|Ahead of print publication
Regenerative endodontic therapy using platelet-rich fibrin in children
Parul Singhal1, Bindu Kadian1, Pawan Midha2, Ritu Namdev1
1 Department of Pedodontics, PGIDS, Rohtak, Haryana, India
2 Department of Oral Surgery, AIIMS, Delhi, India
|Date of Submission||14-Oct-2019|
|Date of Decision||14-Dec-2019|
|Date of Acceptance||03-Feb-2020|
Department of Pedodontics, PGIDS, Rohtak, Haryana
Source of Support: None, Conflict of Interest: None
Regeneration of pulp–dentin complex in an infected necrotic tooth with an open apex is possible if the canal is effectively disinfected. The purpose of this case report is to add regenerative endodontic cases to the existing literature about the use of plateletrich fibrin (PRF). Three clinically and radiographically diagnosed necrotic immature permanent teeth were treated using PRF as a scaffold for revascularization. The therapeutic protocol involved accessing the pulp chamber, irrigating copiously with sodium hypochlorite, applying a triple antibiotic paste as intracanal dressing, and then provisionally sealing it. After 3–4 weeks, the canal was cleaned and PRF was introduced in the canal that would serve as a scaffold for pulp revascularization. Mineral trioxide aggregate was used to seal the chamber and finally restored with composite. All the cases treated with PRF as a scaffold showed magnificant healing and apical end closure along with thickening of dentinal walls. On the basis of the results obtained in our case reports, we conclude that the revitalization of necrotic infected immature tooth is possible under conditions of total canal disinfection, and PRF is nearly an ideal biomaterial for pulp–dentin complex regeneration.
Keywords: Open apex, platelet-rich fibrin, revitalization
| Introduction|| |
The routine endodontic treatment procedures accomplish the chemical–mechanical preparation of root canals to eliminate necrotic or infected pulp tissues and microorganisms. Clinicians are often encountered with cases of immature teeth with open apexes. Treatment in such teeth presents a unique challenge to the dentist, as trauma or infections prevent the root to complete its formation by halting mineral deposition. The presence of thin and fragile dentin of the root walls along with the open apex serves as a potential risk to achieve adequate obturation. Conventionally, the treatment of choice in such teeth was apexification with calcium hydroxide or mineral trioxide aggregate (MTA) aiming at the formation of apical hard-tissue barrier. MTA has been used by placing it in the apical portion of the root canal creating an artificial apical barrier that permits the compaction of obturating material and the placement of coronal restoration. However, both these techniques have the same disadvantage of not allowing the continuity of root development, causing the root to remain weak, and thus increasing the risk of fracture.
In 2004, Banchs et al. performed a study on revascularization therapy which revolutionized endodontic treatments. It seems that revascularization treatments are more suitable than previous treatments as they lead to root development, thickening of dentinal walls, and apex closure. It is dependent on the ability of residual periapical and periodontal stem cells to differentiate. These cells have the ability to generate a highly vascularized and conjunctive rich living tissue, which is able to colonize the available pulp space. Subsequently, these stem cells will differentiate into newly formed odontoblasts that will induce an apposition of hard tissue. In necrotic teeth, a suitable scaffold is necessary for the release of growth factors and for forming a proper space for placement of stem cells.
In the past two decades, an increased understanding of the physiological roles of platelets in wound healing and after tissue injury has led to the idea of using platelets as therapeutic tools. Platelet-rich fibrin (PRF) or the second generation of platelet aggregation was first introduced in 2001 by Choukroun et al. in France. This material is an autogenic fibrin matrix which contains growth factor, platelet, leukocyte, and cytokine, which causes the remaining cells to proliferate. Hence, PRF was used as a scaffold in this case series for revascularization of teeth.
| Case Reports|| |
A 8-year-old female patient reported to the Department of Pedodontics and Preventive Dentistry, Postgraduate Institute of Dental Sciences (PGIDS), Rohtak, Haryana, India, with a chief complaint of pain in the right maxillary anterior tooth region for 1 week. The pain was continuous, throbbing in nature, moderate in intensity, and nonradiating. The patient gave a history of trauma to the same tooth 2 years back. The vital signs were recorded and found to be within the normal range. On extaoral examination, no swelling or gross facial asymmetry was detected. Intraorally, tooth 11 had an Ellis Class III fracture and was tender on percussion. Pulp vitality was negative on cold and electric pulp testing (EPT). Radiographic examination revealed incomplete root formation with periapical radiolucency [Figure 1]. A diagnosis of pulpal necrosis with periapical abscess was made. After evaluating the options, the treatment choice considered was pulp revascularization. The patient was informed about the advantages and disadvantages of the method, and written consent was obtained from the parents to undertake the procedure in that tooth. After local anesthesia and isolation with a rubber dam, coronal access was made with a high-speed round bur. The root length was estimated radiographically using a size 20 K-file. The canal was passively irrigated with 20 mL of 5.25% sodium hypochlorite (NaOCl) for 20 min and 10 ml of normal saline and then dried with absorbent points (Dentsply Maillefer). A freshly prepared antibiotic paste consisting of ciprofloxacin, metronidazole, and minocycline (100 mg of each drug in a 0.5-mL total volume) was placed into the canal using a Lentulo spiral to 3-mm short of working length. The access cavity was sealed with Cavit (3M ESPE, Seefeld, Germany).
|Figure 1: Preoperative radiograph showing open apex and periapical radiolucency in relation to 11|
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On the second visit after 4 weeks, the patient was asymptomatic, and the tooth showed no tenderness to percussion and palpation. Under local anesthesia (without adrenaline) and rubber dam isolation, the temporary restoration was removed. The root canal was irrigated with 20 ml of 5.25% NaOCl solution, 5 ml of 17% ethylenediaminetetraacetic acid (EDTA), and 10 ml of normal saline.
PRF preparation was carried out in a simple, tabletop laboratory centrifugation machine (Remi model no.– R-8C, India). A total volume of 10 mL of whole blood was drawn by venipuncture of antecubital vein. Whole blood was centrifuged (soft spin at 3000 rpm for 10 min) to separate PRF [Figure 2]. It was then introduced into the root canal of the maxillary right central incisor. After 15 min, MTA was placed over the scaffold. Then, a glass ionomer cement base was placed over the MTA and the tooth was then restored with composite.
|Figure 2: (a) Contents of blood after centrifugation. (b) Platelet-rich fibrin membrane|
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Follow-up visits were scheduled after 3 months, 6 months, and 1 year. After 6 months, tooth was completely asymptomatic and periapical radiolucency was resolved with thickening of dentinal walls in radiograph [Figure 3]. At the 1-year follow-up examination, the patient continued to be asymptomatic with complete resolution of the periapical radiolucency and apex formation [Figure 4].
|Figure 3: Follow-up radiograph taken 6 months after completion of treatment. Periapical radiolucency has decreased and there is further closure of the apical foramen|
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|Figure 4: Follow-up radiograph of 12 months after carrying out revascularization treatment. The periapical radiolucency has disappeared, dentinal walls has thickened, and the apical foramen has almost closed|
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A 9-year-old girl reported to the Department of Pedodontics and Preventive Dentistry, PGIDS, Rohtak, Haryana, India, for treatment of her maxillary right maxillary incisor (tooth 11). The patient had suffered a traumatic injury to the same tooth 1 year back. The medical history of the patient was noncontributory, and the patient had no prior dental visit. Clinical examination revealed that the tooth had an Ellis Class III fracture and mobility, and periodontal probing was within the physiological limits. Pulp vitality was negative on cold and EPT, but the patient reported sensitivity to percussion and palpation. A periapical radiograph revealed that the tooth had an incompletely formed apex [Figure 5]. A diagnosis of pulpal necrosis was made for tooth 11. The parents were informed about the limitations and advantages of revascularization as a treatment modality, and informed consent was obtained.
Revascularization treatment was performed following the same protocol as before.
At the 9-month follow-up, the tooth was functional, without sensitivity to percussion and palpation, and normal periodontal findings [Figure 6]. At the 1-year follow-up, the patient continued to be asymptomatic and showed continued development of the root apex in the radiograph. Apical closure and dentinal wall thickening were evident along with the attainment of root length [Figure 7].
|Figure 6: Follow-up radiograph taken 9 months after completion of treatment. Thickening of dentinal walls is evident|
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|Figure 7: Follow-up radiograph after 12 months of treatment. Apical foramen has closed along with thickening of dentinal walls|
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A 12-years-old boy reported to the Department of Pedodontics and Preventive Dentistry, PGIDS, Rohtak, Haryana, India, with the chief complaint of pain in his lower left back region. The patient had suffered a traumatic injury to the teeth on his left mandibular region 1 year back. The medical history of the patient was noncontributory. Clinical examination revealed Ellis Class III fracture of 35and 36 and Ellis Class II fracture of 34. All the teeth were tender on percussion but mobility was absent. On radiographic examination, 34 and 35 teeth had open apex along with periapical radiolucency and 35 and 36 were fractured [Figure 8]a. Root canal treatment and porcelain fused to the metal crown of 36 was done [Figure 8]b and revascularization of 34 and 35 was planned. The same treatment protocol was followed for revascularization and the patient was kept on follow-up.
|Figure 8: (a) Preoperative radiograph showing Ellis Class III fracture in 35 and 36 and open apex of 34 and 35 along with periapical radiolucency. (b) Radiogaph after root canal treatment and crown placement in 36|
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After 3 months, the patient was asymptomatic with no tenderness on percussion in 34 and 35. Radiographically, the periapical radiolucency was resolving around 35 [Figure 9]. At 1-year follow-up, the patient was completely asymptomatic with no pain and tenderness on percussion, periapical radiolucency around 34 and 35 was completely resolved, and dentinal thickening with continued closure of the root apex with respect to 34 and 35 was very well appreciated [Figure 10].
|Figure 9: Radiograph after 3 months of treatment. Periapical radiolucency around 35 has resolved|
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|Figure 10: Follow-up radiograph after 1 year. Periapical radiolucency around 34 and 35 has completely resolved and dentinal thickening with continued closure of root apex with respect to 34 and 35 is well appreciated|
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| Discussion|| |
Presently is an era of regenerative endodontics in dentistry. These procedures result in the replacement of damaged, missing, and insufficient structures by healthy newly produced tissues which restore the shape and function of the pulp–dentin complex. Moreover, it is viable and easy to perform approach which allows for complete root formation.
Successful regenerative endodontic treatment includes a good coronal seal to prevent infection, absence of intracanal infection, a physical scaffold to promote cell growth and differentiation, as well as signaling molecules for the growth of stem cells.
The first step in the endodontic treatment of infected root canals involves disinfection which involves the use of chemical substances and mechanical instrumentation. However, in immature teeth, mechanical instrumentation is not recommended because of the fragility of the thin root walls, requiring a decontamination restricted to the use of irrigant solutions and intracanal medication. Different concentrations of NaOCl from 1.25% to 6% and different concentrations of chlorhexidine (CHX) including 2% and 0.12% have successfully been used for this purpose; however, recent studies have shown that irrigation with CHX may be detrimental to stem cells. Studies have also revealed that CHX irrigation might have cytotoxic effects on human stem cells and interfere with the attachment of dental pulp stem cells to the root canal walls. In addition, it has been reported that interactions between NaOCl and CHX form para-chloroaniline, which is known to be a carcinogen. Recently, Trevino et al. suggest that irrigation protocols that include 17% EDTA appear to promote smear layer removal and attachment of stem cells of the apical papilla to the root canal dentinal wall.
Hence, in the cases presented here, irrigation was done using 5.25% NaOCl and 17% EDTA, and disinfection of canal space was obtained with the use of triple antibiotic paste as suggested by other investigators.
In 1996, Hoshino et al. recommended the use of triantibiotic paste to disinfect the root canal, which was composed of ciprofloxacin, metronidazole, and minocycline and this medicament can be used effectively in regenerative endodontic treatment. On the other hand, Chueh et al. reported that complete disinfection of the canal and regeneration can be achieved using calcium hydroxide alone. Henceforth keeping infection control in mind and considering the conditional role of microorganisms within the root canals, in the present study, triple antibiotic paste was placed in the canal. This paste helps in controlling bacterial infection within the root canal space, more specifically in the periapical location. However, minocycline has long been known to stain dentin. Minocycline can penetrate the tooth through dentinal tubules and can integrate with the crystal structure of the tooth. If the triple antibiotic paste mix (1:1:1 by volume of ciprofloxacin/metronidazole/minocycline) is used, complications of dentinal staining can be avoided by sealing the pulp chamber with a dentin bonding agent or flowable composite, and if esthetics are crucial, eliminating the minocycline or exchanging with cefaclor can be considered. The mean period of time considered necessary for the bacterial disinfection of the canals, leaving the triple antibiotic paste, may vary from 1 to 4 weeks, depending on the condition of the patient. In our cases, care was taken to ensure that triple antibiotic paste remained below cemenol enamel junction to minimize staining.
In revascularization, the ingrowth of new tissue from the periapical area needs a matrix for its support. A matrix of blood clot provides a base not only for stem cell adhesion but also for its growth, differentiation, and migration. Till date, blood clot has been used commonly as a matrix. However, the induction and maintenance of a blood clot is extremely difficult in revascularization procedures and appears to be its limitation. Ding et al. in their clinical study demonstrated a failure to induce bleeding into the canal in 4 of 10 patients leading to an unfavorable revascularization outcome. Moreover, the controlled placement of MTA over a blood clot is technically difficult. Alternatively, the use of collagen as a scaffold or matrix for the ingrowth of tissue into root canals has been attempted. However, it has been found that the collagen acts as a passive scaffold and does not provide any advantage in the stimulation of the revascularization process as it does not contain the factors that promote cell growth and differentiation.
However, platelets can play a crucial role in periodontal regeneration as they are reservoir of growth factors and cytokines, which are key factors for regeneration of bone and maturation of the soft tissue.
PRF is a second-generation platelet concentrate, which releases key growth factors in a slow and sustained manner for at least 1-week and up to 28 days. PRF could stimulate its environment for a significant time during wound healing. This lead to the idea of using a PRF membrane for pulp regeneration. Due to the following advantages, we have followed the revascularization-induced PRF technique to close the root apex in these cases.
In cases 1 and 2, maxillary central incisors had blunderbuss canal with periapical radiolucency. These teeth showed complete resolution of radiolucency and thickening of dentinal walls with closure of the root apex similar to the finding with previous reports., Banchs and Trope in 2004 described a revascularization procedure for the treatment of a necrotic immature mandibular second premolar with an open apex and a large apical lesion, indicating that it might be possible to replicate the unique circumstances of an avulsed tooth to revascularize the pulp in infected necrotic immature roots. After them, many successful case reposts have been published by various authors using revascularization approach and most of them were performed on incisors and premolars of children 8–14 years of age.,, Similar to these reports, revascularization of mandibular premolar was attempted in case 3 which presented with a large radiolucency that healed with closure of the root apex and thickening of walls with proper disinfection and PRF use as a scaffold.
The technique referred to as regenerative endodontics, is, therefore, an effective and conservative option for the treatment of necrotic immature teeth. In addition to promoting apical closure, it permits thickening of dentinal walls and further root lengthening, so resolving the problem of susceptibility to fracture that used to appear following apexification therapy. However, there are still too few large-scale clinical studies involving humans and more research is needed.
| Conclusion|| |
This present study combined with prior reports on revascularization of the nonvital immature permanent teeth suggests that this biologically based treatment approach is of particular value in restoring root development and apical closure in these otherwise difficult cases.
The results of this study suggest that PRF can act as a successful scaffold for regenerative endodontic treatment. Nevertheless, more studies are necessary to evaluate its long-term efficacy and new approaches.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their 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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