Maxillary First Molar Treatment Reveals Five Root Canals
A routine endodontic procedure on a 60-year-old male patient turned into a rare anatomical discovery when clinicians identified a maxillary first molar featuring four separate roots and five distinct root canals, according to a case report published in Cureus. While permanent maxillary molars typically develop three roots—one palatal and two buccal—four-rooted variations occur in approximately 0.047% of cases, with only 27.27% of those presenting five canals.
The patient initially presented to a clinic with severe pain in tooth #3, which sits as the most distal tooth in the upper arch. Clinical examination revealed an extensive distal carious lesion and a positive response to cold testing that lingered for more than 30 seconds. Initial periapical radiographs showed localized bone loss and extensive decay, prompting a diagnosis of symptomatic irreversible pulpitis. Although extraction was initially considered due to the deep decay, the tooth was deemed restorable because it lacked mobility, furcation involvement, or periodontal pockets, and retained sufficient structure to support a restoration.
During initial access preparation under rubber dam isolation and local anesthesia using 2% lidocaine with 1:100,000 epinephrine, clinicians identified four canal orifices arranged in a rhomboidal pattern: a first mesiobuccal, second mesiobuccal, distobuccal, and an initially designated palatal canal. However, working-length radiographs taken with mesial angulation hinted at a missed distopalatal canal. To investigate further, the team captured a cone-beam computed tomography scan.
Equipped with the scan and a dental operating microscope, clinicians extended the access cavity distopalatally toward the internal line angle. Tracing a dark developmental groove with a diamond-coated ultrasonic tip ultimately exposed the hidden distopalatal orifice. This expansion altered the canal configuration from rhomboidal to square, positioning the two palatal orifices notably far apart.
Following the discovery, the dental team performed copious irrigation using 3% sodium hypochlorite paired with ultrasonic activation to remove debris. Canals were shaped using the ProTaper Gold system, reaching size F2 for the buccal canals and size F3 for the palatal canals, alongside 17% ethylenediaminetetraacetic acid. Obturation followed using a single-cone technique with corresponding gutta-percha cones and a bioceramic root canal sealer. A six-month clinical follow-up confirmed that the patient remained entirely free of clinical symptoms.