Comparative analysis of methods to increase the amount of keratinized mucosa before stage-two surgery: a randomized controlled study.

OBJECTIVES: The aim of the present randomized controlled clinical trial was to evaluate the outcomes of the use of free gingival graft (FGG), of a collagen matrix and of vestibuloplasty to increase the amount of keratinized attached mucosa (KM) before healing abutment placement. METHOD AND MATERIALS: The study was a randomized, parallel-group controlled investigation. All patients were treated to increase the KM width before placement of implant-supported prostheses. The implants were placed 3 to 6 months before the interventions. Three techniques were tested: an apically positioned flap (control group), FGG (test group 1), and use of a collagen matrix (test group 2). Biopsy was performed during healing abutment placement by means of a mucotome. RESULTS: A total of 63 patients were recruited and treated, and 58 were available for follow-up visits. After 4 weeks, the KM width gain was 1.93 ± 0.85 mm, 4.85 ± 1.11 mm, and 3.03 ± 0.58 mm, respectively, for control group, test group 1, and test group 2. Postoperative pain was significantly higher in the FGG group than in the others. Edema and hyperemia decreased gradually during the first week without significant differences among groups. CONCLUSION: Despite the limitations of the study, it was found that FGG was the most effective technique to augment the amount of KM in sites of implant placement. The use of a collagen matrix could be a viable alternative to diminish the intervention's impact on patients' postoperative quality of life.