AVERAGE DATES OF MINERALISATION AND ERUPTION
OF THE
PRIMARY DENTITION
|
TOOTH |
MINERALISATION BEGINS |
AMOUNT OF ENAMEL FORMED AT BIRTH |
ENAMEL COMPLETED |
ROOT COMPLETED |
ERUPTION |
|
Upper Central incisor |
4 months in utero |
Five-sixths |
1 1 / 2 months |
1 1 / 2 years |
7 1 / 2 months |
|
Lateral incisor |
41/2 months
in utero |
Two-thirds |
2 1/2 months |
2 years |
9
months |
|
Canine |
5 months in utero |
One-third |
9 months |
31/2 years |
18 months |
|
First molar |
5
months
in utero |
Cusps united |
6 months |
21/2 Years |
14 months |
|
Second molar |
6 months
In utero
|
Cusps still isolated |
11 months |
3 years |
24 months |
|
Tooth |
Mineralisation begins |
Amount of enamel formed at birth |
Enamel completed |
Root completed |
Eruption |
|
Lower
Central incisor |
4 ½ months
in utero |
Three-fifths |
2 ½ months |
1 ½ years |
6 months |
|
Lateral incisor |
4 ½ months in utero |
Three-fifths |
3 months |
1 ¾ years |
7 months |
|
Canine |
5 months in utero |
One-third |
9 months |
3 ¼ years |
16 months |
|
First molar |
5 months in utero |
Cusps united |
5 ½ months |
2 ¼ years |
12 months |
|
Second molar |
6 months in utero |
Cusps still isolated |
10 months |
3 years |
20 months |
It should be remembered that there can be
marked individual variation in mineralisation and eruption
times.
The sequence of eruption is more important than precise time of eruption.
AVERAGE
DATES OF MINERALISATION AND ERUPTION OF THE PERMANENT DENTITION
|
Tooth |
Mineralisation begins |
Amount of enamel formed at birth |
Enamel completed |
Root completed |
Eruption |
|
Lower Central incisor |
3-4 months |
_ |
4-5 years |
9-10 years |
6-7 years |
|
Lateral incisor |
3-4 months |
_
|
4-5 years |
10 years |
7-8 years |
|
Canine |
4-5 months |
-- |
6-7 years |
12-14 years |
9-10 years |
|
First premolar |
1 ¾ -2 years |
_ |
5-6 years |
12-13 years |
10-12 years |
|
Second premolar |
2 ¼ - 2 ¾
years |
_ |
6-7 years |
13-14 years |
11-12 years |
|
First molar |
At birth |
Sometimes a trace |
2 ½ -3 years |
9-10 years |
6-7 years |
|
Second molar |
2 ½ - 3
years |
_ |
7-8 years |
14-15 years
|
11-13 years |
|
Third molar |
8 – 10 years |
-- |
12-16 years |
18-25 years |
17-21 years |
|
Tooth |
Mineralisation begins |
Amount of enamel formed at birth
|
Enamel completed |
Root completed |
Eruption |
|
Upper Central incisor |
3-4 months |
_ |
4-5 years |
10
years
|
7-8 years |
|
Lateral incisor |
10-12 months |
_ |
4-5 years |
11 years |
8-9 years |
|
Canine |
4-5 months |
_
|
6-7 years |
13-15 years |
11-12 years |
|
First premolar |
1 ½ - 1 ¾ years |
_ |
5-6 years |
12-13 years |
10-11 years |
|
Second premolar |
2 – 2 ¼ years |
_ |
6-7 years |
12-14 years |
10-12 years |
|
First molar |
At birth |
Sometimes a trace |
2 ½ - 3 years |
9-10 years |
6-7 years |
|
Second molar |
2 ½ - 3 years |
_ |
7-8 years |
14-16 years |
12-13 years |
|
Third molar |
7 – 9 years |
_
|
12-16 years |
18-25 years |
17-21 years |