Root canal treatment of a maxillary second premolar with two palatal roots: A case report.

Anatomical variations in root canal morphology are an enigma and it is this variability, which is often a complicating factor in a successful root canal treatment. To achieve success in endodontic therapy it is imperative that all the canals are located, cleaned and shaped and obturated three dimensionally. Maxillary first premolar having three separate roots has an incidence of 0.5-6%. Even rarer are reported clinical case reports of maxillary second premolar with three separate roots and three canals. This case report describes the endodontic management of maxillary second premolar with two palatal roots and one buccal root having three root canals.

INTRODUCTION

Anatomical variations in root canal morphology are an enigma. The outcomes endodontic procedures are highly influenced by variable anatomic structures and, therefore, the clinicians ought to be aware of complex root canal structures and cross-sectional dimensions.[1] Maxillary first premolar having three separate roots has an incidence of 0.5-6%.[234567] The maxillary second premolars show an even lesser incidence of 0.3 to 2% in laboratory studies.[89] Even rarer are reported clinical cases of maxillary second premolar with three separate roots and three canals.[1011] Three rooted maxillary premolars look anatomically similar to the molars are sometimes called small molars or radicolous[1213] and usually have a mesiobuccal, a distobuccal and a palatal canal. The root canal morphology of the maxillary second premolar in Indians shows a higher incidence of type II configuration (33.6%).[1] In this case report, we would like to describe the endodontic management of maxillary second premolar with two palatal roots and one buccal root having independent root canals.

CASE REPORT

A 32-year-old female reported to department with pain in her upper right posterior region since one month. On clinical examination an old amalgam restoration was seen on the maxillary right molar and the second premolar adjacent to it had a proximal carious lesion associated with it. The second premolar was tender to percussion. An intra oral periapical radiograph was advised and it showed distoproximal radiolucency of crown approximating the pulp space of the maxillary right second premolar (Image 1). Multiple intra oral peri-apical radiographs were taken using Clark's tube shift technique as the premolar showed multiple roots. Pulp vitality test with electric pulp tester (Digitest, Parkell Products, NY, USA) showed a delayed response for the maxillary second premolar. A diagnosis of irreversible pulpitis was made and endodontic treatment was initiated.

Access opening was done under local anesthesia (2% Lignocaine with 1:80,000 Adrenaline, Lignox, Indoco Remedies Ltd, India) after rubber dam isolation. The unusual anatomy made it difficult to precisely discern, whether the roots were located on the buccal or palatal aspect. The access cavity was modified as described by Balleri et al.,[14] with a tooth preparation at the bucco-proximo angle from the entrance of the buccal canal to the cavosurface angle resulting in a cavity with a T-shaped outline. But only one buccal (B) [Image 2] and one palatal canal (P1) [Image 2] orifices could be located. A modification was again made and the preparation was extended in the palato proximal directions and the orifice of the third root canal (P2) [Image 2] was located mesiopalatally in the palatal aspect.

Working length was determined with apex locator and confirmed with intra oral peri-apical radiograph [Image 3]. The three canals were initially enlarged with hand files until the 15 K file (Mani Inc. Tochigi, Japan) freely glided through the canal, following which the canals were enlarged to size F2 ProTaper rotary files ((Dentsply Maillefer, Ballaigues, Switzerland) sequentially. During canal preparation Glyde (Dentsply Malliefer, Ballaigues, Switzerland) was used as a lubricant and the root canals were copiously irrigated with 3% sodium hypochlorite (Prime Dental Product, Mumbai, India) and 0.9% normal saline (Baxter India Pvt Ltd., Alathur, India) after the use of each instrument. The root canals were properly dried with absorbent paper points and obturated with gutta-percha (Elements Obturation system, Sybron Endo, USA) and resin based sealer (AH plus, Dentsply De Trey, Konstanz, Germany) [Images 4 and 5]. The access cavity was then sealed with IRM (DENTSPLY Caulk, Milford, USA). The patient was recalled after seven days for the permanent restoration and then referred to the Department of Prosthetic Dentistry for a full coverage crown Figure 1 contains the sub images 1-5.

Figure 1

Composite image showing pre operative IOPA, access preparation, working length IOPA, master cone IOPA and obturation IOPA of a maxillary 3 rooted second premolar

DISCUSSION

Extra roots present an additional challenge, which necessitates modifications from the initial assessment stage to the design of the access preparation, cleaning and shaping and obturation of the tooth. So awareness of abnormal variation in the internal anatomy of the tooth is essential for success of an endodontically treated tooth. Velmurugan et al.,[15] have reported that out of 220 maxillary second premolar teeth that were endodontically treated from Indian population, only three of these had three roots and three canals.

Accurate preoperative radiographs (straight and angled) are essential to reveal the number of roots and canals that exist in a tooth.[151619] But radiographic analysis themselves are inadequate in obtaining a suitable abstraction of root and pulp canal system as evident in this case necessitating the use of more advanced methods like CBCT as a diagnostic tool to determine the canal morphology.

A general guideline for the identification of a three-rooted maxillary premolar on preoperative radiograph is that if the mesial-distal width of the mid-root image appears equal to or greater than the mesial-distal width of the crown image, then the tooth most likely has three canals.[18] This guideline may act as a good visual clue but is not necessarily absolute.

The access cavity for maxillary second premolars is usually oval[20] in the bucco-palatal direction. In three rooted maxillary premolar, the buccal orifices are usually close to each other and are hard to locate. Balleri et al., suggested a T-shaped access outline for three rooted maxillary first premolars.[14] This modification allows good access to the two buccal canals. But in this case a further modification had to be done as the canals were on the palatal aspect of the tooth and not buccally as expected from the radiographic interpretation necessitating an extension of the access preparation palato proximally to reveal the third orifice mesiopalatally.

In today's endodontic practice aberrant anatomy has become more common than before and, therefore, clinicians should be constantly on the lookout for variations in anatomy as the successful outcome of any case that depends on the complete debridement and disinfection of all canals.