[Vascularization and connective tissue penetration, factors in the involution of the enamel organ in the rat]

In the albino rat, at the 21th day of gestation, the capillaries entered the stellate reticulum of the molar and came into contact with the stratum intermedium. This vascular penetration was followed on the 10th day of age by a connective penetration. The stellate reticulum was thus disorganized and was built up by small epithelial islands surrounded by collagen and reticulin fibrils. Finally, the reduced enamel epithelium fused with the oral epithelium and formed the epithelial attachment. After a trophic role, the vascularization, with the help of the connective tissue penetration, had a destructive function. Both vascularization and connective tissue invasion contribute to the enamel organ involution.