Nine sugars and sugar alcohols were assessed for their effect on experimental caries with an Intraoral Cariogenicity Test (ICT). Sample bovine enamel surfaces were submitted to simulated cariogenic conditions in the human mouth. The extent of experimental cariogenesis after 1 week was measured by means of surface microhardness tests on enamel samples. Each test sugar was compared to sucrose control, and supplied to one of the two ICT plaques at the same time. There was no detectable difference in the effect of glucose, fructose, and raffinose on ICT cariogenesis. Lactose, mannitol, melibiose, and sorbitol were significantly less cariogenic than sucrose (p < 0.05), while xylose and xylitol were noncariogenic.

An intraoral cariogenicity test (ICT) was used to study the enhancement of fluoride treatments (2% NaF or 8% SnF₂) that resulted from prior cariogenic challenge to human enamel surfaces. Measurements of enamel microhardness and microradiography indicated higher resistance to the cariogenically primed than for the unprimed surfaces. These results are interpreted as an adaptation of enamel to a challenging local environment by the formation of highly caries resistant minerals in the microspaces created by the priming challenge. With this adaptive reaction, tooth surfaces at risk were converted to surfaces of higher resistance than nonprimed surfaces. It is suggested that the concept of enamel adaptation to the cariogenic challenge can be applied clinically to arrest incipient caries, especially in patients who respond well to preventive disciplines that include the use of fluoride treatments.

A study was made of early enamel caries produced artificially by three different systems. Factors involved in each system were varied. The lesions were examined microradiographically to determine preservation of the enamel surface, thickness of the relatively intact surface layer, and depth of the lesion. The radiographs reflected the severity of the artificial caries attack.Microradiographs of natural and artificial carious lesions have been produced in several laboratories with different systems.1-'6 The purpose of the present study was to reproduce the most promising in vivo and in vitro artificial systems in one laboratory, to determine if microradiography reflected the severity of the caries attack, and to identify the simulated caries attack system most useful for relatively quick testing of agents designed to increase the caries resistance of enamel surfaces. Materials and MethodsSlabs of tooth crowns were prepared from sound teeth extracted for periodontal reasons. The slabs were mounted on plastic blocks with wax. The outer enamel surface of each tooth slab was ground off with fine sandpaper to prepare a flat facet, which then was polished with emery polishing paper* in a special device (Fig 1). The three artificial caries systems used were a liquid acid buffer, an acidified gel, and a system that used the oral environment.The tooth slabs for the liquid and gel tests were obtained from the buccal enamel of teeth by sectioning the tooth with a thin sectioning machines; a cut was made parallel