Concentrated growth factor scaffold-based pulpotomy of permanent molars with symptomatic irreversible pulpitis
Article information
Abstract
Objectives
Pulpotomy is a minimally invasive procedure that aims to retain the vitality of the radicular pulp by removing the inflamed coronal pulp tissue. This case series presents the successful management of symptomatic irreversible pulpitis by pulpotomy with concentrated growth factor (CGF) scaffolds.
Methods
Six permanent mandibular molars with a diagnosis of symptomatic irreversible pulpitis were included. Under Local anesthesia and rubber dam isolation, caries were excavated using high-speed bur under coolant. Full coronal pulpotomy was done and hemostasis was achieved. CGF membrane was prepared and placed over the radicular pulp and layered with Biodentine (Septodont). Final restoration of type IX glass ionomer cement and bulk fill composite resin was placed. Patients were assessed for various clinical and radiographic parameters at intervals of 1 week and 3, 6, and 12 months. Five patients fulfilled the success criteria at the end of 1 year.
Results
Pulpotomy is considered an alternative treatment modality for root canal treatment in symptomatic irreversible pulpitis aiming at alleviating symptoms and maintaining vitality. CGF scaffold when used as a capping material acts as a reservoir for growth factors with anti-inflammatory properties and enhances healing.
Conclusions
Scaffold-based pulpotomy can be considered a biological approach to healing inflamed pulp.
INTRODUCTION
Irreversible pulpitis is a clinical diagnosis indicating that the vital inflamed pulp is incapable of healing [1]. Thus, pulpectomy is considered the treatment of choice for irreversible pulpitis. While this procedure is usually effective when executed properly, it is invasive, complex, and time-consuming [2]. The tooth’s structural integrity can be compromised after root canal treatment due to various iatrogenic and non-iatrogenic factors such as loss of tooth structure, loss of hydration of dentin, irrigants, and intracanal medicament effects on dentin collagen, making the tooth prone to fracture [3]. These concerns emphasize the significance of preserving pulpal vitality.
Pulpotomy being a noninvasive procedure, aims to remove the inflamed pulpal tissue and place a biomaterial over the remaining radicular pulp tissue allowing the healing/repair as well as retaining the vitality of the pulpal tissue [4]. The advent of bioactive materials with improved biocompatibility has created a paradigm shift in the management of symptomatic irreversible pulpitis with a minimally invasive approach to conserve the vitality of the remaining pulp.
Recent systematic reviews on coronal pulpotomy in teeth with symptomatic irreversible pulpitis managed with tricalcium silicate biomaterials showed a clinical success rate of 97.4% at 12 months which gradually reduced to 88.39% at 3 years and a radiographic success rate of up to 90% [2,5].
Currently, the focus is on pulpotomy agents which will aid in resolving inflammation thus enhancing regeneration of pulp. Platelet-rich fibrin (PRF), a second-generation platelet concentrate was first used as a scaffold for pulpotomy in mature teeth with symptomatic irreversible pulpitis with a follow-up of 22 months [6]. PRF when used as a scaffold in pulpotomy shows an overall clinical success rate of 85.4% at the end of 1 year [7].
Concentrated growth factor (CGF) is gaining importance in the field of regenerative medicine. In dentistry, it has been extensively used in periodontal regeneration [8]. Growth factor release from CGF is 15 folds higher when compared to platelet-rich plasma (PRP) and, its stiff fibrin structure permits sustained release of growth factor [9].
To the best of the authors’ knowledge, there are no reports on the clinical use of CGF as a natural scaffold for pulpotomy in symptomatic irreversible pulpitis in mature permanent teeth. The present case series portfolio documents the successful management of symptomatic irreversible pulpitis with CGF pulpotomy.
METHODS
The clinical protocol of this study was approved by Institutional Review Board of Meenakshi Ammal Dental College (No. 2017/226).
A total of nine systemically healthy patients (American Society of Anesthesiologists classification I) of the age group of 18 to 35 years who reported to the department diagnosed with symptomatic irreversible pulpitis of permanent mandibular molars with mature root apex were included. Patients with mild to moderate pain (visual analogue scale [VAS] score, 4–6) that was sharp, spontaneous in nature, with lingering response to more than 10 seconds to cold test as well as with periapical index (PAI) score <2 were included [10]. Deep caries extending subgingivally, clinical signs of craze line/crack, radiographic signs of pulp calcifications/periapical lesion, and teeth with necrotic pulps on access opening were excluded. Teeth in which hemostasis was not achieved within 5 minutes, PAI score >2 were also excluded.
Conventional endodontic treatment and pulpotomy treatment options were explained to the patients. Finally, patients who consented for pulpotomy were included. A decision-making chart detailing the workflow of treatment provided to the patients in our portfolio is provided (Figure 1).
Decision-making chart for pulpotomy. DOM, dental operating microscope; EPT, electric pulp test; PAI, periapical index; VAS, visual analogue scale.
Concentrated growth factor fabrication according to Sacco’s protocol
Five milliliters of the patient’s blood was collected by venipuncture of the antecubital vein without anticoagulant and immediately centrifuged (MEDIFUGE; Silfradent Srl., S. Sofia, Italy). The protocol followed for CGF fabrication was –30 seconds acceleration, 2 minutes at 2,700 rpm/375×g, 4 minutes at 2,400 rpm/580×g, 4 minutes at 2,700 rpm/735×g, 3 minutes at 3,000 rpm/905×g, and finally 33 seconds deceleration following which the centrifugation was stopped [11].
Four layers comprising of (a) top of the acellular plasma layer, (b) fibrin clot containing platelet concentrates as a middle layer, (c) liquid phase containing white blood cells and stem cells, and (d) bottom layer of red blood cells were obtained. The fibrin clot was separated from the red blood cell layer using a sterile tweezer. Finally, the dense fibrin layer was placed within a PRF box (Process Ltd., Nice, France) to obtain the CGF membrane of uniform thickness of 1 mm (Figure 1C).
Clinical procedure
Anesthesia was achieved with an inferior alveolar nerve block using 2% lidocaine with adrenaline in 1:80,000 concentration (Xilonibsa; Inibsa, Barcelona, Spain). Under a dental operating microscope (Prima DNT; Labomed, Los Angeles, CA, USA) and rubber dam isolation, the dental caries were removed using #3 sterile round diamond bur (Dentsply Maillefer, Ballaigues, Switzerland) under coolant. The exposed coronal pulp was resected with a high-speed sterile diamond under water coolant to the level of the canal orifice. Hemostasis was achieved within 2 to 3 minutes with manual pressure using a sterile cotton pellet. CGF membrane, the desired size to suit the pulp chamber, was placed over the amputated pulp. It was further layered with 3 mm of Biodentine (Septodont, St. Maur Des Fosses, France). After the initial setting of Biodentine, the remaining cavity was restored with type IX glass ionomer cement (GC Corp., Tokyo, Japan) and direct composite resin (Ivoclar Vivadent AG, Schaan, Liechtenstein) (Figure 2). Ibuprofen was prescribed in case the patients experienced discomfort.
Clinical steps in scaffold-based pulpotomy. (A) Preoperative status of tooth number 18 under the dental operating microscope and rubber dam isolation. (B) Coronal pulp amputated and hemostasis achieved. (C) Preparation of concentrated growth factor (CGF) membrane of 1 mm thickness using platelet-rich fibrin (PRF) box. (D) CGF/PRF membrane placed over the radicular pulp. (E) Biodentine (Septodont, St. Maur Des Fosses, France) of 3 mm thickness approximately layered over the CGF membrane. (F) Final restoration with type IX glass ionomer cement and resin composite.
The patients were followed up at time intervals of 1 week, 3 months, 6 months, and 1 year for clinical assessment of coronal restoration and pulp vitality. The integrity of coronal restoration was assessed using the modified United States Public Health Service (USPHS) criteria. For assessing vitality status, the electric pulp test (EPT) probe was placed on the cervical third on the buccal surface to elicit pulp response. Radiographic assessment was done using a positioning device at 3, 6 months, and 1 year (Figures 3 and 4).
(A) Intraoral periapical radiograph (IOPA) of tooth number 30. (A1) Preoperative radiograph showing caries involving the occlusal surface approximating pulp. (A2) Immediate postoperative radiograph after pulpotomy. (A3) Six-month follow-up. (A4) Twelve-month follow-up. (B) IOPA of tooth number 31. (B1) Preoperative. (B2) Immediate postoperative. (B3) Six-month follow-up. (B4) Twelve-month follow-up. (C) IOPA of tooth number 18. (C1) Preoperative. (C2) Immediate postoperative. (C3) Six-month follow-up. (C4) Twelve-month follow-up.
(A) Intraoral periapical radiograph (IOPA) of tooth number 18. (A1) Preoperative, (A2) immediate postoperative, (A3) 6-month follow-up, and (A4) 12-month follow-up. (B) IOPA of tooth number 21. (B1) Preoperative, (B2) immediate postoperative, (B3) 6-month follow-up, and (B4) 12-month follow-up. (C) Presentation of tooth number 34 (failed case). (C1) Preoperative and (C2) immediate postoperative. (C3) At 4 weeks, clinical presentation under a dental operating microscope (magnification, ×2.5) with the arrowhead pointing to hard calcified barrier on the mesibuccal, mesiolingual, and distal canal. (C4) At 4 weeks, the arrow points to the periapical lesion.
The criteria for clinical success are as follows: absence of clinical signs and symptoms like pain/discomfort/sensitivity during mastication, at least two consistent responses to the EPT, swelling, sinus tract, and integrity of coronal restoration using the modified USPHS criteria. Radiographic success was defined based on normal periodontal ligament space and lamina dura, improvement in the PAI score in case of apical periodontitis, assessment of the pulp chamber, and margins of restoration.
RESULTS
In our case series, all six patients were available during the follow-up period. On clinical and radiographic assessment five patients were found to be asymptomatic with no evidence of pain/discomfort/sensitivity during mastication, mobility, swelling, or sinus tract at the end of 12 months. All cases tested positive for vitality testing at 3, 6, and 12 months. Radiographically, all five patients had no evidence of widening of the periodontal ligament, absence of periapical lesion, and resorption (Table 1). Neither pulp canal obliteration nor root resorption was observed in any of the cases. The clinical outcome for the coronal restoration of all five successful teeth using the modified USPHS criteria was observed to be alpha (Table 1). One patient reported symptoms at 4 weeks after treatment and endodontic treatment was performed. Two patients required analgesics in the first week after pulpotomy.
Clinical and radiographic evaluation at preoperative and postoperative follow-up intervals at 1, 6, and 12 months of all patients
DISCUSSION
On a molecular level, inflammation plays a major role in the repair of dentin pulp complex. Reparative dentinogenesis is a complex process that occurs as a response to intense tissue injury. In the presence of favorable environmental cues, stem cells/progenitor cells get recruited at the site of injury leading to the formation of odontoblast-like cells that secret tertiary dentin culminating in the formation of dentin bridge over the exposed pulp. Multiple key growth factors and several proinflammatory cytokines contribute to the signaling of the angiogenic and neurogenic repair process [12]. Odontoblast provides a fossilized reservoir of growth factors and cytokines and releases them from the dentin extracellular matrix when exposed to carious acids as well as restorative materials [13].
Additionally, multiple clinical factors like preoperative status of the pulp, quality of coronal restoration, caries location (occlusal or proximal), time taken to achieve hemostasis, and age are considered important in the repair of dentin pulp complex [2]. The aforementioned clinical factors along with a radiographic assessment of the periapical status, and integrity of restoration were considered during the follow-up [14].
The rationale of placing a scaffold in direct contact with the pulp may interact with the residual pulp stem cells present within the inflamed pulp thereby inducing the process of regeneration [15]. Immature permanent teeth treated with autologous platelet scaffold-like PRF for pulpotomy have shown less tendency for canal obliteration in comparison to calcium silicate cement [16]. A clinical study that tested the use of PRF as a pulpotomy agent compared with mineral trioxide aggregate (MTA) and calcium hydroxide for irreversible pulpitis in mature molars observed a success rate of 85% at the end of 1 year [17]. Placing a scaffold in direct contact with radicular pulp could be advantageous over the use of only tricalcium silicate materials due favorable environment for increased cell migration, differentiation, vascularization, and innervation [12]. However, there is no strong clinical evidence to support this claim.
CGF, an autologous platelet-derived scaffold that interacts with lipopolysaccharide-induced human dental pulp stem cells, upregulates the expression of proinflammatory mediators like interleukin (IL)-8, IL-6, and tumor necrosis factor alpha (TNF-α) during the first 24 hours which gradually reduces over time. This initial inflammatory phase is required to recruit polymorphonuclear neutrophils and stem cells to the site of inflammation (Figure 5). Later, IL-8 and TNF-α significantly reduce on day 5 which is responsible for cellular proliferation and tissue healing [12]. This phenomenon was not observed in PRF/PRP. The alternated and controlled centrifugation protocol for CGF preparation results in a stronger and denser fibrin structure with a greater number of platelets embedded in the fibrin structure. The dissolution rate of CGF is comparably slower than PRF and has sustained growth factor release up to 13 days. Growth factors such as platelet-derived growth factor, transforming growth factor beta, and vascular endothelial growth factor though not statistically significant, are expressed 2.8, 8.25, and 3 times more than PRP respectively [18]. Immunohistochemical analysis also revealed the presence of CD34+ cells in CGF, which play a significant role in maintaining vascular supply, neovascularization, and angiogenesis [19]. However, this technique has some disadvantages, including the need to draw intravenous blood from patients, which can cause apprehension in some individuals, as well as the additional cost of procuring a CGF centrifuge machine.
Schematic illustration explaining conventional (A) and scaffold-based (B) pulpotomy.
CGF, concentrated growth factor; IL, interleukin; PMN, polymorphonuclear neutrophil; TGF-β1, transforming growth factor beta 1; TNF-α, tumor necrosis factor alpha.
To date, there is no literature on the use of CGF as a scaffold for pulpotomy in the management of irreversible pulpitis of permanent teeth. Thus, we opted to use CGF as a scaffold for pulpotomy in symptomatic irreversible pulpitis.
Partial irreversible pulpitis (PIP) is the intraoperative status of the pulp wherein partial or complete pulpotomy can be considered as the inflammation is confined to the coronal pulp and hemostasis can be achieved within 5 minutes [20]. Pulp exposure in all the cases was due to extensive caries (class 2) involving pulp. It is highly probable that carious pulp exposure will result in more extensive inflammation and infection affecting deeper pulp tissue compared to traumatic pulp exposure (class 1) during excavation [20]. Additionally, complete pulpotomy increases the probability of removing most of the inflamed pulp. Hence complete pulpotomy was preferred over partial in all the cases. Evidence on partial versus complete pulpotomy in PIP in mature teeth affected with caries showed comparable success rates of 88% and 91.6% at the end of 1 year [21]. Similarly, in our case series, a success rate of 83% was observed.
A definite coronal seal plays a pivotal role in the success of vital pulp therapy; however, the type of restorative material did not play a role in the treatment outcome. Restoring with either amalgam or composite has shown a success rate of approximately 92% to 93% [22]. Similarly, a full-coverage crown is better when compared to direct composite restoration with a hazard ratio of 3 [23]. In our case series, we had included teeth that did not require cuspal coverage and with supragingival margins. Thus, a direct permanent restoration was given that enabled better clinical and radiographic evaluation during the follow-up.
The tooth with proximal caries has shown controversial results with a success rate of 43% to 95% [14]. In our case, a series 1 patient had extensive proximal caries reported with pain and periapical rarefaction after 6 weeks. Marginal breakdown of the restoration was observed in the proximal aspect. Clinical and radiographic observation indicated an early failure of the treatment. Preoperative pain correlates with the degree of pulp inflammation and its potential to resolve, therefore considered to be a potential predictor of early failure in pulpotomy [24]. Consistent pulpal response to two vitality tests pointing to symptomatic irreversible pulpitis with mild to moderate pain (VAS < 6) was included in the present study. Despite the preoperative pain score being 4, the patient showed early failure. The probable reason could be attributed to the extent of caries buccolingually as well as gingivally. Careful selection of cases should be considered for pulpotomy. An interesting feature noted during endodontic treatment was that the orifices of the mesiobuccal, mesiolingual canals were obliterated showing evidence of tertiary dentinogenesis.
Traditionally, calcium hydroxide has been the most popular pulp-capping agent due to its antimicrobial properties and ability to form a hard tissue barrier. However, concerns such as high solubility, low mechanical resistance, and the presence of tunnel defects in the mineralized barrier have been reported, particularly for vital pulp therapy procedures. Tricalcium silicate-based materials like MTA have now become the preferred choice for pulpotomy because of their biocompatibility, reduced microleakage, ability to induce a thicker dentinal bridge with fewer defects, and capacity to release growth factors from dentin. Despite its advantages, MTA has some drawbacks, including the potential to discolor teeth and high solubility due to its slow setting reaction. To address these issues, other bioceramic materials like Biodentine and calcium-enriched mixture have been introduced. Unlike MTA, Biodentine has been shown to cause less tooth discoloration [25]. Clinical performance of these materials for pulpotomy is comparable with success rates ranging from 87% to 93% [26]. In the present case series, Biodentine was layered directly on the CGF membrane considering its rapid setting even in moisture and better handling properties. The limitation of the case portfolio is that only six cases are documented. In the future long-term trials with large sample sizes are required to assess the regenerative potential in inflammatory microenvironments are required to validate the use of scaffold as a capping agent for vital pulp therapy.
CONCLUSIONS
The outcome of the portfolio concludes that pulpotomy is considered an alternative treatment modality for root canal treatment in symptomatic irreversible pulpitis aiming at alleviating symptoms and maintaining vitality. Scaffold-based pulpotomy may be a biological approach to healing inflamed pulp compared to conventional pulpotomy which only aims at relieving signs and symptoms. CGF additionally may serve as an anti-inflammatory and growth factor reservoir during the healing phase, unlike the use of only calcium silicate cement. However, the limitations of a case series are the restricted number of cases observed, thus, well-designed clinical trials with longer follow-ups are required to generate high-quality evidence for the use of CGF as a scaffold in pulpotomy in irreversible pulpitis.
Notes
CONFLICT OF INTEREST
No potential conflict of interest relevant to this article was reported.
FUNDING/SUPPORT
None.
AUTHOR CONTRIBUTIONS
Conceptualization, Formal Analysis, Data curation, Visualization: Nandini S. Methodology, Investigation: Harith AK. Validation: Koteeswaran V. Resources: Velmurugan N, Harith AK. Supervision, Project Administration: Kowsky D. Funding acquisition: Natanasabapathy V. Writing - original draft: Koteeswaran V. Writing - review & editing: Nandini S, Koteeswaran V. All authors read and approved the final manuscript.
DATA SHARING STATEMENT
The datasets are not publicly available but are available from the corresponding author upon reasonable request.