|Year : 2016 | Volume
| Issue : 1 | Page : 72-75
Endodontic management of a three-rooted taurodont mandibular second premolar using cone beam computed tomography
Bhuvan Shome Venigalla1, Pinnamreddy Jyothi1, Radhika Venigalla2, Prathibha Mudalapuram1
1 Department of Conservative Dentistry and Endodontics, Sri Sai College of Dental Surgery, Vikarabad, India
2 Dental Surgeon, Jewel Dental Clinic, Hyderabad, Telangana, India
|Date of Web Publication||21-Jun-2016|
Bhuvan Shome Venigalla
Turquoise 1210, My Home Jewel, Madinaguda, Hyderabad, Telangana
Source of Support: None, Conflict of Interest: None
Mandibular second premolars are considered as an enigma to the endodontist because of their wide variations in root canal morphology. Mandibular premolars with three roots are rare and with taurodontism are even rarer. Failure to negotiate and properly treat these cases may result in the loss of the tooth. Knowledge of variations in root canal anatomy and accurate diagnosis with novel diagnostic aids like cone beam computed tomography (CBCT) assist in thorough debridement and three-dimensional obturation of the root canal system, thus increasing the success rate of nonsurgical endodontic treatment. This article describes the successful management of the right mandibular second premolar with taurodontism and three separate roots diagnosed using CBCT.
Keywords: Cone beam computed tomography; mandibular second premolar; taurodontism; three roots.
|How to cite this article:|
Venigalla BS, Jyothi P, Venigalla R, Mudalapuram P. Endodontic management of a three-rooted taurodont mandibular second premolar using cone beam computed tomography. Endodontology 2016;28:72-5
|How to cite this URL:|
Venigalla BS, Jyothi P, Venigalla R, Mudalapuram P. Endodontic management of a three-rooted taurodont mandibular second premolar using cone beam computed tomography. Endodontology [serial online] 2016 [cited 2019 Nov 21];28:72-5. Available from: http://www.endodontologyonweb.org/text.asp?2016/28/1/72/184347
| Introduction|| |
Internal anatomy of the root canal system is complex and variable.  Taurodontism is a morpho-anatomical change in which body of the tooth is enlarged at the expense of roots,  and it was first reported by Gorjanovic-Kramberger in 1908.  Madeira et al. (1986) conducted a study on the prevalence of taurodontism in premolars and concluded that its overall incidence was 0.25% with the highest prevalence in mandibular first premolars (0.42%) and the lowest in maxillary premolars (0%). , Mandibular premolars mostly have a single root and root canal. Zillich and Dawson (1973) reported an incidence of two or more roots in 2.1% and 0.4% of mandibular first and second premolars, respectively. ,
This case report is intended to present the successful management of a case of taurodont right mandibular second premolar with middle third trifurcation.
| Case Report|| |
A 35-year-old female patient walked into our clinic with the chief complaint of severe pain in the lower jaw right posterior region since 2 days. Oral examination revealed occlusal caries in the lower right mandibular second premolar. The tooth was sensitive to percussion and showed an exaggerated response on cold and electric pulp testing. Radiological findings showed coronal radiolucency involving pulp, widening of periodontal ligament (PDL) space, large pulp chamber without any constriction at cementoenamel junction, and roots trifurcating at the middle third. The condition was diagnosed as acute irreversible pulpitis with apical periodontitis in a taurodont premolar, and root canal therapy was planned. As the patient had severe pain, treatment was started immediately to relieve pain. Administration of local anesthesia was followed by rubber dam placement. Access cavity was prepared, and enormous inflamed pulp tissue was removed using # 80 H file. Careful exploration of pulp chamber floor with DG 16 explorer and loupes revealed the presence of three orifices: One mesially (mesiobuccal), one distally (distobuccal), and another lingually (lingual) which were enlarged with Gates-Glidden drills, and canals were negotiated using # 10 K file. Working length was estimated using intraoral periapical radiograph and verified with an apex locator (Root ZX, J Morita Inc., USA) [Figure 1]a. The biomechanical preparation was done using Protaper Universal Niti rotary system (Dentsply, USA) up to size F2 under copious irrigation with 3% NaOCl. Commercially, available paste form of calcium hydroxide (RC Cal, Prime Dental Products, India) was placed inside the root canals; access cavity was sealed with cavit and patient recalled after a week. Further, the patient was referred for cone beam computed tomography (CBCT) examination to confirm the observed findings and also to explore any additional findings if present like any unexplored canals. CBCT examination confirmed the presence of taurodontism trifurcating into three roots with three separate root canals [Figure 2]a and b.
|Figure 1: Radiographs showing (a) working length determination, (b) master cone radiograph, (c) postobturation, (d) postspace preparation with fiber posts insertion|
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|Figure 2: Cone beam computed tomography images confirming the presence of taurodontism (a) and three roots with separate root canals (b)|
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On recall, calcium hydroxide was removed from the root canals using ultrasonics, and suitable master cones were selected [Figure 1]b followed by obturation using F2 Protaper GP points and AH Plus sealer (Dentsply) [Figure 1]c. The tooth had very less remaining dentin thickness (RDT); therefore, postendodontic rehabilitation using fiber-reinforced composite (FRC) posts was planned to reinforce the tooth structure. Postspace was prepared in lingual root canal using heat and mechanical methods [Figure 1]d. Pulp chamber was irrigated using 3% NaOCl and 17% ethylenediaminetetraacetic acid; root dentin was then etched using 37% phosphoric acid for 15 s, rinsed off followed by cementation of fiber post using self-adhesive, and self-curing composite resin cement (Multilink speed, Ivoclar Vivadent). To minimize polymerization shrinkage stresses generated from the excess volume of resin cement, two fiber posts were inverted and placed in the pulp chamber, cemented using core build-up resin cement (Multicore, Ivoclar Vivadent), and light cured [Figure 1]d. Postendodontic restoration was done followed by tooth preparation and Zirconia-based full coverage crown cementation. Fifteen months follow-up radiograph revealed satisfactory healing and healthy status of periapical tissues [Figure 3].
|Figure 3: Fifteen months follow-up radiograph showing Zirconia full coverage crown and healthy status of periapical tissues|
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| Discussion|| |
The morphology of root canal system of mandibular second premolar is complex.  Ingle stated that canal anatomy accounts for a greater chance of endodontic failures in premolars. , Sound knowledge of root canal morphology, vigilant analysis of preoperative radiograph, and careful exploration of pulp chamber floor are essential for the success of root canal treatment.  The advent of three-dimensional imaging techniques such as CBCT, dental operating microscope/loupes, fiber optic transillumination as well as recent developments in root canal instrumentation, and obturation techniques made this challenging task quite simple. Taurodont teeth show wide variations such as apically positioned canal orifices, complex root canal anatomy, and varying degrees of obliteration in root canals which should be taken into consideration during treatment. 
The introduction of CBCT resulted in a paradigm shift in the field of endodontics. CBCT provides a small field of view images at low-radiation dose with good spatial resolution.  Durr et al. stated that in taurodont teeth, morphology could hamper the accessibility of orifices; creating a problem during instrumentation.  Careful exploration of grooves between the orifices, using dental operating microscope or magnifying loupes is recommended to reveal additional orifices. An additional canal should be suspected whenever there is a sudden narrowing of root canal system or if the working length file appears off center in the radiograph.  Good preoperative radiographs taken in two or three angulations, and careful interpretation of root outline and PDL space helps in identifying extra roots.  Analysis of dentinal map and color change on the floor of pulp chamber also help in the detection of extra canals.  Orifice enlargement and preflaring reduces curvature and produces a straight line access to curved apical portion. , The more apically a root canal divides, more difficult it is to access and obturate; therefore, care should be taken to maintain patency during obturation. 
RDT of taurodont premolar with three widely spread roots was less after endodontic treatment, so chances of crown fracture were very high. Therefore to strengthen and reinforce the crown, intra radicular rehabilitation with FRC posts and composite resin cement was done creating a monoblock like effect, which aids in more homogenous stress distribution.  The pulp chamber was filled with three fiber posts cemented using resin cement, to minimize the shrinkage stresses generated by the presence of an excess volume of resin cement when the single post was placed in the wide pulp chamber.  Thus, each endodontic case requires individualized approach and precise planning to ensure 100% success.
| Conclusion|| |
The success of endodontic therapy relies on accurate diagnosis, thorough chemomechanical debridement, and proper obturation of root canal system. Mandibular premolars have high-failure rate due to their extreme variations in root canal anatomy. Novel imaging modalities such as CBCT, magnification, modified obturation, and postendodontic restorative techniques aids in the successful management of these rare cases.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]