Year : 2010 | Volume
: 28 | Issue : 2 | Page : 121--125
Permanent maxillary first molar with single root and single canal: A case report of a rare morphology
A Shigli1, A Agrawal2,
1 Professor and Head, Department of Pedodontics and Preventive Dentistry, Modern Dental College and Research Centre, Indore - 453 112, Madhya Pradesh, India
2 Postgraduate Student, Department of Pedodontics and Preventive Dentistry, Modern Dental College and Research Centre, Indore - 453 112, Madhya Pradesh, India
Department of Pedodontics and Preventive Dentistry, Modern Dental College and Research Centre, Indore - 453 112, Madhya Pradesh
Unusual root canal morphology in multirooted teeth is a constant challenge for diagnosis and successful endodontic treatment. Presence of extra canals, lateral canals, deltas is commonly encountered but the possibility of existence of fewer number of roots and canals also exists. This clinical report presents a maxillary first molar with an unusual morphology of single root with single canal. This report also highlights the role of spiral computerized tomography as a method to confirm the three-dimensional anatomy of teeth.
|How to cite this article:|
Shigli A, Agrawal A. Permanent maxillary first molar with single root and single canal: A case report of a rare morphology.J Indian Soc Pedod Prev Dent 2010;28:121-125
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Shigli A, Agrawal A. Permanent maxillary first molar with single root and single canal: A case report of a rare morphology. J Indian Soc Pedod Prev Dent [serial online] 2010 [cited 2022 Jan 27 ];28:121-125
Available from: https://www.jisppd.com/text.asp?2010/28/2/121/66755
The dentist must have a thorough knowledge of root canal morphology before he can successfully treat a tooth endodontically.  The form, configuration, and number of root canals present in maxillary first molars have been discussed for more than half a century. , Maxillary first molar in majority of cases has three roots and four canals, but tooth with unusual morphology also exists. , Routinely, root canal morphology can be diagnosed using conventional radiographs.  Spiral computerized tomography scan (SCT) is a newer three-dimensional modality to diagnose root and canal morphology.
This clinical report presents a maxillary first molar with an unusual morphology of a single root and single canal, which has not been reported in the literature in pediatric age group so far, and discusses the use of SCT as a diagnostic modality tool to confirm the same.
A 11-year-old female child patient reported to Department of Pedodontics and Preventive Dentistry at Modern Dental College and Research Centre, Indore, India, with a complaint of pain in upper left posterior region since 5 days. She gave a history of intermittent pain for the last 2 months which had increased in intensity since 5 days. She also had a history of difficulty in chewing due to pain on the left side. Examination revealed occlusal caries of left maxillary first molar. The tooth was tender on percussion. Thermal and electrical pulp testing produced negative response in left maxillary first molar. Gingiva showed features of inflammation. All other teeth were normal. Pre-operative periapical radiograph revealed widening of periodontal ligament in relation to left maxillary first molar. The radiograph also showed unusual anatomy of single root with single canal. A diagnosis of nonvital left maxillary first molar with acute periapical periodontitis was made and root canal treatment was planned [Figure 1]a.
Access opening was done in left maxillary first molar under rubber dam isolation. On examination, clinical presence of single wide orifice was found in the center of the pulpal floor. Further inspection of the pulpal floor was done for search of other orifices that were absent. To confirm this morphology, multiple X-rays were taken in variable horizontal angulations which showed broader single canal bucco-lingually. On instrumentation, all scouting files converged into a single broad canal [Figure 1]b.
Working length was determined using radiograph (Angle's Method). Cleaning and shaping was done using step back technique using hand instrumentation. Irrigation between the instrumentations was done using 2.5% sodium hypochlorite solution. Final irrigation was done with 17% EDTA (Ethylene diamine tetraacetic acid) and root canal space was sealed using cold lateral compaction of gutta percha (Dentsply, U.S.A.) and zinc oxide eugenol sealer. The tooth was subsequently restored [Figure 1]c. On follow-up visits, the patient was clinically asymptomatic after 2 years [Figure 1]d and e .
To confirm the three-dimensional morphology of this tooth, dental imaging with SCT was planned. Informed consent from the patient was obtained. A multislice helical or SCT was performed of maxilla (64 Slice Seimen's Machine Germany) using dental software Dentascan. Three-dimensional 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. The image showed that left maxillary first molar had a single root and a single obturated canal. The canal was uniformly oval in shape. The contralateral tooth also had a similar morphology [Figure 2]a-f.
Burns described the maxillary first molar as "...possibly the most treated, least understood, posterior tooth".  A better knowledge of the root canal system is an absolute necessity for a successful root canal treatment.
Weine divided the position of one or two canals within one root into four categories (Weine I-IV).  Vertucci described a classification encompassing eight different types. 
A literature search was done to ascertain the existence of such an unusual morphology. None could be found in pediatric age, Gopalkrishna et al. have reported a case of a 48-year-old female having maxillary first molar with single root and single canal. They stated that anomalies in root canal morphology can be in the form of fewer canals and they used SCT scan to confirm the root canal morphology.  Cobankara et al. reported a case of a 36-year-old male and used radiographs to diagnose unusual morphology of permanent maxillary molar with single root and single canal. 
With the help of conventional radiology, it is possible to get an overview of the position of the root canals; yet problems with the diagnostic result arise due to the superimposition effects of the zygomatic bone.  In addition, the canals often overlap due to the anatomy and X-ray viewpoint, due to which the complexity of the canal system cannot be characterized; also, radiographs are two-dimensional images of three-dimensional structure. ,
Tachibana and Matsumoto (1990) studied the applicability of CT to endodontics. They concluded that this method allowed the observation of the morphology of the root canals, the roots and the appearance of the tooth in every direction. Moreover, the image could be analyzed, altered and reconstructed by the computer. 
The disadvantages of a CT scan include the costs, availability and the higher ionizing radiation exposure. But recent studies have shown that low dose protocols are also available. ,,
In this case report, we first suspected missed canal but finally diagnosed single root with single canal by SCT. In doubtful cases where there is diagnostic dilemma about root canal morphology, SCT is a good three-dimensional investigation tool to confirm root canal morphology.
A large number of studies have been done to study root canal morphology of maxillary first molar. [Table 1] and [Table 2] summarize the various studies performed.
We conclude that this case presents an unusual morphology of single root and single canal in maxillary first molar; anomalies can also be in form of fewer canals. Although such cases occur infrequently, dentists should be aware of them when considering endodontic treatment of a maxillary first molar. SCT is a viable and objective tool for evaluation of unclear root canal configurations of the maxillary first molar.
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