with at least two, paired teeth. The study utilized a within subject treatment comparison to examine non-inferiority according to primary and secondary endpoints 6+ years after therapy. The original study primary efficacy endpoint was keratinized tissue width (KTw); however, in this report, prevention of recession (Rec) was also examined, along with traditional, secondary clinical measures, histopathology of mucosal biopsies and exploratory, patient reported outcomes (PROs) for pain and satisfaction. RESULTS: A total of 23 of the 30 original, study patients were available for 6 to 8-year postoperative assessment, and these patients were representative of the original patient population. For preventing further Rec, CMX was not inferior to FGG (DeltaRec = -0.07 +/- 1.26 mm for CMX and -0.17 +/- 0.78 mm for FGG, P = 0.710). There were no adverse results observed, and histological assessment indicated normal, keratinized gingiva for both therapies. Tissue texture and color match to surrounding, native tissues were significantly better for CMX, and patients preferred CMX over FGG therapy. CONCLUSIONS: CMX appears to be a suitable substitute for FGG 6+ years after therapy.