Degree Name

Master of Science (MS)

Semester of Degree Completion

1978

Thesis Director

William S. James

Abstract

The normal morphological development of the Chinese hamster (Cricetulus griseus) during the last week of gestation was studied. A review of the literature reveals no distinct study of tooth development in this species. An identical gestation period is found in the mouse (Mus musculus) making direct comparison between the embryos of the same age of the two species feasible. During this investigation, it was found that morphological tooth development in the Chinese hamster lagged behind that of the mouse by about 2 days. On day 14 of gestation in the Chinese hamster, the oral epithelium is stratified along the free margin of the jaws. This is the earliest indication of odontogenesis of the development of molars. Included in this description is the thickening and elongation of the dental lamina, appearance of enamel organs and proliferation of these parts through cap and bell stages.

In addition to morphological development, a consideration of some of the molecular components of developing teeth in the Chinese hamster using histochemical techniques is undertaken.

Four histochemical methods were used to show the chemical constituents of the teeth. The four methods used in this study were Lehman's polychrome, pyronine-methyl green (P/MG), periodic acid-Schiff (PAS), and hematoxylin and eosin. These procedures revealed the histochemistry of many areas during prenatal tooth development. Lehman's polychrome stain showed a good overall view of the types of chemical components present in the samples. The P/MG method was used along with the Lehman's polychrome method to distinguish areas of DNA and RNA. The PAS stain tested samples for carbohydrates, including glycogen. Although the results for this method were not very distinct, they do coincide somewhat with the results of previous investigators of other rodents. The eosin-hematoxylin stain distinguished cytoplasmic areas, staining pink, while the nuclei stain dark blue.

Additional chemical aspects of tooth development are found in the definitive text on oral histology and embryology by Orban (1972).

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