Abstract
Aims and Objectives: To compare the efficacy of platelet rich plasma (PRP) and platelet rich fibrin (PRF) in bone regeneration after removal of impacted bilateral third molars. Materials and Methods: The study was carried out as an open clinical trial on 20 patients chosen from the ones referred to the department of Oral & Maxillofacial Surgery for surgical removal of bilateral mandibular third molar. Patients were prepared for surgical procedure, Inferior alveolar nerve block given using 2% lignocaine hydrochloride with 1:2,00,000 adrenaline. Third molar were removed by flap reflection and bone drilling. Finally, PRF in lower left mandibular third molar region and PRP in lower right mandibular third molar region was inserted and wound closure was done. Cone bean computer tomography (CBCT) was made on 1st postoperative day and 4 months after surgery to evaluate alveolar bone height and density. Result: Alveolar bone height and bone density at post-operative 1st day and 4 months were compared between PRP and PRF group. The bone density and bone volume were analyzed, and there was no significant difference between bone density in PRP and PRF at day 1 and 4th month. Conclusion: As per our study and evaluation, in our postoperative follow up there was no statistically significant differences in bone regeneration by placement of PRP and PRF in extracted socket of third molar. Thus, with this study we can conclude that PRF, would be a good option to Oral and Maxillofacial Surgeons in the near future due to ease of extraction.
Keywords: Platelet rich plasma, Platelet rich fibrin, Impacted mandibular third molar, Cone beam computed tomography
Introduction
Surgical removal of impacted mandibular third molar (SRIMTM) is the most common surgery performed in oral and maxillofacial surgery which commonly leads to bone loss or delayed wound healing that affects the oral and maxillofacial region. This is a complicated process particularly after the removal of tooth, fracture of the weakened mandibular bone is common, which requires long-term postoperative care [1]. As platelets are known to play a major role, not only in hemostasis but also in wound healing process, we have compared PRP (platelet rich plasma) and PRF (platelet rich fibrin) used after surgical removal of impacted mandibular third molar to evaluate regeneration of bone. PRP is an autologous concentrate of platelets suspended in plasma which is a proven source of growth factors like platelet derived growth factors like (PDGF) and Transforming growth factors (TGF)-beta 1. PRF was first developed in France by Choukroun et al. [2] and it is an activated form of plasmatic molecules called fibrinogen. These factors can activate the proliferation and differentiation of the local osteoprogenitor cells into bone forming cells leading to formation of new bone matrix and mineralization [3] .This soluble fibrillary molecule is massively present both in plasma and platelet α-granules and plays a determining role in platelet aggregation during hemostasis. This study was carried out to evaluate the efficacy of PRP and PRF in bone regeneration after surgical removal of impacted bilateral mandibular third molars. The results were evaluated clinically and radiographically.
Materials and Methods
The study was carried out as an open clinical trial on 20 patients chosen from the ones referred to our Oral & Maxillofacial Surgery Department for surgical removal of Mandibular third molar. The Institutional Review Board approval and the informed written consent from all the patients was obtained. Inclusion criteria were set to choose patients above 18 years of age, patients with bilateral partially bony impacted mandibular third molar with or without pericoronitis or caries and patients not receiving any antimicrobial medication for at least 6 weeks prior to surgical removal of impacted mandibular third molar. Exclusion criteria consisted patients with compromised immune status or systemic co-morbid condition, those who have any unacceptable oral habits and /or any oral pathology, patients with acute infection in the region of impacted mandibular third molar and patients who have allergy or hypersensitivity to local anesthesia. The patient’s face was prepared with betadine and patient was draped. This is followed by intraoral irrigation with betadine and normal saline and local anesthesia (Inferior alveolar Nerve block) given using 2% lignocaine hydrochloride with 1:2,00,000 adrenaline. Standard Ward’s incision was followed in all the cases. Full thickness mucoperiosteal flap was raised to expose sufficient bone on lateral and distal aspect of the impacted molar. Removal of bone was done with round bur with constant irrigation, tooth was luxated with straight elevator and removed with forceps; further smoothening of bone was done followed by irrigation and finally PRP in 48 and PRF in 38 regions respectively (Fig. 1A and B). Wound closure was done and patient was called on next day for post-operative Cone bean computer tomography (CBCT).
Fig. 1.
Placement of PRP and PRF into extraction socket: A-Placement of PRP; B- Placement of PRF
Preparation of PRP
Around 5ml of whole venous blood was collected in 0.6ml of citrate phosphate dextrose adenosine solution (CPDA). The vacutainers were placed in centrifuge at 1200 rpm for 10 minutes. The result was separation of the whole blood into a lower red blood cell region and upper straw colored plasma. This plasma contains relatively low concentration of platelets (Platelet poor plasma) in the uppermost region and higher concentration of platelet in the boundary layer often called as ’Buffy coat’. A spinal needle (18 gauge and 78 mm long) was attached to 5ml syringe to withdraw straw colored plasma from the tubes by moving the needle from the top downward as the draw continues. The draw stopped when a RBC layer was reached or into the first 1–2 mm of that layer. The tube with straw colored plasma were again centrifuged at 2000 rpm for 10 min. Now the content of the tube consists of the upper layer of clear supernatant serum containing fibrinogen and very low concentration of platelets. The bottom layer often red tinged consist of highly concentrated platelets (Fig. 2).
Fig. 2.
PRP prepared
Preparation of PRF
The PRF protocol is very simple and armamentarium required is same as that of PRP, expect the requirement of CPDA anticoagulant solution and 10% CaCl2. Around 5ml of whole venous blood was collected in each of the two sterile vacutainer tube of 6ml capacity without anticoagulant. The vacutainers were placed in centrifuge at 3000 rpm for 10 min. Then we obtained red lower fraction containing red blood cells, upper straw colored cellular plasma and the fibrin clot was obtained in the middle. The straw colored upper layer was removed and middle layer with fraction 2 mm below dividing line was collected and which is considered as PRF. (Fig. 3) For clinical and radiological evaluation certain landmarks used: Alveolar bone height (ABH) was measured on postoperative 1st (Fig. 4A), and 4-month CBCT by measuring the depth from Cemento-enamel junction (CEJ) of second molar to the apical of mesial socket of the third molar.(Fig. 4B).Bone density was measured on CBCT by “Hounsfield” unit on postoperative 1st and after 4 month minimum and maximum(Fig. 5A-D).
Fig. 3.
Preparation of PRF
Fig. 4.
Alveolar bone height (ABH) measured on 1st day and 4th month postoperatively by CBCT by measuring the depth from CEJ of second molar to the apical of mesial socket of the third molar: A- Alveolar bone height (ABH) measured on 1st day by CBCT; B- Alveolar bone height (ABH) measured 4 months postoperatively
Fig. 5.
Bone density measured on CBCT by “Hounsfield” unit on postoperative 1st and after 4 months minimum and maximum: A- Bone density measured on CBCT on 1st postoperative day when PRP was used; B- Bone density measured on CBCT on 1st postoperative day when PRF was used; C- Bone density measured on CBCT 4 months postoperatively when PRP was used; D- Bone density measured on CBCT 4 months postoperatively when PRF was used
Result
All results were calculated using the mean value and standard deviation for each of the parameters. The differences in results of Alveolar bone height and bone density at postoperative 1st day and 4 month were compared between PRP and PRF group. The use of PRP and PRF is one of the therapeutic strategies clinically available to promote bone repairing and wound healing. The bone density and bone volume were analyzed with ‘Hounsfield Unit’. By using Mann Whitney U test p-value > 0.05 there was no significant difference between mean minimum and maximum bone density in group PRP and PRF at day 1 and 4th month.
Discussion
Platelets play a crucial role not only in hemostasis, but also in wound healing process. Platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) are autologous platelet concentrates prepared from patient’s own blood. Recent researches are being focused on the development of therapeutic alternatives which are easy to prepare, non-toxic or biocompatible to living tissues and economically cheap that might result in the local release of growth factors accelerating hard and soft tissue healing [4]. A natural blood clot contains 94% red blood corpuscles (RBCs), 5% platelets and 1% white blood corpuscles (WBCs), while PRP contains 95% of platelets. PRP obtained from autologous blood is used to deliver growth factors in higher concentration to the site of bone defect or a region requiring augmentation. The classic PRP production protocol requires blood collection with anticoagulant, 2 steps of centrifugation, and artificial polymerization of the platelet concentrate using calcium chloride. The use of PRP has shown to be a valid technique for promoting bone regeneration at the level of the distal surface of the Mandibular second molar following extraction of an impacted third molars.
There are various advantages of PRP reported in the literature such as: [5, 6]
Provides availability of growth factors & bone morphogenetic proteins.
Increasing density and trabecular pattern of bone.
When used with graft, it promotes early consolidation and mineralization of graft.
Starts the osteogenesis cascade in bone graft.
Bhujbal R et al. from their study observed that bone healing and density was significantly increased by using PRP in the third molar extraction socket. Radiographic evaluation also showed an increase the bone density at the 6-month follow up thus establishing the importance of PRP in promoting and accelerating the healing of wound in patients undergoing surgical removal; of impacted mandibular third molar [7]. Another review conducted by Albanese, A et al. concluded that the use of PRP in extraction sockets significantly improved soft tissue healing and had a positive influence on bone regeneration [8].
On the other hand while studying the utility of PRF in third molar socket, Malhotra A et al. [9] concluded that PRF significantly helped in bone regeneration distal to second molar. It was also seen that use of PRF accelerated healing of bone and soft tissue distal to second molar thereby minimizing the possibility of periodontal problems seen after third molar surgery.
Sumanth Unakalkar et al. in their prospective study we able to identify certain advantages of PRF over PRP as follows: [10]
No need of anticoagulant and chelating agent.
PRF has better consistency and can be easily carried to extraction socket.
PRF coverts directly to usable form whereas PRP needs to be converted to gel form so that it can be placed inside the socket.
PRF is an immune and platelet concentrate collecting on a single fibrin membrane, containing all the constituents of a blood sample which are favorable to healing and immunity. Developed in France by Choukroun et al. in 2001, the PRF production protocol attempts to accumulate platelets and released cytokines in a fibrin clot. Though platelets and leukocyte cytokines play an important part in the biology of this biomaterial, the fibrin matrix supporting them certainly constitutes the determining element responsible for the real therapeutic potential of PRF [11]. Clinical studies reveal that this biomaterial would be a favorable matrix for the development of a coherent healing, without any inflammatory excess. PRF in the form of a platelet gel can be used in conjunction with bone grafts, which has several advantages, such as promoting wound healing, bone growth and maturation, wound sealing and haemostasis, and imparting better handling properties to graft materials. It can also be used as a membrane. Many clinical trials suggest the use of PRF to enhance bone density [12].
We wanted to see the comparative evaluation between PRP and PRF as potentially regenerative material in healing of socket after surgical removal of mandibular third molars. We used Cone beam computed tomography (CBCT) for evaluation of bone regeneration in respective bilateral Mandibular sockets. The density of bone formed in extraction socket was calculated by “Hounsfield Unit (HU)” However study conducted by Ling le et al. concluding that PRF released autologous growth factors gradually and expressed stronger and more durable effect on proliferation and differentiation of rat osteoblast than PRP in vitro [12, 13]. The present study had 4-month postoperative follow up. However, this duration of time is adequate enough to evaluate the effects of PRP and PRF in initiating and enhancing both hard and soft tissue healing.
Conclusion
As per our study and evaluation, in our postoperative follow up there was no significant statistically differences in bone regeneration by placement of PRP and PRF in extracted socket of third molar. Given the distinct advantages of PRF such as single stage centrifugation with less use of armamentarium and non-addition of any anticoagulant like thrombin or calcium chloride and prolonged release of growth factors, the authors feel that it is a better option for bone regeneration and soft tissue healing that PRP. However, a longer follow-up is essential to determine the effect of PRF on bone maturation.
Declarations
Conflict of Interest
Authors declare that they don’t have any conflict of interest.
Ethical Approval
The manuscript has been read and approved by all the authors, the requirements for authorship have been met, and each author believes that the manuscript represents honest work.
Informed Consent
The authors confirm that informed consent from the patients and their attenders was taken before their inclusion.
Consent to Participate
The authors confirm that informed consent from the patients and their attenders was taken before their inclusion.
Consent for Publication
Informed consent for publication from the participants was obtained.
Footnotes
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