Root and Root Canal Morphology of Four-rooted Maxillary Second Molars: A Micro–Computed Tomography Study

Abstract Introduction This study examined the anatomy of 4-rooted maxillary second molars by using micro–computed tomography. Methods Twenty-five 4-rooted maxillary second molars were scanned to evaluate the size and curvature of the roots; the distance and spatial configuration between some anatomical landmarks; the number of root canals and the position of apical foramina; the occurrence of fusion of roots and enamel pearls; the configuration of the canal at the apical third; the cross-sectional appearance, the volume, and surface area of the root canals. Data were compared by using analysis of variance post hoc Tukey test (α = 0.05). Results The specimens were classified as types I (n = 16), II (n = 7), and III (n = 2). The size of the roots was similar ( P > .05), and most of them presented straight with 1 canal, except the mesiobuccal that showed 2 canals in 24% of the samples. The configuration of the pulp chamber was mostly irregular quadrilateral-shaped. The lowest mean distance of the orifices was observed between the buccal roots ( P < .05). Accessory canals were present mostly in the apical third. Location of the apical foramina varied considerably. Fusion of roots and enamel pearls occurred in 44% and 8% of the samples, respectively. Mean distance from the pulp chamber floor to the furcation was 2.15 ± 0.57 mm. No statistical differences were found in the bi-dimensional and 3-dimensional analyses ( P > .05). Conclusions All analyzed parameters showed differences between roots, except for the length of the roots, the configuration of the canals at the apical third, cross-sectional appearance, volume, and surface area of the canals.