摘要:

The exposure of bovine enamel to an albumin-containing demineralizing solution results in penetration of protein into the porous enamel. Washing of this albumin-containing enamel results in a complete (low pretreatment albumin concentrations) or partial removal of the albumin (pretreatment concentrations ≧200 μg/ml-1). Subsequent exposure to increasing salt concentrations of fluoride, phosphate, calcium or chloride shows a partial removal of albumin at fluoride or phosphate concentrations of 75 mM while complete removal occurred at 150–200 mM fluoride or phosphate. Exposure to either calcium or chloride, even at 3 M concentrations, showed a negligible albumin release. It is proposed that protein removed at high fluoride or phosphate concentrations is bound by a strong interaction between protein-carboxyl groups and calcium on the surface of the enamel mineral. The partial removal of albumin released at low fluoride or phosphate concentrations indicates an enamel-albumin interaction by means of Ca-bridging between protein-carboxyl groups and mineral phosphates. Finally, it is suggested that salt-free washing removes albumin that has lost its native form upon binding to the partially dissolved crystallites of the enamel. It is concluded that enamel is mainly protected from demineralization by the inhibitory effects of protein penetrated into the pores, in addition to possible protection by the pellicle on the sur

ISSN:0008-6568    

DOI:10.1159/000261216

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Using glucose as a marker, a detailed study of retention at 5 different sites in the mouth of 1 subject and a less detailed examination of 4 selected sites in the mouths of 10 other subjects revealed site-specific differential patterns of oral retention (or clearance). These patterns seemed independent of sometimes large, absolute day-to-day variations in oral retention which occur in all subjects but appeared to vary somewhat between subjects, probably reflecting slight differences in the anatomy and physiology of the individual mouth. In general, the patterns resembled those recently derived from studies of other oral phenomena such as rates of diffusion out of plaque, fluoride uptake by mineral and hydrogen ion concentrations in plaque. They will dictate the concentrations and thereby influence the activity of all extraneous substances in different regions of the oral cavity and may relate to the site-specific patterns of oral disease.

ISSN:0008-6568    

DOI:10.1159/000261217

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Two in vivo experiments were performed, concerning (1) the kinetics of the acquisition of calcium fluoride on enamel during daily rinses with a solution of 0.023% F as sodium fluoride, and (2) the loss of calcium fluoride from enamel slabs which had been topically treated with a neutral solution containing 0.9% F as sodium fluoride. Enamel slabs were carried in the mouth by 6 volunteers for 8 days in both experiments. Sound and etched enamel were included. During mouthrinses moderate amounts of fluoride were acquired by sound enamel, and more as calcium fluoride than as fluoridated apatite, whereas on etched enamel, more fluoride was deposited as fluoridated apatite. On etched enamel there was also a tendency that the deposition of calcium fluoride levelled out whereas the incorporation of firmly bound fluoride continued. This may indicate that calcium fluoride was transformed into fluoridated apatite, probably through remineralization during pH cycling in plaque covering the etched enamel. After single topical application, it was found that etched enamel initially took up more calcium fluoride than sound enamel, but also lost more during the 1st day of in vivo exposure. The loss of calcium fluoride was arrested after 1–2 days, on sound enamel at 70% and on etched enamel at 40% of the original level. It is suggested that the increased amounts of firmly incorporated fluoride in enamel originated from calcium fluoride on enamel, and that calcium fluoride is an important and clinically significant source of fluoride ions on ename

ISSN:0008-6568    

DOI:10.1159/000261218

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Syrup-form medicines have been shown to cause dental caries in chronically sick children. The acid production of 10 syrupy medicines sweetened with sucrose, fructose, sorbitol, xylitol and saccharin or with a combination of these was tested. The subjects consisted of 7 dental students with low buffering capacity and high levels of Streptococcus mutans. The subjects rinsed with sugar-based liquid medicines for 1 min, after which the plaque pH was measured with a Beetrode touch electrode at approximal sites until 40 min after the rinsing. The minimum pH, the ΔpH, and the time under pH 5.7 were measured. From the results it can be concluded that xylitol, xylitol-saccharin and xylitol-sorbitol combinations used as sweeteners in syrup medicines are nonacidogenic, sorbitol is hypoacidogenic, and sucrose and fructose are highly acidogenic

ISSN:0008-6568    

DOI:10.1159/000261219

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Ion-sensitive field-effect transistor (ISFET) pH electrodes were used to monitor changes in plaque pH at the base of artificial occlusal surface fissures and at interproximal sites. Bovine enamel was used to construct fissures (1.5 × 0.1 × 1.0 mm) containing a small ISFET electrode. The fissures were fixed to carrier appliances and worn by 4 human volunteers. After plaque accumulation for 4 days changes in pH were monitored by wire telemetry following 1-min rinses with 10% solutions of either sorbitol or sucrose. Results were compared to data obtained from interproximal sites in the same subjects. Responses to sorbitol in the fissure and on the proximal surfaces were minimal and showed no significant difference in minimum pH (5.9 ± 0.4 and 6.1 ± 0.3, respectively) and area under pH 7.0. The response to sucrose at the two sites was very different revealing unique pH profiles which were statistically significantly different with regard to minimum pH (5.0 ± 0.3, fissure and 4.3 ± 0.2, proximal) and area under pH 5.7. Thus, the acidogenic potential of fermentable carbohydrate at two caries-prone sites in the human dentition is significantly different and conclusions based on interproximal telemetry measurements may not be applicable to occlusal surface fis

ISSN:0008-6568    

DOI:10.1159/000261220

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Some epidemiologic studies from Africa report higher DMF values in second than in first molars. It is generally accepted that the maturation of dental enamel influences the susceptibility of teeth to caries. The purpose of the present study was to test the hypothesis that DMF values of second molars will be higher than those of first molars if the first molars have reached a high degree of maturation before being exposed to increased cariogenic challenge. The study was carried out in a group of 15-year-old students attending secondary schools in Botswana (n = 287). The results showed that in children who assumingly had had a traditional diet during childhood the DMF values were higher in second molars than in first molars. In children who grew up in a more urbanized setting, the results were opposite. The observed differences were due to differences in caries experience in first molars only. The DMF values of second molars did not vary among the groups. Oral hygiene, sugar consumption and knowledge level at age 15 seemed to have no effect upon the caries pattern studied. It is concluded that the results support the hypothesis tested.

ISSN:0008-6568    

DOI:10.1159/000261221

出版商:S. Karger AG    

年代:1989

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000261222

出版商:S. Karger AG    

年代:1989

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000261223

出版商:S. Karger AG    

年代:1989

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000261224

出版商:S. Karger AG    

年代:1989

数据来源: Karger

ISSN:0008-6568    

DOI:10.1159/000261225

出版商:S. Karger AG    

年代:1989

数据来源: Karger