Heal and seal using injectable blood derivative: Case series

Abstract

Regenerative endodontic procedures initially proposed for dental pulp revascularisation in immature permanent tooth resulted in continued root development, increase thickness of dentinal wall and apical closure. Recently with increased knowledge, REP have been used to successfully treat mature permanent tooth with infected necrotic pulp and apical periodontitis. In present Case series two visit revascularisation procedure was performed by placing I-PRF in the root canals. A 3-mm plug of mineral trioxide aggregate was placed to seal the coronal orifice over semicoagulated blood. The access cavities were restored with composite resin. Followups of the treated cases was done using CBCT as measuring tool to evaluate the successful treatment outcome. There was evident reduction in size of lesion. Clinical signs and symptoms were absent in both cases at followup visits at different time intervals. The purpose of this series was to present the potential of using I-PRF as an alternative and promising treatment approach for management of mature teeth with chronic apical periodontitis.

INTRODUCTION

Revascularization has been successfully implemented clinically nowadays providing dentists with outrageous results. It has been 50 years ago that revascularized procedures were proposed in regenerative endodontics. Nygaard-Ostby and Hjortdal reported that a blood clot from root canals induced for bleeding is organized through the gradual transformation of a granulation tissue into a fibrous connective tissue thus omitting surgical endodontics.[1]

According to AAE, the primary goal of REP is the elimination of clinical signs and symptoms and resolution of apical periodontitis. An increase in the thickness of canal walls and continued root development is the secondary goal.[2] Therefore, it can be stated that the primary goal of REP shifts the treatment protocols from surgical to nonsurgical endodontics. Following the concept of minimal invasive dentistry.

Regenerative endodontics can now be implemented through the clinical application of principles such as tissue engineering, pulp biology, and pulp regeneration. This process relies on the interaction of three key components: (1) a scaffold providing structural support, (2) stem cell proliferation, and (3) bioactive molecules such as growth factors. Together, these elements create a conducive microenvironment for regenerative procedures.[3]

Blood derivatives such as platelet-rich fibrin (PRF) and platelet-rich plasma (PRP) serve as effective bioscaffolds, offering a fibrin network that guides stem cells and promotes growth through growth factors. Several PRF protocols including L-PRF, advanced PRF (A-PRF), A-PRF+, and injectable PRF (I-PRF), have been extensively documented, as described by Shah et al.[4]

Introduced in 2014, PRF is a liquid blood derivative developed using the low-speed centrifugation concept.[5] It is rich in platelets, leukocytes, and growth factors. Research shows that I-PRF forms a three-dimensional (3D) fibrin gel containing growth factors, type-I collagen, platelets, leukocytes, and osteocalcin. This gel exhibits antibacterial and anti-biofilm properties, reduces inflammation, and promotes osteogenesis.

This case series aims to explore the potential of regenerative endodontic procedures (REPs) utilizing i-PRF for mature permanent teeth with apical periodontitis and focusing on the resolution of clinical symptoms and periapical lesions through cone-beam computed tomography (CBCT) analysis.

CASE REPORTS

Case report 1

A 27-year-old female patient reported to the department of conservative dentistry and endodontics with a complaint of pain in the lower left back teeth region. The pain was spontaneous that intensified during mastication for the past 1 week. The patient medical history was not relevant.

Clinical examination revealed faulty restoration with respect to 36. The surrounding periodontal tissues were intact with no swelling, draining sinus, or mobility. The pulp sensibility test was done using refrigerant spray (Endo-Frost, Coltene, Germany) and electronic pulp tester (Parkell Electronics Division, New York, USA) yielded negative response.

Intraoral periapical radiograph (IOPAR) [Figure 1a] and CBCT examination revealed periapical radiolucency associated with the mesial root of 36 measuring 11.19 × 3.76 mm [Figure 1g]. Based on clinical and radiographic findings, diagnosis of chronic apical periodontitis was established.

Figure 1.

(a) Preoperative radiograph with respect to 36 (b) Extracted injectable platelet-rich fibrin in syringe (c) Immediate Postoperative Radiograph with respect to 36 (d) 1-month follow-up (e) 3-month follow-up (f) 6-month follow-up (g) Preoperative cone-beam computed tomography (CBCT) with respect to 36 (h) 3-month follow-up CBCT (i) 6-month follow-up CBCT

A two-visit treatment plan with REP using I-PRF was formulated. On the first appointment, REP was comprehensively elucidated to the patient and informed consent was taken. The tooth was anesthetized using 2 ml of 2% lidocaine with 1:100,000 epinephrine. After achieving tooth isolation with a rubber dam, an access cavity was performed. Working length determination was done using the Ingles method. Biomechanical preparation was done following the irrigation protocol with 1.5% sodium hypochlorite as the primary irrigant. The canals were dried, and calcium hydroxide intracanal medicament was placed before sealing the access cavity provisionally with glass ionomer cement.

At the second visit, the procedure began with a 2 ml buccal infiltration of local anesthetic solution. Rubber dam isolation was re-established, and the root canals were irrigated with 17% ethylenediaminetetraacetic acid (EDTA) solution followed by saline. For the preparation of i-PRF, 10 ml of venous blood was drawn using a sterile syringe and was transferred into noncoated, anticoagulant-free blood collection tube to allow natural fibrin polymerization. The blood is then centrifuged at a low speed of 700 rpm (60 g) for 3 min using a centrifuge, as lower centrifugal forces help preserve the platelet count, leukocytes, and growth factors. The extracted i-PRF [Figure 1b] was collected and then injected inside the canals with syringe placed 1 mm short of the working length. A collagen membrane matrix was then placed 1 mm below the level of the canal orifice and then, mineral trioxide aggregate (MTA) was placed over the membrane at the level of the canal orifice. The cavity was then be double-sealed with a glass ionomer cement base and a resin composite restoration [Figure 1c].

The tooth was assessed clinically and radiographically, postoperatively at 1-, 3-, and 6-month follow-up visits [Figure 1d-f]. One month postoperatively, the tooth was found to be clinically asymptomatic. Follow-up, IOPAR, and CBCT revealed a reduction in the size of the periapical lesion from 11.19 × 3.76 mm to 2.78 × 1.45 mm [Figure 1h and i]. The patient is called for follow-up every 3 months. The evaluation of the clinical signs and symptoms showed no pain, sinus tract formation, and swelling throughout the follow-up periods which suggests a successful treatment outcome.

Case report 2

A 30-year-old male patient reported to the department of conservative dentistry and endodontics with a complaint of pain in relation to the mandibular anterior tooth region. Clinical examination revealed discoloration with respect to 31. The surrounding periodontal tissues were intact and gave a negative response when subjected to pulp sensibility tests. IOPAR [Figure 2a] and CBCT examination revealed periapical radiolucency with respect to 31 (7.81 × 6.86) mm [Figure 2g]. Based on clinical and radiographic findings, diagnosis of chronic apical periodontitis was established. A two-visit regenerative protocol with I-prf was carried in similar manner with placement of I-PRF in the canal [Figure 2b].

Figure 2.

(a) Preoperative radiograph with respect to 31 (b) Placement of injectable platelet-rich fibrin inside the canal (c) Immediate Postoperative Radiograph with respect to 31 (d) 1-month follow-up (e) 3-month follow-up (f) 6-month follow-up (g) Preoperative cone-beam computed tomography (CBCT) with respect to 31 (h) 3-month follow-up CBCT (i) 6-month follow-up CBCT

The tooth was assessed clinically and radiographically immediately postoperatively [Figure 2c] and at 1-, 3-, and 6-month follow-up visits [Figure 2d-f]. One month postoperatively, the tooth was found to be clinically asymptomatic. Follow-up, IOPAR, and CBCT revealed a reduction in the size of the periapical lesion from 7.81 × 6.86 mm to 2.56 × 1.92 mm [Figure 2h and i] and similar follow-up protocol is followed.

DISCUSSION

Traditionally, mature permanent teeth with necrotic pulps or apical periodontitis have been treated with nonsurgical root canal therapy due to its predictability and high success rate. However, Biologically it may be preferable to have disinfected root canals filled with hosts own vital tissue rather than with foreign material. Although regenerative procedures were initially restricted to immature teeth, He et al. suggested the potential application of REPs in mature teeth as well.[6]

The success of REPs relies heavily on appropriate case selection. In the present study, cases with a score of 5 periapical lesions (CBCT-PAI) were selected to explore the use of the novel injectable PRF for growth factor accumulation, aiming to standardized avoiding unnecessary surgical intervention.

Effective control of root canal infection is crucial for achieving a successful endodontic outcome. The disinfection protocol in this study adhered to the AAE Clinical Considerations for Regenerative Procedures. A lower concentration of 1.5% NaOCl (20 mL per canal for 5 min) was used to minimize cytotoxic effects on stem cells in the apical tissues, as recommended by Martin et al.[7] In the second visit, 20 mL of 17% EDTA was used due to its chelating properties, which facilitate the release of growth factors embedded in the dentin. Calcium hydroxide was employed as an intracanal medicament because of its strong antimicrobial properties, attributed to its high pH of 12.5–12.8, which creates an unfavorable environment for most bacteria. In addition, the use of calcium hydroxide in REPs has been associated with improved survival rates of apical papilla stem cells.

Scaffolds are pivotal in regenerative endodontics as they stimulate stem cell migration, proliferation, and differentiation.[8] PRF, an autologous biomaterial first introduced by Choukroun et al. in 2001, has become a preferred scaffold in pulp tissue engineering.[9] PRF’s fibrin matrix embeds growth factors that promote cell mitosis, angiogenesis, and osteogenesis, critical for tissue regeneration.

To address the limitations of the solid PRF matrix, i-PRF was introduced in 2014. I-PRF is a second-generation platelet concentrate used in regenerative endodontics due to its rich composition of growth factors such as PDGF, transforming growth factor-β (TGF-β), vascular endothelial growth factor, insulin-like growth factor-1, and EGF, which stimulate angiogenesis, cell proliferation, and differentiation. During the formation of i-PRF blood was centrifuged at 700 rpm for 3 min which resulted in the formation of three distinct layers: the top layer containing platelet-poor plasma, the middle layer containing I-PRF, which appears as a yellow-orange fibrin-rich layer, and the bottom layer consisting of red blood cells (RBCs). Using a sterile syringe, the middle layer (I-PRF) was carefully aspirated, ensuring minimal disruption of the RBC layer. Unlike traditional PRP, I-PRF liquid consistency facilitates direct injection into targeted areas, potentially by accelerating therapeutic outcomes.[8] In addition, the liquid form may improve stem cell stimulation and tissue regeneration efficiency. For instance, Pietruszka et al. (2017) observed the largest bacterial growth inhibition zone when i-PRF was used against plaque microorganisms, outperforming PRP and PRF. Thus, I-PRF was preferred in the present study.[10]

The approach adhered to the principle of maintaining a nonbleeding apical environment in the present study which is in consistent with the findings of Shin et al. and Jung et al.[11,12] Their case reports highlighted the potential for achieving periapical wound healing, canal wall thickening, and ongoing root development without necessitating the induction of periapical bleeding into the canal system, thereby preserving the structural and biological integrity of the periapical tissues.

As articulated by Klevant and Eggink, the resolution of inflammatory periapical lesions is achievable in the absence of root canal fillings, contingent upon meticulous control of root canal infection, and the prevention of coronal leakage.[13] In alignment with this principle, MTA was strategically placed over a collagen membrane and subsequently sealed with a layered approach comprising glass ionomer cement and resin-based restorative material to ensure an impervious coronal barrier. The selection of MTA was predicated on its superior bioinductive and bioconductive attributes, which facilitate cellular proliferation and foster an optimal microenvironment for tissue regeneration and periapical healing.

CBCT-PAI was employed to evaluate healing, leveraging CBCT advanced capabilities as the preeminent 3D imaging modality to overcome the inherent limitations associated with conventional two-dimensional periapical radiographs. Unlike traditional radiographic methods, CBCT demonstrates superior sensitivity in detecting minute lesions, including those restricted to cancellous bone, which often evades detection on standard periapical imaging. Furthermore, its capacity to render 3D reconstructions of pathological sites facilitates a comprehensive spatial assessment while enabling precise quantification of low-density regions, thereby providing an accurate and reliable estimation of the true extent of periapical lesions.

According to American Association of Endodontists guidelines, cases of the i-PRF revascularization technique group were considered successful; where the primary goals of regenerative endodontics were achieved such as the resolution of apical periodontitis and the elimination of clinical signs/symptoms. Furthermore, there was a decrease in the size of the periapical radiolucencies and an increase in periapical bone densities. The bouts of growth factors released by I-PRF increased fibroblast migration and production of PDGF, TGF-β, and collagen1, markers of osteoblastic development in DPSCs contributing to bone healing.[14]

CONCLUSION

The main aim of platelet concentration therapy is to provide sources of growth factors to promote tissue regeneration. Although in the present study, the results were appreciable on CBCT investigations which helped to gain more confidence in nonsurgical treatment protocol. Further randomized clinical trials are recommended to validate the purpose and use of i-PRF in regenerative endodontics.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.