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

Table 1

Frequency of root canal morphology of maxillary first premolars according to Vertucci's [20] classification.

Roots	No. (%)	Root canal types
		I	II	III	IV	V	VI	VII	VIII
		(1-1)	(2-1)	(1-2-1)	(2-2)	(1-2)	(2-1-2)	(1-2-1-2)	(3-3)
One root	234 (72.22%)	81	27	9	85	18	9	5	0
Two roots	86 (26.54%)	0	0	0	86	0	0	0	0
Three roots	4 (1.23%)	0	0	0	0	0	0	0	4
Total	324	81 (25%)	27 (8.33%)	9 (2.78%)	171 (52.78%)	18 (5.56%)	9 (2.78%)	5 (1.54%)	4 (1.23%)