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.