Dental Hypotheses

: 2019  |  Volume : 10  |  Issue : 2  |  Page : 34--39

The Role of Platelet-Rich Fibrin in Increasing the Gingival Thickness and Modifying the Thin Gingival Biotype: A Comparative Clinical Split Mouth Study

Suleiman Dayoub, Mueataz Al-Qershi 
 Department of Periodontology, Dental School, Damascus University, Syria

Correspondence Address:
Mueataz Al-Qershi
Al-Mezzeh, Damascus, Syria


Introduction: Thin gingival biotype (GBT) is of clinical relevance in orthodontic and periodontic treatment, so thick biotype is a requisite for good periodontal health. The aim of this study was to evaluate the effectiveness of platelet-rich fibrin (PRF) with tunnel flap compared to connective tissue graft (CTG) with tunnel flap in increasing gingival thickness (GTH). Material and Methods: Twenty orthodontic patients presenting thin GBTs were included in this study. Treatment sites were divided into test group (PRF) and control group (CTG). Clinical parameters as GTH, GBT, and width of keratinized gingiva (WKG) were assessed at baseline and 6 months post-surgically. Statistical analysis was performed using independent T-test for intergroup comparison. Statistical significance was set at 0.05. Results: The mean GTH at 6 months was 1.57 mm for test group and 1.64 mm for control group. The gain of WKG was 1.57 and 2.08 mm in test and control sites, respectively. Conclusion: Within the limits of this study, using PRF in modifying thin GBT is a successful treatment option and could serve as an alternative to connective tissue grafts (CTGs).

How to cite this article:
Dayoub S, Al-Qershi M. The Role of Platelet-Rich Fibrin in Increasing the Gingival Thickness and Modifying the Thin Gingival Biotype: A Comparative Clinical Split Mouth Study.Dent Hypotheses 2019;10:34-39

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Dayoub S, Al-Qershi M. The Role of Platelet-Rich Fibrin in Increasing the Gingival Thickness and Modifying the Thin Gingival Biotype: A Comparative Clinical Split Mouth Study. Dent Hypotheses [serial online] 2019 [cited 2019 Sep 16 ];10:34-39
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The relationship between orthodontic and periodontic is of clinical relevance. The main goal of orthodontic treatment is to maintain dental and periodontal health and obtain optimal appearance.[1] In orthodontic treatment, clinicians deal with different cases and different gingival biotypes (GBTs); they also use different appliances with variable force magnitudes in different directions.[2] It is known that the dimensions of the buccal gingiva could be affected by the buccal-lingual/palatal position of the tooth. If the tooth is in buccal position, it decreases the gingival dimensions, while the dimensions increase if the tooth is in lingual/palatal position.[3] Muller and Kononen demonstrated that most changes in gingival thickness (GTH) were related to tooth position.[4]

GBT could be identified by the quality of the soft tissue profile surrounding the teeth; this biotype has significant impact on the outcome of periodontal surgery and orthodontic and restorative treatments. GBT was introduced to describe the thickness of the gingiva in a buccolingual dimension (thick or thin).[5] The thick biotype consists of flat soft tissue and thick bony architecture. This type of tissue form is dense and fibrotic with large zone of attachment, thus making them more resistant to gingival recession. The thin biotype is delicate with highly scalloped soft tissue and thin bony architecture. Such type is more prone to recession, bleeding, and inflammation.[6] Thin biotype is frequently characterized by osseous defects like fenestration and dehiscence. A study reports that orthodontic force and appliances could cause gingival recessions in cases of thin biotype; therefore, in these cases periodontal surgery is recommended to modify the thin biotype.[7]

Platelet-rich fibrin (PRF) is one of the plasma-rich derivatives and it is used currently for tissue regeneration in periodontal surgery. It contains cytokines and growth factors that are released over time, and that would stimulate tissue repair and reduce the inflammation and postoperative pain.[8]

Until now, a few studies were conducted to modify the GBT prior to orthodontic treatment using different techniques.[9] The aim of this study was to evaluate the effectiveness of PRF in increasing the GTH compared to connective tissue graft (CTG) using the tunnel flap technique and reject the null hypothesis H0 (the PRF has no effect in increasing the GTH).

 Material and Methods

Study Design

This study was a randomized clinical split mouth trial of thin GBTs in two sites.

A total of 22 patients (9 males and 13 females) from those attending the orthodontic department at the faculty of Dentistry for orthodontic treatment during January–June 2018 were enrolled in this study. Patients must fulfill these criteria: (1) patient age should be 18 to 35 years with the ability to demonstrate a good oral hygiene; (2) patients were at the first or last stage of orthodontic treatment; (3) subjects should be periodontally and systemically healthy; (4) presence of thin GBT. Just 20 patients (9 males and 11 females) were available for follow-up after 12 months [Figure 1].{Figure 1}

The exclusion criteria were as follows: (1)patients who were smokers (more than 20 cigarettes a day); (2) patients suffering from systemic diseases or periodontal diseases; (3) patients having appliances during orthodontic treatment; (4) patients who cannot maintain a good oral hygiene; or pregnant or lactating mothers. Subjects were randomized to test or control treatment by a computer-generated randomization list (SPSS v 22 for win, IBM, Chicago, IL) by the researchers. Twenty thin GBTs were selected to be treated in the test group by PRF and other 20 in the control group by CTG with the tunnel flap technique.

Sample Size

The sample size was determined based on the null hypothesis, which states that the test group (PRF) and the control group (CTG) were not equal. The confidence level determined was 95% and the desired sample power was 95%. The G power (version 3.1.2) was then used and the required sample size was 20 subjects. The selected study sample was increased by two persons, with the possibility of dispensing results of some subjects. The sample size was 22 persons.

Clinical Parameters

The primary parameter was GTH, which was measured directly measured using endodontic file No. (15) with a silicone limiter under local anesthesia. Then the thickness was determined by using electronic digital caliper (High quality LCD Display Electronic Digital Vernier Caliper, China). When the thickness was <1 mm, it was categorized as thin biotype and when the thickness was ≥1 mm, it was categorized as thick biotype.[10]

The secondary parameters were width of keratinized gingiva (WKG). These parameters were assessed prior and after 6 months of the treatment.

The Surgical Procedure

All enrolled subjects received a pre-periodontal treatment (scaling and root planning) before 2 weeks of surgery. On the day of surgery, patients were prepared with a preoperative rinse of 0.2% chlorhexidine for 1 min.

PRF Preparation

Intravenous blood samples were collected before the surgery in a 10-ml glass-coated plastic tube without adding any anticoagulant. Then they were centrifuged immediately at 2.700 rpm for 12 min with a table centrifuge (Hettich, Zentrifugrn D-7200 Tuttlingen, Germany). The fibrin clot, which formed in the middle part of the tube, was taken and transferred to the PRF box and compressed to create L-PRF membrane.[11]

Both sites were treated in the same surgical session. Local anesthesia was given by infiltration technique in the anterior mandible using (2% lidocaine with epinephrine 1:100,000), and then the tunnel flap was done by vertical incision from the middle bottom of the gingival papilla distal to the mandibular canine to the mucogingival junction (MGJ). A full thickness flap was elevated toward the middle line between the mandibular incisors without any intracervical incision in both sides. In control sites, a CTG was harvested from the palate and sutured to its position and then the flap sutured with Silk 0-4 (ACUFIRM, Dreieich, Germany) [Figure 2]. In test sites, the PRF membrane was entered inside the tunnel flap and sutured with Vicryl 5-0 sutures (Johnson and Johnson LLC, Piscataway, New Jersey, USA) and then the flap was sutured with Silk 0-4 (ACUFIRM, Dreieich, Germany) [Figure 2].{Figure 2}

Following surgery, patients received instruction on a written paper that included to rinse twice daily with chlorhexidine rinse 0.2% and to avoid tooth brushing for a month in the surgical area. Patients assumed antibiotic amoxicillin/clavulanate potassium (625 g three times daily for 6 days) and nonsteroidal analgesic diclofenac potassium (50 mg, twice a day for 6 days). Patients were told to come 2 weeks after surgery to remove the sutures. All patients were followed up at 1, 3, and 6 months.

Statistical Analysis

Data were collected and analyzed using SPSS-22 software (SPSS Inc., Chicago, Illinois, USA). Descriptive statistics were done by dispersion measures (mean, standard deviation, and variance). For both test and control groups, data were analyzed using paired T-test at baseline and 6 months for intragroup comparison. Independent T-test was used for intergroup comparisons. Statistical significance was set at 0.05.


Twenty patients (11 female and 9 male) with mean age 27 years were enrolled in this study. Fourteen patients were at the first stage of orthodontic treatment and eight patients were at the last stage. Forty thin GBTs were treated (20 with PRF) and (20 with CTG) with tunnel flap. Clinical parameters were evaluated at baseline and 6-months follow-up in each group. The GTH changed in PRF group from 0.70 to 1.75 mm (p <0.05) and in CTG group it changed from 0.71 to 1.64 mm (p <0.05) [Table 1].{Table 1}

The mean gain of GTH at 6 months was 0.87 mm for test group and 0.93 mm for control group. All the 40 thin biotypes became thick after 6 months. The WKG gain was 1.57 and 2.08 mm in both PRF and CTG groups, respectively. No statistical differences were found between the two groups (p >0.05) [Table 2].{Table 2}


GBT is of clinical importance in orthodontic and periodontic treatment, it determines the result of these treatments. GBT describes the thickness of the gingiva in the buccopalatal/buccolingual dimension. Thick GBT is a requisite for good periodontal health. This clinical study was the first to evaluate the L-PRF technique compared to CTG with tunnel technique in increasing the GTH and modifying the thin GBT among orthodontic patients.

In 2013, a case report was conducted by Alhulaimi and Awartani[9] to modify the thin periodontium biotype prior to orthodontic treatment for a 30-year old female using Alloderm membrane and the outcomes showed that thickening of the soft tissues prior to orthodontic treatment had a clinical positive effect. Nazhvani et al.[12] in 2013 compared two grafts (CTG and collagen sponge with platelet-rich plasma and PRF) to increase width and thickness of keratinized gingiva and found that new approach may be a proper substitute for CTG. Another study in 2016 showed that using chorion membrane could increase GTH during periodontal therapy.[13]

L-PRF technique is very simple, it acts as a fibrin membrane that accelerates wound healing and provides a significant postoperative protection.[14] It has the advantages of incorporating platelets, leukocytes, cytokines, and circulating stem cells.[15] Cytokines, growth factors such as transforming growth factor-β1 (TGFβ-1), platelet-derived growth factor-AB (PDGF-AB), vascular endothelial growth factor (VEGF), and matrix glycoproteins (such as thrombospondin-1) are released over a period of 7 to 11 days, during remodeling of fibrin matrix.[16] L-PRF has been used in periodontal surgery widely to treat gingival recessions and intrabody defects. Several studies compared the use of PRF with other different treatment options. The results showed that PRF enhances GTH and keratinized tissue.[17],[18] A systematic review[19] has been conducted to evaluate the use of PRF in periodontal therapy; it included 49 articles (14 in vitro, 2 animals, 33 clinical studies) and resulted that PRF is considered a therapeutic regenerative biomaterial, which could be used in periodontal surgery alone or in combination with other biomaterials (bone grafts, soft tissue grafts, pharmacologic agent) and would provide safe and promising results in enhancing clinical and radiological parameters in the management of periodontal defects. This systematic review also demonstrated that PRF enhances the GTH and results in thick GBT that shows greater stability during remodeling and enhances blood supply to the underlying structures. In 2018, a spilt mouth study evaluated the use of injectable PRF (I-PRF) to enhance thin GBT and the results were effective. I-PRF could be useful in increasing GTH, the gain in GTH was 0.17 mm.[20] Mufti et al. in 2017 compared the PRF versus CTG with coronally advanced flap in the treatment of gingival recessions; in PRF sites the mean gain of GTH was 0.17 mm versus 0.4 mm in CTG sites. The mean gain of width of keratinized tissue was in PRF sites 0.38 mm versus 0.4 mm in CTG sites.[21]

In this clinical split mouth study, both surgical techniques (PRF versus CTG) were evaluated to enhance the GTH and GBT. Both techniques were effective, and no statistical differences were observed between them. In the test group (L-PRF), the gain in GTH was 0.87 mm at 6 months and the gain of WKG was 1.57 mm. This improvement in clinical parameters could be related to the biology of PRF that contains growth factors and cytokines influencing proliferation and manifestation of the tissue,[22] the main platelet cytokines play a significant role in initial healing due to their capacity to stimulate cell migration and proliferation.[23] These results demonstrated that PRF membrane provides a potential healing and enhances the GBT. Besides reducing the surgical time, its other advantages include eliminating the second surgery to get the graft and providing less resorption during healing. It is also considered as a natural fibrin-based biomaterial favorable to the development of a micro-vascularization.In the control group (CTG), the mean gain of GTH at 6 months was 0.93 mm and the gain of WKG was 2.08 mm. This increase in GTH and WKG in CTG group could be explained by the ability of the connective tissue to induce keratinization of the epithelium and stimulate the formation of the connective tissue, which leads to increase in the thickness of the tissue.[24]

The results of this study agreed with the study of Ozsagir et al.[20] and Mufti et al.[21] in which PRF successfully increased the GTH.


Within the limits of this study, we reject the null hypothesis, both surgical techniques increased the GTH, and all the thin biotypes become thick after 6 months of the surgery. Using PRF seemed to be a successful treatment option for thin GBT and it could serve as an alternative to CTG. Many studies should be done to demonstrate the effectiveness of PRF in increasing GTH.


Dr. Haydar Barakat for his assistance in the manuscript and statistical analysis. The study protocol was conducted in accordance with the Helsinki Declaration of 1975, as revised in 2000, and was approved by the internal Ethical Committee of Damascus University, Damascus, Syria. A written informed consent was obtained from all subjects who participated in the research study. In the form, the patient(s) has/have given his/her/their consent for the surgical procedure and for his/her/their clinical images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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