Indian Journal of Dental Research

: 2011  |  Volume : 22  |  Issue : 5  |  Page : 706--708

Microscope-aided endodontic treatment of maxillary first premolars with three roots: A case series

CS Karumaran1, R Gunaseelan1, J Krithikadatta2,  
1 Chennai Dental Research Foundation, Dr. Radhakrishnan Salai, Mylapore, Chennai, India
2 Department of Conservative Dentistry and Endodontics, Meenakshi Amma Dental College, Maduravoyal, Chennai, India

Correspondence Address:
C S Karumaran
Chennai Dental Research Foundation, Dr. Radhakrishnan Salai, Mylapore, Chennai


Maxillary premolars have a highly variable root canal morphology. However, the presence of three roots is a rare occurrence. This clinical article describes the unusual anatomy detected in maxillary premolars during routine endodontic treatment using microscope. The diagnosis and clinical management of maxillary first premolars with three roots and canals using radiographic interpretation, access cavity modification and visual enhancement with operative microscopes is discussed in the article.

How to cite this article:
Karumaran C S, Gunaseelan R, Krithikadatta J. Microscope-aided endodontic treatment of maxillary first premolars with three roots: A case series.Indian J Dent Res 2011;22:706-708

How to cite this URL:
Karumaran C S, Gunaseelan R, Krithikadatta J. Microscope-aided endodontic treatment of maxillary first premolars with three roots: A case series. Indian J Dent Res [serial online] 2011 [cited 2023 Jun 3 ];22:706-708
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Full Text

A thorough knowledge of both, internal and external anatomy of a tooth is an important aspect of root canal treatment. [1] A major reason for a failed root canal treatment is undetected extra roots and canals. [2] One of the possible variations in maxillary premolars is the presence of extra roots. This anatomical abnormality is an additional challenge to the clinician. The reported incidence and management of three canals in a maxillary premolar varies from 0.5% to 6%. [3],[4],[5],[6] Other rare configuration possibilities of three canalled upper premolars are (i) three canals in a single root, (ii) two canals in the buccal root and one in the palatal root, (iii) three separate roots and canals. Three rooted upper premolars are found more often in persons with Turner's syndrome. [7] One promising non-invasive method of detecting additional canals involves the use of magnifying visual aids. One such aid is the operating microscope, which offers various high- and low-power magnifications. Operating microscopes offer homogeneous illumination without shadows and a three-dimensional view, which combine to allow a clear visualization of the examination site. [8] The present case series is a report of varied root canal configurations of the maxillary premolar identified using the dental operating microscope.

 Case Reports

Case 1

A 40-year-old male patient visited the dental clinic, complaining of pain in his left upper posterior region for the past 10 days. His medical history was found to be noncontributory. Clinical examination of the left maxillary first premolar (tooth No. 12) revealed dental caries with tenderness on percussion. Based on clinical findings, radiographic interpretation and vitality teats, a diagnosis of acute apical periodontitis was made and endodontic therapy was planned. On further examination of the radiograph, an abrupt loss of radiolucency in the pulp canal was noticed. The mesiodistal root diameter was greater than the mesiodistal width of the crown. With these findings, a possible anatomical tooth variation was suspected [Figure 1]a. The tooth region was anesthetized using 2% lignocaine with 1:80,000 adrenaline (Lignox, Indoco Remedies Ltd, Mumbai, India) and isolated with rubber dam. An endodontic access opening was prepared under microscope (G6, Global Surgical Corp, St. Louis, MO, U.S.A). The access cavity was modified with a cut at the buccoproximal angle from the entrance of the buccal canals to the cavo surface angle resulting in a cavity with a T-shaped outline. The mesiobuccal and distobuccal canals were explored with a size 10 K-file (Mani, Inc., Tochigi, Japan) and the palatal canal with a size 15 K file. A working length was established with an apex locator (Propex, Dentsply Maillefer, Ballaigues, Switzerland). A working length radiograph confirmed a type VIII Vertucci root canal morphology [7] [Figure 1]b. Biomechanical preparation was performed using crown-down technique with nickel-titanium rotary instruments (ProTaper, Dentsply Maillefer, Ballaigues, Switzerland), under abundant irrigation with 1% sodium hypochlorite solution. All canals were enlarged to size F3. Final irrigation was done with 17% EDTA and the root canal space was obturated with gutta-percha and resin sealer (AH plus, Dentsply Maillefer, Ballaigues, Switzerland) by lateral condensation [Figure 1]c-e. The coronal access was restored with resin composite (3M ESPE, St. Paul, MN, USA) and was followed by metal ceramic crown.{Figure 1}

Case 2

A 21-year-old male patient with a noncontributory medical history visited the clinic, complaining of pain and sensitivity in the left upper posterior region for a week. The left maxillary first premolar (tooth no. 12) had a deep carious lesion. No swelling or sinus was present. Thermal and electric pulp testing (Vitality Scanner, Analytic Technology, Glendora, CA) revealed exaggerated response. Intraoral periapical radiograph revealed radiolucency involving the pulp chamber. The clinical, pulp vitality results, and radiograph were indicative of irreversible pulpal damage [Figure 2]a. The tooth was anesthetized and a rubber dam was placed. An access opening was prepared. Two orifices, buccal and palatal were located. An operating microscope (G6, Global Surgical Corp, St. Louis, MO, U.S.A) was used to examine the floor of the cavity. Further examination of the buccal orifice showed two separate orifices present deeper in the main buccal orifice. Size 10 K-file was introduced in the newly found orifices within the main canal and a radiograph was taken [Figure 2]b. The radiograph confirmed the presence of two buccal canals (bifid) in the apical end, which is a type XVI root canal morphology (Sert and Bayirli's additional types to Vertucci classification. [9] Cleaning and shaping were done using the crown-down technique with ProTaper series nickel-titanium instruments, finally obturated with cold, laterally condensed gutta-percha and resin sealer [Figure 2]c and d. Type XVI root canal morphology can be well appreciated in [Figure 2]e. The coronal access was restored with silver amalgam. The patient was lost for postendodontic management.{Figure 2}

Case 3

A 24-year-old male patient with a noncontributory medical history visited the clinic. He complained of spontaneous pain in the right upper posterior region for a week. Clinical and sensitivity tests with radiographic interpretation lead to a diagnosis of acute irreversible pulpitis in the right maxillary first premolar (tooth No. 5) and endodontic therapy was planned [Figure 3]a. The canal configuration and the obturation procedures were similar to Case 2 [Figure 3]b and c. The coronal access was restored with silver amalgam [Figure 3]d.{Figure 3}


Three-rooted maxillary premolars were reported to be a rare variation in Asian population (0.6%) as compared to non-Asian population (2.1%). [6]

Three-rooted premolars were mostly identified bilaterally. [10],[11] In Case 1, the left maxillary first premolar and the contralateral premolar had type VIII root canal morphology according to Vertucci classification [Figure 1]f.

When a preoperative radiograph revealed an atypical tooth shape and unusual contour, further radiograph should be taken with different angulations to confirm any unusual anatomical features. [5] When there is an abrupt straightening or loss of a radiolucent canal in the pulp cavity, an extra canal should be suspected in the same root or in the other independent roots. [3],[5]

Whenever the mesiodistal width of the mid root region is equal to or greater than the mesiodistal width of the crowns, the tooth is likely to have extra roots. [3],[5] Diagnostic measures, such as multiple preoperative radiographs, examination of the pulp chamber floor with a sharp endodontic explorer, troughing of grooves with ultrasonic tips, staining the chamber floor with 1% methylene blue dye performing the sodium hypochlorite champagne bubble test and visualizing canal bleeding points are important aids in locating root canal orifices. [4],[12],[13],[14]

Baumann was the first to report the benefit of using an operating microscope for conventional endodontics. The nature of magnification in the endodontic treatment ranges from Χ3 to Χ30. The microscope brings minute details into clear view and helps distinguish microstructures that are not visible to the naked eye. The operating microscope allows the operator to understand the subtleties of pulp chamber anatomy visualize the pulpal floor and locate root canal orifice. Furthermore, the microscope enhances the operator's ability to selectively remove dentine with great precision, minimizing the procedural error. Studies have shown that the microscope increases the ability of the dentist to locate and negotiate the canal. [13],[14] Hence, treatment sequence and prognosis for premolars with three roots should be considered to be the same as those for any maxillary premolars.


Clinicians should be aware of the existence of extra roots and canals and the possible anatomical variations in them before initiating the endodontic treatment. The use of supplementary instruments, such as microscopes, computerized tomography can now be rationally used in endodontic treatment. A good visual enhancement of pulp chamber and radiographic interpretation is important for a successful endodontic treatment.


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