Free gingival grafts for implants exhibiting a lack of keratinized mucosa: Extended follow-up of a randomized controlled trial.

INTRODUCTION: This study is an extended follow-up of a randomized controlled trial that evaluated 18-month outcomes following free gingival grafts (FGGs) around implants with <2 mm keratinized mucosa (KM) compared to implants without KM augmentation. MATERIALS AND METHODS: Follow-up data were obtained over 48 months from 18 implants in the FGG group (11 subjects) and 8 implants in the no-surgery group (7 subjects) within the control group. FGGs were performed after 18 months for 8 implants in the control group; these 8 implants constituted a delayed FGG group (5 subjects). The width of KM, mucosal recession (MR) and crestal bone level (CBL) were obtained. RESULTS: The increased width of KM and the reduced MR following FGGs were maintained for 48 months in the FGG group, which exhibited less MR than the no-surgery group. The amount of crestal bone loss (0.4 +/- 0.4 mm) in the no-surgery group was significantly greater than that in the FGG group (0 +/- 0.4 mm) at 48 months. In the delayed FGG group, reduced MR and no significant differences in CBL were observed compared with the pre-graft measurements. CONCLUSIONS: FGGs can be a practical treatment option to maintain CBL around implants with limited KM.