Endodontic management of an atypical permanent mandibular second molar with one buccal and two lingual roots.

This article describes an unusual location of the orifices and roots in a permanent mandibular second molar with symptomatic irreversible pulpitis and symptomatic apical periodontitis. During its micro-endodontic management, the cone-beam computed tomography evaluation revealed a rare variant of a three-rooted permanent mandibular second molar with four canals. The single buccal root had two canals with Vertucci's Type II pattern and a lingual root dividing into two with a single canal in each root, respectively. Interestingly, the concerned tooth had normal occlusal morphology and alignment in the arch. A follow-up of 9 months after the completion of endodontic therapy exhibited satisfactory clinical and radiographic findings. Copyright:

INTRODUCTION

Permanent mandibular molars have a wide variety of variations in the number of roots and canal configurations. Permanent mandibular second molars generally have two roots mesiodistally, with two canals in the mesial root and one canal in the distal root. Cases with reverse anatomy in the permanent mandibular second molars, one mesial and two distal canals, are also reported.[12] Reports confirm the presence of three rooted permanent mandibular second molars.[3] Based on ethnicity, the prevalence of three rooted permanent mandibular molars varies in different populations. It is 1.78% in the Israeli, 3.5% in the Brazilian, 1.2% in the Thai, and 7.53% to 8.98% in the Indian population.[45678] Three rooted variants of permanent mandibular second molars usually have the extra root either in the distolingual (DL) (Radix entomolaris) or mesiobuccal (MB) direction (Radix paramolaris). Evidence suggests that magnification and cone-beam computed tomography (CBCT) enhance the detection of extra roots and canals, especially in molar endodontics.[910]

This case report addresses a rare variation of a three rooted permanent mandibular second molar with two buccal and two lingual canals. After an extensive literature review involving the permanent mandibular second molars, the authors could not find any reports with a similar type of variation.

CASE REPORT

A 56-year-old Indian female patient complained of pain and sensitivity in her lower left second last tooth region while eating. The pain was severe and persisted for a few minutes after taking food. A few days later, there was spontaneous pain radiating toward the lower jaw and left ear. She took analgesics to relieve the pain. A clinical examination revealed distal caries on the left permanent mandibular second molar (tooth #37) with normal occlusal anatomy [Figure 1a and b]. Cold testing (Roeko Endo Frost, Coltene/Whaledent Inc., OH, USA) elicited delayed response in tooth #37 compared to two adjacent teeth, and it was tender on percussion. An intraoral periapical radiograph [Figure 1c] revealed distal caries approximating the pulp and a slight increase in the width of periodontal ligament space around the distal root of tooth #37. A careful examination of the radiograph suggested three canals with an extralingual root. A diagnosis of symptomatic irreversible pulpitis with symptomatic apical periodontitis was established, and a nonsurgical root canal treatment was planned. After obtaining informed consent, the procedure was initiated in the same visit.

Figure 1

Clinical photographs and radiographs of tooth #37 (a and b) preoperative photographs. (c) Preoperative radiograph of tooth #37. (d) Access showing two buccal canal orifices and one lingual orifice. (e) Working length radiograph. (f) Magnified view of the access opening showing two buccal canals. (g) Magnified view of the access opening showing one lingual canal splitting into two lingual canals (black arrows). (h) Master cone radiograph. (i and j) Postobturation radiographs at different angulations. (k) Radiograph after 9 months follow-up

Local anesthesia was administered using 2% lidocaine hydrochloride with adrenaline 1:80,000 (Lignospan Special; Septodont, France), and a dental dam was applied. After distal caries removal and a preendodontic build-up, the access cavity revealed three orifices on the pulp chamber floor. Two orifices were located buccally and one lingually [Figure 1d]. After the initial orifice enlargement and pulpectomy for the symptomatic relief, the tooth was temporized. A limited field of view (FOV) CBCT was advised, considering the atypical anatomy of the concerned tooth.

CBCT report (FOV 5 cm × 5 cm, Carestream CS9300, Carestream Health, Inc New York) revealed unusual cross-sections in the root's coronal, middle, and apical thirds [Figure 2]. The coronal third exhibited the presence of three bulky root outlines. Two fused roots were evident in the buccal aspect, with two canals and one root in the lingual portion [Figure 2a]. In the middle third, the buccal root showed two canals, the MB and the distobuccal (DB). The lingual root is split into mesiolingual (ML) and DL, with a single canal in each root. The ML and the DL roots diverged toward the mesial and distal directions, respectively [Figure 2b-d]. In the apical one-third, serial axial sections revealed three roots and four canals with significant distance between the lingual roots [Figure 2e-i]. CBCT findings suggested that the two buccal canals, MB and DB, merged in the apical one-third with one apical exit. The buccal canals exhibited Vertucci's Type II pattern. The canals were negotiated using a 10 K-file and established patency in all the canals with this anatomical background. The working length was calculated using an electronic apex locator (Canal Pro, Coltene/Whaledent, GmbH + Co. KG, Germany) and confirmed radiographically [Figure 1e]. Shaping of the canals accomplished to sizes 25/06 (Coltene Hyflex CM, Coltene/Whaledent Inc., OH, USA) for the MB and DB canals, 25/04 for the DB and DL canals under copious irrigation with 5.25% sodium hypochlorite [Figure 1f and g]. After the cone fit radiograph [Figure 1h], sonic activation (Endoactivator, Dentsply Maillefer, Ballaigues Switzerland) of sodium hypochlorite was performed, followed by 17% ethylenediaminetetraacetic acid for 1 min per canal.[11] The canals were flushed with saline and dried using paper points. A warm vertical compaction technique of obturation (Elements, Sybron Endo, Glendora, CA) with AH Plus sealer (Dentsply, DeTrey, GmbH, Germany) was employed. After the composite resin restoration of the tooth, a postobturation radiograph revealed satisfactory obturation of all the canals, including the apical split in the DB root [Figure 1i and j]. A 9 month follow-up demonstrated satisfactory radiographic findings after providing a full-coverage metal crown [Figure 1k].

Figure 2

Cone-beam computed tomography images of the left mandibular arch showing serial axial sections (a) in the coronal third, (b-d) middle third, (e-i) the apical third of tooth #37 (White arrows →)-Buccal root of tooth #37 (White stars*)-Lingual roots of tooth #37

DISCUSSION

A careful evaluation of preoperative radiographs plays a vital role in managing cases with unusual canal configurations. In the present case, the root anatomy and outlines were not very clear in the preoperative radiographs, suggesting some unusual root patterns. Therefore, a preoperative or intraoperative CBCT evaluation is quite helpful in such situations.[12]

The floor of the chamber gives essential information about the pattern of the orifices. A clinician should try to be patient and follow the dentinal map.[13] Magnification can play a pivotal role at this step. Clinical examination under the operating microscope revealed two buccal canals and one lingual canal with a bifurcation in the middle third. CBCT evaluation confirmed the presence of three roots and four canals in the middle and apical third. The prevalence of three roots in permanent mandibular second molars is relatively higher in Indians than in other ethnic groups.[45678] The prevalence of four canals in permanent mandibular second molars is around 17.29% in the Indian population.[8] It is significantly higher than the Chinese and the white American populations, 1% and 5%, respectively.[1415]

This case report highlights a unique variation in a three rooted permanent mandibular second molar with two buccal and two lingual canals. The above-mentioned unusual pattern of the orifices at the pulp chamber floor and the roots suggest that the tooth may be rotated or has abnormal occlusal anatomy. However, there was no malalignment in the arch, and the tooth had normal occlusal morphology [Figure 1a and b]. Therefore, there may probably be some rotation of the entire root complex during the formative stages. As most of the three rooted mandibular second molars are usually radix entomolaris, this case may be considered a rare variant of radix entomolaris but with the rotation of the entire root complex.

CONCLUSION

The present case report highlights a rare variation in a three rooted permanent mandibular second molar with two buccal and two lingual canals. Furthermore, it emphasizes the integrated use of CBCT and magnification for the successful management of such cases.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understand that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.