Endodontic Management of Malpositioned Canine with Two Canals and Subgingival Caries

Introduction

The root canal procedure aims to eliminate the existing infection and prevent reinfection of the tooth.¹ It involves debriding the canals thoroughly and providing a three-dimensional coronal and apical seal. Morphological features of the tooth can adversely affect the endodontic procedures and their treatment outcome.² Most clinicians have the perception that a specific tooth will have a specific number of roots and/ or root canals. However, it is common to find variations intooth morphology. Usually, the mandibular canine exhibits one root and one root canal.³ Investigation reports published by various authors emphasized the variations in canal anatomy associated with mandibular canines.^4,5 According to Vertucci, approximately 15% of mandibular canines present with two canals having one or two foramina, of which 14% exhibit Vertucci’s type 2 canal configuration.⁶ The mandibular canine is considered a strategically important tooth in the dental arch. It plays a vital role in guiding the occlusion during eccentric movements and disocclusion of posterior teeth.⁷ The dentogingival complex is important for maintaining the periodontal health of the tooth.⁸ This complex can be altered or damaged by invading caries, fractures, etc leading to soft tissue inflammation and localized bone loss.⁹ Thus, one of the keys to the longevity of teeth and dental restoration is to maintain gingival health.

Case presentation

A 47-year-old female visited the Department of Conservative Dentistry and Endodontics at RV Dental College with the chief complaint of pain occurring in her lower right canine region. The patient started experiencing pain about 2 weeks ago. It was moderate in intensity, intermittent in nature, and aggravated on mastication. The patient’s medical history was noncontributory. On intra-oral examination, there was the presence of caries on the distolabial aspect and blackish discoloration on the labial aspect of the crown of the lower right canine 43 (Figure 1). The tooth was tender to vertical percussion. The tooth exhibited Miller’s Grade 1 mobility. Pulp vitality testing was done using an electric pulp tester and heat test. Both the tests gave an exaggerated response in the form of lingering pain even after the removal of the stimulus. Extraoral findings were absent. Radiographic examination, OPG (Orthopantomogram) showed radiolucency on the distal aspect of tooth 43. Radiolucency involved enamel, dentin, and pulp and extended to the distal root portion. (Figure 2). Periapical radiolucency was noted wrt tooth 43. Based on the patient’s symptoms, clinical and radiographic examinations, the pulpal diagnosis (according to the American Association of Endodontists) was given as symptomatic irreversible pulpitis and the periapical diagnosis was symptomatic apical periodontitis.

It was decided to treat the tooth by performing nonsurgical root canal treatment and then restore the subgingival cavity with a surgical approach. The treatment plan was explained to the patient and the treatment was started after obtaining written informed consent from the patient. 2% lignocaine hydrochloride with 1:80,000 adrenaline was used to achieve local anesthesia through the inferior alveolar nerve block technique. The tooth to be treated was isolated using a rubber dam. A number 2 round bur was used to excavate caries from the labial and proximal aspect of the crown. At this moment only the supragingival caries was excavated (Figure 3). Access to the canal orifice was gained through the incisal aspect. (Figure 4). The canal orifice was located using an endodontic explorer. A number 10 hand K file (Mani) was used to negotiate the canal and obtain patency. After proper shade selection, the canal was blocked using the number 15 hand K file and the supragingival excavated cavity was restored using composite resin cement. Working length was obtained using the conventional radiographic method. On viewing the working length, the radiograph taken from mesial angulation, a second canal was identified (Figure 5). The access cavity was redefined using Gates Glidden drill and an attempt was made to locate this canal orifice using DG 16 explorer. Precurving number 8 hand K file helped to negotiate the lingual canal. Another radiograph was taken to confirm the location and record the working length of this canal [using the sameside lingual opposite side buccal( SLOB) technique ] (Figure 6). The tooth exhibited Vertucci’s type 2 canal anatomy. Cleaning and shaping of root canals were performed using NiTi rotary files up to 30.06 tapers for the buccal canal and 25.04 tapers for the lingual canal. During the cleaning and shaping procedure, canals were irrigated continuously with 3% sodium hypochlorite and 17% EDTA. Final irrigation was done using saline. The canals were dried thoroughly with sterile paper points. After confirming the master apical cone radiograph, the canals were obturated with corresponding gutta-percha cones and sealapex sealer (Kerr). The immediate postoperative radiograph of tooth 43 is shown in Figure 7.

After completing the endodontic therapy, the patient was prepared for the surgical procedure. The patient was given betadine to rinse her mouth. After giving local infiltration around tooth 43, an envelop flap was planned to get access to subgingival caries. Sulcular and interdental incisions were placed using a No 15 BP blade from the mesial side of 44 to the distal side of 42 and a full thickness mucoperiosteal flap was raised. After reflection of the flap, all the subgingival caries were excavated with a high-speed handpiece and round bur, and all inflamed gingival tissue was curetted. Hemorrhage was controlled by applying pressure and the cavity was irrigated with 2% chlorhexidine solution and saline. The flap was repositioned below the cervical region and was approximated by 2 interrupted sutures (figure 8). The subgingival cavity was dried thoroughly and filled with light cure Glass Ionomer cement. It was contoured using a metal matrix band and the restoration was finished using finishing bur. The access cavity was also filled with light cure glassionomer cement (GIC).

Postoperative instructions were given to the patient and antibiotics were prescribed. The patient was recalled after one week for follow-up. The restoration was polished using the GIC polishing kit (Shofu international, Japan). radiovisography (RVG) was taken (Figure 9). Sutures were removed. The healing of the patient’s tooth was satisfactory. A 4-month follow-up showed an absence of symptoms, and healing of gingival tissues with restoration intact. Clinical and radiographic pictures of 4-month follow-up are shown in figures 10 and 11, respectively.

Discussion

This case report describes the case of a mandibular canine affected by subgingival caries. Restoring subgingival preparations can be challenging to the clinician as access to the lesion is often compromised. Retention is also compromised because of the lack of the box form of the cavity into which the restorative material can be condensed. Achieving isolation of the subgingival cavity using a rubber dam can also be difficult.¹⁰ Hence, in this case after the completion of root canal treatment a surgical approach was attempted to excavate the carious lesions and restore the defect. The labial surface of the crown of the tooth was compromised with caries and the lingual surface was intact, unaffected by caries. Hence, to conserve the remaining tooth structure, it was decided to gain access to the canal orifice from the incisal aspect. Resin Modified Glass Ionomer Cement (RMGIC) was used to restore the cavity. The advantages of using RMGIC are that it is biocompatible with minimum gingival inflammation, allows a controlled setting of cement with a light cure to protect it from contamination as well as releases fluoride for at least 18 months.¹¹ Gultz and Scherer¹² described the subgingival placement of resin glass ionomer cement in various restorative processes. Paolantonio et al also used glass ionomer cement in subgingival restorations and reported satisfactory results.¹³

On 4 months recall, the patient was asymptomatic with decreased mobility of tooth and decreased periapical radiolucency on the radiograph. Hence, the tooth was successfully treated endodontically and with minimum surgical intervention to restore the subgingival carious lesion.

The simultaneous application of endodontic, surgical, and restorative procedures seems a promising approach aimed to reduce the treatment time and diminish patient discomfort.

Conflicts of Interest

None