The primary aim of this retrospective clinical study was to assess the success and bone gain achieved by using the Fibrinogen-Induced Regeneration Sealing Technique (F.I.R.S.T.) in different indications. In this single-center retrospective clinical study, F.I.R.S.T. was performed in the following indications: alveolar ridge preservation (ARP), immediate implant placement, and horizontal and vertical guided bone regeneration (GBR) with simultaneous dental implant placement. F.I.R.S.T. is a modified approach to GBR characterized by the application of a porcine cortical lamina, as a long-term resorbable bone barrier to cover the bone defect, and a fibrin sealant for easy adaptation of the xenogenic bone graft material and the fixation of the collagenic bone barrier. Patients with uncontrolled systemic diseases, medications, or diseases that may alter bone metabolism; local inflammation; poor oral hygiene; and heavy smoking were excluded from this study. Horizontal and vertical bone gain (HBG and VBG) were measured by comparing postoperative and preoperative cone beam computed tomography (CBCT) reconstructions. Patients were recalled for controls and oral hygiene treatment every 6 months. Altogether, 62 patients (27 male, 35 female, age 63.73 ± 12.95 years) were included in this study, and 105 implants were placed. Six implants failed during the 50.67 ± 22.18-month-long follow-up. Cumulative implant survival throughout the groups was 94.29 %. In the immediate implant group, HBG was 0.86 mm (range: -0.75-8.19 mm) at the 2 mm subcrestal level, while VBG was 0.87 ± 1.21 mm. In the ARP group, HBG was 0.51 mm (range: -0.29-3.90 mm) at the 2 mm subcrestal level, while VBG was -0.16 mm (range: -0.52-0.92 mm). In the horizontal GBR group, HBG was 2.91 mm (range: 1.24-8.10 mm) at the 2 mm subcrestal level. In the vertical GBR group, VBG was 4.15 mm (range: 3.00-10.41 mm). F.I.R.S.T. can be utilized successfully for bone augmentation. The vertical and horizontal bone gains achieved through F.I.R.S.T. allow for implant placement with adequate bone width on both the vestibular and oral aspects of the implant.
