Clinical study of the effect of free gingival graft and apically repositioned flap surgery on peri‐implant keratinized gingival augmentation

Abstract

Background Peri-implant disease is defined in two forms- mucositis and peri-implantitis. It is estimated that peri-implant mucositis affects up to 48% of implants during 9–14 years follow-up, and peri-implantitis was observed in up to 20% of patients with dental implants 5–10 years after implant placement. Lack of keratinized mucosa has been investigated as a potential contributing factor to peri-implant disease, however, the implant survival and maintenance has not been studied systematically. Aim/Hypothesis The objective of this study is compare and analyze the clinical outcomes of apically repositioned flap surgery and free gingival graft on keratinized gingival augmentation around implants with limited keratinized mucosa. Material and Methods Totally 13 partially edentulous patients treated with submerged implant surgery in mandibular molar area were recruited and divided into three groups- group 1(mean age- 62 years – 5 patients) and group 2 (mean age- 34 years – 4 patients) received free gingival graft 1 month after submerged implant surgery and second stage implant surgery 3 months after submerged implant surgery+ group 3(mean age- 42 years – 4 patients) received apically repositioned flap and second stage implant surgery 3 months after submerged implant surgery. The widths of keratinized gingiva were measured respectively at the time before the apically repositioned flap surgery free gingival graft and 1 month, 6 months after the surgery. The thickness of keratinized gingiva was measured during the operation. Results The widths of peri-implant keratinized gingiva of group 1 and group 2 were (3.3 ± 1.1) mm and (3.4 ± 1.0) mm 1 month after the free gingival graft surgery, (3.1 ± 1.2) mm and (3.5 ± 1.0) mm 6 months after the free gingival graft surgery, respectively. The widths of peri-implant keratinized gingiva in group 1 and group 2 demonstrated no statistically significant differences (P > 0.05). The widths of peri-implant keratinized gingiva of group 3 was (2.4 ± 0.5) mm 1 month after the apically repositioned flap surgery, (1.9 ± 0.3) mm 6 months after the apically repositioned flap surgery, respectively. The widths of peri-implant keratinized gingiva(1 month and 6 months after the apically repositioned flap surgery) in group 3 showed statistically significant differences when compared with group 1 and group 2 (P = 0.008, P = 0.000). Conclusion and Clinical Implications The implant area treated with free gingival graft or apically repositioned flap exhibited increased width of the keratinized gingiva. The implants treated with free gingival graft exhibited more increased width of the keratinized gingiva compared with those treated with apically repositioned flap. Age showed little impact on keratinized gingival augmentation. Both techniques proved to be efficient and a viable treatment option to reduce mucosal inflammation, and avoid possible peri-implantitis.