Material and Methods
inferior alveolar nerve block, postoperative pain, swelling, allergy, kidney diseases, pain, infection, tooth, systemic endocrine disorders
CLOTS, SYSTEMIC DISEASE, CLOT, INFILTRATION, IMPACTION, DIABETES MELLITUS, RECRUITMENT, KIDNEY DISEASES, ALLERGY, INFECTION, SECONDARY, HYPERTENSION, OSTEOPOROSIS
To address the purpose of this research, the investigators designed and implemented a randomized, split-mouth, double-blind, clinical trial. The study protocol was reviewed and approved by the Local Research Ethics Committee, University of Pernambuco, Brazil (certificate #: 08330919.0.0000.5207) and registered on the (Brazilian registry of clinical trials (ReBEC) number: RBR-64vgjd. All patients gave their written informed consent before randomization. The study was conducted in accordance with the declaration of Helsinki and followed all the protocols of the Consolidated Standards of Reporting Trials Statement (
Flow diagram of the randomized clinical trial and the information about volunteer recruitment and follow up.- Patient SelectionTo be included in the study sample, patients had to fulfill the following criteria: 1) indication for impacted third molar extraction; 2) both third molars with same impaction pattern and fully developed roots; 3) adults aged between 18 and 35 years old; 4) the absence of systemic diseases such as hypertension, diabetes mellitus, systemic endocrine disorders, kidney diseases and osteoporosis; 5) the non-use of medication that could interfere with the outcomes of the procedure such as antibiotics, non-steroidal anti-inflammatory drugs or corticosteroids; 6) having no signs or symptoms of infection; 7) having symmetric third molars, and 8) coagulogram showing normal platelet count (150,000-400,000/mm³). Patients were excluded as study subjects if pregnant or breast-feeding, had history of allergy or contraindication to any of the medications used in the study, or were smokers. Besides, patients who did not participate in all phases of the study, and those who did not have the adjacent mandibular second molar were also excluded.- Study DesignA randomized, split-mouth, double-blind, clinical trial was conducted. On control group socket was sutured with the clot alone and in PRF group clots from two tubes were applied to the socket prior to the final suture. All the surgical procedures were performed by the same surgeon (E. D. R. R.).Randomization regarding the experimental and control sides was performed using a computer-generated randomization code (Microsoft Office Excel® 2010). The randomization data were only known to the surgeon. Patients, the clinician that performed all clinical evaluations (R. A. P. M), the radiologist (A. A. P) and the statistical expert (B. C. E. V.) were blinded to the randomization data until the final analysis of the experiment.Initially, ten patients underwent mandibular third molar extractions (20 extractions) in order to determine the sample size. The sample size was estimated considering the standard deviation of the mean differences in bone volume between the experimental and control groups (4.402 mm³) and the standard deviation [4.364]. The sample size was calculated considering an alpha level of 0.05, a test power of 80% and a 95% confidence interval. Based on this data, the estimated optimum sample was 16 patients.- Surgical TechniqueThe surgical procedures were performed under local anesthesia (buccal and lingual infiltration and inferior alveolar nerve block). An incision was made in the distal region of the gingival sulcus of the second molar; an oblique mesial side incision of this tooth was then made to create the mucoperiosteal flap. Osteotomy and tooth sectioning were done with rotary instruments under manual irrigation. The third molar was extracted, and the surgical wound was cleaned by irrigation with 0.9 % saline. All patients received instructions regarding their diet and oral hygiene.In then PRF group, clots from two tubes were applied to the socket prior to the final suture, whereas in the control group, the socket was sutured with with the clot alone. The flap was repositioned and sutured with 4-0 silk thread (Ethicon). The suture was removed one week after surgery.Postoperatively, we prescribed a 0.12% chlorhexidine digluconate mouthwash for 7 days (15ml/1min/q12hr). Paracetamol (acetaminophen) 750 mg was provided to participants experiencing pain (≥ 3 score) within 4 hours after surgery as a rescue drug and every 6h thereafter.- Clinical Assessment and OutcomesThe predictor variable was the treatment (experimental vs. placebo). Patients had both lower third molars extracted at the same surgical time, and each side was randomly allocated to: 1) the experimental group, in which the socket was filled with a PRF plug; and 2) the control group, in which no filling was received (the opposite side).Bone volume was the primary outcome variable. The secondary outcome variables were trabecular thickness, trabecular distance, greyscale, pain, swelling and wound healing. and probing pocket depth.Cone beam computed tomography (CBCT) was performed using the i-CAT Next Generation (Imaging Sciences International, Pennsylvania, USA) operating at 120 kVp, 18.5 mAs, field of view (FOV) of 6 x 16 cm and 0.25 mm voxel size. CBCT images of each patient were obtained three months after surgery (T3) and exported for evaluation in ImageJ/Fiji software (National Institutes of Health, Bethesda, MD, USA). All CBCT evaluations were performed by an oral and maxillofacial radiologist with 10 years of experience. The images were registered with the Registration/Rigid 3D tool. A cubic volume of interest (VOI) (4mm in height, 4mm in length, and 4mm in depth) was determined over the medullary bone at the base and center of the socket. The standardization of this VOI was achieved with the ROI Manager function of ImageJ/Fiji software. All images were then converted into eight bits and binarized using the "Moments” automatic binarization method (
CBCT obtained three months after surgery (T3). panoramic (A), axial (B), and parasagittal (C) reconstructions showing the bone repair of a L-PRF socket and panoramic (D), axial (E), and parasagittal (F) reconstructions showing the bone repair of control a socket (same patient).The postoperative pain assessment was performed by the visual analog scale (VAS) using a 100 mm scale ranging from 0 (no pain) to 10 (maximum imaginable pain). The patients were asked to indicate the intensity at 30 minutes and at 2, 4, 6, 8, 12, 16, 24, 48 and 72 hours after the surgery, in the postoperative period. The swelling was assessed by comparing the values of three facial lines: 1) the distance from the lateral corner of the eye to the gonial mandibular angle; 2) the distance from the lowest point of the tragus to the mouth commissure; and 3) the distance between the lowest point of the tragus to the pogonion (Fig. 
Swelling measurements.- PRF protocolBlood samples were taken in 10-mL tubes without anticoagulant. The tubes were centrifuged at 2700 rpm (approximately 400 g) for 12 minutes in a Daiki DT4000 centrifuge according to the method described by Dohan - Data analysisData were expressed as the mean, standard deviation, minimum and maximum values. To assess data normality, we conducted a Shapiro-Wilks test. For the normally distributed postoperative times variables, a t-Student test for paired samples was used to compare PRF and control groups at different postoperative times. In contrast, for the data that were not normally distributed, the Wilcoxon test was performed. The data were statistically analyzed using SPSS v. 20.0 (IBM Corp., Armonk, NY) with a significance level of 5%.