Secondary outcome measurements
Pain, pain

Patient-related and surgical-anatomical risk factors were evaluated and compared for the presence of successful (tight) defect closure or open defect (failed-healed) OAC for the study endpoint (evaluation at day 21).Clinical wound healing: Using the wound healing index of Landry et al., the course of wound healing of OAC closure was assessed on day 7 and day 21 in the PRF and BAF group. Two independent assessors (M.M.; G.F.) not involved in the surgical procedure rated the following five items dichotomously (0/1) resulting in a summarized score ranging from 0 (worst) to 5 (highest).color of the surrounding mucosa: inflammatory red (score: 0) / healthy pink (score: 1).bleeding on palpation: presence = 0 / absence = 1granulation tissue: presence = 0 / absence = 1incision margin/re-epithelialization: presence = 0 / absence = 1suppuration: presence = 0 / absence = 1-3) Offset of the mucogingival line: The mucogingival borderline was initially measured from the jaw ridge center to the mucogingival borderline in millimeters using a periodontal probe. Measurements of the distance were done preoperatively (baseline) and on postoperative days 7 and 21 and were compared within the groups as well as between the PRF and BAF group.-4) Postoperative pain/use of painkillers. All patients received a pain protocol for assessing pain level and the pain medications taken daily for the first seven days. Pain level was assessed with a visual analog scale ranging from 0 (= no pain) to 10 (= severe pain). Pain level was followed up for 7 days and was compared between the test group and the control group. In addition, the number of painkillers used was also assessed for 7 days and evaluated for both groups.