|Year : 2018 | Volume
| Issue : 2 | Page : 133-138
Endodontic management of mandibular premolars with three root canals: Case series
Yousef Hamad Al-Dahman1, Saeed Ali Al-Qahtani2, Abeer Abdulkareem Al-Mahdi3, Abdullah Yousef Al-Hawwas4
1 Division of Endodontics, Department of Restorative, Riyadh Colleges of Dentistry and Pharmacy; Department of Dental, Ministry of Health, Qassim Region, Riyadh, Kingdom of Saudi Arabia
2 Division of Endodontics, Department of Restorative, Riyadh Colleges of Dentistry and Pharmacy; Department of Dental, Khamis Mushayt General Hospital, Ministry of Health, Riyadh, Kingdom of Saudi Arabia
3 Saudi Board Resident in Endodontic Division, Department of Restorative, Riyadh Colleges of Dentistry and Pharmacy; Dammam Specialized Dental Center, Ministry of Health, Riyadh, Kingdom of Saudi Arabia
4 Department of Dental, Head of Endodontic Division, King Abdulaziz University Hospital, King Saud University, Riyadh, Kingdom of Saudi Arabia
|Date of Web Publication||5-Apr-2018|
Dr. Yousef Hamad Al-Dahman
Department of Endodontics, Riyadh Colleges of Dentistry and Pharmacy, P. O. Box: 84891, Riyadh 11681
Kingdom of Saudi Arabia
Source of Support: None, Conflict of Interest: None
The proper knowledge of both the external and internal anatomy of teeth is mandatory for adequate root canal treatment. Permanent mandibular premolars are usually single rooted with single root canal. Variations of having more than one canal/root also exist. This paper describes a case series of root canal therapy of permanent mandibular premolars with three root canals. The clinicians must be aware of such anatomical variations and be able to use variety of tools for adequate diagnosis and management.
Keywords: Mandibular premolar, root canal morphology, root canal treatment
|How to cite this article:|
Al-Dahman YH, Al-Qahtani SA, Al-Mahdi AA, Al-Hawwas AY. Endodontic management of mandibular premolars with three root canals: Case series. Saudi Endod J 2018;8:133-8
|How to cite this URL:|
Al-Dahman YH, Al-Qahtani SA, Al-Mahdi AA, Al-Hawwas AY. Endodontic management of mandibular premolars with three root canals: Case series. Saudi Endod J [serial online] 2018 [cited 2019 Sep 19];8:133-8. Available from: http://www.saudiendodj.com/text.asp?2018/8/2/133/229351
| Introduction|| |
Root canal treatment requires a thorough knowledge and understanding of root canal system and its varying morphology which in turn will increase the long-term success level of the treatment.
Mandibular premolars with their pulpal space having an unusual anatomical variation at a high rate lead to many difficulties in treating these teeth.,,,, Several reports have shown that the incidence of one root canal system in mandibular first premolar varied from 69.3% to 86% and two canals varied from 14% to 25.5%.,,, The occurrence of three canals has been reported by Vertucci and Zillich et al. to be 0.5% and 0.4%, respectively.,
Vertucci et al. reported that the mandibular second premolar is having an incidence of one root canal at the apex in 97.5% and two canals in 2.5% of the teeth studied. While the incidence of three root canals reported to range from 0% to 0.4%., Moreover, reports of mandibular second premolar with four and five root canals have been published.,,
In Saudi subpopulation, mandibular first premolar was reported with an incidence of 80% teeth had a single root, 18% had two roots, and three rooted in 2% of the teeth studied. In addition, 72% of the teeth mandibular second premolar had a single canal, 26% had two canals, and 2% had three canals. Moreover, case reports have been published for mandibular second premolar having 2 roots and 3 root canals  and 3 roots with 3 root canals.
Different techniques have been used and described in the literature to study the anatomical variations of human teeth including decalcification, radiography, vertical and cross-sectional cutting, histological evaluation, stereomicroscopy analysis, surgical microscopy, plastic casts, scanning electronic microscopy, cone-beam computed tomography (CBCT), and microcomputed tomography.,
The present case series reported a successful endodontic management of mandibular first and second premolars with three root canals. Each case presented its own morphological configuration and challenges.
| Case Reports|| |
A 24-year-old Saudi male with a noncontributing medical history was reported to endodontic postgraduate clinics of Riyadh College's Dental Hospital, Riyadh, Saudi Arabia, for nonsurgical endodontic retreatment of mandibular right first premolar (number #44). The chief complaint was painful sensation on the lower right side on biting. Clinical examinations revealed a temporary restoration on tooth #44. The tooth was sensitive to percussion and palpation. There was no mobility and the periodontal status was normal. Radiographic examination revealed a previously treated tooth with three root canals, separated instrument in the mesiobuccal canal which has been confirmed by angled radiograph, and periapical radiolucency [Figure 1]a and [Figure 1]b. Based on the clinical and radiographic findings and according to American Association of Endodontics consensus, the tooth was diagnosed as previously treated with symptomatic apical periodontitis.
|Figure 1: (a) Preoperative radiograph. (b) Preoperative angled radiograph confirming the position of separated instrument in mesiobuccal canal. (c) The axial plane of cone beam computed tomography of tooth #44 showing three root canals. (d) The separated instrument was bypassed. (e) The retrieval of the separated instrument. (f) The separated instrument after retrieval (3 mm long H-file). (g) Working length determination. (h) Postoperative radiograph with the tooth having final restoration|
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CBCT was carried out to confirm the numbers of roots and canals of the mandibular right first premolar. The CBCT images were taken out using three-dimensional (3D) Accuitomo scanner (J. Morita, Kyoto, Japan), with Viewer Plus software (J. Morita, Japan), which produced a smallest field of view images, to reduce the radiation dosage. A single root with three canals was found, two buccal and one lingual [Figure 1]c. A nonsurgical root canal retreatment was planned accordingly.
Following the delivery of local anesthesia (2% lidocaine and 1:100,000 epinephrine) and isolation with rubber dam, removal of the temporary filling was made. The pulpal floor was carefully examined under dental operating microscope (DOM) (Global Dental Microscopes, Global Surgical Corporation, USA). Two separate buccal orifices and one lingual were identified. The access cavity outline was modified into triangular shape to establish straight-line access.
The root canal filling was removed using size #10 K-file with chloroform solvent, and the separated instrument was bypassed [Figure 1]d. The retrieval of the separated instrument was done using Terauchi File Retrieval Kit (Dental Engineering Laboratories, Santa Barbara, California, USA) under the DOM [Figure 1]e and [Figure 1]f. The modified Gates-Glidden (GG) drill from the kit was used circumferentially to create a tapering preparation from the canal orifice to the coronal end of the separated file.
Then, the working length was established using Root ZX II (J. Morita, Tokyo, Japan) electronic apex locator and confirmed radiographically [Figure 1]g. The three canals were shaped by ProTaper Next System (Dentsply Maillefer, Ballaigues, Switzerland) to size X2 for all canals. Copious irrigation with 2.5% sodium hypochlorite (NaOCl) followed by 17% ethylenediaminetetraacetic acid (EDTA) was carried out during the instrumentation phase. After the final flush, the canals were dried with paper points (Maillefer, Dentsply, Ballaigues, Switzerland), and calcium hydroxide (Ca(OH)2) (Medidenta, Las Vegas, NV, USA) intracanal medicament was placed in the canals for 2 weeks.
On the next visit, the Ca(OH)2 was washed; canals were dried with paper points and obturated with matching gutta-percha cones and Endosequence BC sealer (Brasseler, Savannah, GA) with preservation of postspace in the lingual canal. The access cavity was sealed with Coltosol temporary filling material (Coltosol ® F, Coltene, Switzerland), and the patient was referred to receive final restoration [Figure 1]h.
A 71-year-old Saudi male with no history of any systemic diseases presented for endodontic treatment of his mandibular right second premolar tooth (#45). The patient was referred to the Department of Endodontics; Riyadh Colleges of Dentistry and Pharmacy, Riyadh, Saudi Arabia, with a chief complaint of seeking continuation of treatment of tooth #45. Radiographic evaluation revealed normal periodontium and presence of more than one root [Figure 2]a. Based on the clinical and radiographic examinations, the tooth was diagnosed as having a previously initiated pulp with normal periapical tissues.
|Figure 2: (a) Preoperative radiograph. (b) The axial plane of cone beam computed tomography of tooth #45 showing three root canals. (c) The coronal plane of cone beam computed tomography of tooth #45 showing three root canals. (d) Working length determination. (e) Postoperative radiograph|
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CBCT was carried out. The CBCT images were taken out using 3D Accuitomo scanner, with Viewer Plus software. Two roots with three canals were found, one buccal and one lingual root [Figure 2]b and [Figure 2]c. A nonsurgical root canal treatment was planned accordingly.
The patient received local anesthesia with 2% lidocaine and 1:100,000 epinephrine, and the rubber dam was placed. Following the removal of temporary filling, careful examination of the pulpal floor under DOM revealed three separated canal orifices (mesiobuccal, distobuccal, and lingual). The access cavity outline was modified and the working length was established using Root ZX II and confirmed radiographically [Figure 2]d. Instrumentation is achieved with ProTaper Next files to size X2, and copious irrigation with 2.5% NaOCl and 17% EDTA was carried out during the instrumentation phase. All canals were dried with sterile paper points and then filled using matching gutta-percha cones and AH plus sealer (Dentsply Maillefer, Ballaigues, Switzerland). Backfill was done using Obtura III (Max System, Obtura Spartan U. S. A). Finally, the access cavity was filled with Fuji resin-modified glass ionomer filling (ChemFil, Dentsply DeTrey, Germany) [Figure 2]e and the patient was referred to prosthodontic department for the final restoration.
A 52-year-old Saudi female, with no history of any systemic diseases, referred to the postgraduate endodontic clinic in Riyadh Colleges of Dentistry and Pharmacy to do root canal retreatment of tooth #45. The tooth was asymptomatic with intact amalgam filling.
Clinical examinations revealed normal response on percussion and palpation. Radiographic assessment showed inadequate root canal filling and an indication of the second root with clear periodontal ligament space [Figure 3]a. CBCT was taken to confirm the number of root (s) and/or canals. Three root canals were detected; 2 lingual and one buccal, in which the main canal was trifurcated from the midroot to the apex [Figure 3]b and [Figure 3]c.
|Figure 3: (a) Preoperative radiograph. (b) The axial plane of cone beam computed tomography of tooth #45 showing three root canals. (c) The coronal plane of cone beam computed tomography of tooth #45 showing trifurcation of canals. (d) Working length determination. (e) Postoperative radiograph. (f) Postoperative radiograph (angled radiograph)|
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A diagnosis of previously treated pulp and normal periradicular tissue was made. The tooth was anesthetized with 1.8 ml of 2% lidocaine with 1:100,000 epinephrine, and amalgam filling was removed and access modified under rubber dam isolation. The previous root canal filling was removed using ProTaper Universal Retreatment rotary files D1, D2, and D3 (Maillefer, Dentsply, Ballaigues, Switzerland) with the help of Carvene GP solvent (Prevest Denpro, India).
Three canals were negotiated (one buccal and two lingual). The pulp chamber was flushed with 2.5% NaOCl solution to remove debris and any dissolved gutta-percha. The working length was determined radiographically at different angles [Figure 3]d.
All the treatment steps were done under DOM set at ×1 magnification. The canals were initially prepared with K-files 10, 15, and 20, then completed with Profile rotary files in crown-down manner up to size 25, 0.6 taper (Dentsply Tulsa). About 2.5% NaOCl solution was used to irrigate the canals and RC-prep gel (MD-Chelcream, META BIOMED, Chungbuk, Korea) was used as lubricant.
Before obturation, the canals were irrigated with 17% EDTA solution and finally flushed with saline. The root canals were dried with sterile paper points and filled with cold, laterally condensed gutta-percha (Maillefer, Dentsply, Ballaigues, Switzerland) and BC sealer. The occlusal access opening was sealed temporarily with glass ionomer cement (Ketac Fil Plus Aplicap Glass Ionomer Restorative, 3M, United States). A final radiograph was taken [Figure 3]e and [Figure 3]f.
| Discussion|| |
Adequate root canal therapy requires locating, cleaning, shaping, and obturating all root canals. Therefore, failure of any of these principles can lead to posttreatment disease, pain, and/or complications of treated tooth.,
Mandibular premolars with their root canal systems are considered the most difficult teeth to endodontically treat due to their wide variation of internal and external root morphology and also that the division of the roots and/or root canals in these teeth usually occurs in the middle and apical thirds which makes detection of these anatomical variations difficult.
In case #1, the first mandibular premolar was single rooted with three root canals, which is the first case reported in Saudi Arabia. This type of morphology is similar to the reported case in Jamaica by Nallapati et al. On the other hand, two Indian cases of mandibular first premolars with two roots and three root canals were reported., In addition, three roots and three root canals were also reported in United States of America, China, United Kingdom, and India.,,,
In case #2, the second mandibular premolar was two rooted with three root canals which is similar to the reported case of Al-Attas and Al-Nazhan of Saudi Arabia. While the third case in this report, a mandibular premolar with three roots and three root canals, was similar in its morphological variation to the previously reported cases.,,,,,
Proper interpretation of conventional periapical radiographs taken in more than one angle is mandatory to detect any morphological variations of teeth., In addition, using advanced diagnostic radiographic techniques such as CBCT is very helpful to detect such variations if conventional radiographic techniques lack to provide obvious information and more details are required.,,, CBCT was taken in the three cases which aid in the detection of morphological variations and management of the treated teeth.
Instrument separation can be encountered at any stage of root canal therapy which includes endodontic files, GG burs, and spreaders. Predisposing factors to instrument separation include instrument design, manufacturing process, dynamics of instrument use, canal configuration, preparation technique, cleaning and sterilization process, and number of uses. In the first case, the main cause of instrument separation is judged to be inappropriate access cavity that obstructs the straight-line access.
No effect on healing of root-filled teeth with a retained instrument fragment was reported on some studies, while other studies reported a lower healing rate when a separated instrument was present. In case #1, the separated instrument affected the prognosis of the previous root canal treatment due to inadequately prepared root canals and the presence of necrotic pulp tissues which lead to inadequate root canal treatment and periapical infection. The root canal status (infected or not) and the level of the separated instrument play an important role in the prognosis of the treated case.
Furthermore, enhancing visualization by the means of DOM will aid in the proper examination of the floor of the pulp chamber, localizing canals orifices, and detecting these variations which could not be seen easily due to the limited access opening.,,, All cases were managed under DOM which enhanced the exploration of the floor of the pulp chamber and detection of canal orifices.
| Conclusion|| |
It is strongly important to use all the available diagnostic tools to find and treat the full root canal system. Cautious interpretation of angled radiographs, good access preparation, proper inspection of pulpal floor, and a detailed examination of the interior of the tooth perfectly under magnification and CBCT are important prerequisites for a successful treatment outcome.
The authors would like to thank Professor Saad Al-Nazhan for his valuable comments on the article.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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