| Abstract|| |
Nonsurgical endodontic therapy of a right maxillary first molar with three roots and seven root canals. This unusual morphology was diagnosed using a dental operating microscope (DOM) and confirmed with the help of cone-beam computed tomography (CBCT) images. CBCT axial images showed that both the palatal and distobuccal root have a Vertucci type II canal pattern, whereas the mesiobuccal root showed a Sert and Bayirli type XVIII canal configuration. The use of a DOM and CBCT imaging in endodontically challenging cases can facilitate a better understanding of the complex root canal anatomy, which ultimately enables the clinician to explore the root canal system and clean, shape, and obturate it more efficiently.
Keywords: Cone-beam computed tomography scanning, maxillary first molar, root canals, root canal anatomy
|How to cite this article:|
Munavalli A, Kambale S, Bandekar S, Ajgaonkar N. Maxillary first molar with seven root canals diagnosed with cone-beam computed tomography scanning. Indian J Dent Res 2015;26:82-5
The main objective of root canal treatment is thorough cleaning and shaping of all pulp spaces and its complete filling with an inert filling material.  A major cause of posttreatment failure is the inability to locate, debride, or adequately fill all canals of the root canal system.  Together with diagnosis and treatment planning, a better knowledge of the root canal system and its frequent variations is an absolute necessity for successful root canal treatment.  Case reports of maxillary first molar with unusual canal morphology are summarized in [Table 1]. ,,,,,,, The present case report discusses the successful endodontic management of a maxillary first molar presenting with three roots and seven root canals.
|How to cite this URL:|
Munavalli A, Kambale S, Bandekar S, Ajgaonkar N. Maxillary first molar with seven root canals diagnosed with cone-beam computed tomography scanning. Indian J Dent Res [serial online] 2015 [cited 2019 Nov 13];26:82-5. Available from: http://www.ijdr.in/text.asp?2015/26/1/82/156818
|Table 1: Summary of case reports of maxillary first molars presenting with six or more root canals |
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| Case report|| |
A 28-year-old male patient presented with the chief complaint of the spontaneous toothache in his right upper back region of the jaw since 2 days. A clinical examination revealed a carious maxillary right first molar, which was tender to percussion. The tooth was not mobile, and periodontal probing around the tooth was within physiological limits. Vitality testing of the involved tooth with heated gutta-percha (Dentsply Maillefer, Switzerland) and dry ice (R C Ice; Prime Dental Products India) caused an intense lingering pain, whereas electronic pulp stimulation (Parkel Electronics Division, Farmingdale, NY) caused a premature response. A preoperative radiograph revealed disto-occlusal radiolucency, approaching the pulp space with periodontal ligament space widening in relation to the distobuccal (DB) root [Figure 1]. From the clinical and radiographic findings, a diagnosis of symptomatic irreversible pulpitis with symptomatic apical periodontitis was made, and endodontic treatment was suggested to the patient.
Radiographic evaluation of the involved tooth did not indicate any variation in the canal anatomy [Figure 1]. Caries excavation was done, and the tooth was restored with posterior composite resin (p60; 3M Dental Products, St. Paul, MN). The tooth was anesthetized with 1.8 mL (30 mg) 2% lignocaine containing 1:200,000 epinephrine (Xylocaine; AstraZeneca Pharma India Ltd.), followed by a rubber dam isolation. An endodontic access cavity was established. Clinical examination with a DG-16 endodontic explorer (Hu-Friedy, Chicago, IL) revealed two canal openings in each of the DB, mesiobuccal (MB), and palatal root. During examination with a surgical operating microscope (Global Surgical Corporation, St. Louis, MO, USA) under ×8 magnification, a third canal was located midway between the MB2 and mesiopalatal (MP) orifices [Figure 2]. Coronal enlargement was done with a nickel-titanium ProTaper series orifice shaper (Dentsply Maillefer, Switzerland) to improve the straight-line access. The working length was determined with the help of an apex locator (Root ZX; Morita, Japan) and later confirmed using a radiograph. Multiple working length radiographs were taken at different angulations [Figure 3] and [Figure 4]. However, the radiographs did not clearly reveal the number and morphology of root canal systems.
To confirm this unusual morphology, it was decided to perform cone-beam computed tomography (CBCT) imaging of the tooth. A multislice CBCT scan of the maxilla was performed (CS9300, Carestream Health Inc., Rochester NY) with a tube voltage of 100 KV and a tube current of 8 mA. The involved tooth was focused, and the morphology was obtained in transverse, axial, and sagittal sections of 0.5-mm thickness. CBCT scan slices revealed seven canals (three MB, two palatal, and two DB) in the right maxillary first molar [Figure 5] [Figure 6] [Figure 7] [Figure 8]. CBCT axial images at the cervical level showed that both the palatal and DB roots have two canals each, whereas the MB root showed three canals. However, CBCT axial images at midroot level showed that fusion of three canals into two canals in MB root, fusion of two canals into one canal in DB root, whereas the palatal root still showed two canals. Interestingly, CBCT images showed a similar configuration of seven canals bilaterally with maxillary left first molar [Figure 5].
|Figure 5: Cone-beam computed tomography axial section of maxillary arch at cervical level of 16|
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|Figure 6: Cone-beam computed tomography axial section of maxillary arch at cervical level of 16 (enlarged view)|
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|Figure 7: Cone-beam computed tomography axial section of maxillary arch at mid-root level of 16|
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|Figure 8: Cone-beam computed tomography axial section of maxillary arch at apical level of 16|
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Cone-beam computed tomography images provided valuable information regarding the canal configuration and confirmed the seven canals that were not clearly seen in the conventional radiograph. At the second appointment, the patient was asymptomatic. After administering 1.8 mL (36 mg) 2% lignocaine with 1:200,000 epinephrine (Xylocaine), cleaning and shaping was performed under rubber-dam isolation using ProTaper nickel-titanium rotary instruments (Dentsply Maillefer) with a crown-down technique. The MB1, MB2, DB1 and DB2 canals were prepared individually till F2 file of ProTaper rotary system having master apical file size of 25 and 8% taper. The MB3 canal was prepared till F1 file of ProTaper rotary system having master apical file size of 20 and 7% taper. The MP and distopalatal (DP) canals were prepared individually till F3 file of ProTaper rotary system having master apical file size of 30 and 9% taper. Irrigation was performed using normal saline, 2.5% sodium hypochlorite solution, and 17% ethylenediaminetetraacetic acid; 2% chlorhexidine di-gluconate was used as the final irrigant. The canals were dried with absorbent points (Dentsply Maillefer), and obturation was performed using cold lateral compaction of gutta-percha (Dentsply Maillefer) and AH Plus resin sealer (Maillefer, Dentsply, Konstanz, Germany) [Figure 9] [Figure 10] [Figure 11]. The tooth was then restored with a posterior composite resin core. The patient was advised a full-coverage porcelain crown and was found asymptomatic on the follow-up period at 6 and 12 months.
| Discussion|| |
A thorough knowledge of root canal morphology and configuration of maxillary molar teeth plays an important role in the success of endodontic therapy. Of the various comprehensive maxillary first molar ex vivo studies in the dental literature, only Filho et al. reported a maxillary first molar with three roots and seven root canals.  Of the 140 extracted maxillary first molars evaluated, only one tooth showed seven root canals, which contained three MB, three DB, and one palatal canal. The frequency of MB2 canals in the MB root was reported to be 92.85% (based on ex vivo results), 95.63% (based on clinical results), and 95.45% (based on CBCT results), whereas the corresponding figures for the DB root (DB2) were 1.15% (ex vivo) and 3.75% (clinical) and those for the palatal root (second palatal canal) were 2.05% (ex vivo), 0.62% (clinical), and 4.55% (CBCT).Traditionally, the MB root of the maxillary first molar has generated more research and clinical investigation than the other roots. Most of the in vitro studies of the MB root canal anatomy have not reported the presence of a third canal in the MB root. In the present case, CBCT axial images clearly depicted the presence of three roots and seven root canals, namely MB1, MB2, MB3, DB1, DB2, MP and DP. CBCT axial images also showed that both the palatal and DB root have a Vertucci type II canal pattern (i.e., two canal orifices join together and exit as one apical foramen),  whereas the MB root showed a Sert and Bayirli type XVIII canal configuration (i.e., three canal orifices join together and exit as one apical foramen),  and DB2 and palatal 2 canals show Kim's type II isthmus. 
Buhrley et al. concluded that when the maxillary first molars were considered separately, the frequency of MB2 canal detection for the microscope, dental loupes, and no magnification groups were 71.1%, 62.5%, and 17.2%, respectively.  In the present case, it was very difficult to predict the root canal anatomy on the basis of preoperative radiograph alone. Inadvertent search for extra canals could have led to perforations and excessive removal of tooth structure. Success in this case was largely dependent on the use of magnification and CBCT imaging, which allowed for the identification of the seven distinct root canals with ease. Hence, clinicians should familiarize themselves with dental microscopy and new imaging technology, such as CBCT scanning, to get additional anatomic information in endodontic practice.
| Conclusion|| |
The present case report discusses the endodontic management of an unusual case of a maxillary first molar with three roots and seven canals and also highlights the role of surgical operating microscope and CBCT scanning as an objective analytic tool to ascertain root canal morphology.
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Department of Conservative Dentistry and Endodontics, Vasantdada Patil Dental College, Sangli, Maharashtra
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11]