Radiographic peri-implant marginal bone change

The mean peri-implant marginal bone level at the different time points is shown in Table 2 and Fig. 2. The mean marginal bone level at follow-up was 0.26 mm (95% CI: 0.01–0.50 mm) in the PRF group and 0.68 mm (95% CI: 0.41–0.96 mm) in the control group. The difference between the groups was − 0.43 mm (95% CI: − 0.80 to − 0.05 mm, p = 0.03), which was statistically significant (p = 0.03). The peri-implant marginal bone level of the groups demonstrated the same progression over time (p = 0.0533).

Radiographic marginal bone change and soft tissue recession of adjacent tooth surfaces

From baseline to follow-up, the mean marginal bone loss was 0.14 mm (95% CI: 0.02–0.25 mm, p = 0.03) in the PRF group and 0.15 mm (95% CI: 0.04–0.26 mm, p = 0.01) in the control group (Table 3). This bone loss was statistically significant within the groups but not between the groups (p = 0.87). A minor soft tissue recession occurred on the adjacent teeth from baseline to follow-up. In the PRF group, a recession of 0.22 mm (95%: CI: − 0.62 to 0.19 mm, p = 0.26) was registered, while in the control group a recession of 0.07 mm (95% CI: − 0.74 to 0.60 mm, p = 0.83) was registered. No statistical difference within or between the groups was seen.

Complications

Primary augmentation

No dehiscence at the donor site was observed for any of the patients at the 1- and 2-week follow-up examination. One patient (control group) demonstrated bone graft dehiscence at the recipient site at both the 1- and 2-week follow-up. Although the block was reduced in thickness with a bur after it was exposed, soft tissue coverage was never obtained. Finally, the graft was removed and a second bone augmentation operation was successfully performed, without further complications.