The present study aimed to evaluate the clinical effect of platelet-rich fibrin to improve epithelialization and decrease postoperative pain in post extraction sockets

Production of PRF membranes A venipuncture was performed, prior of performing any treatment (median basilica vein, median cubital vein, median cephalic vein). Blood was drawn into four sterile, red cover tubes (IntraSpin™, Biohorizons®, Birmingham, Alabama, USA) 10-mL tubes without anticoagulant. The tubes were immediately centrifuged at 2700 rpm for 12 min (~708g) using a vertical/ fixed angle centrifuge (IntraSpin™, Biohorizons®, Birmingham, Alabama, USA). The g-force values were referenced at the bottom of the centrifugation tubes (RCF-max). After centrifugation, each L-PRF clot was removed from the tube and separated from the red element phase at the base with pliers. Four L-PRF clots were squeezed between a sterile metal plate and a metal box to obtain L-PRF membranes, similar in size and thickness.

Surgical procedures and initial clinical measurements The participants underwent periapical radiography or computed tomography (when necessary) and clinical examination to assess the absolute need for dental extraction. The participants underwent initial periodontal treatment, including supra and subgingival scaling, plaque control, and were given oral hygiene instructions.

Before tooth extraction, participants from both groups underwent local anaesthesia with mepivacaine 2% (Mepiadre, Nova DFL, Rio de Janeiro, Brazil). All teeth were extracted using a minimally traumatic procedure. No vertical releasing incisions were performed. To avoid root and bony fractures, the molar teeth were sectioned using a multilaminated drill (Zecrya, Microdont, São Paulo, Brazil). Luxation of the teeth was performed using a periotome followed by removal using forceps. After exodontia, a rigorous inspection and curettage of the socket was performed, followed by irrigation with sterile saline solution (Linhamax, Eurofarma, Rio de Janeiro, Brazil).

The sockets of the test group were filled with two PRF membranes followed by cross suture (Mononylon Ethilon, Johnson & Johnson, NJ, USA) to stabilize the membranes (Figure 1A), while the sockets of the control group received no type of biomaterial (i.e., left to spontaneous healing).

Postoperative control It was prescribed Ibuprofen (400 mg, Advil, Pfizer, São Paulo, Brazil) every 6 h was also prescribed in case of pain. Mouthwash with chlorhexidine gluconate 0.12% (Periogard, Colgate, São Paulo, Brazil) was also prescribed twice per day for 2 weeks. Sutures were removed after 10 days.

Clinical measurements One and two weeks after extraction, an assessment of soft tissue healing around the sockets was performed using the healing index system described by Landry et al (Landry, 1985). The following parameters were used to assess the level of healing: colour of tissues; epithelialisation of wound margins; presence of bleeding on palpation; granulation; and suppuration. The level of healing was scored as very poor, poor, good, very good, or excellent.

Postoperative pain and number of consumed analgesic tablets were recorded and evaluated. To assess postoperative pain, participants were instructed to complete a 10-unit visual analog scale (VAS) in combination with a graphic rating scale. The VAS ranged from 0 (no pain) to 100 (worst pain imaginable). Questionnaires were collected at the one week follow-up visit.

Inclusion Criteria:

• Participants ≥ 18 years of age;
• Participants needing molar extraction in the mandible or maxilla region.

Exclusion Criteria:

• Smokers;
• Pregnant;
• Participants with motor difficulties that impeded or hampered hygien;
• Participants with decompensated metabolic diseases;
• Participants with periodontal disease;
• Participants with history of radiotherapy or use of bisphosphonates.