Micro-computed tomographic evaluation of root and canal anatomy of maxillary first premolars in Iraqi sub-population

Successful root canal treatment requires a thorough understanding of root canal morphology. This study investigated the root canal morphology and the fine anatomical characteristics of maxillary first premolars in an Iraqi sub-population using micro-computed tomography (micro-CT) and classified using Vertucci and Ahmed et al. systems. A total of 151 extracted maxillary first premolars were collected, cleaned and disinfected. The collected teeth were scanned using a micro-CT system. The images were segmented and three-dimensionally (3D) reconstructed using Mimics research software, for the evaluation of root canal morphology, isthmuses and accessory canals. The data were analysed using the Monte Carlo simulations for Chi-Square test with a significance level of 0.05. Results showed that out of the 151 maxillary first premolars, 82 (54.3%) were double-rooted and 69 (45.7%) were single-rooted. The most common root canal configuration in the single-rooted teeth was Vertucci Type VII (Ahmed et al. code ¹MaxP^1-2-1-2), and Vertucci Type IV (Ahmed et al. code ²MaxP B¹P¹) was the most common type in the double-rooted teeth. About 15.2% of the samples could not be classified by Vertucci system and were classified using Ahmed et al. system. Isthmuses were observed in 28.5% of the samples with the middle root third was the most common location. Isthmus prevalence was significantly higher in single-rooted teeth (50.7%) compared to the double-rooted teeth (9.8%) (P < 0.001). The accessory canals were found in 77.5% of the samples, mostly in the apical third of the root, as classified by Ahmed et al. coding system for accessory canals. Accessory canal location varied more in the buccal root compared to the palatal root and single-rooted teeth (P < 0.05). Maxillary first premolars showed wide variations in root canal morphology and fine anatomical features such as isthmuses and accessory canals in the studied Iraqi population. Ahmed et al. system appeared to be more reliable in characterizing the root canal morphology compared to Vertucci classification. Clinicians need to consider utilising advanced imaging techniques, such as CBCT, to provide a clearer visualization of root canals. This allows them to plan disinfection protocols, ensuring thorough cleaning of the entire canal system.