Perforating Internal Root Resorption Sealed with Single-Cone Technique Using Bioceramic Sealer: A Case Report

Introduction

Internal root resorption (IRR) is a rare dental condition in which the dentin within the root canal space is progressively resorbed due to inflammation within the pulp tissue. The exact cause of internal root resorption is not well understood. However, it is believed to occur due to infection, traumatic injury, or orthodontic treatment that damages the predentin and odontoblast layer. This damage exposes the mineralized dentin to clastic cells, leading to IRR, which can also progress and cause perforation [1,2].

Early detection and management of IRR are important to prevent further destruction of the tooth structure and to ensure a better prognosis [3]. The clinical manifestation of internal root resorption is typically asymptomatic and is frequently detected incidentally during routine radiographic examinations. It can be challenging to distinguish between IRR and external cervical resorption (ECR) based on their similar characteristics, which can create difficulties in two-dimensional radiograph analysis [4,5].

Once internal resorption advances to the stage where it breaches the external root surface, it creates a pathway between the root canal system and the periodontal ligament space. This perforation can result in deterioration of nearby periodontal tissues. In such instances, it is important to conduct root canal therapy to kill bacteria and eliminate resorption. This should be followed by repairing the perforation site to prevent further damage to the periodontal tissues, sealing the area, and facilitating healing [6].

In perforated IRR, it is difficult to adequately fill the hard tissue defects caused by the resorptive process. Several root-filling materials are available and suggested for such cases [7–9]. Tricalcium silicate-based cements, such as mineral trioxide aggregate (MTA), have become increasingly popular due to their biocompatibility and sealing ability; however, they have poor flow properties [8,10]. Recently, bioceramic sealers have been used as a filler during root canal obturation by using a single-cone technique instead of cold lateral compaction and thermoplastic techniques using gutta-percha (GP) and traditional sealers such as epoxy resin-based sealer, which are often criticized for being non-biocompatible [11,12]. The flowability of the bioceramic sealers are similar to that of epoxy resin-based sealers; however, bioceramic sealers are preferred due to their superior biocompatibility [13]. Hence, to compensate for the low flowability of MTA and for the lower biocompatibility of thermoplastic GP and traditional sealers, we used a bioceramic sealer to fill in the resorptive defects and the root canal instead of tricalcium silicate-based cements or thermoplastic GP and traditional sealers.

Case Report

CLINICAL MANAGEMENT:

During the first visit, buccal and palatal infiltration with a local anesthetic solution (1 carpule of 2% Mepivacaine with 1: 100 000 epinephrine) was given. Ensuring the patient’s comfort and cooperation is essential for successful treatment, and the use of local anesthesia was necessary to manage any discomfort associated with the clamps. After the rubber dam was placed and disinfected with 5.25% sodium hypochlorite (NaOCl) (Diaa Dental Products, Saudi Arabia), an access cavity was created and the orifice was detected. Working length was determined using a Root ZX dental apex locator (J. Morita, Japan) and confirmed by radiograph. The canal was cleaned and shaped using X1 and X2 ProTaper Next rotary files (Dentsply Sirona, Charlotte, North Carolina, United States). During and after canal shaping, 2 mL of 2.5% NaOCl (Diaa Dental Products, Saudi Arabia) was delivered into the root canal, and the activation device was engaged for 20 seconds to agitate the solution using a Dental Ultra X Ultrasonic irrigation activator (Eighteeth, Changzhou, China). This cycle was repeated 3 times, after which a thorough rinse with saline was performed. Final irrigation was conducted with 17% EDTA (Diaa Dental Products, Saudi Arabia) to chelate any remaining debris. The canal was dried using paper points, and then calcium hydroxide (Ca(OH)2) (Metapaste, META BIOMED, Republic of Korea) was applied as an intracanal medication.

On the second visit, after 1 week, the Ca(OH)2 (Metapaste, META BIOMED, Republic of Korea) was removed by using ultrasonic agitation of a 17% EDTA irrigation solution (Diaa Dental Products, Saudi Arabia). Finally, the apical part of the canal was shaped using an X3 ProTaper Next rotary file (Dentsply Sirona, Charlotte, North Carolina, United States). In this case, given that the initial file size was size #8 and the apical region was almost calcified, an apical preparation size of #30 (X3) with a taper of 0.07 is sufficient for achieving the treatment goals and optimal for preserving tooth structure and preventing unnecessary dentin removal [15]. After drying the canal, the single-cone technique was used to obturate the canal. Bio-C root canal sealer (Angelus, Brazil) was injected into the coronal and middle third of the canal, followed by the insertion of a Protaper Next GP matching cone (X3) to the full working length. The cone was then removed, additional sealer was injected, and the GP cone was placed again. Finally, the cone was seared off using a heated plugger. A Coronal double seal with Cavit and glass ionomer restoration was placed (Figure 3), and the patient was referred for a final permanent restoration. Upon conducting a 1-year and 2-year follow-up clinical examination, it was found that the patient remained asymptomatic, reporting no discomfort or tenderness related to the area affected during this period. The absence of any clinical signs of inflammation or complicating symptoms reinforced the positive outcome of the treatment. Subsequent radiographic examination with CBCT demonstrated an absence of radiolucencies, indicating the presence of sound bone and periodontal tissue (Figure 4). The patient gave informed consent for the publication of this case report and its accompanying images. The patient was informed about the nature of the report and the intended use of the clinical information, and anonymity was ensured. The patient had the right to withdraw consent at any time.

Discussion

This case report presents perforating IRR in tooth number #12 for a 45-year-old female patient, characterized by a radiolucent lesion diagnosed using both periapical radiographs and cone-beam computed tomography (CBCT). Unlike previously reported cases, the management of this case involved the innovative use of bioceramic sealers for obturation, which is particularly noteworthy given that the application of these sealers in resorptive defects has not been extensively documented in existing literature. The positive clinical outcome, indicated by the absence of symptoms and radiographic evidence of sound bone and periodontal tissue over the follow-up period, underscores the potential of these sealers in managing complex endodontic cases involving perforating IRR.

Initiation of IRR occurs when the odontoblast layer and predentin are damaged. However, its progression depends on the bacterial stimulation of clastic cells (without this stimulation, the process is self-limiting) and on the viable blood supply presented in the apical pulp tissue, which is necessary to provide clastic cells and nutrients [16]. When necrosis begins, it usually only affects the part of the root canal coronal to the IRR, while the apical parts remain healthy. Apical periodontitis is initiated when necrosis and bacteria reach the apical part [17]. In the present case, there were no signs or symptoms of apical periodontitis. Therefore, I speculated that the apical part was still vital or sterile, so the periapical diagnosis was considered normal, while the pulpal diagnosis was necrosis.

In most cases, IRR is symptom-free, which makes early detection a matter of luck [18]. This was exactly the scenario in the reported case where the patient had attended a routine dental check-up, during which the referring dentist conducted a radiographic examination. This imaging revealed an unexpected circular radiolucent area in the central portion of the root canal. Consequently, the dentist referred the patient to me for further evaluation and consultation. Conventional imaging has limitations that can lead to misdiagnosis [19]. For an accurate diagnosis in the present case, a CBCT was taken along with a periapical radiograph. CBCT has emerged as a superior diagnostic tool for IRR management, providing detailed information about lesion position, extent, dimensions, and potential perforations. It also effectively differentiates between ER and IRR, eliminating diagnostic uncertainties associated with conventional radiography [14].

The selection of methods and instruments for root canal cleaning and shaping in this case was influenced by multiple considerations. Root canal morphology can make it challenging to remove bacteria and biofilms with standard endodontic instruments and irrigants [20,21]. Adding ultrasonic instruments to activate irrigants can improve debris removal [22]. However, microbes can still persist in confined areas even after chemomechanical debridement [21]. To further reduce bacterial load, an antibacterial medicament like calcium hydroxide is recommended. It has been shown to eradicate bacteria and enhance the effect of sodium hypochlorite in removing organic debris from the root canal system [23,24]. Therefore, it is advisable to use calcium hydroxide as an intracanal, antibacterial medicament alongside conventional root canal treatment.

One of the main goals of endodontic treatment is to fill the root canal space with suitable material that prevents leakage into the root canal. In IRR cases, filling resorptive defects adequately is challenging. The root-filling material must be flowable. Studies found that thermoplastic GP systems like Obtura II produce better fills in simulated resorptive cavities compared to other techniques. These systems also yield higher GP-to-sealer ratios, potentially reducing void formation and leakage risks [7]. However, it is important to note the inherent drawbacks of GP, including its lack of true adhesion to root canal walls and the tendency to shrink during cooling [25]. For cases with root wall perforations, tricalcium silicate-based cements are preferred due to their biocompatibility, superior sealing properties, and effectiveness in repairing perforations [26]. However, these materials have poorer flow properties than heated GP and require ultrasonic activation for effective dispersal [8]. Bioceramic sealers, used in conjunction with a single GP cone, have gained widespread acceptance in root canal obturation. This approach has demonstrated considerable clinical success, with a retrospective study reporting a 90.9% success rate after a 3-year observation period. Sealer extrusion, observed in nearly half the cases, did not impact treatment outcomes [12]. The implementation of a sealer-based obturation technique, which leverages the sealer’s capacity to function as a primary root canal filler together with its flowability and biocompatibility, has facilitated the obturation process in the present case, offering an effective solution to the challenges posed by perforated internal root resorption.

In comparing this case to the existing literature on perforating IRR, it becomes evident that the treatment choices and outcomes discussed here are quite different from traditional approaches. For instance, several studies have documented the use of conventional materials such as GP and epoxy resin-based sealers for obturation in IRR cases, often resulting in compromised adhesion and sealing ability [27,28]. Moreover, while previous research has reported successful treatment outcomes using continuous wave compaction methods that utilize GP cone with bioceramic sealer, voids were clearly observed in the radiographs of those cases [29]. This finding strengthens our case report, which demonstrated a successful use of bioceramic sealers with a single-cone GP, without the presence of voids. Conversely, an ex vivo study on extracted teeth indicated that the single-cone technique using a bioceramic sealer resulted in larger gaps at the sealer-dentin interface than the continuous wave compaction technique [30]. Although ex vivo studies have several limitations, the discrepancies between our case report and this study underscore the need for further robust evidence, such as randomized controlled trials, to better understand the effectiveness of varied obturation techniques in clinical practice.

Conclusions

In this case, the bioceramic sealer demonstrates significant potential for achieving thorough obturation and effectively filling resorptive defects and root wall perforations, owing to its biocompatibility and excellent sealing properties. However, as these conclusions originate from a single clinical case, it is imperative to conduct further randomized clinical trials and comparative studies with other sealing materials and long-term follow-up investigations to validate the efficacy and reliability of bioceramic sealers in sealing IRR with root canal wall perforations.