Platelet-rich fibrin/anorganic bovine bone mineral complex as grafting materials in endodontic microsurgery with a large lesion size: study protocol for a randomised controlled trial.

[INTRODUCTION] Endodontic microsurgery is a treatment of last resort for preserving natural teeth. According to radiographic evaluation, the percentage of complete healing after endodontic microsurgery is only 74.3%. The use of regenerative techniques in endodontic microsurgery for large lesions (>10 mm diameter) is therefore recommended. The most frequently used bone graft in endodontic microsurgery is anorganic bovine bone mineral (ABBM) but this only has an osteoconductive effect. Thus, when platelet-rich fibrin (PRF), a reservoir of growth factors, is used together with ABBM, it increases the regenerative effect. This study is devoted to comparing the clinical outcomes of PRF with/without ABBM as grafting biomaterials in endodontic microsurgery cases with large lesion size to provide some valuable reference data for dentists.

[METHODS AND ANALYSIS] Sixteen patients who are in need of endodontic microsurgery will be recruited. The patients will be randomly assigned to one of two groups: an experimental group, treated with PRF/ABBM complex and collagen membrane, and a control group, treated with ABBM and collagen membrane. Clinical examination including percussion, mobility testing and presence/absence of sinus will be recorded at 7 days, and at 3, 6 and 12 months after endodontic microsurgery. A Visual Analogue Scale will be used by the patients to evaluate pain at 1, 3 and 7 days after endodontic microsurgery. Routine paralleling radiographs will be obtained before and at 3, 6 and 12 months follow-up after endodontic microsurgery. Cone-beam CT (CBCT) scans will be obtained at the 12-month follow-up. Bone formation will be evaluated according to CBCT and paralleling radiographs. The study execute time including follow-ups last from 1 June 2021 to 31 December 2024.

[ETHICS AND DISSEMINATION] This study received approval from the Ethics Committee of Peking University School and Hospital of Stomatology. The results will be disseminated through scientific journals.

[TRIAL REGISTRATION NUMBER] Research data will be registered with the International Clinical Trials Registry Platform (ICTRP), ID: ChiCTR2100046684.