摘要:

Degradation of sodium monofluorophosphate (MFP) by selected oral streptococci, in vitro streptococcal plaque, natural dental plaque, and saliva, was investigated over the pH range 4–9, using a fluoride-ion-selective electrode. At 37 °C, optimum MFP hydrolysis occurred at approximately pH 5, but the level of hydrolysis activity varied depending on the streptococcal strain, plaque type, and incubation period. At the end of 23 h of incubation, the hydrolysis activity ranged from 0.23 μmol MFP decomposed/mg protein for Streptococcus sanguis plaque to 1.92 μmol MFP decomposed/mg protein for the Streptococcus salivarius cell suspension. On this basis, the hydrolysis activity of cell suspensions of S. salivarius ranked relatively the highest, followed by those of Streptococcus mitis and Streptococcus mutans, BHT. No significant differences were observed with the activities for MFP hydrolysis at both the 2- and 23-hour incubation periods between in vitro plaque and cell suspensions for S. mutans, 10449. Likewise, no significant difference in hydrolysis activity was generally observed between saliva from the rinsed and unrinsed mouth, however, the presence of 0.05% of cetylpyridinium chloride in saliva produced a significant change, reducing it to negligible levels compared to cont

ISSN:0008-6568    

DOI:10.1159/000261009

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Oleanolic acid and ursolic acid, extracted and purified from crude drugs, inhibited the insoluble glucan synthesis catalyzed by a crude glucosyltransferase (GTase) preparation from cariogenic Streptococcus mutans OMZ 176. Inhibition of the insoluble glucan synthesis was dependent on the concentration of oleanolic acid or ursolic acid, and was enhanced by pretreatment of crude GTase with these substances. In contrast, synthesis of soluble glucan was not significantly inhibited. These findings suggest that the substances inhibit mainly the synthesis of α-1,3-linkage but not that of α-1,6-linkages. These results indicate that oleanolic acid and ursolic acid are potential inhibitors of dental plaque formation and dental carie

ISSN:0008-6568    

DOI:10.1159/000261010

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Batch culture techniques were used to study the effect of sorbitol and xylitol on the aggregation, adhesion and solubility of the polysaccharides produced by Streptococcus mutans in the presence of 3% sucrose. Both polyols increased the production of soluble polysaccharides: control < xylitol xylitol. Thus, in cell-cell and cell-glass interactions of S. mutans, the ratio of easily soluble to insoluble polysaccharides seems to play a more important role than the absolute amounts of soluble, insoluble or total polysaccharides per

ISSN:0008-6568    

DOI:10.1159/000261011

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

High-resolution transmission electron microscopy is one of the few techniques where it is possible to investigate dental enamel at the individual crystallite level. By measuring interfringe spacings in lattice images of apatite crystallites during a through-focal-series, we were able to identify individual crystallites of fluorapatite from hydroxyapatite, even though their α-axis parameters differ by only 0.5%. We describe both an axial 3-beam and 7-beam method for determining α-axis parameters in apatite crystallites with a precision of < 0.1%. This provides a new method for investigating the interaction of fluoride with apatite crystallites in dental ename

ISSN:0008-6568    

DOI:10.1159/000261012

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

A pH-cycling model has been used to examine the effects of fluoride dentifrices on the saliva-mediated repair of early carious lesions in vitro. Fluoride reactivity was characterized by fluoride uptake, surface microhardness and lesion mineral content (microradiographic) analyses. The fluoride dentifrices, in particular the sodium and amine fluoride preparations, were found to be extremely effective in enhancing the remineralization and acid resistance of early carious lesions. The most prominent effect of the fluoride topicals, however, was found to be the fluoride enrichment of the remineralized enamel. The rank ordered efficacy of the fluoride dentifrices was NaF = AmF > MFP ≥≥ placebo. The remineralization of the early carious lesions was linearly associated with the increased surface hardening of specim

ISSN:0008-6568    

DOI:10.1159/000261013

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The effects of acesulfame K, aspartame, cyclamate, and saccharin on cariogenesis caused by a diet containing 30% sucrose were studied in orally superinfected Cara rats. The addition of any individual sweetener had no appreciable effect on fissure caries development in this animal model. However, a 1.00:1.67:0.10 combination of acesulfame K, cyclamate, and saccharin, which was found previously to effectively inhibit acidogenesis by Streptococcus mutans and other oral microorganisms in vitro, led to a marked and highly significant reduction of fissure caries.

ISSN:0008-6568    

DOI:10.1159/000261014

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The 2-year caries increments of fifth to seventh grade students (mean age 11.7 years) residing in two fluoride-deficient communities (F < 0.1 ppm) on Long Island, N.Y., were compared relative to their use of different fluoride dentifrices. Group I used a conventional Na2PO3F dentifrice (1,000 ppm F) and served as the positive control. Group II used a mixed fluoride dentifrice containing equimolar amounts of NaF and Na2PO3F which provided a total fluoride concentration of 1,000 ppm. Group III also used a mixed fluoride dentifrice containing equimolar amounts of NaF and Na2PO3F with a total fluoride concentration of 2,500 ppm. Brushing was performed unsupervised at home for 23 months. There were no statistically significant differences (F test) in the 2-year caries increments between the dentifrice groups for DMFT, DMFS, and DMFS of specific tooth surface types. Mitigating factors which may have influenced the results were the low proximal caries increments and the degree of compliance. Use of a mixed fluoride dentifrice (NaF/Na2PO3F) at a standard 1,000 ppm F concentration or at 2.5 times standard did not provide superior caries inhibition compared to a conventional Na2PO3F dentifrice containing 1,000 ppm F.

ISSN:0008-6568    

DOI:10.1159/000261015

出版商:S. Karger AG    

年代:1987

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000261016

出版商:S. Karger AG    

年代:1987

数据来源: Karger