Journal of IMAB Annual Proceeding (Scientific Papers) 2014, vol. 20 ...journal-imab-bg.org/issue-2014/issue1/JofIMAB_2014-20-1p504-509.… · / J of IMAB. 2014, vol. 20, issue 1

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C-SHAPED CONFIGURATION OF THE ROOTCANAL SYSTEM – PROBLEMS AND SOLUTIONS

Janet Kirilova, Snezhanka Topalova-Pirinska.Department of Conservative Dentistry, Faculty of Dental Medicine, Sofia, Bulgaria

Journal of IMAB - Annual Proceeding (Scientific Papers) 2014, vol. 20, issue 1Journal of IMABISSN: 1312-773X (Online)http://www.journal-imab-bg.org

ABSTRACTIntroduction: The patients with C-shaped configu-

ration of the root canal system are definitely a problem inthe everyday dental practice. The C-shaped configurationof the root canal can be seen in the mandibular and maxil-lary molars. The treatment of these teeth is very difficult.

Purpose: To trace the treatment of clinical cases withC-shaped configuration of the root canal system.

Material and methods: There are some differentcases that are described with a C-shaped configuration ofthe root canal system with one, two, three and four sepa-rate root canals. Careful exploration of the floor of the pulpchamber, inspection with magnification, use of ultrasonicirrigation and a modified filling technique are of particularuse.

Results and Discussion: Clinical cases of a C-shaped pulp chamber and root canal system shows that thisroot canal aberration occurs in a wide variety and variabil-ity with a single root canal up to two, three and four sepa-rate root canals. The diameter of the root canal themselvesalso varies from very wide to such with a small diameter.

Conclusions: Knowledge of the different anatomi-cal variations will improve the endododntic practice of thegeneral dental practitioners.

Key words: Anatomical variation, C-shaped configu-ration of the root canal system, endodontic treatment

The C-shaped root canal configuration was firstdocumented in endodontic literature by Cooke and Cox in1979 and is so named for the cross-sectional morphologyof the root and root canal of the molar teeth [2]. In thesecases instead of the typical shape of the pulp chamber withthree root canals, there are the C-shaped orifice of the rootcanal on the mandibular molars. C- shaped root canal sys-tem is a single, ribbon-shaped orifice with an arc of 180ºor more (Figure 1). Most often, the C-shape of the pulpchamber is used to describe the mandibular second molars,the maxillary first molars (0.92%) and the maxillary sec-ond molars (4.9%) [2, 3, 4, 13, 15]. Single cases of man-dibular first molars and mandibular first premolars are re-ported [14, 15, 16].

Fig. 1. C- shaped configuration of the root canal system of mandibular second molar.

The orifice starts from the mesiolingual line angle ofthe pulp chamber, curves buccally and ends distally (Figure1). The convex portion of the C-shape is direced vestibullary.

Root canal structure, below the orifice, can be widerange of anatomic variations with one, two, three or fourseparate canals. The teeth can be divided into two basicgroups [3, 4]:

1. Those with a single ribbonlike morphology fromorifice to the apex;

2. Those with more than one separate canal below the

orifice.The first classification of the C-shaped root canals was

done by Melton and co-authors in 1991 [6]. Later based onit, Fan [3] made an anatomic classification:

1. Category I (C1) - continuous C-shaped root canalfrom the orifice to the apex of the root;

2. Category II (C2) -one main root canal and a smallerone;

3. Category III (C3) – two or three root canals;4. Category IV (C4) - an oval or a round canal;

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5. Category V (C5) - no canal lumen or there is oneclose to the apex.

According to this classification, C4 includes teeth thathave only a single and very wide canal. In English literaturethese are the so-called all in one (Figure 2).

Fig. 2. C-shaped configuration Category IV (C4)

Fig. 3. Mandibular right second molar with one root canal category IV (C4): a - pulp chamber; b – post-treatmentX-ray

Fan suggests that 3 types of teeth with C-shaped con-figuration of the pulp chamber are included in the radiologi-cal classification [4]:

1. Type I. Conical or square root with visible separa-tion of medial and distal part. Medial and distal canal mergenear the apical foramen in a single one;

2. Type II. Conical or square root with visible sepa-ration of medial and distal part. Medial and distal canal haveseparate apical foramen but run approximately in parallel andare almost equal in length;

3. Type III. Conical or square root with visible sepa-ration of medial and distal part. Medial and distal canal haveseparate apical foramen, run approximately in parallel butone of them is longer than the other.

MATERIAL AND METHODClinical case No 1 of a mandibular second molar

with C-shaped configuration (one wide root canal)A root and a wide root canal are seen on the diag-

nostic radiography of a mandibular right second molar withexacerbated chronic periapical periodontitis (Figure 3a). Af-ter opening the pulp chamber, the C-shaped configurationof the pulp chamber and a single root canal are confirmed(Figure 3b). It refers to category IV (C4) of Fan’s anatomicclassification.

The lengths of the root canals are measuredelectrometrically with Raypex 4 apex locator. Due to the ex-cessive diameter of the root canal the treatment is performedwith hand canal instruments using step-back technique,combined with irrigation with Smear Clear, 3% hydrogenperoxide and distilled water. Periapical lesions are influ-enced by physiotherapy with iodine-potassium iodide. Seal-ing the particularly widespread endodontic space is accom-plished by the technique of „continuous wave of conden-sation” through System B and Obtura II.

Clinical case No 2a of a mandibular second mo-lar with C-shaped configuration (two root canals)

The clinical finding is a mandibular right second mo-lar with a C-shaped pulp chamber and two root canals - Cat-egory II (C2) according to Fan’s anatomic classification.Figure 4 shows the pulp chamber of the tooth before andafter obturation of the endodontic space.

The extension of the endodontic cavity to the ves-tibular portion of the tooth is probably due to the search ofa mesiobuccal orifice of the root canal in the primary treat-ment, as this is not applicable to this anatomical variation (white arrow on figure 4).

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Fig. 4. C-shaped pulp chamber of mandibular second molar: a – C-shape of the open pulp chamber; b - clearlydefined C of the pulp chamber with filled canals - C2 or Category II according to Fan.

Fig. 5. Mandibular right second molar with a C-shaped root canal system: a - X-ray prior to treatment; b – X-raywith gutta-points in the canals; c - X-ray after filling the canals

Figure 5 shows the diagnostic radiograph of the toothwhich refers to type III according to Fan’s radiological clas-sification. Figure 5 b is a radiographic image of the toothwith gutta-percha points placed in both root canals and in

Figure 5c - after filling. The post obturation radiographypresents the filled root canal space and the existing anasto-mosing network between the main and the accessory canals.

The sealing the endodontic space is accomplished bythe technique of “continuous wave of condensation” bycombining System B and Obtura II for distal root canal andThermafill obturator and sealer for medial root canal.

Clinical case No 2b of a mandibular second mo-lar with C-shaped configuration (two root canals)

Figure 6 shows a madibular right second molar with

a C-shaped pulp chamber and two root canals - CategoryII (C2) according to Fan’s anatomic classification. It is in-teresting that endodontic treatment was made through thecrown (as part of a bridge construction). The pulp cham-ber of the tooth before and after obturation of endodonticspace is shown (Fig. 6a and b), as well as preoperative andpost obturation radiographs (Figure 6b and d).

Fig. 6. Mandibular right second molar with a C-shaped root canal system: a-open and shaped pulp chamber; b –preoperative radiograph; c - pulp chamber after filling; d – post obturation radiograph.

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Sealing the endodontic space is accomplished byThermafill obturators and sealer.

Clinical case No 3 of mandibular second molar withC-shaped configuration (three root canals)

Endodontic retreatment of mandibular left secondmolar with a C-shaped pulp chamber and three root canalsis registered. Evidence for this case is presented in Figure7. In accordance with the radiograph, the tooth is classifiedas type I according to Fan’s radiological classification andas category III according to his anatomic classification (C3).Perforation in mesiolingual part of the pulp chamber oc-

Fig. 7. Mandibular left second molar with C-shaped configuration and three root canals: a - preoperative radio-graph; b - the pulp chamber during the treatment - the two canals with obturation (white arrows), a perforation at one ofthe ends of the pulp chamber (black arrow) and unfilled third root canal (red arrow); c – post obturation radiograph.

Fig. 8. Radiographs of mandibular right second molar: a – preoperative;b – with gutta percha points

curred in previous treatment (black arrow on figure 8b).Probably it was not taken into consideration that the toothhad C-shaped configuration and a mesiolingual orifice ofthe root canal was searched for. It is interesting to note thata C-shaped pulp chamber and root canals of the contralat-eral mandibular second molar, as well as the C-shaped pulpchamber and the root canal system of maxillar left secondmolar are observed with the same patient.

This confirms the conclusion of some authors [8, 9]for presence of similar anatomical facts in contralateral teethin up to 70% of the cases.

Sealing the endodontic space is accomplished byThermall obturators and sealer.

Clinical case No 4 of mandibular second molar withC-shaped configuration (four root canals)

The demonstrated case of mandibular right second

molar with chronic periapical periodontitis. The clinicalcrown is almost completely destroyed. The configurationof the pulp chamber is C-shaped and has four root canals.Preoperative radiograph shows a root canal type II accord-ing to Fan’s radiological classification (Figure 8).

The typical C-shaped configuration of the pulpchamber is seen in Figure 9a. In Figure 9b shows the pulpchamber with filled root canals of the same tooth and in Fig-ure 9 c post obturation radiograph.

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Fig. 9. Mandibular right second molar with C-shaped configuration of the pulp chamber and four root canals: a -C-shaped pulp chamber; b - pulp chamber with Termafill obturators in canals; c – post obturation radiograph.

Sealing the endodontic space is performed by com-bined technique of filling a „continuous wave of conden-sation” using System B and Obtura II and Thermafillobturators and sealer

RESULTS AND DISCUSSIONSClinical cases of a C-shaped pulp chamber and root

canal system show that this root canal aberration occurs ina wide variety and variability with a single root canal up totwo, three and four separate root canals. The diameter ofthe root canal themselves also varies from very wide to suchwith a small diameter.

In literature have found single publications of caseswith a C-shaped canal [1, 7, 9, 11, 12]. According to dif-ferent authors their frequency varies from 2.7% [5, 16] to8% [9]. The teeth with C-shaped root canal configurationare usually mandibular second molars, and more rarely themandibular first premolars, the maxillary first molars, aswell as the mandibular wisdom-teeth (third molars). The C-shaped configuration of the pulp chamber and the root ca-nal system affects more often Asians than Caucasians [11]with frequency of distribution up to 30%. The probabilityof finding C-shaped configuration in the contralateral toothis up to 70% [7, 9, 11].

Successful endodontic treatment of a tooth with a C-shaped configuration is difficult and a real challenge con-sidering decontamination and successful filling of the rootcanal system. The canal instruments, which use, mainly ro-tating and the processing of an elliptical canal is difficultand inefficient. The creation of systems, with reciprocalmotion for machine preparation, is a significant step for-ward. It is inappropriate to apply separately the standardtechnique, step-back or crown-down technique for thepreparation of a C-shaped root canal. Secure shaping andcleaning of such type of root canals require knowledge of

various techniques for instrumentation and their combina-tion.

Qualitative filling of teeth with a C-shaped root ca-nal system only with the methods of the central point tech-nique or cold lateral condensation is impossible. The diffi-culties arise from the fact that with the C-shaped root ca-nals it is the possible to have a thin net of anastomoses inroot canal system [3, 4, 10].

All this requires good knowledge of and combiningdifferent techniques of root canal extension from manual tomachine ones.

It is important to choice the method of irrigation,because the endodontic space is complicate with net of anas-tomosis. Ultrasonic activation of the irrigation solution with2.5 sodium hypochlorite may be advantageous in remov-ing the infected tissues from the canal system, because thevolume endodont contains greater amount of infected chan-nel contents and extrusion of debris or irrigant is possible[7, 15, 16].

Regarding the filling of root canal system onemethod is not enough to seal the endodontic space. It is nec-essary to use also cold lateral condensation through com-bined technique of filling the continuous wave of conden-sation using System B and Obtura II and Thermallobturators and sealer [6, 11, 15, 16].

It is recommended that cases with C-shaped configu-ration of root canal system should be referred to a special-ist for complete treatment.

CONCLUSIONDue to the unusual root canal system of teeth with a

C-shaped root canal system, for successful sealing of en-dodontic space, it’s necessary to know and learn differenttechniques of filling and appropriate equipment with suit-able appliance.

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Address for correspondence:Dr Janet Kirilova, PhDDepartment of conservative Dentistry, Faculty of Dental Medicine1, St. George Sofiiski Str., 1431 Sofia, BulgariaE-mail: [email protected],