A.O Sulaiman1, O.O Dosumu1 and McKing Amedari2

  1. Department of Restorative Dentistry, University College Hospital, Ibadan.
  2. Dental Center, University College Hospital, Ibadan.


The maxillary first premolar is the most commonly bi- rooted tooth with occasional presentation of three roots system; it is a transitional tooth between incisors and molars. Although it usually has two canals, it may rarely have three and this third canal can easily be missed. Thus meticulous knowledge of tooth morphology, careful interpretation of angled radiographs, proper access cavity preparation and a detailed exploration of the interior of the tooth is needed to ensure a proper endodontic treatment. This article reports a rare finding of three canals in a maxillary first premolar with non well defined root outline radiographically during an elective root canal treatment.

Keywords: Maxillary First Premolar, Endodontic Treatment, Elective, Root Canal Morphology


Dr. A.O. Sulaiman
Department of Restorative Dentistry
University College Hospital
Tel: +2348055066685


A clear understanding of the human teeth anatomy is a prerequisite to achieving proper access cavity preparation, thorough cleaning, disinfection and obturation of the pulp space. These objectives can be achieved by detecting the anatomical variations of the tooth under treatment. One of the major reasons for failure of root canal therapy is the inadequate knowledge about the anatomy of the pulp space in the root canals1. Root canals are left untreated when the dentist fails to identify them particularly in teeth that have additional root canals1,2.

The maxillary first premolar has two cusps with the buccal cusp prominently larger than the palatal cusp. This tooth is said to exhibit the greatest variation in root anatomy and root canal morphology2,3,4. Radicular irregularities consist of fused roots with separate canals, fused roots with interconnections or “webbing”, fused roots with a common apical foramen and the unusual but always to be considered three- rooted tooth5. Variations in number and type of root canals are probably some of the most widely described anomalies in literature. The presence of two canals may be considered normal but racial differences in the root canal morphology of this and other premolars have been established2,6,7. The anatomy of a maxillary premolar with three canals, mesio buccal, distobuccal and palatal is similar to the adjacent maxillary molars and they are sometimes referred to as small molars or radiculous3. In a case of three root canals, the buccal orifices are not clearly visible with the mouth mirror. Directional positioning of the endodontic explorer or a small file may identify the canals3,5,8.

The incidence of one root varies from 22% to 49.9%; two roots, 50.6% to 72% and three roots, 0 to 6%9-13. Several studies9,14,15 dealing with the canal morphology of the first maxillary premolar have revealed that in most instances they have two canals, although teeth with one or three canals do exist9,13-15. Mariusz et al16 found 9.2% of first maxillary premolars with three canals.

This article presents the case of a maxillary first premolar with three canals in a non well defined root outline radiographically which is a rare clinical occurrence in our environment.

A 50 year old woman reported at our clinic with a request for replacement of her missing teeth in the upper right quadrant.

Pre operative radiograph of the right maxillary first premolar showed a radiopaque filling material on the distal aspect, coronally. The mesio distal width of the middle third of the root was approximately equal to the mesio distal width of the middle third of the crown with no clearly defined pulpal outline [Fig 1].

Comprehensive rehabilitative treatment plan for the replacement of the missing teeth in the affected quadrant with a fixed prosthesis entailed an elective root canal therapy on the right maxillary first premolar to serve as mesial abutment for the prosthesis. The procedure was commenced under local anaesthesia. Exploration of the pulp chamber was carried out with appropriate Nikel Titanium files sizes10, and 15; leading to clinical and subsequent radiographic confirmation of three canals: the palatal, mesiobuccal, and distobuccal canals [Fig2].

Bio mechanical preparation was carried out using the step back technique with recapitulation to the original working length. Apical preparation was done to size 25file, and coronal preparation to size 35file, all under copious irrigation with sodium hypochlorite. The canals were dried with paper points and the access cavity restored with zinc phosphate cement over cotton wool pledget, A week later, the patient was reviewed and she felt slight tenderness to percussion with the base of the mouth mirror but assessing the canals, they were found to be dry and uninfected.

Biomechanical preparation was again carried out by smoothening the wall of the canals followed by copious irrigation with sodium hypochlorite. Drying was achieved with paper points and the canals obturated with gutta percha and a resin sealer (AH26) using the lateral condensation technique [Fig3]. Two months later the patient was reviewed and the tooth was asymptomatic. A post space was prepared and a nickel titanium post cemented in with zinc phosphate cement. The tooth was prepared to serve as a mesial abutment for four-unit fixed-fixed bridge prosthesis.