Management of a Mandibular Third Molar With Radix Paramolaris: A Case Report

Nonsurgical root canal treatment of mandibular third molars can be challenging, as these teeth frequently exhibit complex and unpredictable root canal anatomy. They are inherently difficult to access due to their posterior location and, as a result, are often managed by extraction rather than retention.^1,2 When retention of the tooth is indicated, clinicians face significant obstacles related to restricted access, limited visibility, and irregular canal morphology. These factors may increase the likelihood of missed anatomy and procedural complications, particularly when treatment is performed through an existing full-coverage restoration.

One uncommon anatomical variation is the presence of a radix paramolaris, an accessory root located on the buccal aspect of the mandibular molar.³ Although most frequently found in first molars, its occurrence in mandibular third molars is rare. Failure to recognize this additional root can result in persistent infection and endodontic failure if the associated canal remains untreated. Because conventional periapical radiographs provide only a 2-dimensional representation of a 3-dimensional structure, accessory roots may be obscured by anatomical superimposition and geometric distortion; consequently, cone-beam computed tomography (CBCT) serves as a valuable diagnostic adjunct when complex or unusual root canal anatomy is suspected.⁴

Modern heat-treated nickel-titanium rotary instrumentation has expanded clinicians’ ability to manage anatomically challenging cases while preserving tooth structure.^5,6 Instruments capable of retaining a pre-bent configuration can be particularly advantageous when treating posterior teeth through conservative access preparations, allowing effective canal negotiation without unnecessarily enlarging the access cavity or sacrificing an otherwise serviceable restoration.

This article describes the nonsurgical management of a mandibular third molar exhibiting a radix paramolaris through an existing crown and illustrates how CBCT imaging and flexible rotary instrumentation contributed to successful treatment.

Case Presentation

An 86-year-old Caucasian man was referred for evaluation of tooth No. 32 after experiencing severe spontaneous pain that would awaken him from sleep. Prior to referral, his general dentist had prescribed a course of antibiotics and performed occlusal reduction, resulting in alleviation of the patient’s symptoms.

Clinical examination revealed an intact full-coverage crown on tooth No. 32 without obvious marginal breakdown. Diagnostic testing demonstrated no response to cold testing, positive responses to percussion and bite testing, and no tenderness to palpation. No abnormal mobility or isolated periodontal probing defects were identified. The patient exhibited normal mandibular opening despite the distal location of the tooth, and the slight mesioangular inclination of the crown was judged to provide clinically acceptable access for nonsurgical root canal treatment (Figure 1 and Figure 2).

CBCT examination demonstrated widening of the apical periodontal ligament (PDL) space consistent with apical inflammation (Figure 3). Additionally, localized radiolucency beneath the buccal crown margin suggested recurrent marginal caries. Most notably, axial CBCT images demonstrated a distinct accessory root consistent with a radix paramolaris arising from the mesiobuccal root complex (Figure 4). Recognition of this unusual anatomy significantly influenced treatment planning by alerting the clinician to the likelihood of an additional canal requiring treatment.

Based on the clinical and radiographic findings, the tooth was diagnosed with pulpal necrosis and symptomatic apical periodontitis. After discussion of treatment options, nonsurgical root canal therapy was recommended in an effort to preserve the existing restoration and maintain the tooth.

First Appointment

Following local anesthesia and rubber dam isolation, conservative access to tooth No. 32 was established through the existing crown. Initial caries excavation confirmed recurrent decay beneath the buccal crown margin, which was removed while preserving as much of the restoration as possible.

Three primary canal orifices were readily identified. Despite careful inspection under magnification, no definitive evidence of the accessory radix canal could be appreciated (Figure 5). Working lengths and apical patency were established using an electronic apex locator.

A heat-treated nickel-titanium rotary system (EdgeOnyx™, EdgeEndo, edgeendo.com) was selected, as its proprietary metallurgy permits pre-bending of rotary instruments while allowing them to maintain their curvature during use (Figure 6). Because the patient demonstrated adequate opening and favorable tooth angulation, standard 25-mm instruments could be utilized.

The initial glidepath was established using a pre-bent 15/.04 X-Follow file under continuous irrigation. The ability to customize the curvature of the instrument facilitated engagement of the mesial canals despite the restricted line of access inherent to a mandibular third molar. No dedicated orifice shaping was required. Once glidepath preparation had been completed, shaping was performed using X-Finisher instruments in a step-back sequence. The mesial canals were enlarged to size 30/.04, while the distal canal was prepared to size 40/.04.

Throughout instrumentation, repeated attempts were made to locate the radix paramolaris. However, visualization remained limited because of the conservative access cavity, the posterior position of the tooth, and concern that excessive troughing could result in furcal perforation. Given the patient’s age, procedural time, and inability to confidently identify the accessory canal without unnecessary dentin removal, a staged treatment approach was elected.

The prepared canals were disinfected and obturated, and postoperative CBCT imaging was obtained before the second appointment. The 3-dimensional images confirmed the anticipated origin of the radix paramolaris from the mesiobuccal canal system and provided valuable spatial orientation for subsequent troughing while minimizing the risk of iatrogenic damage (Figure 7 and Figure 8).

Second Appointment

At the follow-up appointment, the patient remained asymptomatic. The tooth was re-accessed, and attention was directed toward locating the accessory canal.

Careful troughing from the mesiobuccal canal was performed using Munce burs. Due to the angulation of the tooth and limited visibility, it was determined that conventional orifice openers could not predictably engage the suspected canal entrance without excessive dentin removal. Furthermore, aggressive coronal enlargement in this region posed an increased risk of strip perforation because of the close proximity of the furcation.

A pre-bent 09/.09 X-Find rotary instrument was introduced into the trough and was successfully able to negotiate the coronal aspect of the accessory canal, producing the first definitive “file stick” that confirmed canal location (Figure 9). Small stainless-steel hand files were then used to establish working length and apical patency.

Following removal of restrictive coronal dentin, a pre-bent 15/.04 X-Follow instrument was used to negotiate the canal to working length with relative ease. The accessory canal was subsequently enlarged to a final preparation size of 25/.04.

Following copious irrigation and final disinfection, all the canals were obturated using matched-taper gutta-percha points (EdgeFile® X7, EdgeEndo) (Figure 10) with a bioceramic sealer employing a hydraulic condensation technique. A blue bioceramic liner was placed as an orifice barrier before temporary restoration of the access cavity (Figure 11). The patient was referred back to his restorative dentist for definitive coronal management.

Discussion

This case illustrates the convergence of several factors that individually complicate endodontic treatment and collectively create a particularly demanding clinical scenario. Endodontic therapy involving mandibular third molars is inherently challenging because of restricted access, variable root morphology, and diminished visualization. In the present case, these difficulties were compounded by the presence of an uncommon radix paramolaris and the decision to preserve an existing full-coverage restoration through a conservative access preparation.

Accessory roots such as radix paramolaris are uncommon anatomical variations but possess significant clinical importance, and failure to identify and treat the associated canal may result in persistent microbial infection and eventual treatment failure.³ Although careful interpretation of conventional radiographs remains essential, CBCT imaging proved invaluable in this case by identifying anatomy that would likely have remained undetected using 2-dimensional imaging alone. Furthermore, the postoperative CBCT obtained following the first appointment served not only as confirmation of the untreated accessory root but also as a 3-dimensional roadmap that guided conservative troughing during the second visit. Rather than removing dentin indiscriminately in search of the canal, treatment proceeded with a clearer understanding of its anticipated location, thereby minimizing the risk of furcal perforation.

The decision to stage treatment was also important. Although completion of treatment during a single appointment is frequently desirable, persistence in searching for an elusive canal under unfavorable visualization may unnecessarily increase procedural risk. Deferring completion until additional imaging could be reviewed allowed treatment to proceed more predictably while preserving structural integrity.

The instrumentation strategy also contributed substantially to successful treatment. The combination of posterior tooth position, conservative access, and canal angulation necessitated the use of rotary instruments capable of maintaining a customized curvature after pre-bending. Heat-treated nickel-titanium metallurgy (EdgeOnyx files) provided this capability while maintaining sufficient flexibility to negotiate curved anatomy. Because the instruments retained their pre-bent configuration, canal negotiation could be accomplished without enlarging the access cavity or removing additional restorative material solely to improve straight-line access.

The initial negotiation of the accessory canal deserves particular consideration. Conventional stainless-steel hand files were unable to predictably engage the canal because of its unfavorable angle of entry, while traditional orifice openers could not be aligned with the canal without excessive dentin removal. The 09/.09 X-Find instrument effectively removed restrictive coronal dentin while simultaneously negotiating the canal entrance. Once this coronal interference was eliminated, subsequent glidepath preparation and shaping progressed in a predictable manner.

Another practical advantage during this procedure was the enhanced stability of the rotary instruments during off-axis engagement. In posterior teeth requiring significant instrument deflection relative to the handpiece, reduced instrument stability (ie, excessive “wobble”) may diminish tactile control and increase the potential for canal transportation, ledge formation, or instrument fatigue.⁷ Improved stability allowed more precise engagement of the accessory canal despite the compromised angle of approach.

Conclusion

Mandibular third molars exhibiting accessory root anatomy present significant diagnostic and technical challenges. This case demonstrates the importance of CBCT imaging for identifying and managing unusual canal configurations, particularly when treatment is performed through an existing restoration. A conservative, staged approach allowed preservation of tooth structure while minimizing procedural risk, and pre-bendable heat-treated nickel-titanium rotary instrumentation facilitated negotiation of an accessory radix paramolaris that could not initially be located through conventional methods. Careful integration of advanced imaging, conservative access design, and contemporary instrumentation enabled successful nonsurgical management of an uncommon and technically demanding endodontic case.

DISCLOSURE

This article was commercially supported by EdgeEndo.

ABOUT THE AUTHOR

Zak James, DMD
Private Practice limited to Endodontics, Concord, North Carolina; Diplomate, American Board of Endodontics

Figures and Images

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Figure 11

Figure 1

Preoperative periapical radiograph, tooth No. 32. The tooth presented with slight mesial inclination and was distalized along the ascending ramus. A zirconia crown was present with possible evidence of recurrent decay and a ditched or open distal margin. The mesial root showed apical curvature. The radix paramolaris was not clearly evident with 2-dimensional imaging. Apices did not appear to encroach the mandibular canal.

Figure 2

Preoperative panoramic radiograph showing tooth No. 32 was fully functional with opposing tooth No. 2. Tooth No. 1 was absent. Tooth No. 30 has been extracted, resulting in mesial drift of teeth Nos. 31 and 32.

Figure 3

Preoperative CBCT imaging, tooth No. 32. Canals appeared to be patent and not calcified. Some apical PDL widening was appreciated. Normal alveolar bone levels suggested a low probability of crown-to-root fracture. The radix paramolaris was not evident in the sagittal view.

Fig. 4

Axial view of the CBCT showed the radix paramolaris along the buccal aspect (red arrow). No furcal bone loss was noted. The canal appeared to be patent.

Figure 5

Cone fit, tooth No. 32. Cones for the three primary canals were seated with bioceramic sealer. A cone-cut of the radiograph was secondary to the difficulty of capturing the third molar digital sensor image with rubber dam isolation. The radix paramolaris was barely discernible with careful inspection, but was not yet negotiated.

Figure 6

EdgeOnyx instruments.

Figure 7

Frontal view of CBCT showing the radix paramolaris in relation to the mesiobuccal canal. Slight apical dilaceration could be appreciated.

Figure 8

Axial CBCT view showing the canal orifi ce of the radix paramolaris originating near the mesiobuccal orifi ce, and swiftly diverging distally (red arrow). Thin furcal and buccal tooth structure remains between the two canals, leaving little margin for deviation with troughing.

Figure 9

CBCT at the second appointment to confi rm the location of the radix paramolaris.

Figure 10

Matching gutta-percha points.

Figure 11

Postoperative periapical radiograph, tooth No. 32. All four canals were obturated to optimum length, density, and taper. The distal root apical lateral anatomy was fi lled with bioceramic sealer. The orifi ces were properly sealed with bioceramic liner. Final coronal restoration will be assessed by the general dentist.