Table 2 : Proportion of closed root apices for permanent incisors and first molars by age group.


Age group (years) 16
Distal root
16
Mesial root
12 11 21 22 26
Mesial root
26
Distal root
n % n % n % n % n % n % n % n %

Maxillary

6-7.99 2 4.3 3 6.2 2 7.4 3 5.3 3 5.7 2 6.5 3 6.2 4 8.7
8-9.99 16 29.6 17 29.8 16 28.9 19 30.2 20 31.7 19 35.2 28 44.4 24 42.1
10-11.99 45 83.3 49 83.1 51 81.0 63 87.5 64 90.1 60 84.5 63 91.3 59 92.2

Mandibular

Age group (years) 46
Distal root
46
Mesial root
42 41 31 32 36
Mesial root
36
Distal root

6-7.99 3 5.4 3 5.4 5 9.8 11 20.0 12 21.4 4 8.3 3 5.6 3 5.5
8-9.99 28 43.1 25 37.9 29 49.2 42 66.7 42 65.6 31 47.7 27 40.9 23 34.8
10-11.99 68 89.5 72 93.5 71 94.7 78 98.7 79 98.8 71 93.4 68 90.7 66 90.4

*FDI world dental federation notation: 46-mandibular right first molar, 42-mandibular right lateral incisor, 41-mandibular right central incisors,
31-mandibular left central incisor, 32-mandibular left lateral incisor, and 36-mandibular left first molar.

Mugonzibwa et al.Oral Biology and Dentistry  2018 6:1DOI : 10.7243/2053-5775-6-1