<Table> <Tr> <Th> </Th> <Th_colspan="8"> Maxillary (upper) teeth </Th> </Tr> <Tr> <Th> Primary teeth </Th> <Th> Central incisor </Th> <Th> Lateral incisor </Th> <Th> Canine </Th> <Th> First molar </Th> <Th> Second molar </Th> </Tr> <Tr> <Td> Initial calcification </Td> <Td> 14 wk I.U. </Td> <Td> 16 wk I.U. </Td> <Td> 17 wk I.U. </Td> <Td> 15.5 wk I.U. </Td> <Td> 19 wk I.U. </Td> </Tr> <Tr> <Td> Crown completed </Td> <Td> 1.5 mo </Td> <Td> 2.5 mo </Td> <Td> 9 mo </Td> <Td> 6 mo </Td> <Td> 11 mo </Td> </Tr> <Tr> <Td> Root completed </Td> <Td> 1.5 yr </Td> <Td> 2 yr </Td> <Td> 3.25 yr </Td> <Td> 2.5 yr </Td> <Td> 3 yr </Td> </Tr> <Tr> <Th> </Th> <Th_colspan="8"> Mandibular (lower) teeth </Th> </Tr> <Tr> <Td> Initial calcification </Td> <Td> 14 wk I.U. </Td> <Td> 16 wk I.U. </Td> <Td> 17 wk I.U. </Td> <Td> 15.5 wk I.U. </Td> <Td> 18 wk I.U. </Td> </Tr> <Tr> <Td> Crown completed </Td> <Td> 2.5 mo </Td> <Td> 3 mo </Td> <Td> 9 mo </Td> <Td> 5.5 mo </Td> <Td> 10 mo </Td> </Tr> <Tr> <Td> Root completed </Td> <Td> 1.5 yr </Td> <Td> 1.5 yr </Td> <Td> 3.25 yr </Td> <Td> 2.5 yr </Td> <Td> 3 yr </Td> </Tr> </Table> <Tr> <Th> </Th> <Th_colspan="8"> Maxillary (upper) teeth </Th> </Tr> <Tr> <Th> Primary teeth </Th> <Th> Central incisor </Th> <Th> Lateral incisor </Th> <Th> Canine </Th> <Th> First molar </Th> <Th> Second molar </Th> </Tr> <Tr> <Td> Initial calcification </Td> <Td> 14 wk I.U. </Td> <Td> 16 wk I.U. </Td> <Td> 17 wk I.U. </Td> <Td> 15.5 wk I.U. </Td> <Td> 19 wk I.U. </Td> </Tr>

A stage that takes place during the early phases of pathogenesis