Evaluation of the root canal morphology of mandibular second premolars in an Iranian population

A detailed knowledge of root canal anatomy is a prerequisite for successful endodontic treatment. Such information is highly dependent upon the ethnicity of the population of interest. Lack of sufficient national information concerning internal anatomy can lead clinicians to increase their rate of treatment success. The aim of this study was to evaluate external root morphology and root canal anatomy of mandibular second premolars in an Iranian population.

Two hundred seventeen human extracted mandibular second premolars were selected. Each tooth was radiographed both mesiodistally and buccolingually. Then, access cavities were prepared for each tooth and root canal negotiated before being immersed into 1% fuchsine solution. Teeth were de-coronated and their roots sectioned into three equal (cervical, middle and apical) parts. Cross sections were visualized under 40X magnification.

Among all roots examined, 132 were straight both mesiodistally and buccolingually, 56 were mesiodistally curved, but buccolingually straight, 11 were mesiodistally straight, but buccolingually curved and 18 samples were curved in both aspects. Internal anatomical evaluation showed 198 samples (91.24%) with a single and 19 (8.75%) with more than one canal.

Although straight roots are common in mandibular second premolars, curvatures in mesiodistal, buccolingual or both directions are not uncommon in the Iranian population. Single-canalled roots are also frequent in these teeth, but Vertucci's types II, III, IV, V, and C-shaped configurations are also encountered.