Root and root canal morphology of four-rooted maxillary second molars: a micro-computed tomography study.
BACKGROUND
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.
Department of Restorative Dentistry, Dental School of Ribeirão Preto, University of São Paulo, São Paulo, São Paulo, Brazil.
Marco Aurélio
MA
Versiani
Jesus Djalma
JD
Pécora
Manoel Damião
MD
de Sousa-Neto
D000704:Analysis of Variance; D063405:Anatomic Variation; D003743:Dental Enamel / Q000002:abnormalities; D003786:Dental Pulp Cavity / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D005671:Fused Teeth / Q000000981:diagnostic imaging; D006801:Humans; D008437:Maxilla; D008963:Molar / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D014092:Tooth Root / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D055114:X-Ray Microtomography