Journal of Indian Society of Pedodontics and Preventive Dentistry
Journal of Indian Society of Pedodontics and Preventive Dentistry
                                                   Official journal of the Indian Society of Pedodontics and Preventive Dentistry                           
Year : 2014  |  Volume : 32  |  Issue : 3  |  Page : 242--245

A rare case of maxillary first molar with single root and single canal diagnosed using spiral computed tomographic scan

Ajay Saxena, Avantika Singh, Anuja Ikhar, Manoj Chandak 
 Department of Conservative Dentistry and Endodontics, Sharad Pawar Dental College, Sawangi, Wardha, Maharashtra, India

Correspondence Address:
Ajay Saxena
Department of Conservative Dentistry, Sharad Pawar Dental College, Sawangi, Wardha - 442 004, Maharashtra


Variations in dental anatomy and canal morphology are found in all teeth. Knowledge of these variations, particularly the location and treatment of all canals, plays a key role in the success of endodontic therapy. The presence of extra canals, apical ramification, or lateral canals is commonly encountered, and their incidence and significance have been well-documented. However, the clinician should also be aware of the possibility of the existence of fewer root and/or canal numbers. Here is a case report of left maxillary first permanent molar with a single root and single canal. The goal of this clinical article is to report a maxillary molar with single root and single canal and to highlight the role of spiral computed tomography (SCT) as a method to confirm the three-dimensional (3D) anatomy of teeth.

How to cite this article:
Saxena A, Singh A, Ikhar A, Chandak M. A rare case of maxillary first molar with single root and single canal diagnosed using spiral computed tomographic scan.J Indian Soc Pedod Prev Dent 2014;32:242-245

How to cite this URL:
Saxena A, Singh A, Ikhar A, Chandak M. A rare case of maxillary first molar with single root and single canal diagnosed using spiral computed tomographic scan. J Indian Soc Pedod Prev Dent [serial online] 2014 [cited 2020 Sep 18 ];32:242-245
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Variations in dental anatomy and canal morphology are found in all teeth. The complexity of the root canal system of maxillary molars presents a constant challenge; the dentist must have a thorough knowledge of root canal morphology to provide successful endodontic treatment. The form, configuration, and number of root canals present in maxillary first molars have been discussed for more than half a century. [1]

Radiographic examination is an essential component of endodontic management aspects of diagnosis, treatment planning, intraoperative control, and outcome assessment. [2] They are not very helpful in the diagnosis and endodontic management of tooth with complicated root canals as they are two-dimensional (2D) pictures of three-dimensional (3D) objects.

Advanced diagnostic methods such as computerized tomography (CT), Spiral CT (SCT), or Helical CT are of great help as they provide the three-dimensional (3D) images. These imaging techniques overcome the disadvantage of radiographs and have emerged as a powerful tool for evaluation of root canal morphology. [3],[4] With SCT, it is possible to reconstruct overlapping structures at arbitrary intervals, and thus the ability to resolve small objects is increased.

This case report presents a very rare morphologic variation of a single root with single canal in two maxillary first molars and highlights the role of SCT as a pivotal diagnostic tool to confirm the morphologic variations.

 Case Report

A 12-year-old female patient was reported in the clinic with chief complaint of pain in upper left posterior region of jaw. She was having intermittent pain for past two months, which had increased in past two days. Intraoral examination revealed that the left maxillary first molar was carious and tender on percussion.

Thermal and electrical pulp testing elicited a negative response in maxillary left first molar. The pre-operative radiograph shows widening of periodontal ligament space with left maxillary first molar and crestal bone loss was also noted. The radiograph also revealed an unusual anatomy of involved tooth with single root and single canal. Based on the clinical and radiographic evaluation, diagnosis of an irreversible pulpitis with acute apical periodontitis of left maxillary first molar was made, and endodontic treatment was planned.

Access opening was done in the left maxillary first molar under rubber dam isolation. On examination, clinical presence of single canal orifice was found in the centre of the pulpal floor. Further inspection of the pulpal floor revealed the lack of any other canal orifices. To ascertain this unusual morphology, multiple X-rays in variable horizontal angulations were taken. These X-rays revealed the presence of a single canal. Finally, a radiograph was taken with file in the canal [Figure 1].{Figure 1}

To confirm the 3D morphology of this tooth, dental imaging with SCT was planned. Informed consent from the patient was obtained. SCT was performed for maxilla using dental software Dentascan. 3D image of the maxilla was obtained, the tooth in question was focused and its morphology was obtained in longitudinal and transverse cross section of 0.5 mm thickness [Figure 2], [Figure 3], [Figure 4], [Figure 5]. The images revealed that the right maxillary first molar had a single root with a single canal. The canal was uniformly oval in shape. It is interesting to note that during SCT of maxilla, it was observed that the contralateral first maxillary molar also had a similar morphologic variation of single root with single canal [Figure 6].{Figure 2}{Figure 3}{Figure 4}{Figure 5}{Figure 6}

Working length of left maxillary first molar was determined using an apex locater (i Pex, Nsk, Japan). Cleaning and shaping was done using crown-down technique with ProTaper NiTi rotary instruments (Dentsply-Maillefer, USA). Irrigation between instrumentation was done using 5% of sodium hypochlorite solution (Hyposept, Asuwaldi, India). Final irrigation was done with normal saline (NS, Nirlife, India), and root canal space sealed using cold lateral condensation of gutta percha and AH-Plus sealer (Dentsply-Maillefer, USA). The tooth was then subsequently restored [Figure 7].{Figure 7}


Dental anomalies are formative defects and may occur during any of the developmental stages of the tooth, which are manifested clinically in later life once the tooth is fully formed. [5] Morphologic dental anomalies may involve a single tooth, a group of teeth, or the entire dentition. [6]

There are few case reports that were found to have reported similar dental anomalies: Ackerman et al., [6] Holan and Chosack, [7] Gopikrishna et al., [8] Metgud et al. [4] There appears to be a disagreement regarding the term used to describe such a tooth, this includes "pyramidal," "fused," and "conical" but all investigators believe that the failure of invagination of Hertwig epithelial root sheath [5] is responsible for such an anomaly. The presence of pyramidal or conical type of root form in the relatively stable first molars appears to be partly related to multiple invaginations and extrusions of the odontogenic apparatus during morphodifferentiation. [4]

Although extra canals are more of a rule rather than an exception, the clinician should also be aware of the fact that in certain cases, there is a possibility of fused if not fewer canals than the normally presumed canal morphology. Otherwise, the clinician's effort to find another canal may lead to perforation or failure of endodontic treatment. Conventional intra-oral periapical radiographs are an important diagnostic tool in endodontics for assessing the canal configuration. Nevertheless, it is not completely reliable owing to its inherent limitation. [8] Recently, newer diagnostic methods such as CT and SCT overcome the disadvantages of radiographs by providing a 3D image. These imaging techniques have emerged as a powerful tool for evaluation of root canal morphology. [3] The position and inclination of the root within the mandible could only be assessed using CT. CT should be considered before the surgical treatment of mandibular premolars and molars when on the dental radiograph the mandibular canal is not visible or is in close proximity to the root. [9]

The uptake of CT in endodontics has been slow for several reasons, including the high effective dose and relatively low resolution of this imaging technique. [10] However, current CT scanners have a linear array of multiple detectors, allowing "multiple slices" to be taken simultaneously because the X-ray source and detectors within the gantry rotate around the patient who is simultaneously advanced through the gantry. This results in faster scan times and therefore, a reduced radiation exposure to the patient. [11] Thus, in this particular case, SCT was carried out to rule out any possibility of missed canals since presence of single canal in the maxillary first permanent molar is a rarity rather than a rule.


The morphology of teeth is supposed to be the foremost in importance when performing root canal treatment. Anatomical variation continues to be the most challenging aspect of conducting successful endodontic therapy. Precisely, more importance is given to extra canals, merging and demerging canals, apical deltas, and lateral canals but the clinician should also focus on the presence of fewer canals. Recent advances in imaging techniques have made it possible to view an image in 3D, which was missing in two-dimensional (2D) imaging.


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