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

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 (alpha = 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. (J Endod 2012;38:977-982)

General mortgage : Lehigh and New England Railroad Company to guarantee trust and safe deposit company, trustee : $15,000,000 general mortgage gold bonds : dated July 1, 1914, principal due July 1, 1954.

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The charter of the Albany and Greenbush Bridge Company : and a statement of its claims on the public interest in connection with the Boston, Hoosac Tunnel and Albany Railroad.

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Location decisions and industrial mobility in Michigan, 1961; a sample survey of Michigan and Ohio manufacturers conducted by the Survey Research Center of the University of Michigan.

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Report to the President by the Emergency Board appointed January 14, 1948 pursuant to section 10 of the Railway labor act, as amended, to investigate unadjusted disputes between the Chicago, North Shore and Milwaukee Railway Company and certain of its employees represented by International Union of Amalgamated Association of Street Electric Railway and Motor Coach Employees of America, a labor organization.

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Great canals of the world. The Suez, the Kaiser Wilhelm, the Manchester, the Canadian, the St. Marys Falls, the New York State, and other canal systems of the world.

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In the matter of the application of the Norfolk and Western Railway Company for authority to acquire control by lease of the railroad of the Virginian Railway Company. October 12, 1925 [Jan. 28, 1926]

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