Histochemical demonstration of various dehydrogenases in human carious dentine

Abstract

Fresh, undemineralized sections of carious dentine from teeth in situ or of teeth with carious lesions were cut in a cryostat and the localization of various dehydrogenases demonstrated. Succinate, lactate, glutamate, glucose 6-phosphate, glutathione and lipoamide dehydrogenases could be demonstrated in dental plaque, in the superficial necrotic layer and the infected zone of demineralization of carious dentine. Glutamate, lactate, lipoamide and glutathione dehydrogenases were present deep in the sterile layer of demineralization and glutamate, succinate, lipoamide and glutathione dehydrogenase in the predentine layer close to caries. No enzyme activity was observed in normal dentine. Strong activity-density of glucose 6-phosphate, glutamate and succinate dehydrogenase was found in liquefaction foci. These findings indicate that the formation, or potential removal of lactic acid, for example, might occur in sterile layers of carious dentine.