An atypical anatomy of permanent mandibular second molar with five roots

Abstract

Especially in molars that may have sometimes aberrant additional root canals, the complexity of tooth internal morphology in individual cases sometimes does not match to admitted classification rules and underlines the risk of missed anatomy during the endodontic management. To our knowledge, a permanent mandibular second molar with independent five roots, three mesial and two distal, each of them harboring a single canal, was not yet reported. Despite the treatment difficulties this tooth could be successfully approached by using dental operative microscope and cone-beam computed tomography (CBCT) with small field of view. Though CBCT is not a routine imagistic examination, in case of atypical tooth anatomy aiming to establish adequate diagnosis and treatment plan, the successful clinical outcome prevails over the irradiation dose.

Figure 1

Preoperative intraoral periapical radiograph of permanent mandibular second molar (tooth 47) showing the unusual presence of two distal roots

Figure 2

The distal canals of tooth 47, DL and DB, are quite distant from each other as they belong to separate roots. DB: Distobuccal; DL: Distolingual

Figure 3

CBCT coronal view of tooth 47 revealing two separate roots, DB and DL. CBCT: Cone-beam computed tomography; DB: Distobuccal; DL: Distolingual

Figure 4

The larger ML canal orifice of tooth 47 which bifurcates in two independent canals, ML and MM. The third mesial orifice, viewed after enlargement, belongs to the MB canal. DB: Distobuccal; DL: Distolingual; MB: Mesiobuccal; ML: Mesiolingual; MM: Middle mesial

Figure 5

CBCT coronal view showing three mesial roots in tooth 47, ML, MM, and MB. CBCT: Cone-beam computed tomography; MB: Mesiobuccal; ML: Mesiolingual; MM: Middle mesial

Figure 6

CBCT coronal image in tooth 47 revealing the MB separate root having a calcified canal at its emergence and two apparently superimposed lingual roots, MM and ML. CBCT: Cone-beam computed tomography; MB: Mesiobuccal; ML: Mesiolingual; MM: Middle mesial

Figure 7

CBCT coronal view located at the emergence of larger common orifice of both ML and MM canals, showing their bifurcation below the floor of the pulp chamber. CBCT: Cone-beam computed tomography; ML: Mesiolingual; MM: Middle mesial

Figure 8

CBCT axial image in tooth 47 just below the floor of pulp chamber revealing the separate orifices of DB and DL canals, the common larger ML orifice of ML and MM canals as well as the calcified orifice of MB canal. CBCT: Cone-beam computed tomography; DB: Distobuccal; DL: Distolingual; MB: Mesiobuccal; ML: Mesiolingual; MM: Middle mesia

Figure 9

– CBCT coronal view in another slice plane showing three separate mesial roots in permanent mandibular second molar (47). CBCT: Cone-beam computed tomography

Figure 10

CBCT sagittal image of tooth 47 mimicking an apparent normal view of two-rooted permanent mandibular second molar but actually showing MB and DB roots at this slice level. CBCT: Cone-beam computed tomography; DB: Distobuccal; MB: Mesiobuccal

Figure 11

CBCT axial image at furcation level in tooth 47 demonstrating its five roots ML, MM, MB, DB, and DL; MM is located close to ML root. CBCT: Cone-beam computed tomography; DB: Distobuccal; DL: Distolingual; MB: Mesiobuccal; ML: Mesiolingual; MM: Middle mesial.

Figure 12

CBCT axial image in middle third of tooth 47 revealing its five roots ML, MM, MB, DB, and DL; MM root is closer situated to ML root. CBCT: Cone-beam computed tomography; DB: Distobuccal; DL: Distolingual; MB: Mesiobuccal; ML: Mesiolingual; MM: Middle mesial

Figure 13

CBCT axial image in apical third of tooth 47 showing independent apices of five roots: ML, MM, MB, DB, and DL. CBCT: Cone-beam computed tomography; DB: Distobuccal; DL: Distolingual; MB: Mesiobuccal; ML: Mesiolingual; MM: Middle mesial.

Figure 14

CBCT sagittal image of tooth 47 revealing two of its three mesial roots, ML and strongly distally directed MM root. CBCT: Cone-beam computed tomography; ML: Mesiolingual; MM: Middle mesial

Figure 15

– Postoperative intraoral periapical radiograph of permanent mandibular second molar (tooth 47) showing root canal obturation of independent five roots