摘要:

Thirty-one children, aged 0.8–3.8 years, were studied with respect to dental caries, the presence of Streptococcus mutans in dental plaque, and the amount and avidity of specific antibodies against S. mutans serotype c in serum and saliva. Twelve of the children harbored S. mutans in plaque and all 4 children with carious lesions belonged to this group. Comparison of S. mutans-positive and -negative children revealed no significant differences in the concentrations of total immunoglobulins (isotypes A, G and M) in serum or saliva, nor did the amount of intact secretory IgA molecules in saliva differ between the groups. All children had developed serum antibodies against S. mutans, irrespective of the presence of this bacterium in their plaque samples. Significantly more specific serum antibodies of IgG type (p = 0.001) were detected in S. mutans-free children than in those whose dentition was infected with this bacterium. Specific salivary IgA antibodies to S. mutans were found in only 26% of all children (8/31) with no correlation to the presence of oral S. mutans. Our results could be explained by the observation that the oral exposure to antigens in early infancy results preferably in a systemic (serum) immune response, which may be due to the incomplete antigen exclusion in the intestinal epithelium of human neonatal infants. Furthermore our data indicate that the specific serum IgG antibodies may be protective against the colonization of primary teeth by S. mutans in early childhoo

ISSN:0008-6568    

DOI:10.1159/000261032

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The influence of salivary pellicles on the demineralization of human dental enamel by 1% citric acid was studied. The pellicles were formed on embedded human tooth surfaces incubated in vitro with various solutions for periods of up to 6 days. Pellicles induced by unstimulated whole saliva gave an approximately 45% and those from parotid saliva a 25% inhibition of demineralization. On the other hand, a pellicle formed from mixed submandibular and sublingual (SM-SL) saliva in 30 min gave a retardation in lesion formation of at least 40% and after a 60-min exposure to SM-SL saliva, the lesion formation was completely prevented. In contrast, when the mucins were removed from SM-SL saliva by ultracentrifugation, protection against demineralization by the pellicle formed on exposure to the supernatant was only 30%. The effect of pellicles obtained by isolated salivary mucins was also studied. Human whole salivary mucins (HWSM) were isolated from both human SM-SL saliva and whole saliva of two individuals with blood group A. The mucins contained 18% protein, 72% carbohydrate, 1.4% sulfate and 0.14% phosphate. The major components of the protein moiety were threonine (14.7%), valine (12.6%) and serine (10.8%). The molar ratio of the sugar residues was: galactose: N-acetylglucosamine: N-acetylgalactose: fucose: N-acetylneuraminic acid = 6:4.5:4:7:1. A pellicle formed by a 3-day exposure to salivary mucins in vitro gave 100% protection of the tooth surface against demineralization by citric acid. These data suggest that the mucins in human saliva contribute to a large extent to its protective effect against acidic attacks on the tooth surface.

ISSN:0008-6568    

DOI:10.1159/000261033

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

An in vitro experimental caries model is described in which an ultramicro system of analysis was used during simulated decay to study the composition of fluid in micro wells drilled within human enamel. In this experiment, hydrochloric acid was used as the demineralizing agent because the results could be directly compared to recent bench-scale studies using a two-compartment diffusion cell. The two sets of results agree in principle and generally confirm an earlier ‘diffusion-controlled’ caries model. Furthermore, the results are contrary to caries models based on the assumption that the rate-controlling process is release of ions from the enamel crystal surfaces because: (1) The solutions at various points in the lesion remained satured during the attack, although a highly demineralized lesion was used in the experiment, and a high degree of undersaturation was used to drive the demineralization. (2) The Ca/P ratio in the lesion solution increased during the demineralization. (3) The calcium and phosphate concentrations increased during the demineralization above their initial values although there was no concentration gradient for hydrochloric acid in this system. (4) Small membrane potentials developed during the demineralization, indicating that the tooth surface was permselective. (5) The directions of the changes in the concentrations of all the ions in solution could be predicted from the permselectivity using the ‘diffusion-controlled’ model. These results have major implications relative to the design of theoretical physicochemical models employed to elucidate the mechanism of

ISSN:0008-6568    

DOI:10.1159/000261034

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The cariostasis of a mouthrinse containing 100-ppm fluoride versus a vehicle control was evaluated against experimental root caries on human and bovine cementum mounted on prosthetic devices. Subjects swished 10 ml of mouthrinse for 60 s twice daily and immersed their appliances with the test specimens into 0.1 M lactic acid buffer (pH 4.0) for 10 min three times daily. Recovered specimens were submitted to fluoride biopsies or to an acid test in vitro. The 100-ppm fluoride mouthrinse contributed to increased fluoride incorporation into the experimental lesions. The microradiographic lesions showed a thicker layer of acid-resistant mineral at the outer layer of specimens exposed to the fluoride mouthrinse than on those exposed to the vehicle control.

ISSN:0008-6568    

DOI:10.1159/000261035

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Fluoride acquisition by human enamel from topical application of either fluoride solutions or self-gelling fluoride systems with tetraethoxysilane (TES) was studied in vitro. Also studied was fluoride deposition from self-gelling systems incorporating certain positively charged polymers (Jaguar C-15 or DEAE dextran) to reduce the rate of fluoride release from the gels. The systems tested were all 0.65 M with respect to fluoride and of neutral pH. Sodium fluoride with 2% cetylpyridinium chloride (CPC) and ammonium fluoride with 1% sodium lauryl sulfate (SLS) were tested either as solutions or as self-gelling preparations with 20% TES. Additional studies involved gels with (1) sodium fluoride, 0.5 M sodium phosphate and 1% SLS; (2) sodium fluoride with 5% Jaguar C-15 and 1% CPC; (3) ammonium fluoride, 0.5 M ammonium phosphate and 1% SLS, and (4) ammonium fluoride with 5% DEAE dextran and 1% Tergitol 15-S-12. The findings showed that self-gelling systems deliver more fluoride to the enamel than their solution counterparts. The amount of firmly bound fluoride resulting from topical interaction was also greater from the self-gelling sodium fluoride system than from the application of an analogous sodium fluoride solution throughout the outer 20 μm of the enamel. The ammonium fluoride self-gelling system was only superior to the solution in this respect at the very enamel surface (i.e. depth of 2.5 μm). Incorporation of positively charged polymers in the gel systems resulted in decreased deposition of total fluoride and also of firmly bound fluorid

ISSN:0008-6568    

DOI:10.1159/000261036

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

To test for the presence of a cariostatic agent the cariogenicity of cooked and uncooked home-prepared maize, factory-milled maize and factory-milled sorghum was compared to cooked wheat starch and sucrose, and to maize plus sucrose and sorghum plus sucrose, using a rat caries model. Comparison of test groups to control groups indicated that the model system worked well. Maize and sorghum, whether cooked or uncooked, had a low cariogenicity but this was increased by the addition of 20% sucrose. The results of the investigation did not support the presence of a cariostatic agent in maize and sorghum.

ISSN:0008-6568    

DOI:10.1159/000261037

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The caries inhibitory effect of topical applications of 200 ppm fluoride from neutral sodium and ammonium fluoride solutions was tested in the hamster. Similarly, 1,000 ppm fluoride from sodium and ammonium fluoride solutions with and without orthophosphate at pH 5 and 7 was tested in the rat. Also tested in the hamster study was the combination of neutral sodium or ammonium fluoride with Zonyl FSC (DuPont de Nemours, Wilmington, Del., USA). This positively charged surfactant accelerates the formation of apatitically bound fluoride during fluoride enamel interactions. Findings in the hamster study show that repeated fluoride treatments (4 per week) depressed caries in (M1 + M2), but not in M3. Considering individual groups, only the animals treated with the sodium fluoride with Zonyl FSC experienced significantly less caries than the control group (M1 + M2). The findings in the rat showed all the fluoride-treated animals to experience less caries than the control group. Although the greatest caries inhibition resulted from repeated applications of ammonium fluoride with phosphate at pH 5, there was no statistically significant superiority of ammonium fluoride over sodium fluoride, irrespective of the presence of orthophosphate. On the other hand, solutions with orthophosphate were more effective than those without at pH 5, irrespective of whether the cation was sodium or ammonium. Finally, in the presence of orthophosphate, the sodium and ammonium fluoride solutions were more effective at pH 5 than at pH 7. A hypothesis is proposed explaining the differences in reactivity between NH4- and Na-fluoride solutions with enamel on the basis of the structure of the solutions and access of the ions to the solid-liquid interface.

ISSN:0008-6568    

DOI:10.1159/000261038

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Dental erosion is often seen on the lingual tooth surfaces. For this reason tongue pH after consuming orange juice, Coca-Cola (old and new formula), Coca-Cola Light, Jaffa orange beverage, Hart-Sport sport drink, coffee (with and without sugar), beer, sour milk, and strawberry yoghurt was studied in a test panel. The lowest pH values which also remained low for the longest time were observed after consuming Hart-Sport (pH down to 3.80), orange juice, yoghurt, Coca-Cola, and Jaffa, in comparison with coffee (pH down to 5.26), Coca-Cola Light, and beer (p < 0.001). The total glucose concentration in the products and in saliva after consuming them was measured in order to assess the clearance of the products from the mouth. Hart-Sport yielded the highest salivary glucose concentrations (14,000 ppm total glucose) immediately after consuming while yoghurt (4,520 ppm) and coffee with sugar (6,480 ppm) caused the least elevation (p < 0.05). All study products, however, were quickly cleared from the mouth and practically no glucose was left in saliva 30 min after ingestion. Since all the studied products caused lowering of tongue pH below pH 5.5, they have the potential to cause adverse effects on the teeth in patients with impaired salivary function. In the healthy subjects in this study, however, the buffering capacity in the mouth was so strong that not even tongue mucosa could be shown to keep low pH levels a couple of minutes after consumption.

ISSN:0008-6568    

DOI:10.1159/000261039

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

A sample of 729 noninstitutionalized, dentulous, adult males has been followed for 10 years, with a series of 4 comprehensive oral and radiographic examinations carried out under standard conditions at intervals of about 3 years. Individual counts of new decayed and filled surfaces (DFS) occurring during the intervals between examinations and sound surfaces at risk have been determined in order to calculate mean DFS rates per 100 surfaces at risk adjusted to a period of 1 year. The range of observed mean, annual rates is 1.03–1.92, with a mean annual rate of 1.36 new DFS per 100 surfaces at risk. Due to the difficulty in identifying secondary caries, the above rates provide an underestimate of the actual values. However, those rates observed for adults fall within the range of rates calculated according to the same formula for children 7–12 years of age. This demonstrates that caries attack rates may be similar in children and adu

ISSN:0008-6568    

DOI:10.1159/000261040

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

This study aimed at examining whether tactile examination with an explorer may produce traumatic defects in occlusal fissures. The study was carried out in 10 young male adults each of whom was due to have one pair of newly erupted third molars to be extracted. One randomly selected molar in each pair was clinically examined with a dental explorer and the teeth extracted after 1 week. The teeth were serially sectioned and a total of 196 ground sections were examined in a stereomicroscope. Defects were observed in 60% of the sections from experimental teeth in contrast to 7% in the control sections. There was a positive correlation between the size of the defect and the area of enamel opacity which again was associated with the surface morphology. Results indicate that classical use of sharp explorers may produce irreversible traumatic defects in demineralized areas in occlusal fissures favouring conditions for isolated lesion progression.

ISSN:0008-6568    

DOI:10.1159/000261041

出版商:S. Karger AG    

年代:1987

数据来源: Karger