. 2016 Jun 21;12(3):152–167. doi: 10.1080/15476278.2016.1197460

TABLE 2.

Expression of IGF-1R and IGF-2R in epithelial and mesenchymal parts of human incisor tooth germ between the 7^th and 20^th week of development.

Tooth germ parts		Epithelial								Mesenchymal
Age (weeks)	Factor	tb	dl	oee	iee	cl	sr	si	pa	dp	df	po
7	IGF-1R	++	+	/	/	/	/	/	/	+	/	/
7	IGF-2R	++^*	+	/	/	/	/	/	/	++^*	/	/
10	IGF-1R	/	+	++	++	++	+	/	/	+	−	/
10	IGF-2R	/	+	+^*	++^*	++^*	–	/	/	++^*	+	/
12	IGF-1R	/	+	+++	+++	+++	+	/	/	+	−	/
12	IGF-2R	/	+	+^*	++^*	+^*	+	/	/	++^*	+	/
14	IGF-1R	/	+	+++	+++	+++	+	++	/	+	−	/
14	IGF-2R	/	++^*	+^*	++^*	++^*	+	+^*	/	++^*	+	/
20	IGF-1R	/	+	++	+++	+++	+	++	+++	++	−	+++
20	IGF-2R	/	++^*	+^*	++^*	+++^*	+	++^*	++^*	++^*	+	+^*

Legends: tb – tooth bud; dl – dental lamina; oee – outer enamel epithelium; iee – inner enamel epithelium; cl – cervical loop; sr – stellate reticulum; si – stratum intermedium; pa – pre-ameloblasts; dp – dental papilla; df – dental follicle; po – pre-odontoblasts

Reactivity:

– (absent);

+ (mild);

++ (moderate);

+++ (strong);

/(absence of tissue);

(expression in individual cells)