Patient: 79 year-old male with glaucoma
Chief Complaint: Biting, Chewing Sensitivity on the lower back right jaw area
Dental History: The patient presented with no recent restorations and biting sensitivity localized to the mandibular right first molar (tooth #30) which had a full gold crown placed many years earlier
Significant Findings (tooth #30): The tooth measured a positive response to cold thermal stimulation, severe chewing sensitivity, and moderate percussion sensitivity. The periodontal and all other clinical findings were within normal limits. The radiograph demonstrated a radiopacity at the mesial and distal distal areas of the crown approximating the mesial and distal pulp horns. A THIRD DISTINCT MOLAR ROOT WAS ALSO NOTED
Pulp and Periradicular Diagnosis: Stressed pulp and acute periradicular periodontitis (tooth #30)
Treatment Prognosis: Good
Treatment Plan: Nonsurgical Endodontic Therapy with Fracture Exploration (Tooth #30)
Special Considerations of Performed Treatment:
The advent of limited field CBCT scanning for the dental office has revolutionized dental imaging and noninvasive dental diagnosis. It has created a controversy whether the CBCT scan should be performed on every single patient presenting or a potential need for endodontic treatment or if it should be employed for “special” presenting cases.
This author selectively utilizes CBCT scanning as it can be employed at any time during the treatment process if confusion over the tooth status or root anatomy exists. Often times a pretreatment CBCT scan is not as useful as a later scan when the metal restorations are removed and a radiopaque material can be placed in preliminarily accessed root canal system. Patient concerns over radiation, although scientifically unfounded for most modern microCT machines, sometimes dictate the clinician’s use of a CBCT so it is often best to consider the most useful point in treatment to take it.
In this case the preoperative radiograph demonstrated a rare and very challenging root anatomy variation called the “radix entomolaris”. The “radix”, or third root, is often anomalous, angled, and smaller than the common mesial and distal roots. Extreme care must be taken to avoid perforation. In this case the radix root entity was very narrow, concave, curved, and exited the distolingual aspect of the pulp chamber at the corner almost at a 90 degree angle. The anomalous root anatomy was noted on the initial traditional preoperative radiograph but it was decided to perform initial access and place intracanal calcium hydroxide before taking a CBCT. The CBCT was taken to assess the how safely the radix root canal system could be cleaned and shaped without risking perforation.
Direct line access to the radix was compromised and a narrower gutta percha cone was placed than would have been chosen for a common prepared mandibular molar root canal system. Numerous small precurved hand file recapitulations with copious irrigation was performed to clear the system. The other four root canal systems (ML, MB, DB, DL) were cleaned, shaped, and obturated routinely. Immediately after obturation a bonded resin core was placed (Luxacore/Photobond). No crown-root fracture was found to be present and the patient was scheduled for routine follow-up examination.
Key Learning Points:
CBCT scanning can detect and greatly enhance the management of teeth having unusual root anatomy
A thoughtful decision when to take a CBCT scan prevents unnecessary preoperative scans unlikely to provide a critical option determinant
Failure to take a CBCT scan when one is indicated may lead to mismanagement of challenging cases
CBCT scans are often best taken when the root canal system is filled with a radiopaque marking material like calcium hydroxide, or when all metal restorations are removed to prevent distortion of the image in the cervical region due to beam hardening
- The radix entomolaris root variation can occur in mandibular molars and should be recognized and considered as very challenging requiring special endodontic management
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