- Development of the primary epithelial band
The first sign of tooth development occurs at the 6th week of intrauterine life. Underneath the oral ectodermal epithelium there is a condensation of mesenchymal cells in areas where teeth will eventually form. The ectodermal epithelium thickens in these areas and protrudes into the mesenchymal cells, forming the primary epithelial band.
- Development of the vestibular band and dental lamina
At 7 weeks of intrauterine life the primary epithelial band develops two processes: the vestibular band and the dental lamina. The vestibular band forms buccally and will eventually form the vestibule, separating the lips and checks from the teeth and gingivae. The dental lamina forms lingually and develops into an arch-shaped band on which the tooth germs will develop (Fig).