|Year : 2016 | Volume
| Issue : 1 | Page : 57-59
Unusual location of second mesiobuccal orifice in maxillary second molar
Kalpana Kanyal1, Parul Bansal2, Vineeta Nikhil2, Shashank Shekhar3
1 Department of Conservative Dentistry and Endodontics, Bharati Vidyapeeth Deemed University Dental College and Hospital, Pune, Maharashtra, India
2 Department of Conservative Dentistry and Endodontics, Subharti Dental College, Meerut, India
3 Department of Endodontist, Private Practitioner, Ghaziabad, Uttar Pradesh, India
|Date of Web Publication||21-Jun-2016|
Department of Conservative Dentistry and Endodontics, Bharati Vidyapeeth Deemed University Dental College and Hospital, Pune, Maharashtra
Source of Support: None, Conflict of Interest: None
Presence of second canal in mesiobuccal root of maxillary second molar is not uncommon but generally found closer to mesiobuccal orifice. This article reports a case of a maxillary second molar with an orifice of second mesiobuccal canal closer to palatal canal orifice.
Keywords: Maxillary second molar; mesiobuccal orifice; palatal orifice.
|How to cite this article:|
Kanyal K, Bansal P, Nikhil V, Shekhar S. Unusual location of second mesiobuccal orifice in maxillary second molar. Endodontology 2016;28:57-9
| Introduction|| |
Successful root canal therapy requires a thorough knowledge of root canal system. Extra roots or root canals if not detected, can lead to an endodontic failure. Maxillary molars show considerable anatomical variations with respect to the number of roots and root canals, most common being the presence of the second canal in the mesiobuccal root (MB2).  In most of the teeth, the location of the second mesiobuccal orifice (MB2) is present mesial to an imaginary line between the mesiobuccal (MB1) and palatal (P) orifice at about 1-4 mm from MB1 orifice. ,,, Very few cases have been reported with unusual position of the second mesiobuccal orifice.  This case report describes the detection and endodontic management of a maxillary first molar presenting with an unusual location of second MB canal orifice, which was located adjacent to the palatal canal orifice.
| Case Report|| |
A 42-year-old patient reported to the Department of Conservative Dentistry and Endodontics with the chief complaint of pain in his tooth of upper right back region for the past 4 days. Clinical examination revealed deep carious lesion in relation to maxillary right second molar (17). The tooth was tender on percussion. Preoperative diagnostic radiograph with respect to the distal aspect of 17 revealed deep carious radiolucency approximating pulp with periapical changes [Figure 1]. Vitality tests were suggestive of irreversible pulpitis. After clinical and radiographic examination in relation to maxillary right second molar, diagnosis of irreversible pulpitis with apical periodontitis was established. Root canal treatment was planned, and patient consent was obtained.
After administration of local anesthesia, under rubber dam isolation conventional endodontic access was made. After removing pulp tissue, four orifices were observed - palatal, mesiobuccal, and distobuccal located in regular locations and an extra orifice was located very close to the palatal orifice and was presumed to be a second palatal orifice. The conventional triangular access was modified to a trapezoidal shape to improve access to the additional canal [Figure 2]. The working length of each canal was estimated by means of an electronic apex locator (Root ZX; Morita, Tokyo, Japan) and then confirmed radiographically [Figure 3]. There were no variations such as second palatal root or canal observed in the preoperative radiograph; working length radiograph suggested that the instrument in the extra canal was of second mesiobuccal canal present in the mesiobuccal root. Multiple angulated radiographs confirmed the presence of second mesiobuccal canal (MB2) with palatally positioned orifice. Root canal preparation was completed with protaper system till size F1 for mesiobuccal and distobuccal canals and till F2 for palatal canal under irrigation with 3% NaOCl and 17% ethylenediaminetetraacetic acid. Master cone radiograph was taken with corresponding protaper gutta-percha followed by obturation with gutta-percha and AH plus sealer [Figure 4] and [Figure 5]. Access cavity was restored with composite. The patient was asymptomatic in the follow-up period.
| Discussion|| |
Majority of endodontic literature described the maxillary second molar as having three roots and three or four root canals, with two canals in mesiobuccal root.
In various in vitro and in vivo studies, the location of the second MB canal (MB2) has been reported closer to the mesiobuccal (MB) canal in the buccolingual direction, , slightly mesial to a line joining the MB and palatal canals, ,,, at 1-4 mm from the mesiobuccal orifice ,,, and at sometimes even 4 mm from palatal canal. 
Krasner and Rankow have proposed definite guidelines in the form of laws to determine the number and position of orifices of root canals of any tooth. According to these laws of orifice location, the orifices of root canals are always located at the junction of the walls and the floor, at the angles in the floor-wall junction, and at the termini of the root developmental fusion lines. In the present case, though the detection of all the orifices was through the routine exploration of the floor of the pulp chamber, the position of the MB1, distobuccal, and palatal canal orifices were in justification with all the three laws of orifice location. While the position of the MB2 orifice abided the first law of orifice location. 
These MB1 and MB2 orifices may be joined by a groove or sometimes may be separated by a broad bridge of dentin at the level of the chamber floor. , In the present case, no groove was present between the two orifices. The MB2 orifice was located immediately adjacent to the palatal orifice, which was presumed to be a second palatal orifice. There were no variations such as second palatal root/canal observed in the preoperative radiograph and working length radiograph revealed that orifice was that of the second mesiobuccal canal.
Such aberrant location was confirmed with careful exploration of pulp chamber and the use of multiple angulated intraoral periapical radiographs.
A thorough review of the literature revealed only a few cases, which described maxillary first molars with similar type of orifices and canals arrangement.  This reported case presents a second mesiobuccal canal (MB2) orifice location near to the palatal orifice.
| Conclusion|| |
Presence of second mesiobuccal canal is a frequently encountered clinical situation which is usually located adjacent to MB1. This case report highlights that orifice of second mesiobuccal canal may be displaced palatally at times, and may lie far from MB1 orifice and closer to the palatal orifice. Thus, more attention should be focused on the morphological variations adopted orifices in the chamber floor to facilitate the localization of the elusive MB2 canal.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]