The tooth germs of first mandibular molar from 3-day-old mouse were used. In order to eradicate the basal lamina, the predentin of tooth germs were mechanically removed. After the separation of tooth components, the recombined epithelial and mesodermal components were incubated in a humidified incubator at 37°C in an atmosphere of 5% CO₂, 45% N₂ and 50% O₂. A daily change of regeneration of new basal lamina was observed by electron microscope.

The non-periodic fine fibrils which were deposited on the epithelial cell surface increased as the time of cultivation prior to formation of new basal lamina. The new basal lamina deposited at five days after the cultivation. These results suggest that non-periodic fine fibrls have a close association with the regeneration of basal lamina.