Roots Form and Canals Morphology of Maxillary Second Premolar in a Sample of Yemeni Population

Background: The present study aimed to investigate the root form and canal anatomy of the permanent maxillary second premolar in a sample of Yemeni population using cone beam computed tomography (CBCT). Methods: A total of 362 CBCT scans of maxillary second premolars of Yemeni patients aged between 15 and 60 years were analyzed to determine the anatomy of this tooth including number and form of roots, number of canals, number of orifices, and root canal configurations. Chi-square test was used to analyze the association between different variables. Results: Of the 362 examined maxillary second premolars, 87.6% had one root, 12.1% had two roots, and 0.3% had three fused roots. Regarding the canal number, one canal was found in 181 teeth (50%), while two canals were found in 180 teeth (49.7%), three canals were found in one tooth (0.3%). One orifice was observed in 263 teeth (72.7%), two orifices in 98 teeth (27.1%), and three orifices were reported in one tooth (0.3%). Regarding root canal configuration, 98.6% of the sample were within the eight types of Vertucci classification. The majority of single-rooted second premolars (46.1%) exhibited type I canal configuration, type III found in 14.1%, and type II found in 9.9%. However, type IV found in 13.2% (48 teeth) of the sample, out of these, 88.6% (39 teeth) had two roots. Type VIII was observed in the three-rooted tooth (0.3%). Supplemental and additional canal types were found in 1.1% of the sample. Moreover, a new canal type was observed in 0.3% of the sample. According to Ahmed's coding system the most prevalent type was ¹MSP ^1-1 (46.1%) followed by ¹MSP^1-2-1 (4.1%), then type ²MSP B¹ P¹ (10.8%). Chi-square tests showed that the difference in root canal configurations among male and female was statistically significant. Conclusions: Root and canal morphology of maxillary second premolars among the evaluated Yemeni population is highly variable and requires cautious evaluation prior to endodontic treatment. Majority of the sample were single-rooted teeth, most of them had a complicated and variable canal configuration. Moreover, significant gender disparities in internal and external morphology were observed.