Single-rooted maxillary first molar with a single canal:endodontic retreatmentFrancisco de la Torre, DDS,a Rafael Cisneros-Cabello, MD, PhD, DDS,a

José Luis Aranguren, DDS,a Roberto Estévez, DDS,a

Eugenio Velasco-Ortega, MD, PhD, DDS,b Juan José Segura-Egea, MD, PhD, DDS,b Madridand Seville, SpainEUROPEAN UNIVERSITY OF MADRID AND UNIVERSITY OF SEVILLE

This case report presents an unusual root canal system in a maxillary first molar tooth: a single canal in asingle root. The endodontic access cavity displayed only 1 canal orifice. This case demonstrated that: 1) cliniciansmust have adequate knowledge about root canal morphology and its variations; 2) the location and morphology ofroot canals should be identified radiologically before the root canal treatment; and 3) careful examination ofradiographs and the internal anatomy of teeth is essential. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;

106:e66-e68)

Clinicians must have adequate knowledge about rootcanal morphology and its variations to achieve a tech-nically satisfactory endodontic outcome.1 Therefore,the root canal system of maxillary molars must beexamined meticulously by the clinician, preferably un-der magnification provided by a surgical operating mi-croscope.2 The literature describes complex root canalsystems in maxillary molars that may be difficult tomanage.3,4 Variations often occur in the mesiobuccalroots,5,6 the most common finding being the occurrenceof 2 canals. In maxillary first molars, cases of morpho-logic variations, abnormal numbers of roots, or theexistence of C-shaped canals have been reported pre-viously.2,7-9 Moreover, 410 and 511 roots with a corre-sponding number of canals have been reported in max-illary molars. Case reports with 4,12 5,13 and 6 rootcanals,14,15 have also been presented.

However, the configuration of 1 canal in a 1-rootedmaxillary first molar has rarely been described in stud-ies describing tooth anatomy and root canal anatomy onthe basis of extracted teeth and/or using cross-sec-tions.16 The present report describes the root canalretreatment in a maxillary first molar with 1 root canal.

aDepartment of Endodontics, School of Dentistry, European Univer-sity of Madrid.bDepartment of Stomatology, School of Dentistry, University ofSeville.Received for publication Jul 9, 2008; accepted for publication Jul 27,2008.1079-2104/$ - see front matter© 2008 Mosby, Inc. All rights reserved.

doi:10.1016/j.tripleo.2008.07.024

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CASE REPORTA 45-year-old caucasian (Spanish) woman, whose medical

status was noncontributary, was referred for endodontic re-treatment of the maxillary right first molar. The tooth hadbeen root-filled previously and restored, but had lost thecoronal restoration 5 years before (Fig. 1), and the root fillinghad been exposed to oral environment during this time. Thepatient had pain on percussion. After adequate anesthesia andisolation with rubber dam, an endodontic access cavity wasestablished. Only a single canal orifice was located (Fig. 2).The cervical third of the old root filling was removed usingthe K3 rotary files system (Sybron Endo, Orange, CA). Theapical two-thirds of the gutta-percha/sealer were re-treatedusing conventional K-files (Maillefer; Dentsply Maillefer,Ballaigues, Switzerland) with chloroform. The criteria forcompletion of re-treatment were the presence of clean filings,no evident gutta-percha or sealer present on the files or paperpoints, and smooth canal walls. Increments of 0.05 mL chlo-roform were injected into the canal to soften the gutta-percha.After apical patency was established, the root length wasestimated using an apex locator (AFA Apex Finder; AnalyticTechnology, CA) and then confirmed with a periapical radio-graph (Fig. 3). Hedström files (Dentsply Maillefer) startingfrom size 25 up to size 45 were used, in sequential order, forinstrumentation to the working length. During the re-treat-ment, the root canal was irrigated with 5% NaOCl and EDTA.After cleaning and shaping, the canal was dried and filledwith AH26 (Dentsply DeTrey, Konstanz, Germany) and gutta-percha using the System B (EIE Analytic Technology, Red-mond, WA) (Fig. 4). Cavit (ESPE America, Norristown, PA),was used as temporary restorative filling material (Fig. 5) andthe patient was then referred for a permanent restoration. The2-year follow-up radiograph displayed normal periradicularappearance (Fig. 6).

DISCUSSIONThe variability of the root canal system of multi-

rooted teeth represents a challenge to both endodontic

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diagnosis and treatment.9 Although the incidence ofroot variations is rare, as far as the prognosis of indi-

Fig. 1. Initial periapical radiograph.

Fig. 2. Pulp chamber showing only a single canal orifice.

Fig. 3. Periapical radiograph: estimation of the working length.

vidual cases is concerned, their importance should not

be underestimated. Root canal morphology should beexamined further during treatment through the evalua-

Fig. 4. Pulp chamber showing the obturated canal.

Fig. 5. Periapical radiograph after root canal re-treatment.

Fig. 6. Periapical radiograph after 2 years.

tion of radiographs taken from different horizontal an-

OOOOEe68 de la Torre et al. December 2008

gles. The use of a preoperative radiograph and anadditional radiographic view from a 20-degree mesialor distal projection is a good way to detect root canalmorphology and anatomy.2,9

Case reports of variations in the number of rootcanals of maxillary first molars have been pub-lished.8,17,18 Beatty17 reported a maxillary first molarwith five canals, three of which were in the mesio-buccal root. Bond et al.15 and Maggiore et al.8 reportedmaxillary first molars with 6 root canals. But aberra-tions such as 1 root canal have also been reportedpreviously in maxillary second molars.19

Clinicians must have adequate knowledge about rootcanal morphology and its variations. The location andmorphology of root canals should be identified radio-logically before the root canal treatment. Careful ex-amination of radiographs and the internal anatomy ofteeth are essential.

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17. Beatty RG. A five-canal maxillary first molar. J Endodon1984;10:156-7.

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19. Carlsen O, Alexandersen V, Heitmann T, Jakobsen P. Rootcanals in one-rooted maxillary second molars. Scand J Dent Res1992;100:249-56.

Reprint requests:

Dr. Juan J. Segura Egeac/ Avicena s/n Facultad de Odontología41009-SevilleSpain

segurajj@us.es