Patient: 70 year-old male with unremarkable medical history
Chief Complaint: Intermittent pain localized to the mandibular left posterior jaw area noted within the previous few months.
Dental History: Large periapical radiolucency (mandibular left first molar) noted on a radiograph taken by the patient’s prosthodontist. The mandibular left first molar (tooth #19) had been restored with a zirconium crown within the past 5 years.
Clinical examination revealed localized palpation sensitivity on the buccal alveolar mucosa opposite the roots of #19. The patient responded negatively to cold thermal (ice) testing. The periapical radiograph revealed large periapical radiolucencies over the mesial and distal roots of #19.
Pulp and Periradicular Diagnosis: Necrotic pulp with a symptomatic periapical abscess (#19)
Treatment Prognosis: Good (#19)
Treatment Plan: Nonsurgical root canal treatment (#19)
Special Considerations of Performed Treatment:
Radix Entomolaris is a molar anatomic variation used to describe an additional root located in a distolingual position. The term was first mentioned by Carabelli in 1844 and more recently the diverse forms were classified by Song et al (2010) based on morphologic characteristics evaluated from CBCT scan observations:
Type 1-No Curvature
Type 2-Curvature in the coronal third and straight
continuation to the apex
Type 3-Curvature in the coronal third and additional buccal curvature from the middle third to the apical third of the root
Small type-Root length less than half that of the distobuccal root
Conical type-Cone-shaped extension with no root canal
The tooth presented was a very challenging small Type 2.
The anomalous root was not obvious from the initial radiologic exam (Figures 1 and 2). Initial access revealed a distolingual canal orifice in an extreme lingual position (Figure 3). The distobuccal, mesiobuccal, and mesiolingual root canal systems were cleaned, shaped, filled with calcium hydroxide and the access was filled with a Cavit temporary filling without a spacer (Figure 4). A limited field CBCT scan was take which revealed the anomalous radix entomolaris root morphology (Figures 5 and 6). It was suspected that the root may not be treatable so the alternate option was to perform a root amputation which minor lingual crown lengthening.
The second visit was dedicated to just finding, cleaning, shaping, and filling the distolingual (radix) root with calcium hydroxide (Figure 7). The root canal system was negotiated by tedious passive recapitulation with a series of hand files with minimal use of rotary files. Constant flushing with 8.25% sodium hypochlorite was performed with periodic irrigation with small quantities of 90% trichloroacetic acid which prevented debris blockage. The small associated periapical radiolucency of the radix root suggested there was patent canal space and that it needed to be treated.
On the third visit all root canal systems were obturated with gutta percha and Kerr sealer via the vertical compaction of warmed gutta percha technique (Figures 8, 9, 10, and 11). The access was restored with a resin bonded composite and the patient was scheduled for a recall examination in one year.
Key Learning Points:
Anomalous root anatomy should always be considered. Expect the unexpected. If unusual anatomy is suspected preoperatively then a CBCT scan should be taken to understand the potential complexities before starting treatment.
- Prepare the patient for the possibility of more appointments than anticipated. If you start root canal treatment and the preoperative radiograph fails to show a complicated anomaly, then more time will be required to perform treatment.
- A mid-treatment CBCT scan should be taken if the root anatomy becomes confusing. There is a good case to be made for taking a CBCT scan before starting any root canal treatment but some patients are concerned about radiation and the additional expense. It is most important to be sure you understand the root anatomy with clarity if you choose not to take a CBCT scan. It should be considered the standard of care to have easy access and availability to CBCT scanning if performing root canal treatment.
- Definitive quality root canal treatment requires time and patience without rushing. Appointment scheduling should allow for flexible time needed to treat challenging cases. Unusually challenging cases should be scheduled to be open-ended without the presence of a subsequent patient creating anxiety and the impulse to rush.
- Look for creative alternate options if treatment objectives cannot be satisfactorily met. In this example, the alternate option of amputating the distolingual root provided a sense of peace and calm that a back-up option could still lead to saving the tooth.