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 Table of Contents  
Year : 2021  |  Volume : 11  |  Issue : 2  |  Page : 252-255

Endodontic management of thin and double-curved root of maxillary lateral incisor

1 Department of Conservative Dentistry and Endodontics, Guru Nanak Dev Dental College and Research Institute, Sunam, Punjab, India
2 Department of Community Dentistry, PG Student, Surendra Dental College, Sri Ganganagar, Rajasthan, India

Date of Submission31-Mar-2020
Date of Decision10-Jun-2020
Date of Acceptance26-Jun-2020
Date of Web Publication8-May-2021

Correspondence Address:
Mandeep Singh Matta
36-A, Officers Enclave, Phase 1, Street No. 2, New Officers Colony, Patiala - 147 001, Punjab
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/sej.sej_58_20

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The present case report discusses the endodontic management of maxillary lateral incisor with very thin and double-curved root, also known as bayonet-shaped root. A young healthy male patient presented with acute pain in the left maxillary incisor. Clinical examination and radiographic analysis confirmed the diagnosis of previously treated pulp and symptomatic apical periodontitis. Endodontic treatment was carried out with hand and rotary instruments, and the canal was filled using lateral compaction technique. Six-month radiographic follow-up showed good signs of periapical healing. Technique to prepare and obturate such thin and double-curved root requires preoperative measurement of canal curvature angles with creation of glide path to the apex to maintain the taper of the canal and to avoid mishaps.

Keywords: Bayonet shaped, double-curved root, glide path, maxillary lateral incisor, root canal treatment

How to cite this article:
Matta MS, Kaur M. Endodontic management of thin and double-curved root of maxillary lateral incisor. Saudi Endod J 2021;11:252-5

How to cite this URL:
Matta MS, Kaur M. Endodontic management of thin and double-curved root of maxillary lateral incisor. Saudi Endod J [serial online] 2021 [cited 2021 Jun 17];11:252-5. Available from: https://www.saudiendodj.com/text.asp?2021/11/2/252/315652

  Introduction Top

Root with double curvature is common in posterior teeth, but it is relatively uncommon in anterior teeth. The root may deviate from the axis of the crown due to some trauma during development.[1] Maxillary anterior teeth are well known to have a straight single root that usually encases a single root canal; nevertheless, clinicians may still face a root/root canal configuration with an aberrant morphology, resulting in challenges even in accessing the root canals.[2]

Curved/dilacerated root canals exhibit great difficulty in cleaning, shaping, and obturation of the root canal system; therefore, determining the degree of curvature of root canal before starting the endodontic treatment is mandatory.[3]

The prevalence of dilacerations ranges from 0.32% to 30.9% where the maxillary arch is affected more than the mandibular arch. Furthermore, permanent teeth are affected more frequently than primary teeth and posterior teeth more than anterior teeth with no gender predilection.[4],[5],[6] The present study discusses the access, preparation, and obturation of thin double-curved canal that should progress in a very systematic manner without leaving any chance for errors such as ledge, perforations, loss of working length in apical curve, and fractures in the root as well as to prevent instrument-related mishaps for better outcomes.

  Case Report Top

A 35-year-old healthy male patient reported with a chief complaint of pain and tenderness in the upper left front tooth who had a history of root canal treatment 1 year ago that was not completed as the patient missed the last appointment and got crown 6 months ago from another dentist. Clinical examination revealed tenderness to percussion in the maxillary left lateral incisor that also had a porcelain fused to metal (PFM) crown. Preoperative periapical radiograph showed extremely curved root with double curvature mimicking a bayonet shape associated with large radiolucency having diffused borders [Figure 1]a. Cone-beam computer tomography (CBCT) could not be afforded by the patient for the treatment. History of previously initiated endodontic treatment of the maxillary left central incisor and an apical radiolucency was also associated with central incisor on radiograph [Figure 1]. The case was diagnosed as previously treated pulp associated with symptomatic apical periodontitis.
Figure 1: Preoperative radiograph showing S-shaped root with large apical pathosis (a). Initial negotiation of the canal with #10 K-file (b). Complete negotiation of the working length (c). Placement of calcium hydroxide in tooth #22 and working length of #21 (d). Master cone radiograph of tooth #22 (e). Postobturation of #21 and 22 (f). Three-month follow-up radiograph (g)

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Treatment planning included removal of the crown on lateral incisor followed by endodontic treatment of lateral and central incisor. Treatment was explained to the patient, and patient consent was taken before treatment.

The crown on the left lateral incisor was removed by cutting with Transmetal Burs (Dentsply, India), and endodontic treatment of central and lateral incisor was initiated simultaneously.

Local anesthesia containing lidocaine with 1:200,000 adrenaline (Lignocaine-ADR, Searle, India) was infiltrated in the mucobuccal fold near the apices of the left central and lateral incisor. Rubber dam (Hygienic, Coltene) was applied for isolation and dry field. Access cavity was prepared with Endo Access bur (Dentsply) in high-speed handpiece for both teeth. Access cavity for lateral incisor was extended mesially and buccally for straight line access to the first curve of the root distally. The canal was calcified in the coronal part of the canal [Figure 1]a. Ethylenediaminetetraacetic acid gel (Avueprep, India) was applied to the calcified orifice that was light colored than the surroundings. No. 10 K-file (Mani Inc., Japan) was used in light watch winding motion and was wiggled to the first curve of the canal [Figure 1]b. The straight line access was confirmed radiographically with the help of 10 K-file (Mani Inc., Japan) as the root was assessed to be very thin near the first curvature in preoperative radiograph [Figure 1]b.

Working length with apex locator (Root ZX, J. Morita, Japan) followed by radiographic confirmation for the central incisor was done. 10 K-file was binding at the first curvature at 15 mm length of the lateral incisor. The hand file was not pushed in the canal to avoid unnecessary ledging of the curvature [Figure 1]b.

Step-back technique was followed after apical preparation to size 50 K-file (Mani Inc., Japan) for the right central incisor. The shaping of the lateral incisor was started with preparation of the first curvature that was found to be up to 15 mm length radiographically [Figure 1]b. The canal was enlarged to size 15 K-file (Mani Inc., Japan) followed by ProGlider (Dentsply, India) rotary file up to 15 mm length of the first curvature.

10 K-file (Mani Inc., Japan) negotiated canal further up to working length of 23.5 mm that was confirmed with apex locator (Root ZX, J. Morita, Japan) followed by a radiograph [Figure 1]c. Size 20 K-file (Mani Inc., Japan) was used for apical preparation followed by rotary preparation of the canal up to working length with size 20 and 04 taper Neoendo Flex file (Orikam Healthcare, India). The root was very thin in the middle third; hence, decision was made for 04 taper of the preparation till working length as greater tapers may have caused perforation of the root in the middle third. Copious alternating irrigation with normal saline and 3% sodium hypochlorite (Parcan, Septodont, India) along with special attention to the torque and rpm as recommended by the manufacturer for rotary file was followed during preparation. Prepared canal was packed with radiopaque calcium hydroxide (Avuecal, Dental Avenue, India) with the help of size 20 hand K-file (Mani Inc., Japan) [Figure 1]d.

Master cone radiograph was taken with size 20 taper 04 gutta-percha (Dentsply, India) and tug-back was confirmed for the cone fit [Figure 1]e. Final irrigation was done with copious normal saline followed by 5 ml of 2% chlorhexidine (Dentochlor, Ammdent, India) with positive pressure side vented 30-gauge irrigation needle (Krident Surgicals, India). The canal was dried with size 20 taper 04 paper point (Dentsply, India). Obturation was completed with lateral compaction technique using nickel–titanium spreaders (Mani Inc., Japan) and calcium hydroxide-based sealer; Sealapex (Sybron Endo, USA) was used as a sealer [Figure 1]f.

Follow-up radiograph after 6 months indicated good healing of the periapical tissues [Figure 1]g.

  Discussion Top

Prognosis of a root-filled tooth mainly depends on the adequate debridement of the root canal system when maintaining the original root canal shape after instrumentation.[7] In the present case, two curvatures were encountered, one in the middle third and the other in the apical third [Figure 1]. Root canal curvatures exhibit different shapes. It may be apical, gradual, sickle shaped, severe, moderate-straight curve, bayonet/S-shaped curve, and dilacerated curve. S-shaped canals exhibit great difficulty in all steps of endodontic therapy[8] as seen in the presented case. Strategic planning has a very important role in the management of double-curved, S-shaped, or dilacerated root canals.[9]

The application of CBCT in such cases can help determine the exact position and angulation of the dilacerations, but if the dilaceration occurs to be mesially or distally, it can be clearly identified on a periapical radiograph.[4] Hence, CBCT imaging was not taken in this case as the curvatures could be easily identified in the periapical radiograph.

The access cavity was flared in the coronal third, to reduce the angle of curvature that makes the approach to the second curve much easier. The access was also encroached more to the mesial marginal ridge and the incisal edge to have control and better tactile sensation of the two curves in the root.

Double-curved canal as in this case requires flexible instruments for preparation and obturation; hence, glide path files such as ProGlider file (Dentsply Maillefer, Switzerland) were used in two phases for each curvature after manual instrumentation with 10 K-file (Mani Inc., Japan). The glide path for coronal canal preparation was followed by 04 taper preparation of the canal that allowed further negotiation of the apical third of the canal with manual instrumentation and the glide path preparation easily. 04 taper was kept for the final preparation. The final results of instrumentation of curved canals are influenced by several factors such as the flexibility and diameter of the endodontic instruments, instrumentation techniques followed, location of apical foramen, and hardness of dentin. The flexibility of the preparation instruments has a very important role.[10]

The undesirable occurrences that have been observed after preparation of curved root canals include ledge formation, canal blockages, loss of working length, perforations, and apical transportation.[11] Therefore, determination of the degree of curvature before starting endodontic treatment becomes a necessity to avoid these errors. In the present case, angles of curvature were measured with Schneider's method for the first and second curve of the canal to be 70° and 45°, respectively, that pointed to the high level of difficulty of the case.[12] It was used for root because of its simplicity and wider acceptance.[3],[13]

A customized treatment plan is necessary for the management of S-shaped root canals. It was done for this case. The degree of root canal curvature is categorized as straight when angle is 5° or less, moderate when the angle is 10°–20°, and severe when the angle is 25°–70°.

S-shaped canal has two curves, with the apical curve being very difficult to negotiate. The chances of strip perforation are very high in such cases. Preflaring the coronal one-third of the curved canal was suggested by Gutmann.[14] He claimed that it will reduce the angle of curvature to avoid mishaps. In this case, although coronal preflaring was achieved meticulously, loss of dentin on the inner wall of the first curve was observed due to thin dentinal walls. Various techniques have been suggested in literature for the management of curved root canals that reduce the incidence of procedural errors:

  1. Decreasing the restoring force of the file by precurving the hand file, using smaller ISO sized files for initial negotiation, use of intermediate size of files, and using flexible files
  2. Decreasing the length of the actively cutting files by anticurvature filing, modification of the cutting edges, using coronal flaring, and crown-down technique.[3],[15],[16]

In the present case, straight line access was achieved followed by precurved small no. 10 K-file was used to negotiate the middle third of canal, and then a flexible glide path file “ProGlider” and Neoendo 04 tapered file were used. The same procedure was repeated after complete cleaning of the first and second curvature of the canal with 3% sodium hypochlorite solution.

Obturation was completed with gold standard lateral condensation technique using standard 04 taper gutta-percha and flexible nickel–titanium spreaders with minimal pressure to avoid perforation or fracture of the root. Warm obturation method was avoided in this case. It might induce fracture in thin roots with the vertical force although it has been shown to have sealability and radiographic density almost similar to that of lateral condensation technique.[17]

  Conclusion Top

The double-curved root requires a strategic approach for managing each curvature with glide path taking into consideration the thickness of the root and angle of curvature of the root canal with knowledge, skill, and judgment of the operator.

It is important for a clinician to have complete knowledge of internal anatomy relationships and careful interpretation of radiographs before any treatment of a double-curved canal.[4]

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


Conflicts of interest

There are no conflicts of interest.

  References Top

Mahgoub MM, Hashem AA, Ahmed HM. Endodontic management of a maxillary lateral incisor with an unusual root dilaceration diagnosed with cone beam computed tomography. Saudi Endod J 2017;7:50-3.  Back to cited text no. 1
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Ahmed HM, Hashem AA. Accessory roots and root canals in human anterior teeth: A review and clinical considerations. Int Endod J 2016;49:724-36.  Back to cited text no. 2
Sakkir N, Thaha KA, Nair MG, Jospeh S, Christalin R. Management of dilacerated and S-.shaped root canals – An endodontic challenge. J Clin Diagn Res 2014;8:ZD22-4.  Back to cited text no. 3
Jafarzadeh H, Abbott PV. Dilaceration: Review of an endodontic challenge. J Endod 2007;33:1025-30.  Back to cited text no. 4
Malcić A, Jukić S, Brzović V, Miletić I, Pelivan I, Anić I. Prevalence of root dilaceration in adult dental patients in Croatia. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2006;102:104-9.  Back to cited text no. 5
Udoye CI, Jafarzadeh H. Dilaceration among Nigerians: Prevalence, distribution, and its relationship with trauma. Dent Traumatol 2009;25:439-41.  Back to cited text no. 6
Peters OA. Current challenges and concepts in the preparation of root canal systems: A review. J Endod 2004;30:559-67.  Back to cited text no. 7
Jain N, Tushar S. Curved canals: Ancestral files revisited. Indian J Dent Res 2008;19:267-71.  Back to cited text no. 8
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Machado R, Chaniottis A, Vera J, Saucedo C, Vansan LP, Silva EJ. S-shaped canals: A series of cases performed by four specialists around the world. Case Rep Dent 2014;2014:359438.  Back to cited text no. 9
Mounce R. Negotiating challenging mid root curvatures: Rounding the bend. Dent Today 2007;26:108, 110, 112.  Back to cited text no. 10
Hamasha AA, Al-Khateeb T, Darwazeh A. Prevalence of dilaceration in Jordanian adults. Int Endod J 2002;35:910-2.  Back to cited text no. 11
Schneider SW. A comparison of canal preparation in straight and curved root canals. Oral Surg Oral Med Oral Path 1971;32:271-5.  Back to cited text no. 12
Balani P, Niazi F, Rashid H. A brief review of the methods used to determine the curvature of root canals. J Res Dent 2015;3:57-63.  Back to cited text no. 13
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Gutmann JL. Problem Solving in Endodontics. 3rd ed.. Missouri: Mosby-Year Book Inc.; 1997. p. 116.  Back to cited text no. 14
Ansari I, Maria R. Managing curved canals. Contemp Clin Dent 2012;3:237-41.  Back to cited text no. 15
[PUBMED]  [Full text]  
Vinothkumar TS, Kandaswamy D, Arathi G, Ramkumar S, Felsypremila G. Endodontic management of dilacerated maxillary central incisor fused to a supernumerary tooth using cone beam computed tomography: An unusual clinical presentation. J Contemp Dent Pract 2017;18:522-6.  Back to cited text no. 16
Gilhooly RM, Hayes SJ, Bryant ST, Dummer PM. Comparison of cold lateral condensation and a warm multiphase gutta-percha technique for obturating curved root canals. Int Endod J 2000;33:415-20.  Back to cited text no. 17


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