Experimental caries in young human permanent teeth implanted in removable dentures

Abstract

Carious lesions were produced in young intact permanent teeth placed in dentures. The pulp chamber in one of the teeth in contralateral pairs was treated with fluoride solution or filled with cement with a high concentration of fluorides. This did not reduce the incidence of caries. There was no indication that an internal fluid phase carrying substances from the pulp or periodontium plays a role in the development of caries in vivo. Examination of the experimental lesions with microradiography and scanning electron microscope revealed that bacteria were present both in enamel and dentine at an early stage. In the dentine, the bacteria attacked predominantly peritubular dentine and the enamel-dentine junction. Demineralization in enamel and dentine was slightly in advance of the bacterial invasion. The peritubular area seemed to be the structure first removed. Radiopacity was present in carious dentine, at the surface of several cavities, the centre of the lesion and at the lateral border, indicating a local remineralization process induced by substances originating from caries or from saliva. No sclerosis was found in dentine between the lesion and the pulp chamber. This is considered to support the view that such changes in vital teeth are due to distribution of substances from the pulp.