## 4 Discussion
Interestingly, PRP/PRF has been used in combination with autologous free fat graft [46], statins [47], and allogeneic dental pulp stem cells [48] in the treatment of established ORN with promising results. However, most of the available data promoting the use of platelet concentrates in ORN are obtained from case-reports with relatively low-level of evidence [46; 47; 48; 49; 50]. The use of platelet concentrate as an adjunct in management of MRONJ was first described in 2007 by [PERSON] et al., where a combination of osseous resection, PRP, and a resorbable membrane was used to treat 12 patients with refractory MRONJ. Ten of the patients recovered with complete mucosal and bone healing [51]. Different forms of autologous platelet concentrates (APCs) have been described in the management of MRONJ, namely PRP, PRGF, and PRF [52; 53; 54]. Systematic review of the use of APC in the treatment and prevention of bisphosphonate-related osteonecrosis of the jaw (BRONJ) conducted by [PERSON] et al. in 2015 showed that the adjunct of APC may produce a significant benefit in the treatment BRONJ by reducing the recurrence of such conditions [52]. Results showed that satisfactory healing was observed in 91.6% of 143 patients with BRONJ treated with surgery and APC [52]. This was a superior outcome when compared to findings from another systematic review/literature review in which complete healing of the lesion was observed in 60.4% of a total of 124 patients treated with surgical treatment alone [55] and 85.98% among 123 patients in eight studies using the PRP and L-PRF [30]. Recent studies on the use of L-PRF on MRONJ showed successful short-term results, i.e., mucosal integrity, absence of infection, and pain evaluation [56]; however, there was no statistically significant difference in terms of improvement between APC application and surgical treatment [57], and combination of antibiotic therapy, surgery, L-PRF, and photobiomodulation may contribute to MRONJ management [58]. In addition, recent reports on L-PRF and ORN showed good results on the healing [46; 50]. Many of the above studies did not show high level of evidence to establish the effectiveness of autologous platelet concentrates (APC) in prevention and management of MRONJ, mainly due to the scarcity of randomized controlled trials, lack of multicentric studies, discrepancy in definition of treatment success, heterogenous drug administration, small sample sizes, and use of different treatment protocols among studies [52; 57; 30]. Although the current case series yielded satisfactory treatment outcomes, however, it is not without limitations. This study included a small sample size and as this is a retrospective analysis of the patient records, the treatment protocols lack uniformity. Subjects who are asymptomatic and/or at risks of developing ORN and MRONJ were excluded from this case series as we aimed to assess the treatment outcomes using the L-PRF. This series focused on cases who received L-PRF alone, and there was no control involved. The usefulness of the L-PRF addressed in this study was purely from clinical observation alone based on the outcome mentioned in Section 2.5. In addition to its retrospective design nature, the other limitation of this case series is that it does not comply fully to the case series guidelines, for example, The Preferred Reporting of CasE Series in Surgery (PROCESS) guideline [59]. Future studies with larger sample of ORN and MRONJ patients (with cases and controls) using standardized treatment protocol are needed to validate the therapeutic efficacy of L-PRF.