摘要:

The aim of this study was to investigate the effectiveness of a school-based fortnightly 0.2% sodium fluoride mouthrinse programme after children ceased to participate. The programme, which commenced at age 6 and ceased at age 12, was investigated 4 years following its cessation. Three groups of 12-year-olds and three groups of 16-year-olds were examined, i.e. children who had participated in the mouthrinse, those attending non-participating nearby schools and lifetime residents of a fluoridated community. Significant differences in mean DMFT in the 12-year-olds between the mouthrinse and the control group were not found in the 16-year-old group. Mean DMFT for the mouthrinse group and those in a fluoridated community (which were the same in 12-year-olds) showed a statistically significant difference in those aged 16. Most caries found, both in 12-year-olds and in 16-year-olds, occurred on molar teeth and was found on pit and fissure surfaces. The cessation of these programmes at age 12 should be reappraised and the combination of school-based fluoride mouthrinse programmes with a fissure sealing programme is recomended.

ISSN:0008-6568    

DOI:10.1159/000262109

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

A 3-year, double-blind caries trial was conducted to evaluate the caries-reducing effect of a modified technique to use toothpaste. At the outset, 369 children, 4 years of age, were randomly assigned to four groups. At the end of the study, when the children were 7 years old, 281 (76%) had completed the trial. Two of the groups (test groups, n=131) were given the following instructions regarding ‘toothpaste technique’: (1) to spread the paste evenly on the teeth prior to brushing, (2) not to expectorate more than necessary during brushing, (3) to filter the remaining dentifrice foam in the dentition, together with a sip of water, by active cheek movements for 1 min before expectorating, and (4) not to carry out any further water rinsings afterwards, and not to eat or drink for 2 h after brushing. The children in the other two groups (control groups, n = 150) were not given any instruction how to use the dentifrice and how to rinse after the brushing, but were, as the children in the test groups, encouraged to use the test dentifrice and to brush their teeth twice daily. Two commercial fluoride dentifrices (A and B) were compared: one of the test groups and one of the control groups used each product. Approximal carious lesions were scored on bite-wing radiographs at baseline and at the end of the study on the distal surface of the first and on the mesial surface of the second primary molars. No difference in caries increment was found between toothpastes A and B. The children in the two test groups developed a mean of 1.14 new dfs during the 3 years compared to 1.55 in the two control groups (p < 0.05). Thus, the results indicate that the modified toothpaste technique reduced approximal caries in preschool children by an average of

ISSN:0008-6568    

DOI:10.1159/000262111

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Although fluoride toothpastes are widely used for caries prevention, little is known about the impact of fluoride dentifrices on plaque composition. Also the issue of adaptation of mutans streptococci to grow in vivo in a fluoride environment has received little attention. Such an adaptation may be of interest as it has been suggested that adapted mutans streptococci may show reduced glycolytic activity thereby being less cariogenic. In the present experiments the impact of the suspension of the use of fluoride toothpastes on plaque composition, fluoride tolerance and acid production of mutans streptococci was studied. Pooled plaque samples from the lingual surfaces of the lower incisors were collected from individuals (n = 13) just before and 7 weeks after they had replaced their fluoride toothpastes (0.1–0.15% F) with a non-fluoride one. The samples were analysed for fluoride and the numbers and proportions of streptococci,Streptococcus mutans, Streptococcus sobrinus, Actinomyces species, and lactobacilli, respectively. The fluoride tolerance of the mutans streptococci was estimated by culture of the plaque samples on TYCSB agar supplemented with of 0,1, 2, 3, 4, and 5 mmol/l fluoride (NaF) at pH 7.2. From each plaque sample six S. mutans strains were isolated for the measurement of the rate of acid production (Vap) at pH 7 in the presence of 0, 5, and 10 mmol/l F. The overnight final pH was measured in cultures of the S. mutans strains with excess of glucose and 0, 5, and 10 mmol/l F. The results showed that the removal of the fluoride pressure from plaque did not affect the numbers or proportions of the various species and genera of bacteria. The fluoride tolerance of the mutans streptococci, and the Vap or the overnight final pH of the isolated strains had not changed. These results suggest that the use of fluoride toothpaste had not affected plaque composition, nor fluoride tolerance or acidogenicity of mutans streptococci. Probably the amount of fluoride delivered by fluoride dentifrices to dental plaque is too low to induce such adaptation

ISSN:0008-6568    

DOI:10.1159/000262112

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The development of dental caries from the age of 2.5 to 3.5 years was studied longitudinally in 692 children living in the southern suburbs of Stockholm. The parents answered a structured questionnaire concerning the family’s social and immigrant background as well as the dietary habits, oral hygiene and fluoride exposure of their children. Furthermore, the occurrence of mutans streptococci and lactobacilli was determined in samples taken from the tongue of the children, and the buffer capacity of the saliva was measured. At baseline examination, 11.3% of the children exhibited dental caries. At follow-up, 1 year later, decayed and/or filled surfaces were registered in 36.7% of the subjects. The majority of the new lesions were located on the occlusal surfaces of the second molar. Ninety-two percent of the children with caries at baseline developed new carious lesions during the 1-year period, compared to 29% of the children who were caries-free at baseline (p < 0.001). Of the lesions diagnosed at baseline as initial caries, 64% progressed to manifest lesions during the 1-year period. The study indicates that children with early caries development exhibit high caries progression as well as a high risk for further development of an extensive number of new carious lesion

ISSN:0008-6568    

DOI:10.1159/000262113

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The limited usefulness of caries activity tests based solely on counts of mutans streptococci has been recognised increasingly. Such tests do not account for potential differences in cariogenicity of Streptococcus mutans strains harboured by individual patients. Hence, this study describes the evaluation of a simple and inexpensive method involving the dissolution of powdered hydroxyapatite as a means of determining the cariogenic potential of 64 freshly isolated strains of S. mutans from 24 children. Whilst it is apparent that differences between strains isolated from individuals could be demonstrated using this test, the variability observed was such that it was not possible to relate in vitro cariogenicity to actual clinical caries experience.

ISSN:0008-6568    

DOI:10.1159/000262114

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Dental caries explorers may become contaminated during routine caries examinations with pathogenic organisms and thereby potentially transmit infections from one tooth to another within a patient. The purpose of this study was to test the hypothesis that the contamination status of explorers influenced the caries risk of second molars. Two explorer contamination statuses were defined: (1) contamination status 1 – explorers which had probed a carious molar just prior to examining the second molar versus explorers which had probed a sound molar prior to examining the second molar, and (2) contamination status 2 – sterile explorers versus explorers which had probed several teeth. Caries examinations were performed by 4 dentists on a cohort of 4th grade students in Belize City. The examination dates and sample sizes (n) were: September-October 1989 (n = 1,277), January 1991 (n = 1,111), and January 1992 (n = 961), and January-February 1993 (n = 861). Within this cohort, there were 221 subjects who (1) had at least one pit and fissure carious onset on a caries-free second molar, (2) had no evidence of dental treatments, and (3) were examined by the same examiner during the entire study. After adjusting for confounding variables, the examination of a second molar with a dental caries explorer in either contamination status 1 or 2 had no substantial effect on the caries risk (rate ratio 0.95, 95% confidence interval: 0.77–1.18, and rate ratio 1.18,95% confidence interval: 0.89–1.56, respectively). If a true rate ratio of 1.7 or greater was associated with the contamination status 1 and 2, these analyses had more than 99 and 80% probability of detecting it, respectively. Conclusions: Examining a sound second molar with a contaminated dental explorer either does not affect the caries risk, or results in such a small increase in caries risk that it can only be reliably identified in studies where the exposure of sound teeth to contaminated dental explorers is ran

ISSN:0008-6568    

DOI:10.1159/000262115

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Erosion of the buccal incisor enamel, most frequent in the upper jaw, has been associated with excessive oral exposure to citric acid-containing foodstuffs. The aim of the study was to determine the retention of citric acid at different sites in the mouth after a standardized exposure. Thirty-four normal subjects rinsed with 95.2 mmol/l (2%) citric acid, pH 2.1, for 5 s. At 1 min 55 s after the rinse a pre-weighed cotton pellet was used to collect saliva samples from upper labial incisor surfaces (UB), lower labial incisor surfaces (LB) and sublingually (SL). The citric acid concentration was determined enzymatically. The concentrations were (mean ± SD): 32.12+19.50, 11.90+8.60 and 1.52 ± 1.90mmol/l in the saliva collected from the UB, LB and SL sites, respectively Analysis of variance revealed that the citric acid concentration in the upper incisor site differed significantly from that of the lower incisor site (p < 0.001) and the sublingual site (p < 0.001), and that the lower incisor site differed significantly from the sublingual site (p < 0.001). The individuals differed significantly with respect to citric acid retention (p < 0.05). A significant correlation was found between UB and LB sites (r = 0.61, p < 0.05

ISSN:0008-6568    

DOI:10.1159/000262116

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Loss of enamel due to dietary causes, either by acid erosion or the fermentation of dietary sugars, is well known. These processes will be affected by a number of factors, one of which is the ability of the food to adhere to the enamel. The aim of this study was to determine the thermodynamic work of adhesion of a number of soft drinks to enamel. The results indicated significant differences in the ability of various drinks to adhere to enamel in vivo. In addition to obtaining a ranking of the drinks under test, the likelihood of them being displaced by saliva was considered.

ISSN:0008-6568    

DOI:10.1159/000262117

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Two independent cross-over studies have now been carried out to evaluate the effect of a regime of chewing sucrose-containing gum on enamel lesion remineralization. The first study has been reported in detail elsewhere. This further study aimed to increase the data set with an additional 13 volunteers. Similar protocols were followed in both studies. Weighted averages from the two studies showed &karsi028;z values corresponding to 16.8% remineralization for the gum versus 11.6% remineralization for the control (p = 0.046, two-sided). A significant difference between test and control was evident for lesion body (p = 0.0004, two-sided) but not for surface zone (p = 0.32, two-sided)

ISSN:0008-6568    

DOI:10.1159/000262118

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The mechanisms of organic matrix breakdown in the root caries process are not well understood. Therefore, the combined and separate effects of lactic acid and proteolytic enzymes on the degradation of human dentin collagen, glycoproteins, proteoglycans and phosphoproteins were investigated in the present study. Dentin powder was pretreated with lactic acid (pH 4.0), distilled and deionized (dd) water (pH 7.0) and EDTA/guanidine HCl (pH 7.4) for 24 h. Pellets of acid- or dd water-pretreated dentin powder were washed, dried, and then treated with trypsin, bacterial or mammalian tissue collagenase, or control buffer for 3 h. The released dentin proteins were analyzed by reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting to identify degraded type I collagen, proteoglycans, glycoproteins and phosphoproteins. All water and acid pretreatment and enzyme treatment groups demonstrated two collagen fragment bands with molecular weights at approximately 79 kD. Further studies showed that the 79 kD proteins from acid-pretreated dentin collagen were degraded by tissue collagenase, suggesting that endogenous collagenase may be involved in the degradation of root dentin collagen. Dentin proteoglycans were detectable in all the treatment groups by protein slot blotting. Relatively few distinct glycoproteins and proteoglycans, and no phosphoproteins were detected by immunoblotting. Results from this study suggest that both acids and proteolytic enzymes from either host or microbial origin are important in the degradation of human dentin matrix and the mechanisms involved in the release of various noncollagenous proteins may be different.

ISSN:0008-6568    

DOI:10.1159/000262119

出版商:S. Karger AG    

年代:1995

数据来源: Karger