Assessment of PD and BOP revealed that most implants were characterised by healthy peri-implant tissues. The mean PD at implant level was 2.19 mm in the PRF group and 2.13 mm in the control group. Similar findings of long-term clinical outcomes of implants placed in an autogenous bone block [12] and native bone have previously been published [41]. All implants were positioned approximately 2.5 mm apically from the buccal gingival margin, which in some patients resulted in placement of the implant top apically to the marginal bone level (Table 2, Fig. 2). At the final follow-up, both groups demonstrated favourable peri-implant marginal bone levels, although the PRF group revealed a 0.43 mm (p = 0.03) higher peri-implant marginal bone level than the control group, meaning that the bone level was higher around the implant for the test group. This difference may be caused by a higher number of incisor implants in the control group (Table 1), since a more pronounced bone resorption rate in the anterior region compared to the posterior region following bone block augmentation has previously been described [26]. One patient in the PRF group demonstrated bone resorption around the implant at the abutment operation of more than 1 mm, but the marginal peri-implant bone level of that implant was stable both when the impression was taken and at the final follow-up. In contrast, one patient in the control group demonstrated a stable peri-implant marginal bone level both at the abutment operation and when the impression was taken, but showed a peri-implant marginal bone loss of more than 2 mm at the final follow-up. Consequently, the long-term prognosis of this implant may be compromised. The histological evaluation [27] of the biopsies retrieved at implant placement of this patient sample has previously been described. The above-mentioned patients were the only two patients (2/25 patient) in which their bone biopsy was characterized by moderate to heavy inflammation, indicating that the bone resorption and thereby the peri-implant marginal bone level are associated with resolution of the inflammatory process [42]. For both groups, the peri-implant marginal bone level of the implants was comparable to levels reported in previous studies involving implant placement in non-augmented and augmented sites [12, 13, 39].