Chapter 21
Chronology of Teeth Eruption
141
71, 81 – 6 to 10 months
Lower central incisors (71, 81)
51, 61 – 8 to 12 months
72, 82 – 10 to 16 months
52, 62 – 9 to 13 months
54, 64, 74, 84 – 13 to
19 months
Upper central and lower lateral
incisors (51, 61 and 72, 82)
Upper lateral incisors (52, 62)
Upper and lower rst
molars (54, 64 and 74, 84)
53, 63 – 16 to 22 months
73, 83 – 17 to 23 months
Lower and upper canines
(53, 63 and 73, 83)
Lower and upper second
molars (55, 65 and 75, 85)
55, 65 – 25 to 33 months
75, 85 – 23 to 31 months
81
82
51 61
52
62
54
53
63
55
65
85
75
64
72
71
84
83
73
74
Figure 21.1
The chronological sequence of eruption of primary teeth. (Teeth in the process of eruption are shaded and erupted teeth are
coloured white. Boxes on the left side show the sequence of eruption and boxes on the right side show the age of eruption.)
SEQUENCE OF PERMANENT TEETH ERUPTION
Permanent dentition gradually replaces the primary
dentition from around 6 years of age. The beginning of
eruption of permanent teeth is marked by the eruption
of lower permanent first molars followed by upper
permanent first molars. The first permanent molars
erupt at around the sixth year of life and are called
sixth-
year molars
.
The exchange of dentition usually begins with
exfoliation of lower primary central incisors and
eruption of lower permanent central incisors. A period
of
mixed dentition
exists when both primary and
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