The neural development of the human fetal dentition

Abstract

Since there has been a limited amount of research performed concerning the neural development of the human fetal dentition, this investigation was undertaken to eliminate some of the existing speculation. A series of twelve human fetuses were histologically examined with respect to the dental neural development. The fetuses ranged in age from 1O to 40 weeks. The mandibles were dissected and prepared for histological study by saggital 15u sections. After the digestion of collagen with pepsin solution, neurological staining of the slide sections was accomplished with the use of Bodian silver stain and aniline blue counter stain. A few sections were stained with hemotoxylin and eosin and Goldman-Bloom modified mallory stain. Microscopic examination was performed on the sectioned fetal mandibles. Several areas were investigated throughout the sections. Of particular interest were the sights and direction of tooth bud innervation. Nerve fibers and fiber bundles were monitered from their alveolar and follicular origins, through the base of the papilla, and termination in the odontoblast, predentin, and dentin layers. Attention was also given to the development of the subodontoblastic (Raschkow’s) plexus. A Iook at the cervical areas of the fetal molar and incisor teeth demonstrated a rich innervation of this highly sensitive area. A common finding was mechkels cartilage whose role in the developing mandible is still controversial. An interesting view of cystic degeneration of the dental lamina was noted when possible with the use of Goldman-Bloom modified mallory stain. The dental papilla became more organized, complex and specialized as blood vessels, nerve fibers and bundles, collagen developed in preparation for mineralization. Based on these sections of the fetal mandible, some of the speculation of dental innervation hopefully can now be elucidated.