|Year : 2022 | Volume
| Issue : 3 | Page : 322-330
Management of mandibular premolars with various C-shaped root canal configurations: A case series
Najma Abdulla Essa Al-Mahroos1, Sara Abdulla Essa Al-Mahroos2, Saad Al-Shahrani3
1 Department of Endodontics, Dammam Medical Complex, Eastern Health Cluster, Ministry of Health, Dammam; Department of Dental, Armed Forces Hospital, Dhahran, Saudi Arabia
2 Department of Endodontics, Dammam Medical Complex, Eastern Health Cluster, Ministry of Health, Dammam, Saudi Arabia
3 Department of Dental, Armed Forces Hospital, Dhahran, Saudi Arabia
|Date of Submission||01-Feb-2022|
|Date of Decision||24-Mar-2022|
|Date of Acceptance||26-Mar-2022|
|Date of Web Publication||1-Sep-2022|
Dr. Najma Abdulla Essa Al-Mahroos
Department of Endodontics, Dammam Medical Complex, Eastern Health Cluster, Ministry of Health, P.O. Box: 13834 Dhahran 31311
Source of Support: None, Conflict of Interest: None
C-shaped canal configuration poses a challenge to the clinician, both at the diagnostic and treatment levels. The present case series aims to describe the management of mandibular premolars that have various C-shaped configurations. Three healthy Saudi females were referred to the endodontic department for the management of premolars that appear unusual radiographically. The teeth response was normal to palpation and percussion. The cold test was negative for the concerned premolars. A diagnosis of either necrosis or previously initiated was established for the pulpal condition. The periapical tissues were diagnosed as normal/asymptomatic apical periodontitis. Modern endodontic tools such as a limited field of view cone-beam computed tomography, the dental operating microscope, and nickel–titanium files were used to negotiate, clean, and shape the root canal system. While EndoActivator sonic irrigant activation was used to effectively disinfect the uninstrumentable ramifications, thermo-plasticized gutta-percha in continuous-wave compaction technique was used to fill the root canal system. During a 12-month follow-up, the clinical and radiographic evaluation revealed no signs and symptoms and periapical healing of the lesion associated with the tooth in case #1. The other premolars were also free of signs and symptoms, with normal apical tissues.
Keywords: Anatomical aberrations, C-shaped, mandibular premolar, root canal morphology, unusual configuration
|How to cite this article:|
Al-Mahroos NA, Al-Mahroos SA, Al-Shahrani S. Management of mandibular premolars with various C-shaped root canal configurations: A case series. Saudi Endod J 2022;12:322-30
|How to cite this URL:|
Al-Mahroos NA, Al-Mahroos SA, Al-Shahrani S. Management of mandibular premolars with various C-shaped root canal configurations: A case series. Saudi Endod J [serial online] 2022 [cited 2022 Oct 5];12:322-30. Available from: https://www.saudiendodj.com/text.asp?2022/12/3/322/354833
| Introduction|| |
C-shaped morphology is an anatomical configuration that has been described first by Cooke and Cox in 1979. This pattern is assumed to be caused by a lack of fusion of Hertwig's epithelial root sheath during tooth development or by continuous cementum deposition on the lingual side. That results in a groove or concavity formation on the external root surface, which gives a C-shaped root configuration. In addition, the canal shape is not always continuous from the canal entrance to the apical foramen and can vary along the root length with isthmuses connecting individual canals.
Various classification has been proposed for this pattern based on the cross-section, Fan et al. modified the findings of Min et al. and Wu et al. to create new categories which include category I (C1): a continuous 'C' with no separation or division; category II (C2): discontinuation in the 'C' outline (semicolon-like); category III (C3): two separate round, oval or flat canals; category IV (C4): only one round, oval or flat canal in that cross-section; category V (C5): three or more separated canals in the cross-section; and category VI (C6): no canal lumen could be observed. The C-shaped canal was divided into three distinct axial planes: coronal; 2 mm below the cementoenamel junction, middle (halfway between coronal and apical), and apical (2 mm just above the anatomical apex).
C-shaped canals present a significant challenge to clinicians in terms of diagnosis and therapy. This is due to the fact that the distinctive anatomy of the root canal system is not easily apparent on a conventional two-dimensional periapical radiograph.,, Therefore, the operator may only become aware of the root canal system's anatomy when faced with unusual shape and floor of the pulp chamber. With the limited field of view cone-beam computed tomography scanning (CBCT) for endodontic treatment planning, clinicians may be able to discover and diagnose C-shaped canals more accurately before initiating root canal treatment. Even if a C-shaped canal is recognized, cleaning, shaping, and obturating, a C-shaped canal system presents a difficulty to the clinician throughout the root canal procedure.,
It is not uncommon to encounter anatomical variations such as the C-shaped pattern when treating mandibular second molars; they may also be encountered to a lesser extent in mandibular and maxillary molars as well as mandibular premolars.
Many studies have been conducted to investigate the prevalence of C-shaped configuration in mandibular premolars among different ethnic groups.,,,,,,,, Boreak et al. conducted a recent study in Saudi Arabia using CBCT regarding the cross-section of premolars and found significant variation in the coronal and middle root canal cross-sectional shapes, though the circular shape was the most prevalent root canal cross-section in the apical third. They found also that a C-shaped cross-section occurred only in 1% of mandibular first premolars. This supports the low incidence of C-shaped root canal configuration in mandibular premolars. Al-Mahroos et al. were the first to report the management of C-shaped mandibular premolars in Saudi Arabia. More case reports were published later.,, Although the number of published C-shaped root canal treated cases in Saudi Arabian population is low, this does not reflect that they are in fact, few; rather, they are not documented or categorized. The purpose of this case series is to describe the diagnosis and clinical management of four mandibular premolars with C-shaped roots with various root canal morphologies using modern endodontic technologies. These cases were treated in the dental department of the Armed Forces Hospital in Dhahran, Saudi Arabia.
| Case Reports|| |
Cases 1 and 2
A 23-year-old female was referred to the endodontic department for the treatment of the lower-left premolars that appeared unusual on the periapical radiographs. Her medical history was noncontributory. The past dental history revealed multiple restorations and root canal treatments. The extraoral assessment revealed no significant findings.
On intraoral assessment, the mandibular left first premolar (#34) had an occlusal-distal defected glass ionomer restoration while the mandibular left second premolar (#35) had a temporary filling [Figure 1]a. Teeth #34, #35 responded negatively to the cold test (Endo-Frost, Coltene Whale Dent, Germany) and responded normally to palpation and percussion. The depth of the periodontal pocket was measured and found to be within normal ranges [Table 1]. Radiographic examination of both teeth revealed unusual anatomy with normal periapical tissue in #34 while #35 had a periapical lesion [Figure 1]b and [Figure 1]c. A limited field of view CBCT was performed on the lower left quadrant, confirming the presence of C-shaped roots with longitudinal mesiolingual external grooves and a common coronal canal that bifurcate into two canals in the middle one-third, rejoining in the apical third to exit from the same foramen [Figure 1]d, [Figure 1]e, [Figure 1]f. Based on Fan et al.'s classification, the canal cross-section was found to have the following categories; C1 in the coronal third, C2 in the middle third, and C4b in the apical third of the canal.
|Figure 1: (a) Preoperative clinical photograph of #34 and 35. (b and c) Straight and mesial angulated preoperative radiographs. (d) Axial view CBCT showing the middle third of C-shaped mandibular first and second premolar. (e) Coronal view CBCT of tooth #35 showing canal configuration. (f) Coronal view CBCT of tooth #34 showing canal configuration. (g) Tooth #35 working length radiograph. (h and i) Straight and mesial angulated immediate postoperative radiographs of tooth #35. (j) Tooth #34 working length radiograph. (k and l) Straight and mesial angulated immediate postoperative radiographs of tooth #34. (m and n) 12 months recall straight and mesial angulated periapical radiographs of teeth #34 and #35. CBCT: Cone-beam computed tomography|
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Clinical and radiographic examination of #34 led to the diagnosis of necrotic with normal apical tissue, while #35 was previously initiated with asymptomatic apical periodontitis; therefore, nonsurgical root canal treatment (NSRCT) was recommended in both. Following patient approval, it was preferred to begin with #35, as this had previously been initiated, and the patient was still in pain. Old defective restorations and caries were removed under local anesthesia (2% Xylocaine with 1:80,000 epinephrine) and rubber dam isolation. The access cavity was modified using an Endo Z bur (Dentsply Maillefer, Ballaigues, Switzerland). Examination under the dental operating microscope (DOM) confirms the existence of a C-shaped canal configuration in the coronal third of the root with mid-root bifurcation. The bifurcation was hardly negotiated with two 10 K-files (Dentsply Maillefer, Ballaigues, Switzerland) since the two canals were abruptly furcating.
Ultrasonic tips were utilized to create straight-line access under the DOM, which helped to avoid the removal of unnecessary dental structures. The canals' coronal orifices were enlarged using ProTaper SX rotary files (Dentsply-Tulsa Dental), which were used with a brushing motion. The working length was measured using an electronic apex locator (Root ZX II, J. Morita, Tokyo, Japan) and radiographically verified [Figure 1]g. After establishing canal patency with pre-curved size 10 K-files, the canals were instrumented using ProTaper files operated at 300 rpm, and all canals were irrigated after each file with 5.25% sodium hypochlorite (NaOCl), The canal preparation was continued with S1 rotary file followed by the S2, F1, and F2 rotary files. The canals were then rinsed with 17% ethylenediaminetetraacetic acid, with a final flush of 5.25% NaOCl, and dried using paper points. To maximize the effect of the irrigation, it was paired with the use of the EndoActivator device. Matching gutta-percha cones and an AH Plus sealer (Dentsply Maillefer, Ballaigues, Switzerland) were used to three-dimensional obturate and seal the root canal system using continuous-wave compaction technique [Figure 1]h and [Figure 1]i. Finally, Cavit (3M, ESPE, St. Paul, MN, USA) and self-curing glass ionomer restorative material (Riva self-cure, SDI, Victoria, Australia) were utilized to double seal the access cavity, and the patient was scheduled for another appointment to manage tooth #34.
After 2 weeks, the patient returned for the management of tooth #34. On clinical examination, she reported that the symptoms associated with tooth #35 gradually subsided after the treatment. The NSRCT of tooth #34 was conducted following the same protocol described in case report #1 [Figure 1]j, [Figure 1]k, [Figure 1]l. Following that, the case was referred to a prosthodontic clinic for final restorations of both premolars. After 12 months, the patient presented with no signs or symptoms, soft tissues were normal. The periapical radiograph indicated normal periapical tissues apical to tooth #34, and periapical healing of the lesion related to tooth #35 [Figure 1]m and [Figure 1]n.
A 32-year-old female was referred to the endodontic department for the treatment of the tooth #34 that appeared unusual on the periapical radiographs. Her medical history was noncontributory. The past dental history revealed multiple restorations and extractions. The extraoral assessment revealed no significant findings.
On intraoral assessment, tooth #34 had an occlusal-distal glass ionomer restoration [Figure 2]a. The tooth demonstrated a negative response to the cold test but exhibited normal palpation and percussion responses. Periodontal pocket depth was measured and found to be within the normal range [Table 1]. Radiographic evaluation showed an unusual anatomical configuration with normal periapical tissue [Figure 2]b and [Figure 2]c. A limited field of view CBCT scan of the left mandibular quadrant indicated that #34 had a C-shaped root with an exterior longitudinal groove and a single coronal canal that bifurcated into two canals in the middle third and exited through distinct apical foramina [Figure 2]d, [Figure 2]e, [Figure 2]f, [Figure 2]g. Based on Fan et al.'s classification, the coronal third of the canal has a C1 root canal configuration, whereas the middle and apical thirds have a C3 root canal configuration. The clinical and radiographic examination led to the diagnosis of previously initiated pulp therapy with normal apical tissue. As a result, NSRCT was advised. Under local anesthesia (2% Xylocaine and 1:80,000 epinephrine) and rubber dam isolation, the previous defective restorations and caries were removed. DOM inspection revealed a C-shaped canal pattern in the coronal region of the canal [Figure 2]h. The root canal treatment steps were carried out in the same way as in cases 1 and 2 [Figure 2]i, [Figure 2]j, [Figure 2]k. The access cavity was double sealed using Cavit and self-curing glass ionomer restorative material. Following that, the case was referred to a prosthodontic clinic for the final restoration. After 12 months, the patient presented without any signs or symptoms, soft tissues were within normal, and the tooth received final restoration (composite build up). Periapical radiograph revealed normal periapical tissues [Figure 2]l, [Figure 2]m, [Figure 2]n.
|Figure 2: (a) Preoperative clinical photograph of tooth #34. (b and c) Straight and mesial angulated preoperative radiographs. (d) Axial view CBCT in the coronal third of the root showing C-shaped configuration. (e) Axial view CBCT in the middle third of the root showing two canals. (f) Coronal view CBCT showing mesio-lingual groove. (g) Sagittal view CBCT showing canal configuration. (h) Clinical photograph of the access cavity. (i) Working length radiograph. (j and k) Straight and mesial angulated immediate postoperative radiographs. (l and m) 12 months follow up straight and mesial angulated periapical radiographs. (n) 12 months follow up clinical photograph. CBCT: Cone-beam computed tomography|
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A 45-year-old female patient reported an emergency case to the Endodontic Department with the chief complaint of pain related to the mandibular posterior left premolar area. Her medical history was not relevant. Multiple restorations were detected in the patient's dental history. No significant findings were revealed during the extraoral examination.
The intraoral assessment revealed that Tooth #35 had a fallen temporary restoration, recurrent caries, and exposed pulp [Figure 3]a. The tooth demonstrated a negative response to the cold test but exhibited normal palpation and percussion responses [Table 1]. The periodontal pocket depth was assessed and found to be within the normal range. The tooth's radiographic examination revealed uncommon anatomy with normal periapical tissue [Figure 3]b and [Figure 3]c. Clinical and radiographic examinations lead to the diagnosis of previously initiated pulp therapy with normal apical tissues, indicating the need for NSRCT. Under local anesthesia (2% Xylocaine and 1:80,000 epinephrine) and isolation with a rubber dam, previous defective restorations, and caries were removed. The access cavity was modified using an Endo Z bur then the working length was determined [Figure 3]d and [Figure 3]e. Under DOM, it was observed that the coronal third of the root has a C-shaped canal configuration that is divided into three root canals (two buccal and one lingual). Based on Fan et al.'s classification, the canal was found to have the following categories; C1 in the coronal third, C5 in the middle third, and C4a in the apical third of the canal. The NSRCT was performed in the same manner as in previous cases, and the access cavity was double sealed with Cavit and a self-curing glass ionomer restorative material [Figure 3]f and [Figure 3]g. Following that, the patient was referred to a prosthodontic clinic for the final restoration. After 12 months, the patient presented without any signs or symptoms, the soft tissues were within normal, and the tooth received composite build-up. Periapical radiograph revealed normal periapical tissues [Figure 3]h, [Figure 3]i, [Figure 3]j.
|Figure 3: (a) Preoperative clinical photograph of tooth #35. (b and c) Straight and mesial angulated preoperative radiographs. (d) Working length radiograph. (e) Clinical photograph of the access cavity. (f and g) Straight and mesial angulated immediate postoperative radiographs. (h and i) 12 months follow up straight and mesial angulated periapical radiographs. (j) 12 months follow up clinical photograph|
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| Discussion|| |
The mandibular premolar, commonly known as the “Endodontist's Enigma,” is one of the most difficult teeth to treat endodontically and can present a significant challenge for successful endodontic therapy. This is due to their anatomical complexity, unpredictability, as well as a having variety of morphological aberrations.
One of the morphological variations in mandibular premolars is the C-shaped canal configuration with a unique cross-section and three-dimensional geometry marked by external radicular grooves and internal isthmuses connecting individual canals. In this case series, four mandibular premolars have been identified based on the Fan's classification as having C-shaped roots and various root canal configurations.
There were no male patients in the present cases which were reflective of Huang and Sert's findings., On the other hand, most other studies did not pay attention in comparing the differences between male and female patients.
Understanding root canal system morphology before performing any treatment significantly improves chemomechanical preparation, permits three-dimensional obturation, and protects the tooth from catastrophic damages. Conventional radiography does not provide as much information as CBCT does when managing challenging endodontic cases in clinical practice. As it is a two-dimensional image presenting a three-dimensional object? CBCT can help in determining root canal morphology as it provides the clinician with three-dimensional comprehensive morphological details without superimposition. The AAE and AAOMR Joint Position Statement forcefully reinforced this approach.
CBCT image was taken in three cases, but the CBCT machine was not working in the fourth, so we relied mostly on an angulated periapical radiograph and the DOM to carefully treat and manage that case. DOM provides numerous advantages, including improved visibility, overall quality and accuracy of treatment, more ergonomic working position, and digital documentation. The usage of DOM in the present cases allowed for the early detection of the C-shaped canal systems, allowing for the management of all cases to be completed accurately with less time and effort.
Teeth with radicular grooves more often presented with a greater incidence of complicated root and root canal anatomies., These results coordinate with this clinical case series, where the presence of a radicular groove was detected in the CBCT with variable root canal morphology.
Vertucci categorized root canal configurations into eight categories; this classification was expanded by Sert and Bayirli to cover 14 additional configurations, allowing us to categorize more complex canal configurations. In the current case series, two C-shaped premolars presented with type III root canal configuration, one with type V, and the last premolar had type XVII root canal configuration which is rare, and up to our knowledge, it was not reported before in the literature as a clinical management report. Conventional NSRCT was the treatment of choice as it has an excellent long-term outcome due to its ability to disinfect and three-dimensional seal the root canal system., Effective root canal debridement is mainly dependent on precise measurement of working length; the electronic apex locator aided in this determination., In terms of accuracy, Root ZX is the most precise electronic apex locator available, with a precision of 94% within ±0.5 mm of the working length. In our cases, we also employed radiographs to determine working length measurements because the use of an electronic apex locater in conjunction with radiographs can improve the accuracy of working length measurement and length control throughout root canal treatment.
C-shaped canal morphology has a flat oval surface. Regardless of the instrumentation approach employed, the preparation of oval-shaped root canals leaves a variable amount of surface area unprepared. However, treating oval canals as two distinct canals during preparation seems to be advantageous in terms of expanding the overall prepared surface. Endodontic outcomes appear to be dependent mainly on root canal disinfection. Microorganisms are eradicated using a combination of mechanical preparation and irrigation.,, In our cases, ProTaper rotary files were used in brushing motion combined with copious irrigation of 5.25% NaOCl for optimal canal disinfection with extra caution in the area of the radicular groove as it has the thinnest dentin thickness. Clinicians should be aware of the higher risk of root perforation at danger zones during shaping and postspace preparation procedures. To ensure the success of the therapy and minimize the possibilities of failure, the thermoplastic gutta-percha is used in the continuous-wave compaction technique to obtain three-dimensional obturation of the root canal system.,
The treatment method in the current cases demonstrated a good clinical and radiological outcome. After 12 months of follow-up, clinical and radiological examination revealed periapical healing of the lesion related to the second premolar in the first case and the absence of pain and periapical pathosis in other cases.
One study using CBCT and few case reports was published that deal with C-shaped mandibular premolars in Saudi Arabia.,,,,, More studies are needed to update the knowledge of local clinicians and their understanding of complex root canal morphology. The clinician's growing experience and acceptance of the new patterns revealed by dramatic advances in the era of Endodontics may all contribute to raising awareness and accumulating evidence. This case report was prepared according to the PRICE 2020 Guidelines [Figure 4].
| Conclusions|| |
This series confirms the significant morphological variation of mandibular premolars, especially those with radicular grooves and C-shaped roots. Keeping that in mind, as well as the prudent use of all available radiographic imaging, magnification, tools, and materials, will assist the clinician in early identifying and managing that complex configuration more efficiently, thereby aiding in the restoration of patients' oral health, comfort, and wellness.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for 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 identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]