摘要:

The amounts of loosely bound fluoride (F) deposited on human enamel by 4-min and 2-hour treatments with either acidulated phosphate fluoride (APF) or a monocalcium phosphate monohydrate and sodium hexafluorosilicate (MCPM-SHFS)-containing gel were measured with the use of a constant-composition F washing method. Enamel biopsies conducted before treatment and after washing were used to determine the firmly bound F uptake. The results showed that the MCPM-SHFS treatments produced significantly more loosely bound F than did the APF treatments. The 4-min treatment with either APF or MCPM-SHFS did not produce significant firmly bound F deposition, but the 2-hour treatments did, with that produced by MCPM-SHFS being significantly greater. The MCPM-SHFS gel, which had the same F content as APF and which may be applied to the proximal tooth surfaces in vivo without the use of a tray, has the potential to be more efficacious than APF because it deposits greater amounts of both loosely bound and firmly bound F.

ISSN:0008-6568    

DOI:10.1159/000261462

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Unerupted fluorotic human enamel was obtained from teeth surgically removed from patients with dental fluorosis. Fluoride was measured in samples produced by serial acid etching from the surface to the interior of blocks of buccal and lingual enamel. The severity of fluorosis, according to the TF index, was determined from the macroscopic and microradiographic appearance of the specimens. The shape of the fluoride profiles was not affected by the degree of severity of fluorosis, but the fluoride concentrations increased with increasing severity of lesions. Fluoride concentrations were similar to those previously recorded in erupted fluorotic enamel and were not related to the length of time the teeth had been present in the jaws. It was concluded that the fluoride content of erupted fluorotic enamel represents fluoride acquired during tooth formation and that further uptake prior to eruption may be negligible.

ISSN:0008-6568    

DOI:10.1159/000261463

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

It has previously been shown that the susceptibility of human teeth to acid dissolution can be reduced by the presence of various chemical agents in the dissolution medium or by pretreatment of the teeth with laser irradiation. Now synergism between these two approaches to improving acid resistance has been demonstrated. Extracted human teeth were irradiated with a continuous-wave carbon dioxide laser at a wavelength of 10.6 μm. Energy doses of either 65 or 130 J/cm2 given over periods of 2 or 4 s, respectively, were applied and the teeth subjected to a severe acid challenge (0.1 M acetate buffer, pH 4.5, no calcium or phosphate common ion present) for 24 h. Mineral loss was assessed by measurement of mineral density profiles with quantitative microradiography. Experiments were carried out in the presence or absence of three chemical inhibitors with distinctly different mechanisms of action: ethane-1-hydroxy-ll-di-phosphonic acid, fluoride, and dodecylamine HCl. Laser irradiation alone was found to lead to increased resistance of the teeth to acid challenge, with the higher energy dose being more effective than the lower dose. Each of the chemical inhibitors was effective on both lased and unlased teeth, with the percent reduction of dissolution greater when the inhibitors were applied to teeth lased with an energy dose of 130 J/cm2 which were already more resistant to acid challenge than were unlased teeth or teeth lased with a dose of 65 J/cm2. Thus, the inhibitors and the higher energy laser treatment were synergistic, with the combination of laser treatment and each of the inhibitors resulting in almost complete inhibition of dissolution for the entire 24 h of acid challenge as compared with a loss of about 140 μm of enamel from the surface of the control teet

ISSN:0008-6568    

DOI:10.1159/000261464

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Glass ionomer fillings have been suggested to act as a fluoride-releasing system in the mouth. The aim of the present study was to evaluate whether a glass ionomer slab applied on the enamel can increase the fluoride content of the enamel and plaque of adjacent teeth in real-life conditions with frequent exposure to fluoride from other sources. Twenty-five adults living in a town with fluoridated drinking water participated in the study. The initial enamel fluoride content on the buccal surface of the contralateral premolars was determined using the acid etch biopsy technique. A round glass ionomer slab was placed buccally on the first molar on a randomly chosen side of the mouth (test side). After 2 weeks, the enamel fluoride content of premolars on the test and control sides was again determined whilst avoiding the site of the first biopsy. In addition, one biopsy was made on a previously etched area. After 2 and 4 weeks, plaque was collected from three approximal surfaces both on the test and control side, and the total fluoride content of the plaque was analysed. There were no significant differences in the fluoride content of sound or etched enamel before and after placement of glass ionomer. The fluoride content of approximal plaque of teeth close to glass ionomer was not higher than that of the control teeth, either after 2 or 4 weeks. Using the present method, no increase in the fluoride level of teeth adjacent to glass ionomer could be demonstrated. This may be due to the masking effect of fluoride from other sources.

ISSN:0008-6568    

DOI:10.1159/000261465

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The release rates of fluoride from discs made from three glass ionomer products, Miracle Mix (MM), Ketac-Silver (KS) and Ketac-Bond (KB), into artificial saliva for 3 weeks were determined. The discs were either not varnished, varnished or varnished and finished. The release rates were not proportional to the fluoride concentrations of the products and were ordered: MM > KB > KS. The rates declined sharply as a function of time regardless of the product or treatment. Varnishing the discs caused a reduction of 61-76% depending on the product. Finishing the varnished discs produced a significant increase in the fluoride release from MM but had no effect on the release from KS or KB. In a separate study with MM, it was determined that the release rate of fluoride was inversely proportional to the powder: liquid ratio used to prepare the discs.

ISSN:0008-6568    

DOI:10.1159/000261466

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

In the literature, secondary caries around composite restorations is reported often. Fluoridated composites are therefore interesting materials because they might reduce or inhibit secondary caries. In this article an in situ model investigation is presented in which the effect of F-releasing composites on enamel demineralisation around an artificial gap of 200 μm width was quantified after 1 month. The fluoride content of the composites varied between 0 and 26 vol%. The beneficial effect of the fluoride released was larger in the gap than at the outer enamel surface. In the gap, all fluoridated composites reduced the enamel demineralisation statistically significantly with respect to the non-fluoridated control. Microradiography showed a reduction of lesion depth values of 27–45%, and a reduction of mineral loss values of 25–56%. At the outer enamel surface next to the artificial gap, a beneficial fluoridation effect was measurable only near the most fluoridated composite. The results indicate that fluoridated composites may play a role in the future prevention of secondary ca

ISSN:0008-6568    

DOI:10.1159/000261467

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Erythritol is a sugar alcohol produced by Aureobasidium sp. from glucose. It is 75–80% as sweet as sucrose and is also nonhygroscopic. The aim of this study was to evaluate this sugar substitute from a cariological point of view. Erythritol was neither utilized as a substrate for the lactic acid production nor for plaque formation of mutans streptococci (serotypes a-h) and certain oral microorganisms. It was not utilized for water-insoluble glucan synthesis or cellular adherence by glucosyltransferase from Streptococcus mutans PS-14 (c) and Streptococcus sobrinus 6715 (g). Finally, a significantly lower caries score (3.1 ± 0.5; mean ± SEM) was observed in specific pathogen-free rats infected with S. sobrinus 6715 and fed with a diet containing 26% erythritol, as compared to control rats fed with a diet containing 26% sucrose (60.5 ± 2.0). Also, rats provided a diet containing 56% erythritol chocolate (23.8% erythritol) and challenged with S. mutans PS-14 exhibited a significantly lower caries score (6.7 ± 0.8) compared to the sucrose chocolate group (82.8 ± 2.8). The main conclusion from this study is therefore that erythritol is a promising sugar substitute from a cariological point o

ISSN:0008-6568    

DOI:10.1159/000261468

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Stevioside and rebaudioside A, two intense natural sweeteners, that are constituents of the South American plant Stevia rebaudiana, were tested for cariogenicity in albino Sprague-Dawley rats. Sixty rat pups colonized with Streptococcus sobrinus were divided into four groups and fed stevioside, rebaudioside A or sucrose added to basal diet 2000 as follows: group 1,30% sucrose; group 2, 0.5% stevioside; group 3, 0.5% rebaudioside A, and group 4, no addition. All four groups were sacrificed after 5 weeks. S. sobrinus counts were made and caries was evaluated according to Keyes’ technique. There were no differences in food and water intake and weight gains between the four groups. There were significant differences in sulcal caries scores (p < 0.02) and S. sobrinus counts (p < 0.05) between group 1 and the other three groups. There were no significant differences between the stevioside, rebaudioside A and no-addition groups. It was concluded that neither stevioside nor rebaudioside A is cariogenic uner the conditions of this stud

ISSN:0008-6568    

DOI:10.1159/000261469

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

With the introduction of fluoridated domestic salt in France in 1986, questions have arisen with respect to its efficacy in caries prevention. It has been of interest to compare the urinary excretion of fluoride in children who consume fluoridated salt to that in children who take fluoride tablets. Ninety-three schoolchildren, 10-14 years of age, participated in the study and were divided into four groups: group I consumed fluoridated salt with every meal; group II ate at a school restaurant once a day and consequently consumed fluoridated salt at only their evening meal, as fluoridated salt is not authorized for use in collective restaurants; group III consisted of children taking fluoride tablets (1.0 mg F/day) exclusively, and group IV did not receive any systemic administration of fluoride for prevention and constituted a low-fluoride control group. Total 24-hour urine samples were collected from all subjects. The average daily urinary flow rates varied from 0.51 to 0.68 ml/min, but showed no statistically significant differences among the groups. The average urinary fluoride concentrations were 0.60, 0.30, 0.99, and 0.28 mg/l, respectively, for groups I–IV. The mean 24-hour urinary fluoride concentrations and excretion rates for children who consumed fluoridated salt at all meals (group I) were not statistically different from those using tablets (group III). There were also no statistically significant differences between groups II and IV. The differences between urinary fluoride concentrations and excretion rates of groups I and III, as compared with group IV, were statistically significan

ISSN:0008-6568    

DOI:10.1159/000261470

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

We have studied the possible relationship between indigenous salivary antimicrobial agents, indigenous mutans streptococci and the capability of added mutans streptococci to grow in saliva. Stimulated whole saliva was collected from 19 healthy donors. Saliva samples were sterilized, supplemented with glucose and inoculated with Streptococcus mutans or Streptococcus sobrinus. The mixtures were incubated for 20 h followed by counting of viable cells. Saliva samples were analysed, both before and after sterilization, for indigenous antimicrobial agents and the bacterial flora. The subjects could be divided into two groups: those (n = 9) whose saliva promoted and those (n = 10) whose saliva inhibited the growth of the inoculated streptococci. A statistically significant correlation (+0.82, p < 0.001) was found between the numbers of viable cells of S. mutans and S. sobrinus after incubation in saliva. The sterilization procedure reduced the content of all antimicrobial proteins. Salivary antimicrobial factors, or levels of indigenous mutans streptococci, did not differ between the two groups. We conclude that none of the individual salivary antimicrobial factors alone can explain the large individual differences in growth-promoting or growth-inhibiting patterns of saliva on S. mutans and S. sobrinus. Inter-individually, saliva either supports or inhibits the growth of mutans streptococci, indicating a similar response of these two species in relation to the properties of saliva.

ISSN:0008-6568    

DOI:10.1159/000261471

出版商:S. Karger AG    

年代:1992

数据来源: Karger