Clin Oral Invest DOI 10.1007/s00784-013-1170-5

ORIGINAL ARTICLE

Platelet-rich fibrin in the treatment of localized gingival recessions: a split-mouth randomized clinical trial Gülnihal Eren & Gül Atilla

Received: 21 September 2013 / Accepted: 11 December 2013 # Springer-Verlag Berlin Heidelberg 2013

Abstract Objectives The aim of this study is to evaluate the clinical efficacy of platelet-rich fibrin (PRF) in combination with coronally advanced flap (CAF) in the treatment of localized gingival recessions. Materials and methods Twenty-two patients with localized gingival recession defects (Miller I, II) participated in this split-mouth trial. Forty-four defects received either CAF+ PRF (test) or CAF with subepithelial connective tissue graft (SCTG) (control). Gingival recession depth (RD), gingival recession width (RW), keratinized tissue width (KTW), recession area (RA), probing depth (PD), clinical attachment level (CAL) and gingival thickness (GT) were evaluated at baseline and 6 months. RD, RW, RA and KTW were calculated on standardized photographs with a computer image analysis program. Results Percentage of root coverage in test group was 92.7 % and in control group was 94.2 % (p>0.05). Percentage of complete root coverage of the test and control groups was 72.7 and 77.3 %, respectively (p>0.05). KTW and GT were increased in both groups from baseline to 6 months (p0.05). Conclusion Within the limits of the present study, it can be concluded that localized gingival recessions could be successfully treated with CAF+PRF as well as CAF+SCTG. The digital measuring method provided high accuracy and precision in the evaluation of treatment outcomes after both surgical procedures. Clinical relevance PRF might be suggested as an alternative to SCTG for the treatment of localized gingival recessions. G. Eren (*) : G. Atilla Department of Periodontology, School of Dentistry, Ege University, 35100 Bornova, İzmir, Turkey e-mail: [email protected]

Key Words Gingival recession . Fibrin . Connective tissue . Plastic surgery . Microsurgery . Case–control studies

Introduction Various surgical techniques have been suggested to treat gingival recession defects. These include laterally positioned flap [1], free gingival graft [2], the coronally advanced flap (CAF) [3], subepithelial connective tissue graft (SCTG) [4] and guided tissue regeneration with membranes [5, 6], enamel matrix derivative (EMD) [7] or the application of an acellular dermal matrix (ADM) [8] and platelet-rich plasma (PRP) and plateletrich fibrin (PRF) in combination with CAF [9–13]. The CAF with SCTG (CAF+SCTG) technique is accepted as the gold standard and shows greater degree of predictability for obtaining complete root coverage [14]. However, SCTG technique is time consuming and increases the risk of morbidity since requirement a second surgical procedure, patient discomfort, post-surgical pain and bleeding and limited supply of donor tissue. Potential morbidity associated with root coverage techniques could be reduced with the use of alternative materials. EMD, ADM and PRP in combination with CAF have been compared to CAF+SCTG in the treatment of gingival recession defects, but none of them matched the effectiveness of CAF+SCTG with regard to clinical measurements [15, 16]. PRF is defined as an autologous platelet and leukocyteenriched fibrin biomaterial [17, 18]. The advantages of PRF technique over PRP include shorter time of preparation, lack of requiring anticoagulant and bovine thrombin, composed of more dense fibrin matrix and easiness of application [19]. Without an anticoagulant, PRF is polymerized naturally and has the characteristic of slowly composed dense fibrin matrix, which makes PRF a manipulative material. It can be used as membranes, when squeezed between two hard surfaces [20].

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The PRF consists of platelets, leukocytes, growth factors and presence of circulating stem cells [21]. The natural polymerized fibrin architecture of PRF seems responsible for releasing high amounts of growth factors and other matrix glycoproteins for approximately 7 days [20]. These biochemical components and fibrin formation of PRF support cell migration, wound healing and tissue regeneration [22]. PRF was applied in periodontal procedures, including furcation defects [23], sinus floor augmentation [24], intrabony defects [25] and multiple and localized gingival recessions [10–13]. Recently, a case–control study has shown that CAF+ PRF is an effective technique in the treatment of localized gingival recession defects; however, recession parameters in that study have been measured by only using a standard periodontal probe [12]. As PRF may enhance the healing potential of soft tissues, we hypothesized that its placement under CAF could be as effective as the CAF+SCTG technique for the treatment of localized gingival recessions. In assessment of clinical effectiveness, the evaluation of standardized photographs with image analysis program for residual recession defects might provide more detailed and definite measurements than standard clinical assessment. Therefore, the aim of this split-mouth, randomized, controlled clinical study was to compare the clinical efficacy of PRF in combination with CAF to the use of SCTG with CAF in the treatment of localized gingival recessions by using image analysis program.

Methods Patient selection and experimental design All consecutive patients were recruited from Ege University, School of Dentistry, Department of Periodontology, İzmir, Turkey, between January 2010 and November 2011 (Clinical trials number NCT01793389). All selected patients gave full written informed consent in accordance with Helsinki Declaration and the study protocol was approved by the Ethics Committee of the Ege University Izmir, Turkey (2010; no:10-9/5). Periodontally and systemically healthy nonsmoking patients over 18 years participated in this study based on the following inclusion criteria: (1) similar bilateral or contralateral Miller Class I or II [26] localized gingival recessions at least ≥2 mm, located on incisors, canines or premolars on both jaws; (2) identifiable cemento-enamel junction (CEJ); (3) age≥18 years; (4) presence of tooth vitality and absence of restorations and superficial caries in the area to be treated; (5) no periodontal surgical treatment in the previous 24 months on the involved sites; (6) gingival thickness at least≥0.8 mm for the recession area; and (7) sufficient palatal donor tissue at least≥2.5 mm thickness for the indicated SCTG. Patients in a pregnancy or lactation period or with self-reported history of

antibiotic medication within 3 months were excluded. Molar, mobile or fully restorated teeth were also excluded. This clinical study was designed as a split-mouth, randomized, controlled clinical trial. Bilateral or contralateral gingival recession defects were randomly assigned to the test (CAF+ PRF) or the control (CAF+SCTG) groups with the use of computer-generated randomization table after assessment of clinical and digital parameters at baseline. Data collection Two kinds of measurements were performed in this study. Clinical measurements were performed at the clinic on patients while digital measurements were assessed on computerbased image program. Clinical measurements Periodontal parameters including plaque index (PI) [27], gingival index (GI) [28], probing depth (PD), clinical attachment level (CAL) and gingival recession parameters including recession depth (RD), recession width (RW), keratinized tissue width (KTW) and gingival thickness (GT) were assessed by a calibrated examiner (G.E.). PD, CAL, RD, RW and KTW values were recorded by a Williams probe graduated in 1-mm increments and rounded up to the nearest millimeter (Hu Friedy, Chicago, IL, USA). The following measurements were recorded at the mid-buccal point of the teeth at baseline and 6 months after surgery. The intraexaminer reproducibility for RD measurements was assessed, and the interclass correlation coefficient was 99 %. GT was evaluated using #15 endodontic reamer attached to a rubber stopper inserted perpendicularly into the gingival tissue 2 mm below the gingival margin under local anesthesia, and then the thickness was measured to the nearest 0.1 mm using a caliper. Digital measurements Standardized photographs were obtained by using the same digital SLR camera (Nikon D-80) from each treatment site. For all photographs, the lens was placed perpendicularly in relation to the long axis of the tooth with the same magnification (1/1) to achieve proper recording with minimal distortion. A 4-mm length wire was used to check the reproducibility of the photographs. RD was measured from the CEJ to the gingival margin, RW was measured tangentially at the mid-facial CEJ and RA was calculated as the area within the contour of denuded root. KTW recorded as the distance from the mucogingival junction to the gingival margin. Duplicate measurements were made for RD, RW, RA and KTW with an interval of 24 hours and the average value of two measurements was used for the assessment. All digital parameters were carried out by a single masked examiner (G.A.) in a digital analysis program (ImageJ Windows, National Institutes of Health, Bethesda, MD). Percentages of root coverage and complete root coverage were calculated according to the following standard formulae.

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Percentage of root coverage: ½ðpre−operative RA−post−operative RAÞ=ðpre−operative RAފ  100:

Percentage of complete root coverage: ½ðteeth with complete root coverageÞ=ðall treated teethފ  100:

Primary outcome variables of the present study were percentages of complete root coverage and RD. The secondary outcome variables included those of KTW and GT. PRF preparation and SCTG harvest Before surgery in the test site, intravenous blood was collected in a 10-mL glass-coated plastic tube without any anticoagulant and centrifuged immediately using a table centrifuge (Nüve Laboratory Equipments, NF200, Ankara, Turkey) for 12 min at 400×g. [17] (Fig. 1A, B). The fibrin clot was removed from the tube and separated by microsurgical scissors as described previously [29]. PRF was squeezed in a special metal box that produces membranes at a constant thickness of 1 mm. Then the PRF membrane was doubled by placing one part onto the other and placed onto the recession area immediately. SCTG was obtained from the palate with a parallel doublebladed scalpel (1.5 mm between blades) (Harris Double Blade Graft Knife, H&H Company, Ontario, CA) as described previously [30]. The epithelial border was trimmed and discarded. Then the palatal donor site was sutured. Treatment and post-surgical care Following a preliminary periodontal evaluation, all patients received oral hygiene instructions and were motivated towards the maintenance of oral health to eliminate habits related to the etiology of the gingival recession. Professional tooth cleaning was performed if needed. All patients demonstrated adequate plaque control with a full mouth plaque score [31] ≤20 % prior to surgery. All surgeries were performed by the same expert periodontist (G.E.). The recession sites were prepared similar to the

technique described by Langer and Langer [4]. After achieving local anesthesia using 2 % lidocaine, epinephrine at 1:100,000, sulcular incisions were made on the recipient teeth and joined to horizontal incisions extending into the adjacent interdental areas slightly coronal to the CEJ. The horizontal incisions were connected to two vertical incisions that began at the line angles of the adjacent teeth. A trapezoidal-shaped, partial-thickness flap was elevated, providing a vascular connective tissue bed for placement of the selected graft material. Incisions were made with a 15-C blade (Swann-Morton LTD, Sheffield, England) on each recipient tooth using microsurgical instruments and 2.5× loupes (Heine Binocular Loops, Herrsching, Germany) (Fig. 2B). Recession defects were thoroughly scaled using curets (Gracey Curettes, Hu-Friedy, Chicago, IL, USA). At each site, both grafts extended apically beyond the apical base of the recession defect by ≥3 mm. At test site, PRF membrane (2-mm thick) and, at control site, SCTG (1.5-mm thick) were placed over the defect (Fig. 2C). Both grafts were secured to the interdental papillae and adjacent soft tissue at the apical part with horizontal mattress sutures. Each partial-thickness flap was further released and positioned over the graft to cover the CEJ and sutured with 7– 0 polypropylene sutures (Doğsan Surgical Sutures, İstanbul, Turkey) (Fig 2D). Gentle pressure was applied for 3 min to minimize the thickness of clot. Preoperative and postoperative standardized photographs were taken at baseline and at 6 months (Figs. 3 and 4). The patient was given a non-steroidal anti-inflammatory drug (Etol Fort, Nobel, İstanbul, Turkey) as needed for pain and advised to brush all teeth except the operated one, which is to be cleaned with a cotton pellet. Sutures were removed 10 days later and plaque control was reinforced. The patient was instructed in mechanical tooth cleaning in the operative areas using a soft-bristle brush. All patients were followed up postoperatively at 1, 3 and 6 months and oral hygiene instructions reinforced. Sample size calculation A sample size calculation suggested that a minimum of 21 patients were needed to demonstrate a 1-mm difference in the RD levels between study groups after treatment (85 % power, α of 0.05, standard deviation of 1.1) [48]. Considering a dropout rate, to achieve at least 21 evaluable patients, a total sample of 27 patients was enrolled in this study. Statistical analysis

Fig. 1 a, b PRF clot after centrifugation

Descriptive statistics were expressed as mean±standard deviation. Statistical analysis was performed with the patient as the analysis unit. Clinical and digital variables were calculated for each patient per treatment and per-protocol analysis was applied for statistical comparisons. Shapiro-Wilk test was used

Clin Oral Invest Fig. 2 a A 22-year-old woman presented with a localized gingival recession at maxillary right canine. b Surgical incisions performed and the flap was elevated. c PRF membrane placed and sutured on the recipient site. d CAF sutured over PRF

for whether all data distributed normally. RD, RW, RA, PD, CAL, GT and KTW values were normally distributed and compared using paired samples t-test within each group and between groups at baseline and at 6 months. GI and PI variables were not normally distributed and Wilcoxon test was used to detect significant differences within and between each group before and after therapy. Percentages of root coverage and complete root coverage between study groups at 6 months were assessed by Wilcoxon signed rank test and chi-square test, respectively. Reliability analysis with Cronbach’s alpha value was used for evaluating the compatibility between clinical and digital measurements for RD, RW and KTW. Statistical analyses were performed using a statistical package (SPSS Inc., Ver. 13.0, Chicago, IL, USA). Differences were considered significant when p-value was