Efficacy of keratinized mucosal augmentation with a collagen matrix concomitant to the surgical treatment of peri-implantitis: A dual-center randomized clinical trial.

The tested surgical modalities resulted in similar improvements of the clinical parameters. Both free gingival graft and collagen matrix significantly increased the peri-implant keratinized mucosa, but this KM gain was significantly higher with the free gingival graft. Use of CM, however, was better appreciated by the patients, in terms of pain perception and analgesic consumption, although the surgical time was similar.