Inhibitory effects of apple polyphenols and related compounds on cariogenic factors of mutans streptococci.

The inhibitory effects of apple polyphenols (APP) on the synthesis of water-insoluble glucans by glucosyltransferases (GTF) of streptococci of the mutans group and on the sucrose-dependent adherence of the bacterial cells were examined in vitro. APP markedly inhibited the activity of GTF purified from the cariogenic bacterial cells. However, APP showed no significant effect on the growth of the cariogenic bacteria. The strongest GTF inhibitors in APP were apple condensed tannins (ACT), a mixture of procyanidins. The 50% inhibitory doses of ACT against the GTF of S. sobrinus and that of S. mutans were 1.5 microgram/mL and 5 microgram/mL, respectively. The ACT efficacy largely depended upon the degree of polymerization. Interestingly, while the other polyphenols known to inhibit GTF such as tannic acid markedly inhibited salivary alpha-amylase activity, APP and ACT only scarcely inhibited that enzyme activity. This means that APP and ACT might selectively inhibit the bacterial GTF activity under oral conditions.

The effect of various fluoride compounds on the development of experimental root surface caries in hamsters.

The aim of this investigation was to evaluate the effect of topical applications of various fluoride compounds on the development of root surface caries in hamsters. Male golden hamsters (n = 115) were divided into 7 groups and were given a caries-promoting diet. Six groups were infected with Actinomyces viscosus ATCC 15987; and to 5 infected groups, distilled water (DW) and solutions containing 500 ppmF of acidulated-phosphate fluoride (APF), stannous fluoride (SnF2), copper fluoride (CuF2), and titanium tetrafluoride (TiF4) were applied topically to the first mandibular molars once daily, 7 days a week, over a 24-week period. A grid method was used to asses the periodontal changes and root surface caries on the first molars. Plaque accumulation was reduced most by SnF2; and alveolar bone loss was more reduced by SnF2 and CuF2. Root surface caries was significantly prevented in all fluoride groups when compared to an infected control group; and TiF4 was the most effective fluoride compound followed by SnF2, CuF2, and APF. Root caries scores of the TiF4 and SnF2 groups were significantly lower than those of the DW group. It was concluded that all fluoride tested may prevent the development of root surface caries in hamsters.

Experimental root surface caries in hamsters the development of the disease after inoculations of two types of cariogenic bacteria.

The aim of this study was to investigate the development of root surface caries in hamsters fed a high-sucrose diet over a 24-week period after inoculations of two types of cariogenic bacteria. Twenty-one day old male golden hamsters (n = 103) were divided into 5 groups. Four groups were given diet 2000, and one group was given a stock diet CE-2, Of the groups given diet 2000, three groups were infected with Actinomyces viscosus ATCC 15987 and Streptococcus mutans NTCC 10449 separately (AV and SM groups) or in combination (AVSM group), and one group remained uninfected. A grid method was used to evaluate the plaque accumulation, alveolar bone loss, and root surface caries. After 12 weeks, root surface caries developed mainly on the first mandibular molars in the three infected groups. At 24 weeks, the prevalence of root surface caries was highest in the AV group, but root caries scores were not significantly different among the three infected groups. In the groups SM and AVSM, the molar crowns were extensively destroyed by caries, while in the AV group the crowns were almost intact. It was concluded that challenge with Actinomyces viscosus may be appropriate to study root surface caries in hamsters.