Author : Dr. SHIKHA B.D.S, M.D.S., SENIOR LECTURE, Subharti Dental College, Meerut

ABSTRACT
Aberrations in the root canal anatomy is a commonly occurring phenomenon especially with respect to mandibular premolar. Mandibular second premolars usually have a single root and a single root canal. The incidence of more than one root is rare. This case report presents a successful endodontic management of a mandibular second premolar with three separate roots and three distinct root canals.

Figure 1.Pre operative IOPA of mandibular second premolar showing variation in root and canal morphology

Introduction
The success of root canal therapy is dependent on a thorough knowledge of the root and root canal morphology in order to locate all canals and properly clean, shape and obturate the canal space in three dimensions.¹

Slowey indicated that probably because of variations in canal anatomy, mandibular premolars are the most difficult teeth to treat endodontically.²The mandibular second premolar is typically described in text as a single-rooted tooth with a single root canal system.^1,3-5However, the root morphology and canal morphology of the mandibular second premolar can be extremely complex and highly variable.⁶Variation in root canal morphology was suggested as the most likely reason for the frequency of endodontic flare-ups and failures associated with mandibular premolars.^1,2,7

Awareness and understanding of the presence of unusual internal root canal morphology largely contributes to the successful outcome of root canal treatment. This case report presents a successful endodontic management of mandibular right second premolar with one mesial and two distal roots with three distinct root canals.

CASE REPORT

A 20 year old male presented with symptoms of pain and sensitivity in lower right side of jaw. Dental history revealed that patient had severe pain one month back for which endodontic therapy had been initiated elsewhere. Clinical examination revealed previously treated lower right mandibular second premolar which was extremely tender on percussion. Electric pulp testing revealed a negative response from the concerned tooth. IOPA radiograph of the concerned tooth revealed an abnormal morphology of mandibular second premolar with three roots, one mesial and two distal. RVG imaging (Gendex,Dentsply) of the concerned tooth pointed towards the possible presence of more than one canal in the mesial root (Figure 1).

The access cavity was modified with Endo-Z in order to locate the orifices and to achieve a straight line access. A DG 16 explorer was used to locate the orifices. Four separate orifices were located, two in the mesial root and one in each of the distal roots. Profinders (Maillefer, Dentsply, Ballaigues, Switzerland) No. 10, 13 and 17 were used to scout the canals and establish glide path and patency. Working length radiographs revealed the presence of 4 canals, two mesial and two distal (Figure 2).However the two mesial canals appeared to be separated by a thin isthmus. Working length was confirmed using apex locator (iPex NSK). Biomechanical preparation was done using Rotary Protaper (Maillefer, Dentsply, Ballaigues, Switzerland) instruments along with copious irrigation with 3% NaOCl. Apical finishing in each canal was achieved with size F1. Obturation was done with size F1 Protaper cone using AH Plus (Dentsply) as sealer. A post obturation angulated IOPA radiograph revealed well obturated canals (Figure.3).

Figure 2. IOPA x-ray showing files at working length	Figure 3.IOPA x-ray showing Obturation

DISCUSSION
This case report illustrates unusual morphology of the roots and root canal system of mandibular second premolar. Coronal anatomy and dimensions were within normal limits and provided no indication of complex morphology of the radicular portion in the premolar.

Reports in the literature vary grossly with respect to root and root morphology of mandibular premolar teeth compared with the standard description of one root, one canal found in texts on dental anatomy. Three rooted mandibular second premolar tooth, as described in this case report occurs, in patients occasionally and may be reported in the literature.⁸

The diagnosis and management of extra roots or root canal morphology in mandibular premolars is undoubtedly an endodontic challenge. In order to achieve this, the clinician must have a thorough understanding of the normal root canal anatomy and its common variations. Inability to find and obturate a root canal has shown to be a major cause of failure in endodontic therapy. Hoen and Pink⁹ found that in the teeth needing retreatment, there was 42% incidence of missed roots or canals in the teeth, hence reinforcing the fact that all canals need to be located and treated during the course of endodontic therapy. A number of studies reported showing a high percentage of mandibular premolars to have more than one canal. Shapira and Delivanis reported a case of mandibular second premolar with three roots and three canals.¹⁰ A case of mandibular second premolar with four roots and four canals has also been reported.¹¹

The success of endodontic therapy was evaluated in a study at the University of Washington which showed, out of all teeth, the failure rate of root canal treatment in mandibular first and second premolars was 11.45 and 4.5%.1 A number of case reports in the literature emphasize on the number of root canals but only a few case reports emphasize on the variations in the number of roots occurring in mandibular premolars.^11,12,13

Serman and Hasselgren reported a high incidence (18.5) of multiple roots and canals in mandibular premolar teeth in a series of radiographic surveys with mandibular first premolar involved in 15.7% of patients and mandibular second premolar in 7% of patients. Multiple roots or root canals were situated in both bucco-lingual and mesio-distal orientations in that study.⁸

Also, in the cases of retreatment, on of the problems that come up is loss of anatomic landmarks due to an already prepared access cavity, Difficulty in location of root canals is increased manifold and hence the clinician has to look more thoroughly for location of canal orifices.

The presence of extra roots and root canals in mandibular premolars may occur far more than one can expect.

CONCLUSION

Successful endodontic management of a mandibular second premolar with 2 separate roots and four distinct root canals has been presented. The success of this case could be attributed to the successful diagnosis, thorough biomechanical debridement and complete obturation of all the four canals.

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