This study was approved by Trakya University Clinical Research Ethics Committee with the number 06/09 and was conducted on patients who applied to Trakya University Faculty of Dentistry, Department of Oral and Maxillofacial Surgery between 08.11.2019 and 27.02.2020. All patients included in the study were informed about the purpose and method of the study, and an informed consent form was used to obtain their permission to participate. In the power analysis performed using the G*power 3.1 program, VAS values in the control and PRF groups were found to be between 8% and 25% (alpha error probability=0.05), and a result of the sample size analysis performed with a power value of 0.8, the total number of samples required to be taken was determined to be 48.
The study was completed by extracting a total number of 96 teeth from 48 patients who met all the criteria. Patients between 18 and 50 years old, did not have any systemic disease that could affect the healing process, had asymptomatic teeth and did not smoke with impacted bilateral MTM in a symmetrical location (Vertical and mesioangular position according to Winter classification, and class II, position B and C position according to Pell & Gregory classification) (Fig 1) were included in this study. Pregnancy, having a chronic disease, having a local infection in the impacted tooth area, and smoking were exclusion criteria for this study.
The control group was formed by standard extraction of impacted teeth, and the PRF group was formed with local PRF application to the extraction socket in addition to standard impacted tooth surgery (Fig 2). The group the tooth will be included in was determined by the closed envelope method just before the surgery on the first operation day. After 3 weeks, the other impacted tooth of the same patient was extracted with the appropriate surgical procedure and included in the relevant group. During the study, 6 patients were excluded because they did not come to the second appointment and 4 patients were excluded because the procedure time exceeded 30 min due to root fracture during surgery. In all, 48 patients were included in the study.
Operations
All surgical procedures were performed by the same surgeon, with the same flap design and the same surgical technique. 2 ml of a local anesthetic solution containing 40 mg/ml articaine HCl and 0.006 mg/ml epinephrine HCl was used for N. alveolaris inferior and N. buccalis blockage. The mucoperiosteal flap was removed by making a horizontal incision starting from the retromolar region, through horizontally in the buccal, circular around the neck of the mandibular second molar, and continuing vertically at the mesial half of the mandibular second molar tooth. Alveolotomy and/or division of teeth and/or roots were performed with sterile tungsten carbide burs with an electric controlled motor rotating at 20,000 rpm under 0.9% saline irrigation during operation. Roots were removed from the alveoli with the help of a bein elevator placed on the buccal and/or mesial parts of the teeth. After tooth extraction, the bone, soft tissue residues, and debris in the area were removed, and the socket was irrigated with 0.9% saline. In the control group, primary suturing was performed after bleeding control without any application to the extraction socket, while in the PRF group, PRF was applied to the socket just before suturing (Fig 3). All patients were prescribed antibiotics (amoxicillin-clavulanic acid, 1gr, 2x1) (Augmentin-BID, GlaxoSmithKline, London, England), analgesic (Acetaminophen, 500 mg, 3x1) (Parol, Atabay, Istanbul, Turkey) and mouthwash (120-mg %0.12 chlorhexidine gluconate and 150 mg %0.15 benzydamine hydrochloride, 200 ml, 3x1) (Kloroben, Drogsan, Ankara, Turkey) after the surgical procedure.
PRF Preparation
Blood sampling was performed through the peripheral antecubital vein by selecting a suitable granule for the patient's vascular structure with a closed vacuum system. PRFs were prepared according to the method of Choukron et al. [7]. 10 ml blood samples were inserted in a centrifuge device (Intra-Lock International Inc., Boca Raton, USA), under 2700 rpm for 12 min using high speed. The platelet-rich fibrin layer remaining between the acellular plasma and red blood cells in the tube was separated with the help of scissors or a scalpel.
Obtaining edema, pain, and serum marker data
A visual analog scale (VAS) of 100 mm was given to the patients to determine the severity of pain on the operation day and the 2nd and 7th postoperative days, with 0 indicating no pain and 100 indicating the worst pain they had ever experienced. In order to evaluate the severity of edema, the tragus - buccal commissure and lateral canthus - gonion distances of the patients were measured using a flexible ruler before the operation and on the 2nd and 7th days postoperatively, and the results were recorded. To evaluate the trismus level, the interincisal distance of the patients was measured with a flexible ruler before the operation and on the 2nd and 7th days postoperatively in both groups. The progression of swelling and trismus was measured in millimeters and evaluated by comparing it with the value obtained at baseline [14].
For objective data, ESR values were measured using the Vision ESR analyzer (YHLO Biotech Co., Shenzhen, China), and CRP values were measured using the BN II nephelometric analyzer (Siemens Healthcare Diagnostics, Marburg, Germany). IL-6 levels (pg/ml) were determined using the Human IL-6 Elisa Kit (Elabscience Biotechnology Co., Wuhan, China), and TNF-a levels (pg/ml) were determined using the Human TNF-α Elisa Kit (Elabscience Biotechnology Co., was measured using Wuhan, China).
Statistical Evaluation
Data were analyzed with the IBM SPSS® V23 (IBM Company, Chicago, IL, United States) package program. Mann–Whitney U test was used to compare non-normally distributed data according to paired groups, and an independent two-sample t-test was used to compare normally distributed data. The significance level was taken as p<0.05.