Micro–Computed Tomography Analysis of the Root Canal Morphology of Palatal Roots of Maxillary First Molars

•The internal anatomy of molar palatal roots was assessed by micro-CT.•All palatal roots was classified as Vertucci type I.•Curvatures (>40%), oval-shaped (>60%) and lateral canals (25%) were found.•The absence of apical constriction in the majority of cases was observed.•The complexity of the anatomy of palatal roots should not be disregarded.

IntroductionA thorough knowledge of root canal anatomy is critical for successful root canal treatments. This study evaluated the internal anatomy of the palatal roots of maxillary first molars with micro–computed tomography (microCT).MethodsThe palatal roots of extracted maxillary first molars (n = 169) were scanned with microCT to determine several anatomic parameters, including main canal classification, lateral canal occurrence and location, degree of curvature, main foramen position, apical constriction presence, diameters 1 and 2 mm from the apex and 1 mm from the foramen, minor dentin thickness in those regions, canal volume, surface area, and convexity.ResultsAll canals were classified as Vertucci type I. The cross sections were oval in 61% of the canals. Lateral canals were found in 25% of the samples. The main foramen did not coincide with the root apex in 95% of the cases. Only 8% of the canals were classified as straight. Apical constriction was identified in 38% of the roots. The minor and major canal diameters and minor dentin thickness were decreased near the apex. The minor dentin thickness 1 mm from the foramen was 0.82 mm. The palatal canals exhibited a volume of 6.91 mm3 and surface area of 55.31 mm2 and were rod-shaped.ConclusionsThe root canals of the palatal roots were classified as type I. However, some factors need to be considered during the treatment of these roots, including the frequent ocurrence of moderate/severe curvatures, oval-shaped cross-sections, and lateral canals, noncoincidence of the apical foramen with the root apex, and absence of apical constriction in most cases.