Endodontic ManagementEight Root Canal SystemComputed Tomography SJojo Kottoor, MDS, Natanasabapathy Ve

AbstractIntroduction: Root canal treatment of maxillary molarspresenting with complex root canal configurations canbe diagnostically and technically challenging.Methods:Nonsurgical endodontic therapy of a left maxillary firstmolar with three roots and eight root canals wassuccessfully performed. This unusual morphology wasdiagnosed using a dental operating microscope (DOM)and confirmed with the help of cone-beam computedtomography (CBCT) images. Results: CBCT axial imagesshowed that both the mesiobuccal and distobuccal rootcontained a Sert and Bayirli type XV canal, whereas thepalatal root showed a Vertucci type II canal configura-

a mesio-occlusal radiolucency approaching the pulp space with a widened periodontal

Case Report/Clinical Techniquesligament adjacent to the mesiobuccal root. From the clinical and radiographic exami-nation, a diagnosis of symptomatic irreversible pulpitis with symptomatic apical perio-dontitis was made, and nonsurgical endodontic treatment was recommended.

Radiographic evaluation of the involved tooth did not indicate any variation in theroot canal anatomy (Fig. 1A). The mesial surface of the tooth was restored withcomposite resin (Z100; 3M Dental Products, St Paul, MN) after caries excavation toenable optimal isolation. Local anesthesia was induced using 1.8 mL 2% lidocainewith 1:200,000 epinephrine (Xylocaine; AstraZeneca Pharma Ind Ltd, Bangalore,India). A rubber dam was placed, and a conventional endodontic access openingintense lingering pain, whereas electric pulp testing (Parkel Electronics Division, Farm-ingdale, NY) showed pulpal vitality on tooth #14. Preoperative radiographs revealedtion. Conclusions: The use of a DOM and CBCT imagingin endodontically challenging cases can facilitate a betterunderstanding of the complex root canal anatomy,which ultimately enables the clinician to explore theroot canal system and clean, shape, and obturate itmore efficiently. (J Endod 2011;37:715719)

Key WordsCone-beam computed tomography scanning, maxillaryfirst molar, root canal anatomy, root canals

From the Department of Conservative Dentistry andEndodontics, Meenakshi Ammal Dental College and Hospital,Chennai Tamil Nadu, India.

Address reqeusts for reprints to Dr Jojo Kottoor, Depart-ment of Conservative Dentistry and Endodontics, MeenakshiAmmal Dental College and Hospital, Alapakkam Main Road,Maduravoyal, Chennai Tamil Nadu, India 600 095. E-mailaddress: drkottooran@gmail.com0099-2399/$ - see front matter

Copyright 2011 American Association of Endodontists.doi:10.1016/j.joen.2011.01.008JOE Volume 37, Number 5, May 2011of a Maxillary First Molar withs Evaluated Using Cone-beamcanning: A Case Reportlmurugan, MDS, and Smitha Surendran, MDS

The main objective of root canal treatment is thorough cleaning and shaping of allpulp spaces and its complete filling with an inert filling material (1). A major causeof post-treatment disease is the inability to locate, debride, or adequately fill all canals ofthe root canal system (2). Together with diagnosis and treatment planning, a betterknowledge of the root canal system and its frequent variations is an absolute necessityfor successful root canal treatment (3). The form, configuration, and number of rootcanals in maxillary first molars have been discussed for more than half a century (4).Maxillary first molars commonly present with three roots and three canals, witha second mesiobuccal canal (MB2) canal seen in 56.8% and 96.1% of the cases(57). Apart from these presentations, a wide variation of root and canalconfigurations of the maxillary first molars has been documented in the dentalliterature. This includes a single root canal in a single root (8), two root canals (9),five root canals (10), six root canals (11), C-shaped canals (12), and an additionalpalatal root (13). Recently, Kottoor et al (14) reported the endodontic managementof a maxillary first molar with seven root canals. Case reports of maxillary first molarspresenting with six or more root canals are summarized in Table 1. This case reportpresents a maxillary first molar with an unusual morphology of three roots and eightroot canals, which has neither been reported in any clinical or laboratory studiesnor clinical case reports so far. This unusual morphology was confirmed with theaid of cone-beam computed tomography (CBCT) scanning.

Case ReportA 30-year-old Indian male patient reported to the postgraduate clinic of the

Department of Conservative Dentistry and Endodontics, Meenakshi Ammal DentalCollege, Chennai, India, with the chief complaint of spontaneous pain in the upperleft posterior for the past 5 days. He revealed a history of intermittent pain for thelast 2 months, which had increased in intensity in the preceding 5 days. The patient re-ported subjective symptoms of prolonged sensitivity to hot and cold and the recentheightened intensity of pain, which awakened the patient throughout the night. Clini-cally, the left maxillary first molar (tooth #14) had a deep mesio-occlusal cariouslesion. The patients medical history was unremarkable. Palpation of the buccal andpalatal aspects of the tooth did not reveal any tenderness; however, the tooth was tenderto vertical percussion. Periodontal probing around the tooth and mobility were withinphysiological limits. Thermal testing (heated gutta-percha and dry ice) caused an8 Root Canals in Maxillary First Molar 715

root (Fig. 1E) were taken to confirm the working lengths. Cleaning and

Six o

can

tob

2

21

2

2

32

23

Case Report/Clinical Techniqueswas established with an Endo Access bur and an Endo Z bur (DentsplyTulsa, Tulsa, OK). Initially, the mesiobuccal (MB1), the distobuccal(DB1), and the two palatal canals (mesiopalatal [MP] and the distopa-latal [DP]) were located. While viewing the floor of the pulp chamberunder a dental operating microscope (DOM) (Seiler Revelation, StLouis, MO), two additional root canal orifices were located palatallyto the MB1 and DB1. However, several attempts to introduce a fileinto these orifices were unsuccessful. On troughing away the dentinoccluding the orifices using ET 18D ultrasonic tips (Satelec/Acteon,Merignac, France), the second and third mesiobuccal (MB2 andMB3) and distobuccal (DB2 and DB3) root canal orifices were located.The conventional triangular access was modified to a trapezoidal shapeto improve access to the additional canals. Coronal enlargement wasperformed with a nickel-titanium ProTaper SX rotary file (DentsplyMaillefer, Ballaigues, Switzerland) to improve the straight-line access(Fig. 1B). Root canals were explored with ISO #10 K-files. CBCT scan-ning was used to confirm and ascertain the unusual root canalmorphology. All the root canals were dried and no medicament placed.A sterile cotton pellet was placed in the pulp chamber and Cavit G (3M

TABLE 1. Summary of Case Reports of Maxillary First Molars Presenting with

Rootconfiguration No. of canals

Root

Mesiobuccal Dis

3 roots 6 3

3 roots 6 23 roots 6 2

4 roots(MB, MP, P, DB)

6 MB, MP, M, P, DP, DB

3 roots 6 2

3 roots 6 2

3 roots 6 23 roots 6 2

3 roots 7 33 roots 8 3ESPE Dental Products, St Paul, MN) was used to seal the access cavity.Informed consent was obtained from the patient, and a computed

tomography scanwas performedwith a CBCT scanner (Kodak 9500 ConeBeam 3D, Chennai, India) at a tube voltage of 60 kVp and tube current of5 mA. All protective measures were taken to protect the patient from radi-ation according to As Low As Reasonably Achievable guidelines. Axialimages were transmitted to a commercially available dental program (Ko-dak Dental Imaging Software 3D module v 2.4) to reformat panoramicand cross-sectional images in all three planes. Axial slices of the maxillaof 200-mm thickness were obtained at different levels to determine theroot canal morphology (Fig. 2AC). CBCT scan slices revealed eightroot canals (three mesiobuccal, three distobuccal, and two palatal) inthe left maxillary first molar (Fig. 2AG).

CBCT images provided valuable information regarding the canalconfiguration and confirmed the eight canals that were not clearlyseen in the conventional radiograph. At the next appointment after 2weeks, the patient was asymptomatic. After administering 1.8 mL 2%lidocaine with 1:200,000 epinephrine, the working lengths were deter-mined with the help of an apex locator (Root ZX; Morita, Tokyo, Japan)under rubber dam isolation. Individual intraoral periapical radio-graphs for the mesiobuccal (Fig. 1C), distobuccal (Fig. 1D), and palatal

716 Kottoor et al.shaping were performed using ProTaper nickel-titanium rotary instru-ments (Dentsply Maillefer) with a crown-down technique. The MB1,DB1, MP, and DP canals were enlarged to ProTaper F3; whereas theMB2, MB3, DB2, and DB3 canals were enlarged until ProTaper F2.During root canal preparation, irrigation was performed using normalsaline, 2.5% sodium hypochlorite solution, and 17% EDTA. Finalrinsing of the canals was performed using 2% chlorhexidine digluco-nate coupled with ultrasonic agitation. The canals were dried withabsorbent points (Dentsply Maillefer), and obturation was performedusing cold lateral compaction of gutta-percha (Dentsply Maillefer)and AH Plus resin sealer (Maillefer Dentsply, Konstanz, Germany). Afinal radiograph was taken to establish the quality of the obturation.After completion of root canal treatment, the tooth was restored witha posterior composite filling (Z100; 3M ESPE Dental Products, StPaul, MN) (Fig. 1F). The patient experienced no post-treatment discom-fort and was subsequently referred for appropriate coronal restoration.r More Root Canals

al anatomy

Referenceuccal Palatal

1 Martnez-Berna andRuiz-Badanelli (1983)

(3 cases) (15)2 Bond et al (1988) (16)

3 (apical thirdtrifurcation)

Maggiore et al (2002) (17)

Adanir (2007) (18)

2 de Almeida-Gomes et al(2009) (19)

2 Karthikeyan andMahalaxmi (2010)

(4 cases) (20)12 Albuquerque et al (2010)

(3 cases) (11)2 Kottoor et al (2010) (14)2 Present caseDiscussionThe anatomy of teeth is not always predictable. A great number of

variations could occur in formation in both the roots and their shape.Hess (21) reported the wide variation and complexity of root canalsystems establishing that a root with a tapering canal and a singleforamen was the exception rather than the rule. Weine et al (22) dividedthe position of one or two canals within a root into four basic types. Ver-tucci (2) described a much more detailed canal system and identifiedeight pulp space configurations. Recently, 14 new additional canal typeswere reported by Sert and Bayirli highlighting the complexity of rootcanal systems (23).

Of the various comprehensive maxillary first molar ex vivo studiesin the dental literature, only Baratto Filho et al (24) reported amaxillaryfirst molar with three roots and seven root canals. Of the 140 extractedmaxillary first molars evaluated, only one tooth showed seven rootcanals, which contained three mesiobuccal, three distobuccal, andone palatal canal. The frequency of MB2 canals in the mesiobuccalroot 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 distobuccal root (DB2)were 1.15% (ex vivo) and 3.75% (clinical) and those for the palatal

JOE Volume 37, Number 5, May 2011

Case Report/Clinical Techniquesroot (second palatal canal) were 2.05% (ex vivo), 0.62% (clinical),and 4.55% (CBCT).

Traditionally, the mesiobuccal root of the maxillary first molar hasgenerated more research and clinical investigation than the other roots(25). Most of the in vitro studies of themesiobuccal root canal anatomy(2630) have not reported the presence of a third canal in themesiobuccal root. Two such studies have reported their incidence tobe between 1.1% and 10% (31, 32). However, its presence has beendocumented in a few case reports (10, 14). The third canal in thedistobuccal root of maxillary first molars is rare, with only twodocumented reports in the dental literature (20, 24). These reportspresented a Gulabivala type III (33) and a Sert and Bayirli type XVIIIroot canal configuration (23) in the distobuccal root of maxillary firstmolars.

The maxillary first molar is predominantly a three-rooted toothwith a buccolingually broad mesiobuccal root and a rounded or ovoiddistobuccal root in the cross-section (5). This anatomic differencecould possibly explain for the higher incidence of multiple canals inthe mesiobuccal root (25). In the present case, CBCT axial imagesclearly depicted that the distobuccal root was broad buccolingually,similar to the mesiobuccal root (Fig. 2B). The contralateral distobuccal

Figure 1. (A) A preoperative radiograph of tooth #14. (B) Access opening showitooth #14 to confirm the working length in the (C) mesiobuccal, (D) distobuccal, aangulation showing the root canal system of the tooth.

JOE Volume 37, Number 5, May 2011root also presented with a similar anatomy (Fig. 2B and C). This vari-ation in the external root morphology may perhaps explain for the rareinternal anatomy of three root canals within the distobuccal.

Conventional intraoral periapical radiographs are an importantdiagnostic tool in endodontics for assessing the root canal configura-tion. Nevertheless, it is not completely reliable because of its inherentlimitation (34). The application of further analytic diagnostic toolssuch as CBCT scanning for the assessment of unusual root canalmorphology has been highlighted, aiding the correct endodonticmanagement of complicated and challenging cases (14, 35). CBCTimages are reconstructed using significantly lower radiation dosescompared with alternative conventional computed tomographyscanning. This is because with CBCT scanning the raw data areacquired in the course of a single sweep of a cone-shaped x-ray sourceand reciprocal detector around the patients head. The efficient use ofthe radiation beam and the elimination of the need for a conventionalimage intensification system used in conventional computed tomog-raphy scanners result in a huge reduction in radiation exposure.

CBCT data were particularly useful in assessing the root and canalmorphology in the present case. CBCT axial images confirmed the pres-ence of three roots and eight root canals, namely the MB1, MB2, MB3,

ng the eight root canal orifices. (CE) Eccentrically angulated radiographs ofnd (E) palatal roots. (F) A postobturation radiograph of tooth #14 in eccentric

8 Root Canals in Maxillary First Molar 717

e (Aing

Case Report/Clinical TechniquesDB1, DB2, DB3, MP, and DP (Fig. 2AF). The contralateral toothappeared to have a normal root canal anatomy (Fig. 2AC).CBCT axial images also showed that both the mesiobuccal and thedistobuccal root had a Sert and Bayirli type XV canal configuration(23) (ie, the first and second canals of both roots joined at themiddle third and exited through one apical foramen, whereas thethird canal had a separate canal orifice and exiting foramen).The palatal root presented with a Vertucci type II canal pattern(2) (ie, two canal orifices joining together and exiting into oneapical foramen) (Fig. 2B and C).

The removal of vital and necrotic remnants of pulp tissues, micro-organisms, and microbial toxins from the root canal system is essentialfor endodontic success (36). Extensive isthmuses, anastomosis, fins,cul-de-sacs, and other parts of the canal system that are difficult to

Figure 2. (AC) CBCT images of the maxillary arch showing axial sections at thimages of tooth #14 at the (D) cervical, (E) middle, and (F) apical level showdebride via mechanical instrumentation have been found to be presentin all multirooted teeth (37). Therefore, chemical irrigation usingsonics and ultrasonics should be an essential part of root canal debride-ment because it allows for cleaning beyond what might be achieved byroot canal instrumentation alone (38).

The role of microscopy in endodontics should not be underesti-mated. Buhrley et al (7) had preformed an in vivo study to determinethe practitioners ability to locate the MB2 canal in maxillary molarsusing the DOM and/or dental loupes. They concluded that when themaxillary first molars were considered separately, the frequency ofMB2 canal detection for the microscope, dental loupes, and no magni-fication groups were 71.1%, 62.5%, and 17.2%, respectively. In thepresent case, success was largely dependent on the use of magnification,which allowed for the identification of the eight distinct root canalorifices with ease. Hence, clinicians should familiarize themselveswith dental microscopy and new imaging technology, such as CBCTscanning, to get additional anatomic information in endodontic prac-tice.

ConclusionThe clinical significance of the present case is that this is the first

report of a case with three roots and eight root canals in a maxillary firstmolar. The routine use of DOM while performing endodontic treatment

718 Kottoor et al.is suggested because it will definitely be helpful in identifying and treat-ing all root canals successfully.

AcknowledgmentsThe authors deny any conflicts of interest related to this study.

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Endodontic Management of a Maxillary First Molar with Eight Root Canal Systems Evaluated Using Cone-beam Computed Tomograph ...Case ReportDiscussionConclusionAcknowledgmentsReferences