Dimensional changes of keratinized mucosa after accordion versus conventional free gingival graft around dental implants: A randomized two-arm parallel clinical trial.

OBJECTIVES: Free gingival graft (FGG) is the most effective way to increase the apico-coronal width of the keratinized mucosa. In case of limited donor tissue, the accordion technique can be used. This study compared FGG for dimensional and clinical changes using accordion and conventional methods. MATERIALS AND METHODS: Ninety-four implants with keratinized tissue deficiency (<2 mm) were randomly assigned to treatment with accordion (49 implants) and conventional (45 implants) FGG. Endpoints including apico-coronal keratinized tissue width, vertical shrinkage, vestibular depth, probing depth, bleeding on probing, and plaque index were measured. The graft harvesting and recipient bed preparation method were similar in the two groups, and the only difference was the graft length. FGG was harvested with a length 40% shorter than the mesiodistal length of the recipient area in the accordion method and as much as the recipient area in the conventional method. RESULTS: vertical graft shrinkage 1, 3, and 6 months following conventional graft placement was 12.04 +/- 14.99, 17.12 +/- 20.40, and 23.29 +/- 24.63 percent, respectively. In the accordion graft group, the shrinkage was significantly greater with 30.10 +/- 16.12, 36.99 +/- 15.51, and 43.75 +/- 18.78 percent at 1, 3, and 6 months, respectively (p-value < .001). Other factors did not show a clinically significant difference between the two groups. CONCLUSIONS: Comparison of vertical shrinkage changes shows that the shrinkage rate in the accordion group is significantly higher than the conventional group. REGISTRATION NUMBER: IRCT20190721044296N1 (Evaluation of dimensional changes of peri-implant attached mucosa following the treatment of free gingival graft by conventional and accordion methods; randomized clinical trial two-arm parallel).