Comparative enzyme histochemical studies on the development of teeth in man and mouse

Summary On the basis of a material consisting of primordia of deciduous teeth from 17 human foetuses and tooth germs from 20 newborn mice and 4 mouse foetuses, the histochemical distribution of succinic dehydrogenase, LDH, BDH, glucose-6-phosphate-dehydrogenase, NADH₂ cytochrome C reductase, and NADPH₂ diaphorase was studied.The investigation comprised partly mapping of the above-mentioned oxidative enzymes in human tooth germs during the period from bud stage to bell stage with incipient hard-tissue formation, and partly a comparative enzyme histochemical investigation of the dental development in man and in the mouse.In both materials there was an increase of all the demonstrated enzyme systems in the ameloblasts in early amelogenesis. On the other hand, the ameloblasts of the two materials showed differences during the period of matrix production: In the human ameloblasts there was activity of succinic dehydrogenase basally as well as apically, while the non-human ameloblasts showed such activity only basally.The odontoblasts of both materials showed a definite reaction for glucose-6-phosphatedehydrogenase, LDH, and BDH, but slight activity of succinic dehydrogenase. This indicates the existence of the pentose shunt as the source of energy in dentinogenesis. On the basis of the enzyme reactions studied, neither material showed a subodontoblastic layer or any reaction in the hard tissues.Material supplied by the Association for the Aid of the Crippled Children, New York. Aided by grants from the Danish State Research Foundation and the Rask-Ørsted Foundation.