[Root canal therapy of maxillary molars with atypical canals: A report of three cases]

Maxillary molar with three roots and 3 to 4 canals is a common occurrence. However, in addition to common root canal anatomy, there may be significant differences in the number, distribution, and morphological structure of root canals. The success of root canal treatment is dependent on ensuring that all the intricate details associated with it are meticulously followed. Failure to locate all canals could have a negative effect on the treatment as it may lead to initiation or continuation of periapical pathology. Missed canals were the main reason for patients reporting back for nonsurgical root canal retreatment. Moreover, the bacteria residing in such canals could also result in persistence of symptoms. Root canal anatomy is complex, and the recognition of anatomic variations could be a challenge for clinicians. This article presents three cases of endodontic management of maxillary molars with atypical canal morphology. In the three cases of this study, the patients underwent cone beam computed tomographic (CBCT) examination before root canal treatment. The CBCT images revealed that the maxillary molars in case 1 and case 2 had 5 canals. Case 1: 2 mesiobuccal (MB, MB2), two distobuccal (DB and DB2), and one palatal canal. Case 2: 2 mesiobuccal (MB, MB2), one distobuccal (DB), and two palatal canals (MP and DP). In case 3, CBCT scan slices showed that the maxillary first molar presented as a C-shaped root canal with a rare tooth anomaly of taurodontism. Although C-shaped root canals were most frequently seen in the mandibular second molar, they might also appear in maxillary molars. A literature search revealed only a few case reports of C-shaped root canal systems in maxillary molars. Case 3 described the fusion between mesiobuccal and palatal roots of the maxillary first molar, forming a C-shaped mesiopalatal root canal. The above cases suggest that endodontists should always be aware of aberrancies in root canal system apart from the knowledge of normal root canal anatomy. CBCT as a means of diagnosis can be helpful for identifying and managing these complex root canal systems. This case series also highlights the importance of magnification and illumination. Through using an endodontic microscope, clinicians can identify root canals that are difficult to locate or overlooked with normal vision. A correct access opening is a most important step to locate and negotiate the orifices of root canals. The use of ultrasonic tips can refine the access cavity and allow controlled and delicate removal of calcifications and other interferences to the canal orifices, thereby helping to locate the extra orifices.