PMC3485491_01
(a) Diagnostic radiograph, (b-d) computed tomographic scan in coronal, middle, and apical segments, respectively, (e) access cavity preparation, (f) working length determination, (g) post obturation, and (h) full coverage restoration.
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fig1
Radiographic examination (Figure 1(a)) revealed the restoration close to the distal pulp horn and periapical lamina dura widening. In addition, a computed tomographic scan (Figures 1(b), 1(c), and 1(d)) of the lower jaw of the patient was available for surgical reasons. On evaluation, the scan illustrated the nature of origin and curvature of the extra root in a mesiobuccal direction as depicted by the arc (Figure 1(d)). In addition a dark line guided the operator towards an extra orifice located towards the distolingual part of the pulpal floor (Figure 1(e)). The root canals were explored with precurved K-file ISO number 15 (Dentsply Maillefer, Ballaigues, Switzerland), and radiographic length measurement was performed (Figure 1(f)). ProTaper gutta percha points (Figure 1(g)). Postendodontic coronal restoration was done with full metal crown (Figure 1(h)).
PMC3485491_02
(a) Diagnostic radiograph, (b) access cavity preparation, (c) working length determination, (d) master cone confirmation, (e) postobturation, and (f) eight-month followup.
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fig2
Radiographic examination (Figure 2(a)) revealed periapical lesion in relation to both the mesial and distal roots of the tooth. On further exploration, another orifice was located towards the distolingual part of the pulpal floor (Figure 2(b)). ISO number 15 and radiographic length measured (Figure 2(c)). Instrumentation was carried out using the ProTaper rotary files with intermittent irrigation using 1% sodium hypochlorite in all the canals. Master cone radiograph was obtained (Figure 2(d)). AH Plus sealer (Figure 2(e)). An eight-month follow-up radiograph of the patient illustrated resolving periapical radiolucency (Figure 2(f)).
PMC3485491_03
(a) Diagnostic radiograph, (b) access cavity preparation, (c) working length determination, and (d) postfilling.
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fig3
To confirm this observation, another radiograph at a horizontal angulation of 20 degrees was taken which clearly revealed the presence of an extra distal root that curved severely towards the mesial root (Figure 3(a)). Upon access to the pulp chamber, the distal orifice was seen located eccentrically towards the buccal aspect of the tooth (Figure 3(b)). Since there was a sharp apical curvature (Figure 3(c)) in the disto-lingual root, C+ files (Dentsply, Maillefer, Ballaigues, Switzerland) with batt tips (a unique feature of C+ files) were used to negotiate the canal. The canals were shaped from coronal to middle and apical to a ProTaper size F2 (Dentsply, Maillefer, Ballaigues, Switzerland) and obturated (Figure 3(d)) using the corresponding gutta percha cones. 
(a, e, and i) Lateral view of the extracted teeth, (b, f, and j) mesial view of the extracted teeth, (c, g, and k) access cavity preparation, and (d, h, and l) radiographic appearance.
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fig4
In all of the teeth, the extra root emerged from the lingual aspect of the tooth (Figures 4(a), 4(e), 4(i), 4(b), 4(f), and 4(j)) either attached to the distal root or midway between the mesial and the distal roots. Thus care should be taken not to overprepare and shape such root canals to avoid any inadvertent perforation of the root (Figures 4(d), 4(h), and 4(l)).  Access opening was performed on all of the extracted molars (Figures 4(c), 4(g), and 4(k)).