摘要:

The ability of human saliva supernatant to support the in vitro growth of Streptococcus mutans and Streptococcus sanguis 10,000). Growth of the organisms on the protein subfraction was not affected by the intrinsic proteolytic activity of saliva indicating that the proteins and not digestion products were utilized. Analysis of saliva supernatant and its subfractions for cysteine and half-cystine revealed that saliva contains very low levels of freely available cysteine, but higher levels of half-cystine, particularly in the protein subfraction.

ISSN:0008-6568    

DOI:10.1159/000260242

出版商:S. Karger AG    

年代:1977

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000260293

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

A dissolution cell has been constructed for use in measuring the rate of acid dissolution of test surfaces. Using discs of compressed hydroxyapatite in this specially constructed dissolution cell, their initial rate of dissolution in potassium acetate buffer (pH 4.65) can be determined with a coefficient of variation < 1 %. The reduction in the rate of dissolution of the hydroxyapatite discs after a 1-min topical application of fluoride solutions or slurries of fluoride toothpaste, having concentrations as low as 0.2 ppm F––, was easily demonstrable. This test was also sensitive enough to demonstrate fluoride activity after as little as 10 sec exposure of the discs to fluoride solutions. Enamel mosaics prepared from human caries-free teeth could also be employed in the dissolution cell. Results of 1 min pretreatment of these mosaics with monofluorophosphate toothpastes indicated activity of a similar order to that found using discs of pure hydroxyapat

ISSN:0008-6568    

DOI:10.1159/000260243

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The fluoride uptake from six different fluoride solutions applied to the buccal surfaces of extracted, newly erupted premolars was measured. The fluoride concentration of two symmetrically situated areas were compared at various distances from the enamel surface after treatment of one of the areas with a fluoride solution. Exposure of enamel to sodium fluoride, acidic phosphate fluoride, monofluorophosphate, stannous fluoride, sodium hexafluorostannate and cetylaminhydrofluoride was found to produce significant but widely variable increases in the fluoride content of the superficial layers. The uptake of fluoride from all test solutions, except cetylaminhydrofluoride appeared to be confined mainly to the outermost 10–15 μm of enam

ISSN:0008-6568    

DOI:10.1159/000260244

出版商:S. Karger AG    

年代:1977

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000320678

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The in vitro fluoride uptake in human dental enamel treated with four different dentifrices was evaluated using a standardized technique. The fluoride concentration in two symmetrical areas of buccal surfaces of newly erupted premolars was analyzed in eight subsequent layers. One of the areas was treated with the dentifrice and the other served as a control. Fluoride gradient curves were computed for the two areas and the differences in the fluoride concentration at various distances from the enamel surface was calculated. Application of a dentifrice resulted in a small increase in the fluoride concentration of the enamel surface. After 1 h of treatment, however, the fluoride uptake was confined to the outer 5 μm of the enamel surface. No definite relationship was found between the fluoride ion activities in the dentifrice slurries applied to the tooth surface and the fluoride uptake. The small fluoride uptake in the enamel from the dentifrices, containing fluoride, may possibly be one reason for the moderate caries reduction obtained by daily use of fluoride-containing dentifrices

ISSN:0008-6568    

DOI:10.1159/000260245

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The effects of common contaminants of sodium monofluorophosphate; fluoride and pyrophosphate, on the course of the monofluorophosphate-apatite reaction have been studied. Both fluoride and monofluorophosphate are capable of undergoing reactions with dental mineral. Neither reaction is independent of the other. However, it appears that dentifrice compositions with relatively low contents of free fluoride are as clinically effective as those with more elevated fluoride levels. This indicates that the fluoride ion is not the sole source of anticaries activity. A rat caries test indicated that such trace levels of free fluoride do not provide the substantial anticaries activity associated with similar pastes containing sodium monofluorophosphate. Pyrophosphate, when present, inhibits the reaction between apatite and monofluorophosphate. The fact that no free pyrophosphate could be found on analysis of a dentifrice is attributed to adsorption of this contaminant by the abrasive and indicates that the pyrophosphate was not responsible for the observed anticaries activity. These findings lead to the conclusion that the monofluorophosphate anion possesses anticaries activity in its own right.

ISSN:0008-6568    

DOI:10.1159/000260246

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The rate of Sn3F3PO4 formation subsequent to in vitro SnF2 interaction with human dental mineral has been investigated using light microscopy, surface replicas and infrared internal reflection spectroscopy. It was found that formation of Sn3F3PO4 is a time-dependent phenomenon. Further, it was hypothesized that Sn3F3PO4 crystals are probably not a significant factor with regard to the clinical efficacy of topical SnF2 treatment of sound dental tissues.

ISSN:0008-6568    

DOI:10.1159/000260247

出版商:S. Karger AG    

年代:1977

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000260295

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Since the enamel surface is etched with an acid solution prior to the application of a fissure sealant, eventual loss of material may expose a surface more susceptible to caries. The purpose of this in vitro study was to assess the susceptibility to dissolution of enamel surfaces which had been (1) acid-etched, (2) etched and exposed to saliva and (3) sealed and then abraded to remove the sealant. Microsolubility studies were carried out to compare dissolution rates of the above surfaces with adjacent sound enamel controls. Results show that acid-etched enamel surfaces have higher solubility rates than sound enamel. However, after a 24-hour exposure of etched surfaces to whole saliva, remineralization brought about a significant reduction in solubility rate, such as to approach the level for sound enamel. After removal of sealant from the enamel surface, the remaining surface was still less soluble than adjacent sound enamel. This must be related to the retention of tags of sealant which penetrate deep into the enamel surface, remaining after grinding off the sealant.

ISSN:0008-6568    

DOI:10.1159/000260248

出版商:S. Karger AG    

年代:1977

数据来源: Karger