Current literature on platelet rich fibrin (PRF) use in apicoectomies, also known as endodontic microsurgery, is sparse. PRF use in oral surgery or periodontal surgery has been more thoroughly researched. Whether it is able to reduce post-op pain or if it improves success rate in endodontic microsurgery is not well known. It is also not well known if it will be able to increase the rate of healing. This study will evaluate the success of endodontic microsurgery with and without PRF.

Periradicular surgery is an endodontic procedure comprising of surgical access to the periapical area to perform direct periradicular curettage, root-end resection, root-end preparation and filling. In situations where the outcome of primary root canal treatment is not sufficient, nonsurgical retreatment is considered the option of choice. Surgical endodontic treatment is usually employed to manage apical periodontitis when the orthograde approach (root canal treatment or retreatment) to the apical root anatomy (and infection) is irretrievably obstructed.

However, If the existing root canal anatomy cannot be successfully explored and instrumented with the radiographic presence of apical periodontitis, nonsurgical retreatment has been reported to be as low as low as 40%. In addition, a variety of tooth-related factors may necessitate surgical retreatment, including complicated root canal anatomy, the pathophysiology of the apical pathosis, extreme root curvatures, severe root canal alterations caused during treatment, non-removable root filling materials, existing posts at great risk for retreatment, and root fractures as well as perforations, resorptions, or root fractures. Furthermore, a surgical approach may be indicated when the periradicular tissues require direct visualization, debridement, excision, biopsy or management due to biomechanical failures.

Yan et al. found that the use of concentrated growth factors may influence the outcome of endodontic microsurgery. A systematic review by Mehta found that the use of platelet aggregates, such as PRF gave a favorable effect on the healing of apico-marginal defects, the research suggests that more studies are needed on the healing outcomes of endodontic microsurgery with PRF.

PRF has been widely used in regenerative dentistry, periodontics, and oral surgery with varying degrees of success. It is made through centrifugation of peripheral blood with the resulting centrifuged product is a solid fibrin clot sandwiched between the supernatant and blood cells. The matrix of the solid fibrin clot is a matrix consisting of platelets, leukocytes, a variety of growth factors, and cytokines as well as high biocompatibility due to its autologous source.

In this study patients will receive endodontic microsurgery with one group having the osteotomy filled with PRF prior to closure and another group having surgery completed without the use of PRF. Healing will be evaluated through a series of follow up exams, limited field of view cone beam computed tomography, and periapical radiographs. Additionally, patients will be asked to completed a visual analog scale post surgery for 7 days to track the patients pain response.

Inclusion Criteria:

• Maxillary or Mandibular Anterior teeth and premolars #4-13 and #20-29 with a history of failing RCT and a periapical radiolucency will be accepted

Exclusion Criteria:

• Patients with vertical root fractures
• Patients with non-restorable teeth
• Patients with class 3 mobility
• Pregnant
• Smoker
• Systematic disease contraindicating surgery

At this time we are undecided if IPD will be shared.

Oral Radiologist assessing healing will not be aware if the patient had received PRF.