Abstract
Objectives To investigate the root morphology and root canal anatomy of maxillary first premolar using microscopic computed tomography (micro-CT). Methods 324 maxillary first premolars were collected and scanned. The root and canal diameter, canal wall thickness, root taper, and cross-sectional shapes were determined in the single root with 1 canal (SR1C), single root with 2 canals (SR2C), and 2 roots with 2 canals (2R2C) by micro-CT. Results The results showed that single-rooted maxillary premolars were more common than other types. The incidence of SR1C, SR2C, and 2R2C reached 25%, 26.39%, and 26.39%, respectively. Root and canal diameters and canal wall thickness were decreased from coronal third to apical foramen. The three parameters and canal taper showed increases from buccal and palatal (BP) to mesiodistal (MD) aspects. The root canal tapers were smallest of the middle third level. The findings showed the different variations in 2R2C teeth. The root canal cross-sectional morphology in maxillary first premolars is complicated, including round, oval, long oval, flat canal, and irregular canal shapes. The distribution varied in different aspects. Conclusion Root canal morphology showed a wide variation and complicated structure. The single-rooted teeth were more common in the Chinese adolescent population, and the majority of maxillary first premolars have two canals.
Highlights
Understanding and mastering of the appearance and internal structure of human teeth are essential for endodontists and researchers
Maxillary first premolars have unique anatomical features owing to its variation in root numbers and canal configuration. e anatomical structure of maxillary first premolars is complex, including bifurcated roots, great variations of root and canal morphology, and multiple canals [1,2,3]. ese complex structures increase the difficulty of root canal treatment and postcore restoration, incompletion of root canal cleaning, and root canal lateral penetration or even root fracture [4]. us, a thorough understanding of the anatomical characteristics of the root canal system in the maxillary first premolar is essential for improving the success rate of root canal therapy and postcore restoration and reducing complications
Based on the micro-CT technology, it has already been reported that pulp cavities [8], threedimensional images of root canal morphology [9], crosssectional root canal shape (CSRCS) [10], buccal root with furcation groove [11], and root surface area [12] were observed and investigated in maxillary first premolars
Summary
Understanding and mastering of the appearance and internal structure of human teeth are essential for endodontists and researchers. E anatomical structure of maxillary first premolars is complex, including bifurcated roots, great variations of root and canal morphology, and multiple canals [1,2,3]. Us, a thorough understanding of the anatomical characteristics of the root canal system in the maxillary first premolar is essential for improving the success rate of root canal therapy and postcore restoration and reducing complications. Based on the micro-CT technology, it has already been reported that pulp cavities [8], threedimensional images of root canal morphology [9], crosssectional root canal shape (CSRCS) [10], buccal root with furcation groove [11], and root surface area [12] were observed and investigated in maxillary first premolars
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