Endodontic management of maxillary first molar with unusual anatomy

Abstract

This article reports nonsurgical endodontic management of bilateral maxillary first molars with an unusual morphology of a single root and a Sert and Bayirli type-IX canal configuration. A 41-year-old female reported with dull continuous pain in the maxillary left and right quadrants. On clinical examination, the maxillary first molars on both sides were carious with pulpal exposure and radiographic evaluation revealed an unusual anatomy of single root and single canal for both of them. Based on clinical and radiographic examination, tooth numbers 16 and 26 were diagnosed with symptomatic irreversible pulpitis and symptomatic apical periodontitis. Root canal treatment was initiated and cone-beam computed tomography (CBCT) imaging was advised on encountering unusual internal anatomy. The CBCT images revealed the presence single root and a Sert and Bayirli type-IX canal configuration bilaterally. Root canal treatment was performed under magnification using the dental operating microscope.

INTRODUCTION

A thorough knowledge of root canal morphology is imperative for successful endodontic treatment. However, anatomical variations may complicate the treatment procedure.[1] Inability to detect and treat these complexities is the most common reason for failure of endodontic treatment.[2] Anatomical variations in maxillary first molars such as additional root, extra canals, apical ramifications, apical deltas, or lateral canals are commonly encountered and their incidence and significance have been well-documented.[1,2,3] The operator should also be aware of the possibility of the existence of fewer numbers of roots or canals than the normal root canal anatomy.[3]

Several authors have put forth various classification of root canal configurations. Vertucci's classification is a standardized method for categorizing known root canal anatomical variations. However, variations observed were wider than set 08 from Vertucci's. Hence, Sert and Bayirli reported additional 14 new canal configurations (Type IX–XXIII), taking Vertucci's classification as reference.[4]

Conventional intraoral periapical (IOPA) radiograph is routinely used diagnostic tool in endodontics for assessing the canal configuration. Nevertheless, it is not completely reliable as it produces a two-dimensional image of a three-dimensional object. Newer diagnostic methods such as cone-beam computed tomography (CBCT) and micro-CT overcome the disadvantages of these conventional radiographs by producing a three-dimensional image.[5,6] Micro-CT has a major disadvantage of not being suitable for clinical use, it can only be used in laboratory-based studies, whereas CBCT is appropriate for patient care.[6]

The present case reports the management of a single-rooted maxillary first molar with an unusual morphology of a single root and a Sert and Bayirli type-IX canal configuration bilaterally, which has not been reported in the literature and highlights the use of CBCT as a diagnostic tool to confirm the same.

CASE REPORT

A 41-year-old healthy female patient presented to the Department of Conservative Dentistry and Endodontics, Army College of Dental Sciences, Secunderabad, India, with the chief complaint of dull, continuous, and radiating pain which aggravates at night and by thermal stimuli in relation to the right and left upper back tooth region for 1 week.

Clinical examination revealed a deep carious lesion on the distal aspect of maxillary right first molar (tooth no. 16) and mesio-occlusal aspect of maxillary left first molar (tooth number 26). They were tender to percussion. There was no pain on palpation of the buccal and palatal aspects of the teeth. The mobility and periodontal probing all around the teeth were found to be well and within the physiological limits. Thermal testing of 16 and 26 with heat and cold elicited an intense lingering pain, and an electric pulp tester (Gentle Pulse Analog Pulp Tester, Parkell, Edgewood, NY, USA) gave a premature response.

A preoperative orthopantomography (OPG) [Figure 1a] and IOPA revealed mesio-occlusal radiolucency in tooth number 26 and distal radiolucency in tooth number 16 approaching the pulp space with periodontal ligament space widening and an unusual anatomic configuration of the root suggesting the presence of single root and single canal (type I Vertucci's canal configuration). From the clinical and radiographic findings, a diagnosis of symptomatic irreversible pulpitis with symptomatic apical periodontitis in relation to tooth numbers 16 and 26 was made and endodontic treatment was advised to the patient.

Figure 1.

(a) Preoperative OPG showing single root and single canal with respect to 16 and 26. (b) Three-dimensional CBCT image of tooth number 26 showing sagittal section. (c) Three-dimensional CBCT image of tooth number 16 showing sagittal section. (d) CBCT image of tooth numbers 16 and 26 showing the axial section. OPG: Orthopantomography, CBCT: Cone-beam computed tomography

To ascertain the three-dimensional anatomy of the tooth, a CBCT imaging (NewTom 5G, CEFLA S.C., Verona, Italy) of the maxillary arch was advised before initiating the endodontic treatment with the following parameters: 90 kV, 2.5 mA, 15 s Acquisition time, Flat panel sensor, 14 bits gray scale, 75 μm voxel size, and 1024 images were obtained with the X-ray tube without sacrificing image quality and following “as low as reasonably achievable.” The internal anatomy was studied in transverse, axial, and sagittal sections. CBCT images showed single root and root canal with trifurcation at the middle third of the 16 and 26 exiting as three separate canals presenting Sert and Bayirli type-IX canal configuration [Figure 1b-d].

The treatment protocol for both teeth was explained to the patient and informed consent was obtained. Tooth number 16 was anesthetized with 1.8 mL (30 mg) 2% lignocaine containing 1:80,000 epinephrine (Lignox 2% Adr injection, Indoco Remedies Ltd., Mumbai, Maharashtra, India) followed by rubber dam isolation. An endodontic access cavity was established using Endo Access 3 (Dentsply Maillefer, Tulsa, OK, USA) and Endo-Z bur (Dentsply Maillefer, Tulsa, OK, USA), under a dental operating microscope (DOM) (Prima; Labomed, Los Angeles, CA) [Figure 2b]. Three canal orifices were located deep into the pulp chamber. The canals were explored with number 10 K-file (Mani Inc., Japan), and working length was determined with the help of an electronic apex locator (Propex-II, Dentsply, Switzerland) later confirmed using radiographs at two angulations [Figure 2a].

Figure 2.

Tooth number 16 (a-d): (a). Working length confirmed through radiograph (b). Three canal orifices seen under a dental operating microscope, (c and d). Master cone radiograph and obturation, respectively. Tooth number 26 (e and f): (e). Working length confirmed through radiograph (f). Three canal orifices seen under a dental operating microscope, (g and h). Master cone radiograph and obturation, respectively. (i) Postoperative OPG. OPG: Orthopantomography

The glide path was established using the ProGlider file (Dentsply Maillefer, Ballaigues, VD, Switzerland). Cleaning and shaping were performed with single-file technique using WaveOne Gold primary file (Dentsply Maillefer, Ballaigues, VD, Switzerland) in reciprocating motion of the motor (X-Smart Plus, Dentsply Maillefer). An irrigation protocol followed irrigation with 5 mL of 3% sodium hypochlorite solution (Vishal Dentocare Private Ltd., Ahmedabad, GJ, India) between instrumentation, activated using the EndoActivator system (Dentsply Tulsa Dental Specialties, Tulsa, OK, USA) and followed by 5 mL 17% ethylenediaminetetraacetic acid (pH = 7.7, Dentwash, Prime Dental, Kalher, Bhiwandi, MH, India). Five milliliter of normal saline (Eurolife Healthcare Pvt. Ltd., Uttarakhand, India) was used in between irrigants and as a final rinse. The canals were dried with absorbent paper points (Medicept Dental India Pvt., Ltd.) master cone was verified with an IOPA radiograph (Dentsply Maillefer, Ballaigues, Switzerland) [Figure 2c]. Canals were coated with AH Plus sealer (Dentsply International Inc.) and Warm vertical compaction (Calamus dual 3D obturation system [Dentsply Maillefer, Ballaigues, Switzerland]) was performed. A postoperative IOPA radiograph was taken [Figure 2d] and postendodontic restoration was done using composite (Tetric N-Ceram starter kit, Ivoclar, Vivadent). The patient was recalled for endodontic treatment in 16 after a week.

In the next visit, tooth 26 was anesthetized with 1.8 mL of 2% lignocaine containing 1:80,000 epinephrine. An endodontic access cavity was established under rubber dam. The DOM was used to locate the three canals which were deep into the pulp chamber [Figure 2f]. The working length was determined [Figure 2e], cleaning and shaping were performed under the same irrigation protocol as with the other side. Obturation was done using warm vertical compaction [Figure 2g], and postendodontic restoration was done using composite [Figure 2h]. Final postoperative OPG was taken [Figure 2i].

DISCUSSION

Maxillary first molar has shown variation in the number of roots from 1 to 5, while canals have shown to vary from 1 to 8.[2,3,5] Studies and reports showing roots and canals <3 in number are rare.[3] The Asian population shows a higher prevalence for single-rooted maxillary molars. Kim et al. reported the incidence of such single-rooted maxillary molars in the Korean population to be 0.25%.[7] Gopikrishna et al. and De Souza et al. reported the presence of a single root and single canal in the maxillary first molar.[3,8]

The present case exhibited a single root on radiograph. CBCT was used for a better understanding of the complex root anatomy.[5] CBCT images showed a single root and root canal with trifurcation at the middle third exiting as three separate canals. This represents Sert and Bayirli type-IX canal configuration. Ordinola-Zapata et al. reported the presence of type-IX canal configuration in 15.2% of mandibular premolars.[9] Rwenyonyi et al. had reported the presence of type-IX canal configuration in 0.5% of the mesiobuccal root of the maxillary first molar.[10] According to Ahmed HA et al., type-IX canal configuration is seen in 5% of mesial roots and 2% of distal roots in mandibular molars.[11] To date, there is no case report on maxillary first molar with single root and type-IX canal configuration. The present case revealed identical presentation on both sides.

A study by Plotino et al. showed that maxillary first molars had symmetrical anatomy in 71.1% of patients.[12]

The most common iatrogenic errors such as perforations and excessive tooth removal during access opening are caused during the search for the missing or extra canals.[13] These can be minimized if the clinician has the thorough knowledge on root canal morphology. Forty percent of endodontic retreatment is due to missed canal.[14] Although extra canals are more of a rule rather than an exception, the clinician should be aware of the fact that there is a possibility of fused if not fewer canals than the normally presumed canal morphology.[3] Although the varying morphology of the root canals is normally ascertained with radiographs of different angulations or careful examination of the floor of the pulp chamber, the use of additional diagnostic aids such as CBCT and DOM aid tremendously. A study by Matherne et al. compared CBCT scanning in identifying root canal systems with images obtained using digital radiography. They concluded that CBCT images resulted in identifying a greater number of root canal systems and also improves the outcomes of an endodontic treatment.[15] The use of DOM, proper illumination, and access preparation also improves canal location and treatment outcome.

CONCLUSION

The present case report discusses the endodontic management of maxillary first molar with single root and type-IX canal configuration bilaterally and also highlights the role of CBCT as an objective analytic tool to ascertain root canal morphology.

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.