From: A micro–computed tomographic analysis of the root canal systems in the permanent mandibular incisors in a Chinese population
Age
N
Central incisors (n = 53)
Lateral incisors (n = 53)
Total incisors (n = 106)
Single
Double
< 30 yrs
10
3
1
6
4
30 ~ 60
48
25
14
5
39
9
> 60
17
20
8
37
11
Total
106
45
16
82
24