Root Canal Anatomy of Maxillary First Premolar by Microscopic Computed Tomography in a Chinese Adolescent Subpopulation

Table 4

Root canal diameter in different levels of maxillary first premolar (mean ± SD, mm, n = 70).

Groups	Cervical third	Middle third	Apical third	Apical foramen
SR1C
BP	3.34 ± 0.85^a	2.16 ± 0.61^a	1.57 ± 0.32^a	0.59 ± 0.18^a
MD	0.75 ± 0.23	0.42 ± 0.13	0.42 ± 0.10	0.3 ± 0.11
SR2C
Buccal canal
BP	—	1.38 ± 0.21^a	0.87 ± 0.25^a	0.62 ± 0.17^a
MD	0.98 ± 0.30	1.01 ± 0.31	0.59 ± 0.09	0.44 ± 0.09
Palatal canal
BP	—	1.09 ± 0.21^a	0.57 ± 0.14^a	0.21 ± 0.05
MD	0.82 ± 0.31	0.66 ± 0.11	0.35 ± 0.06	0.21 ± 0.02
2R2C
Buccal canal
BP	—	1.66 ± 0.23^a	0.38 ± 0.14^a	0.12 ± 0.06^a
MD	1.12 ± 0.30	0.96 ± 0.28	0.77 ± 0.13	0.50 ± 0.09
Palatal canal
BP	—	1.25 ± 0.21^a	0.75 ± 0.11^a	0.65 ± 0.10^a
MD	1.15 ± 0.30	0.93 ± 0.23	0.55 ± 0.09	0.33 ± 0.06

a represents vs. the corresponding MD, . SR1C, single root with 1 canal; SR2C, single root with 2 canals; 2R2C, 2 roots with 2 canals; BP, buccal and palatal diameters; MD, mesiodistal diameter.