A case report on endodontic management of the rarest Vertucci's Type VIII configuration in maxillary second molar with three mesiobuccal canals.

Anatomic variations in mesiobuccal root (MBR) of maxillary molars are common. This variation is found to be more common in maxillary first molars as compared to second molars. However, finding three independent mesiobuccal (MB) canals in the MBR of maxillary molars is clinically a rare entity. With the use of magnification, illumination, and cone-beam computed tomography, combined with the skill of the operator, there is an increased possibility of detecting such additional canals. The present case report describes the successful clinical management of a second molar in a 58-year-old female patient having three MBR canals (MB1, MB2, and MB3) with a Vertucci's Type VIII canal configuration and an almost obliterated pulp chamber. The canals were prepared using hand and rotary instruments, followed by obturation. Very few such cases have been documented clinically in the literature. Copyright:

INTRODUCTION

For a successful root canal therapy, complete debridement of the canal system is a prime necessity. Sound knowledge of the internal anatomy of the teeth and its possible anatomic variations is essential to perform a successful treatment. Posttreatment disease can occur when additional canals or anatomic variations are overlooked.[1] It is said that, “you can only treat what you can see,” hence magnification plays an important role and should be incorporated in routine endodontic cases for a better outcome.[2]

A substantial amount of literature exists on second mesiobuccal (MB) canals in first and second maxillary molars.[34] However, existence of three canals in the MB root (MBR) is rare, reporting an incidence of 0.6%–4.2% clinically.[56] Clinically, a third MB canal was first reported by Martínez-Berná and Ruiz-Badanelli in the maxillary first molar.[7] Ozcan et al. reported a third MB canal in the maxillary second molar with a 3-2 canal configuration.[8] This rare case report depicts the presence of a third MB canal (MB3) in a maxillary second molar, with a Vertucci's Type VIII canal configuration, i.e., three independent canals. To the best of our knowledge, this canal configuration in maxillary second molars has not been reported clinically till date.

CASE REPORT

A 58-year-old Indian female patient reported to the Department of Conservative Dentistry and Endodontics with pain in her upper left maxillary region, which was continuous in nature and aggravated on intake of hot food. The patient's medical history was noncontributory. Clinically, the left maxillary second molar had a deep carious lesion mesio-occlusally. The tooth was tender on percussion. Overlying soft tissues were normal. Periodontal probing around the tooth showed a normal sulcular depth with the absence of pockets and pathologic mobility. Cold test (Endo-Frost, Coltene, Switzerland) and electric pulpal testing showed a delayed response suggesting irreversible pulp damage. The preoperative intraoral periapical radiograph revealed a mesio-occlusal radiolucency approaching the pulp space with a widened periodontal space around the apex of tooth 27 [Figure 1a]. Hence, a diagnosis of symptomatic irreversible pulpitis with symptomatic apical periodontitis was made.

Figure 1

(a) Preoperative radiograph of tooth 27. (b) Intraoral image – occlusal view of access opening illustrating first, second, and third mesiobuccal, distobuccal, and palatal canal orifices (c) and (d) Working length radiographs showing mesiobuccal 1, mesiobuccal 2, mesiobuccal 3, and mesiobuccal 1, distobuccal, and palatal canals. (e) Postobturation radiograph showing all three mesiobuccal canals. (f) Follow-up radiograph at 6 months showing normal periapical structure

After clinical and radiographic examination, nonsurgical endodontic treatment was planned for tooth 27. Informed consent was taken from the patient. The patient was then administered with 2% lidocaine with 1:80,000 epinephrine (La-Force, Vishal, India) to achieve local anesthesia. Rubber dam isolation was done and access opening was made using Endo Access Bur (Dentsply Sirona, UK). On clinical evaluation of the pulp chamber, three principal root canal orifices were located: MB, distobuccal (DB), and palatal (P). The calcification in the pulp chamber was scraped using an ultrasonic tip (E7D, Helse Ultrasonics, USA). Two small hemorrhagic points were noted in a line connecting the MB orifice to the palatal orifice. Hence, a DG-16 explorer (Dentsply Sirona, UK) was used to confirm the presence of additional canals (MB2 and MB3) [Figure 1b]. The entire procedure was done under ×3.0 magnification using dental loupes (TTL, ×3 magnification) (Zumax, China).

The working lengths of all five canals were estimated by means of an electronic apex locator (J Morita Root ZX II, USA) and were found to be 17 mm in MB1, MB2, and MB3; 18 mm in DB; and 20.5 mm in P canal, respectively, which was then confirmed radiographically using different angulations [Figure 1c and d]. A limited volume FOV (5 cm × 5 cm) cone-beam computed tomography (CBCT) (Carestream CS9300, 85 kV, 8 mA, 19.96 s with a slice thickness of 90 microns) was done to confirm the existence of three individual canals in the MBR showing a Vertucci's Type VIII root canal configuration [Figure 2]. Glide path was prepared up to a size 20, 0.02 taper, in all five canals using stainless steel hand K-files (Mani, Japan), followed by rotary instrumentation with NiTi HyFlex CM files (Coltene, Switzerland) to a size of 25, 0.04 taper. The canals were irrigated with one milliliter of 2.5% sodium hypochlorite (NaOCl) (Prime Dental Pvt Ltd, Maharashtra, India) per canal per instrument change. An Endoactivator tip (Dentsply Sirona, UK) was selected that fit loosely within 2 mm of working length and was activated, using a pumping motion in short 2-mm strokes for 1 min. Normal saline was used to flush out the NaOCl, following which 17% ethylenediaminetetraacetic acid (Prevest Denpro, Jammu, India) was used for smear layer removal. A 30-gauge open-ended needle was used for irrigation, slightly short of the working length, such that it did not bind in the canal. Irrigants were then activated by an Endoactivator. The canals were dried with paper points. Since all three MB canals had a separate portal of exit, cone fit was checked for apical tug back to the respective working lengths. All the canal walls were then coated with AH Plus sealer (Dentsply Sirona, UK) and obturated using a single-cone technique with the Gutta-Percha of corresponding sizes of the rotary files used [Figure 1e]. The access cavity was restored with miracle mix in the same visit and occlusion was checked. On follow-up visit, crown was given.

Figure 2

A cone-beam computed tomographic scan displaying Vertucci's Type VIII root canal configuration in the mesiobuccal root of tooth 27 – axial sections (a) cervical third, (b) middle third, (c) apical third; coronal sections (d) three mesiobuccal canals, (e) Three portals of exit seen at the apex of mesiobuccal root

At 6-month follow-up, radiographic examination revealed a continuous periodontal ligament with no signs of apical periodontitis and the patient was completely asymptomatic [Figure 1f].

DISCUSSION

The complexity of root canal systems, especially in MBR of maxillary molars, is a challenge to the endodontist. Anatomically, the openings of canals situated palatal to the MB canal are difficult to locate because of their smaller size. As explained by Eskoz et al.,[9] initially the canal in the MBR is the shape of a kidney bean. As the deposition of secondary dentin continues, the isthmus between the poles becomes narrower and eventually close, leaving a small space. Multiple canals thus formed, are more difficult to locate.[10]

Careful examination of the preoperative radiographs as well as taking working length with different horizontal angulations leads to decreased chances of missing additional canals. However, due to the small size of MB2 and MB3 or due to the superimposition of the main MB canal, they tend to be missed frequently. With the help of advanced visual aids such as loupes and advanced radiographic techniques such as CBCT, the presence of such canals can be confirmed and the canal configurations can be determined. However, limited volume CBCT should be preferred for endodontic use to avoid exposure to higher radiation doses.[1112]

The patient's age is an important preoperative predictor for the detection of extra canals in maxillary molars.[5] With age, root canals or their orifices may calcify, making the detection of extra canals more difficult. Majority of the case reports documented about the presence of three MB canals in maxillary second molar, were of patients younger than 40 years.[5810131415] As in contrast to the age statistics, in this case, MB3 was found in the tooth of a patient aged 58 years where the chances of calcification are high and difficulty to locate such additional canals is more. Furthermore, such canals are reported more in males in contrast to the present case.[5]

In vitro studies using clearing, exploring, CBCT, or micro-CT, reported three-canaled MBRs to occur in 0.6%–4.2% in maxillary second molars, out of which the in vitro study done in Indian population using CBCT, reported an incidence of 0.9%[5] Ex vivo studies using micro-CT imaging systems reported a higher percentage frequency of MB3 canals in maxillary second molars (0.8%–7.1%),[16] when compared to studies using the CBCT method (0.2%–1.8%)[516] or using magnification and ultrasonics (1.82%).[17] Clinically, only five such case reports have been published till date, with MB3 in maxillary second molars.[5810131415]

In the former case reports published, Type 3-2 was the predominant configuration reported.[58131415] In another case report by Arora et al., a 3-2-1 canal configuration was found in the maxillary second molar of a female patient of Indian origin.[10] Additionally, in an in vivo CBCT study in a Spanish population, Vertucci's Type VIII configuration (3-3) was found only in 0.9% of maxillary second molars.[18] Although such a canal configuration has been reported in maxillary first molars in various populations, it has not yet been reported clinically in maxillary second molars in any population.[5] In the present case report, Vertucci's Type VIII canal configuration was confirmed by CBCT wherein three canal orifices were seen ending apically as different portals of exit, i.e., 3-3 canal configuration.

In the present case report, CBCT was used to measure distances between MB1, MB2, MB3, and P canals. The additional MB canals were located mesial to an imaginary line connecting MB1 to P. MB1 was 0.5 mm from MB2 canal, and MB2 was 0.5 mm from MB3 canal, while MB3 was 1.7 mm away from P canal. In a former case report, MB2 was found approximately 2 mm from the MB1 orifice, in a palatal direction. MB3 was located with the aid of explorer, approximately, 2 mm from the palatal root canal in the same line.[7] In another case report, MB2 was located palatally, approximately 1 mm away from the MB1 canal orifice, and MB3 was located palatally approximately 1 mm away from the MB2 canal orifice. These three MBR canals were located on the same line.[8] Similarly, Gusiyska found MB2 orifice nearly 1 mm on the imaginary line between the MB1 and P orifice, while MB3 orifice was located approximately 1.5 mm in palatal direction.[13] Hence, as reported in the former case reports, the three root canals are usually located on a straight line, and the distance between their orifices ranges from 1 to 2 mm. However, none of these case reports used CBCT as a diagnostic tool.[7813] Such a complex root canal system of the MBR possesses a constant challenge for every clinician during root canal treatment. Therefore, one should use all the available tools to find and treat all canals to ensure a successful treatment outcome. Proper design of access cavity to visualize the entire pulp chamber floor and to establish straight-line access to canal orifices, is of utmost importance. Thus, when extra canals in the MBR are suspected, the access opening is extended on the mesial side to have a trapezoidal rather than a triangular shape. The “road map” of the pulpal floor should be followed to locate extra canals. This can be done by exploring the floor with a DG-16 explorer, troughing with ultrasonic tips, staining the pulpal floor with a dye, performing the champagne test with sodium hypochlorite, and visualizing canal bleeding points.[18] Magnifying tools such as loupes or a dental operating microscope enhance the vision in the operating field and thus increase the probability of locating extra canals compared with the naked eye.[18]

Over-enlargement of the additional canals should be avoided, especially in the coronal two-thirds of the root, to prevent strip perforation as well as to conserve the pericervical dentin.[19] Hence, smaller taper files are preferred, when additional canals are present. Additionally, narrow canal spaces and isthmi between them still pose a problem in regard to disinfection. Hence, an Endoactivator was used, to ensure adequate disinfection, before obturation. Sealing all the apical foramina of the tooth leads to the success of nonsurgical treatment. Hence, when three separate root canals were present, each canal was debrided and obturated up to its apical end.

Above all, the experience, skill, and knowledge of the tooth anatomy of the operator plays a major role in the detection and management of extra canals.

CONCLUSION

The present case reports one of the very rare clinical cases of maxillary second molars having three independent MB canals and its successful management in an aged female patient, where otherwise calcified canals are expected. Such anatomic variations are identified with the use of magnification devices and studying the dentinal map well.

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

Nil.

Conflicts of interest

There are no conflicts of interest.