Case Profile: Navigating a Radix Paramolaris by Dr. Zak James

A case report utilizing EdgeOnyx for an atypical mandibular third molar

by Dr. Zak James

An 86-year-old male patient presented for evaluation of tooth #32 (Figs. 1 and 2). The patient reported a chief concern of severe spontaneous pain which caused him to awake from sleep. His general dentist prescribed a course of antibiotics and also performed occlusal reduction, which have alleviated the patient’s symptoms prior to endodontic consultation.

Fig. 1: Preoperative PA of tooth #32 showing slight mesial inclination, an existing zirconia crown and possible recurrent decay.

Fig. 2: Panoramic radiograph showing tooth #32 in function with mesial drift following extraction of tooth #30.

Clinical exam showed #32 with full coronal coverage intact. The tooth was nonresponsive to cold testing and tested positive to percussion and bite pressure while remaining negative to palpation. No mobility, isolated probing defects or clinically evident marginal caries were observed. The patient presented with normal opening, and the mesioangular tilt of #32 made clinical access tenable.

A CBCT captured revealing apical PDL widening (Figs. 3 and 4). Possible evidence of recurrent marginal caries were noted beneath the existing crown. Axial views of the CBCT showed an ostensible radix paramolaris originating from the MB canal. The tooth was diagnosed as necrotic with symptomatic apical periodontitis, and nonsurgical root canal treatment was recommended.

Fig. 3: Preoperative CBCT demonstrating apical PDL widening and patent canals.

Fig. 4: Axial CBCT view demonstrating the radix paramolaris.

After rubber dam isolation, conservative access was made through the crown. Buccal marginal decay was excavated. Three primary canals were located, but no clear evidence of the radix was initially apparent. Working lengths and patency were confirmed with electronic apex locator. The EdgeOnyx rotary file system (Fig. 5) was elected for this case. As the patient presented with sufficient opening and slight mesioangular tilt of the crown, 25 mm files were able to be used. The Firewire shape memory of the files allowed the X-follow 15.04 file to be conveniently pre-bent in order to accommodate the conservative access and angle into the mesial orifices. No orifice shaping was required, but the files were carefully negotiated to length under continuous irrigation. Once glidepath was achieved, the X-finisher files were used in a step-back manner, beginning with 25.04 and finishing the mesial canals at a 30.04 and the D canal at 40.04, respectively (Fig. 6).

Fig. 5: The EdgeOnyx rotary file system.

Fig. 6: Cone-fit radiograph showing the three primary canals before negotiation of the radix.

At the initial visit, and because of limited visibility, careful troughing failed to show the orifice of the radix paramolaris. Because of time constraints, the initial canals were obturated and the patient scheduled for a follow-up appointment to locate and shape the radix. CBCT shows the radix paramolaris emanating from the MB canal (Figs. 7 and 8). Great care had to be taken in troughing for the orifice, as minor deviation could result in furcal perforation. A CBCT scan was captured in order to help orient the provider for continued troughing and negotiation of the canal.

Fig. 7: Frontal CBCT view showing the relationship of the radix to the MB canal.

Fig. 8: Axial CBCT view demonstrating the radix orifice adjacent to the MB canal and the limited furcal tooth structure.

At the second appointment, the patient remained asymptomatic. The tooth was re-accessed. Munce burs were used to trough from the MB orifice until evidence of the radix became apparent with a file stick. Because of the angulation and limited visibility of the third molar, traditional orifice openers would not be able to directly engage the orifice. The EdgeOnyx X-find 09.09 file was used to easily negotiate the coronal third of the radix. Working length and patency was confirmed with small hand files. Once coronal triangular dentin was removed by the X-find, the 15.04 X-follow was able to negotiate the radix to length with relative ease. The radix was finished at a 25.04 X-finisher shape. All canals were obturated with EdgeFile X7 gutta percha points and bioceramic sealer hydraulic technique. Blue BC liner was placed as an orifice barrier, and the patient directed to return to his dentist for final restoration (Fig. 9).

Fig. 9: Postoperative PA demonstrating obturation of all four canals.

Takeaways
The complexity of this case is highlighted not only by the atypical and variable third molar anatomy, but also by the difficulty in accessing the root canal system because of the distal position of the third molar. While recurrent caries were noted, every effort was made to maintain the coronal restoration with a conservative access preparation, further restricting visibility and ease of negotiation. Radix paramolaris is an uncommon finding.¹

The EdgeOnyx files were instrumental in this case because their heat treatment allowed all of the files, including the X-find, to be pre-bent while holding their shape. Without the ability to pre-bend the rotary files, preserving the coronal restoration and accessing the canals would not have been possible.

Because of the limited access and the need to bend the files relative to the handpiece, the lack of wobble with the EdgeOnyx files was a huge benefit. Significant wobble with other heat-treated files may lead to file separation, canal transportation or ledging.

Most notably, the only file able to initially negotiate the radix orifice was the EdgeOnyx X-find 09.09. Neither hand files nor traditional orifice openers could engage the orifice initially, and overtapered orifice openers risked strip perforation given the proximity to the furcation. Therefore, I do believe the EdgeOnyx system’s engineering made a very clinically challenging case not only possible, but relatively straightforward.

Reference
1. Filip L. Calberson, Roeland J. De Moor, Christophe A. Deroose, The Radix Entomolaris and Paramolaris: Clinical Approach in Endodontics, Journal of Endodontics, Volume 33, Issue 1, 2007, Pages 58-63, ISSN 0099-2399, https://doi.org/10.1016/j.joen.2006.05.007.

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Dr. Zak James is a diplomate of the American Board of Endodontics. He graduated summa cum laude from Clemson University Honors College and earned his DMD from the Medical University of South Carolina in Charleston, where he finished in the top five of his class. He completed a general practice residency at Harvard and received his endodontic certificate from UT Health San Antonio. He is currently based in Concord, North Carolina.