Root canal treatment of a maxillary first premolar with three roots.

Successful root canal treatment needs a thorough knowledge of both internal and external anatomy of a tooth. Variations in root canal anatomy constitute an impressive challenge to the successful completion of endodontic treatment. Undetected extra roots and canals are a major reason for failed root canal treatment. Three separate roots in a maxillary first premolar have a very low incidence of 0.5-6%. Three rooted premolars are anatomically similar to molars and are sometimes called "small molars or radiculous molars." This article explains the diagnosis and endodontic management of a three rooted maxillary premolar with separate canals in each root highlighting that statistics may indicate a low incidence of abnormal variations in root canal morphology of a tooth, but aberrant anatomy is a possibility in any tooth. Hence, modern diagnostics like cone beam computed tomography, and endodontic operating microscope may have to be used more for predictable endodontic treatment.

Successful root canal treatment needs a thorough knowledge of both internal and external anatomy of a tooth.[1] Undetected extra roots and canals are a major reason for failed root canal treatment.[2] Slowey has stated that root canal morphology has limitless variability and clinician should always be aware that anatomic variations constitute an impressive challenge to the successful completion of endodontic treatment.[3]

Three separate roots in a maxillary first premolar have an incidence of 0.5–6%.[45] Three rooted premolars are anatomically similar to molars and are sometimes called “small molars or radiculous molars.”[67] They usually present with mesiobuccal distobuccal, and palatal canals. Rarely, first premolars present with other configurations such as (i) Three canals in a single root, (ii) two canals in the buccal root and one in the palatal root, (iii) one canal in buccal and two canals in palatal.[5] Persons with turner's syndrome may often present with three rooted upper premolars.[8] This article explains the diagnosis and endodontic management of a three rooted maxillary premolar with separate canals in each root.

Case Report

A 25-year-old male patient reported to the department with pain in his upper right posterior region since 1-week. On clinical examination, a mesioproximal caries lesion was detected on maxillary right first premolar (14), The premolar was tender on percussion. An intraoral periapical radiograph revealed mesioproximal radiolucency of the crown extending close to the pulp chamber of 14 [Figure 1]. Intraoral periapical (IOPA) X-ray also revealed a complex radicular anatomy with two buccal roots and a separate palatal root for 14. Electric pulp testing also was done, and 14 exhibited a delayed response. Maxillary right first premolar (14) was diagnosed with irreversible pulpitis and after discussing with patient root canal treatment of 14 was initiated.

Figure 1

Preoperative X-ray of maxillary 1st premolar showing two separate buccal roots and one palatal root

After rubber dam isolation of 14, access opening was done under local anesthesia (2% lignocaine with 1:80,000 Adrenaline, Lignox, Indoco remedies Ltd., India). Expecting two buccal canals, the access opening was made mesiodistally wider than normal on the buccal aspect making the access opening T-shaped. The palatal canal was first located, and dentinal map on the floor of the pulp chamber was traced to locate two separate buccal canals. Working length was determined with electronic apex locator (i-pex, NSK, Nakanishi, Japan) and was confirmed with IOPA X-ray [Figure 2]. The three canals were cleaned and shaped using k files till size 15. After this canals were instrumented sequentially with ProTaper rotary files (Dentsply Tulsa Dental) till size F2. While instrumenting canals were lubricated with Glyde (Dentsply Malliefer, Switzerland) and irrigated with 3% sodium hypochlorite (Prime Dental products, India) and 0.9% normal saline (Baxter, India). The root canals were dried with paper points, obturated using Gutta-percha with resin based sealer (AH Plus, Dentsply, Detrey, Konstanz, Germany) and the postobturation radiograph is shown in Figure 3. The access cavity was then sealed with IRM (Dentsply Caulk, Milford, USA) and restored with composite after 7 days. The patient was referred to the Department of Prosthodontics for full coverage restoration.

Figure 2

Working length X-ray showing files in two buccal canals and one palatal canal

Figure 3

Postobturation X-ray showing maxillary first premolar with two separate buccal canals and one palatal canal

Discussion

Root canal treatment of maxillary premolar may be very difficult because of variations in the number of roots, the number of canals, differences in pulp cavity configurations, and difficulty in visualizing the root apices by radiographs.[9] An endodontist should be aware of all possible variations in root canal anatomy for successful endodontics. Vertucci and Gegauff reported that 5% of maxillary first premolars had 3 canals. Of this 0.5% existed as three canals in a single root, 0.5% exhibited 2 canals in one root and one canal in a second root, and 4% presented with one canal each in three separate roots.[10] Carns and Skidmore found six premolars of a total of 100 maxillary premolar to demonstrate 3 separate canals all of which were present in separate roots.[11] Ozcan et al. in a study in Turkish population found that of 653 first premolar examined only three premolars (1.1%) had three separate roots and that 10 teeth (1.5%) had three canals.[12] No data are available on the incidence of 3 rooted premolars with three canals in Indian population.

An accurate preoperative radiograph should always be carefully studied before starting a root canal procedure. The straight angled radiograph should be supplemented with angled X-rays so that any additional roots or canals may be visible. However, radiographs being two-dimensional may not always be adequate for assessing morphological variations in root anatomy. Advanced diagnostic tools like cone-beam computed tomography (CBCT) may give a more accurate picture of root canal morphology.[13] In this case, the preoperative X-ray itself was showing the presence of two buccal roots and one palatal root with separate canals in each root. Hence, advanced and costly diagnostic tools like CBCT were not employed in this case. According to Sieraski et al. three roots should be expected in a premolar when the mesio-distal width of the mid root image is equal to or greater than the crown image.[14]

The access cavity for maxillary premolars is usually oval shaped in bucco-palatal cross section. Chauhan and Singh have suggested a T-shaped access cavity for a three rooted maxillary first premolar. This modification is for convenient access to the buccal roots.[15] Following this suggestion access cavity was made T-shaped in this case.

Studies may be indicating a low incidence of three roots and root canals in a maxillary premolar. Even then, a clinician doing root canal treatment should always look for additional roots and canals in all cases. Use of modern diagnostic tools like CBCT and use of operating microscopes may help a clinician to detect and manage any variations in root canal morphology thereby, to increase the success rate of endodontic treatment.

Conclusion

Variations in the number of roots and root canals may occur in any teeth. Any clinician doing root canal treatment should be aware of this and should be on the lookout for aberrant anatomy during each step of root canal treatment. This case report also emphasizes the same.

Clinical significance

Statistics may indicate a low incidence of abnormal variations in root canal morphology of a tooth, but aberrant anatomy is a possibility in any tooth. Hence, modern diagnostics like CBCT and endodontic operating microscope may have to be employed more for predictable endodontic treatment.