Three-rooted maxillary first premolars incidentally detected on cone beam CT: an in vivo study

  • Andrea BorghesiEmail author
  • Silvia Michelini
  • Angelo Zigliani
  • Ingrid Tonni
  • Roberto Maroldi
Original Article



To explore the incidence and analyze the morphology of three-rooted maxillary first premolars (MFPs) incidentally detected on cone beam computed tomography (CBCT) scans.


Of 1328 patients who underwent CBCT scans of the maxilla, only patients with three-rooted MFPs were selected. Morphological features, including the lengths and diameters of palatal, mesiobuccal (MB) and distobuccal (DB) roots, the positions of bucco-palatal (B-P) bifurcations, the distances between root canal bifurcations and cementoenamel junctions (CEJs) and the distances between the apical thirds of the roots, were measured. The canal configuration and the visibility of root canals were also evaluated.


A total of 16/1328 (1.2%) patients had one or two three-rooted MFPs, and a total of 22/2656 (0.8%) three-rooted MFPs were enrolled. The lengths and diameters of palatal roots were significantly greater than those of other roots. The positions of B-P bifurcations were located mainly at the middle third of the root. The median distances between root canal bifurcations and CEJs were 3 mm for B-P bifurcations and 5.2 mm for MB–DB bifurcations. The distance between MB and DB roots was significantly shorter than the distances between other root pairs. All teeth had a type VIII canal configuration. Palatal roots exhibited the best visibility of root canals, whereas the worst visibility was observed within DB roots. A gender-related relationship was observed only for the lengths of the roots.


The occurrence of three-rooted MFPs is not unusual; therefore, preoperative CBCT evaluation could be suggested whenever endodontic procedures are planned on an MFP.


Bicuspid Tooth root Anatomic variation Cone-beam computed tomography 


Author contributions

AB: Project development, Data collection and data analysis, Manuscript writing and editing; SM: Data analysis, Literature research, Manuscript editing; AZ: Data collection, Manuscript editing; IT: Literature research, Manuscript editing; RM: Manuscript editing.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical standards

All procedures performed in this study were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

This study was retrospective, and it did not alter the management of the patients; thus, no specific consent was required.


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Copyright information

© Springer-Verlag France SAS, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Radiology, Medical SchoolUniversity of BresciaBresciaItaly
  2. 2.Department of RadiologyFondazione Poliambulanza Istituto OspedalieroBresciaItaly
  3. 3.Dental School, Dental ClinicUniversity of BresciaBresciaItaly

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