Cone-beam Computed Tomography Analysis of the Root Canal Morphology of Maxillary First and Second Premolars in a Spanish Population.

INTRODUCTION We investigated the root canal configuration of maxillary premolars in a Spanish population by using cone-beam computed tomography. METHODS Images of 804 maxillary first and second premolars were obtained from 620 patients who underwent cone-beam computed tomography scanning during preoperative assessment (before implant surgery, orthodontic treatment, dentoalveolar trauma diagnosis, or difficult root canal treatment). We determined tooth position, number of roots, root canal configuration (Vertucci's classification), number of root canals, and number of apical foramina per root and used the χ(2) test to analyze the correlation between root number and tooth position. RESULTS In the maxillary first premolar group (n = 430), 46% (n = 198) had 1 root, 51.4% (n = 221) had 2 roots, and 2.6% (n = 11) had 3 roots. Most exhibited a type IV canal configuration (n = 227, 52.8%). Single-rooted teeth had a more variable canal configuration, whereas most 2-rooted teeth showed a type IV configuration (n = 215, 97.3%). In the maxillary second premolar group (n = 374), 82.9% (n = 310) had 1 root, 15.5% (n = 58) had 2 roots, and 1.6% (n = 6) had 3 roots. The majority of single-rooted second premolars exhibited a type I configuration (n = 147, 47.2%). Overall, type VIII canals were only observed in 3-rooted teeth. No statistical correlation was evident between root number and gender and tooth position. CONCLUSIONS There was a high frequency of 2-rooted and single-rooted teeth among maxillary first and second premolars, respectively. The canal morphology of single-rooted teeth was highly variable.