Abstract:
Successful root canal treatment counts on the clinician’s knowledge and ability to manage unusual anatomic variations. One root with one canal is the usual appearance of the mandibular canine. This report presents an endodontic management of uncommon case of a mandibular canine with two rooted and two canals.
Thirty-year-old Saudi female referred from the prosthodontic clinic for root canal treatment of the lower left canine. All steps were conducted within the current state-of-the-art practices in endodontics, starting with appropriate clinical and radiographical interpretation and diagnosis, proper anaesthesia, watertight seal rubber dam isolation and dental microscopic and ultrasonic endodontic tips usage to facilitate access cavity preparation and canal localisation. Distinct debridement and accurate instrumentation of the canals followed by 3D obturation promote the successful treatment of such anatomical aberrations. Inadequacy of any step may lead to post-treatment disease and further failure of the treatment.
Introduction:
Canines are the “cornerstone” of the mouth and the reason behind this is their efficiency in mastication, stability of dental arch, and support natural facial expression.1
The reported configuration and number of root canals in permanent mandibular canine had high variation among different studies, in most of the cases mandibular canines have only one canal.2,3 The incidence of getting a single-rooted with two canals in mandibular canine is approximately 15%.2–5 While getting two rooted with two canals is reported to be up to 5%.6,7
Successful root canal treatment intents to eradicate microorganisms from the entire root canal space, complete sealing of the canal space, and preserve the integrity of periapical tissue that requires full understanding of the root canal morphology.8,9
The following case report outlines the management of a mandibular canine with uncommon morphology including two canals in two separated roots.
Case Presentation:
Thirty-year-old Saudi female presented to the Endodontic clinics at Princess Nourah Bint Abdulrahman University, Dental college, Riyadh, KSA for endodontic management of the left mandibular canine by a referral from the prosthodontic clinic in order to restore the tooth with post and core followed by a crown. She was medically fit neither having allergies nor taking any medications. Clinical examination revealed a defective restoration with recurrent caries. Thermal tests exhibit a negative response. Normal palpation and percussion response. Periodontal pocket depth was within normal. Radiographic evaluation revealed a loss of the continuity within the middle third of the canal with normal periapical tissue (Figure 1). Based on the findings, a diagnosis of necrotic pulp with normal apical tissue, therefore a primary root canal treatment was planned.
A consent form was obtained, local anaesthesia was given with epinephrine using infiltration technique, rubber dam isolation. Caries and defective restoration were removed. Dental operating microscope (DOM) (Global Dental Microscopes A6, Global Surgical Corporation, USA) was used for the inspection of the pulp chamber floor. Two orifices were found buccally and lingually using ultrasonic tips. Preparation of a straight-line access cavity focusing on preventing extreme removal of tooth structure. Electronic apex locator Root ZX II (J. Morita, Tokyo, Japan) was used to establish the working length and proved radiographically (Figure 2a-d).
Instrumentation was accomplished to size 35 Profile rotary system (Dentsply Maillefer, Ballaigues, Switzerland). Sodium hypochlorite 5.25% and Ethylenediaminetetraacetic acid (EDTA) 17% were used for irrigation in combination with the use of the EndoActivator system kit (Dentsply Maillefer, Switzerland). Paper points were used to dry the canals then Gutta-percha cones along with AH Plus sealer (Dentsply Maillefer, Ballaigues, Switzerland) were used in continuous wave compaction technique for obturation. Accurate length and density of the obturation that was shown in the radiographs.
Access cavity was sealed using GIC (GC Fuji II LC, United states). The patient was referred to the prosthodontic clinic to proceed with the prosthetic treatments.
The 6-month follow-up radiograph showed cast post and core with interim crown, upon clinical and radiographic examinations (Periapical radiographs and CBCT), the tooth revealed absence of tenderness or pain and normal periapical tissues (Figure 3a-d).
Discussion:
The key for successful root canal treatment includes appropriate diagnosis, thorough cleaning, shaping, and tight seal obturation. Neglection of any step will cause postoperative complications, pain, and disease. Thus, the clinician needs to be familiar with any bizarre anatomy and interpret the preoperative radiographs thoroughly by taking multiple angles.10,11
Fast break of the root canal that appears in the radiograph indicates the presence of divided root canal. Inserting gutta-percha cone or file in the canal that appears eccentric will confirm the presence of this condition.12 The use of Cone Beam Computed Tomography (CBCT) is a helpful method to study the root canal morphology because of its ability to produce a 3D image with no superimposition and complete morphologic details.13 CBCT considered a valuable tool in endodontic diagnosis and follow-up.14
Inadequate access preparation causes difficulty in locating all canals which can lead to incomplete removal of bacteria and failure of the endodontic treatment.15 Hoen and Pink reported that 42% of endodontically failing teeth had missed canals.16 A dental operating microscope is a valuable tool in the field of endodontics for the diagnosis of different aberrations in the root canal anatomy.17,18
The use of an electronic apex locator provides accurate working length during root canal treatment.19 Root ZX considered a precise electronic apex locators used for measurement of the root canal working length.20
None of any available irrigation techniques completely eliminate the smear layer from the root canal, especially apically. However, combining the conventional needle irrigation with EndoActivator was more effective at smear layer removal than conventional needle irrigation by itself.21 The use of NiTi endodontic rotary files allows shaping of the canals in a shorter time compared to the conventional manual files, despite complexities of the case.22
Root canal morphology of mandibular canine was studied by many authors. Vaziri et al., reported the incidence of mandibular canines with one root and two canals to be 12% using stereomicroscope.23 Han et al., reported the incidence of having a mandibular canine with two roots was 6.5% using CBCT.24 Moreover, Monsarra et al., reported the incidence of mandibular canines with two roots and two canals to be 2.5%.10 Bizarre anatomy like three canals in two or three roots also have been recorded.25,26
In Saudi Arabia, Aldahman et al., in 2019 reported the incidence of having one root with single canal 95.4% and single root with two canals to be 4.6% while having two roots and two canals 0.2% using CBCT.13
Conclusion:
Despite the limitation of literature reports about the incidence of mandibular canines with two separate roots, clinicians must have an accurate knowledge and a full consideration of the unusual alterations in root canal morphology that can lead to successful endodontic treatment.

Endodontic Treatment of Uncommon morphology of Two-Rooted Mandibular Canine: A Case Report