Discussion
oroantral communication defect, pain
CLOTS, SECONDARY
The findings of the present study confirm the initial hypothesis that there are no differences between surgical treatment with a buccal advancement flap and the treatment with platelet-rich fibrin clots/membranes regarding the clinical success rates for the closure of oroantral communication. The final evaluation at the study endpoint on day 21 showed a closure success rate of 90% for both methods demonstrating that the use of platelet rich fibrin (PRF) may be a promising alternative approach for OAC closure.However, there is inconsistent data about the recommended number and form of PRF clots. The findings of the present study as well as the results of the previous studies by Bilginaylar, Gülsen and Agarwal have indicated high success rates, although a different number of clots was used in each study [Interestingly, the findings of the univariate analysis evaluating the risk factors affecting the defect healing outcome revealed differences between the use of PRF or the buccal advancement flap. For the use of the buccal advancement flap, the patient-related and surgery-related/anatomical risk factors did not differ between successful and failed wound healing outcome. Hence, the failed wound healing observed with a buccal advancement flap may be preferably attributed to patient compliance (nose breathing) and/or surgery-related reasons such as extensive flap tension. In contrast, for the PRF group, the univariate analysis showed significant differences for risk factors such as patient age and defect dimension. In detail, a significant difference between the defect size and success of defect closure was found, suggesting that clinical wound closure may be influenced by the number of platelet-rich fibrin clots used, considering that all patients received the same amount of PRF clots. Consequently, an individualized number of clots depending on the defect size might be the key to an improved outcome for oroantral communication defect closure. This will have to be evaluated in future studies.Furthermore, the univariate risk factor analysis revealed that patient age seems to be a risk factor for a failed or successful outcome when using PRF. This is consistent with the findings of the studies by Miron et al. (2019) and Mamajiwala et al. which demonstrated that platelet-rich fibrin shows age-related differences regarding the protein content. Specifically, PRF from younger patients exhibits a higher platelet concentration, antimicrobial activity, and a denser fibrin network [The results of the systematic review of Miron et al. evaluating 31 clinical studies highlight the positive effects of PRF on wound healing after regenerative treatment of various soft tissue defects in medicine and dentistry [Although the use of PRF has been reported with excellent clinical outcome, no detailed information is available regarding the wound healing course. The findings of the present study using the wound healing score indices of Landry et al. [Regarding the evaluation of the secondary outcome measurements, the displacement of the mucogingival borderline also showed a significant difference between the two methods. The displacement of the mucogingival borderline after the buccal advancement flap procedure was to be expected, however, there was also a slight displacement of the mucogingival borderline in the platelet-rich fibrin group. This may be attributed to the remodeling process as a result of bundle bone resorption of the extraction sockets. While the extensive displacement of the mucogingival borderline with the buccal advancement flap occurs due to iatrogenic/surgically induced reasons, the comparatively small shift in the PRF group is based on the physiological remodeling processes.The findings of this present study also confirm the hypothesis that the presence of pain and the use of painkillers needed was significantly different between the two groups. This is consistent with the findings of Bilginaylar et al. and may either be attributed to the less invasive treatment protocol or to the anti-inflammatory activity and immune regulation effects of the platelet-rich fibrin content [