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doi: 10.1159/000260120pmid: 4525799
56 strains of Streptococcus mutans, comprising organisms from various laboratory culture collections and some original isolates, were examined by cell wall carbohydrate chromatography. Three patterns of reducing sugars were detected: pattern 1, glucose, galactose and rhamnose; pattern 2, galactose and rhamnose, and pattern 3, glucose and rhamnose. 14 strains fell into pattern 1, four strains into pattern 2, and 38 strains into pattern 3. Cell wall agglutination tests using antisera prepared against strains representative of the five serotypes of Strep. mutans allowed further subdivision of organisms with cell wall patterns 1 and 3. Strains of cell wall pattern 2 fell into a clearly defined group of strains of serotype b. Pattern 3 included examples of serotype c and e, and type specific sera could be produced by cross-absorption with cell walls. Pattern 1 strains included serotype a and d; serotype a strains could be separated using cross-absorbed sera, but strains resembling serotype d appeared to be more heterogeneous. The results indicate that for Strep. mutans serotypes a, b, c and e at least one of the type antigens, probably carbohydrate, is located in trypsin-treated cell walls. The type d antigen or antigens which have previously been demonstrated by immunofluorescence do not appear to be associated with trypsinized cell walls, and further subdivisions of the serotype d strains was possible upon the basis of cell wall agglutination tests.
Tatevossian, A.; Jenkins, G.N.
doi: 10.1159/000260121pmid: 4525800
The effect of sucrose on the dissolution of calcium hydroxide, tricalcium phosphate, enamel powder and whole teeth in a range of buffers and in saliva supernatant was studied in vitro. While sucrose increased the amount of calcium hydroxide dissolving at a pH above 11, it did not increase the solubility of the substances tested in the pH range usually found in the mouth. In this pH range the amount of calcium phosphate, powdered or intact enamel dissolved was decreased in the presence of sucrose. The nature of the calcium saccharates formed by the interaction of sucrose with calcium hydroxide was investigated and evidence was obtained that the complexes so formed are readily dissociated. The results indicate that calcium saccharate formation is unlikely to be a factor in the dissolution of enamel in caries and that the cariogenicity of sucrose cannot be ascribed to a direct complexation reaction with tooth enamel.
Miller, William A.; Everett, Mona M.
doi: 10.1159/000260122pmid: 4600852
Although there has been a number of biochemical studies on carious dentine, the localization of any changes recorded is generally not possible due to the sampling techniques employed. Carious human teeth, which had clinical details available, were fixed in neutral buffered formalin. The teeth were bisected to produce ground sections and a hemisection, which was decalcified in 10% formic acid and embedded in paraffin or ester wax 1960. Methods applied to 6-Min serial sections were: FDNB, FDNB-H-acid, Millon, Barrnett and Seligman, coupled tetrazonium (Tetraz), Tetraz for tyrosine, DMAB-nitrite, Sakaguchi, anionic dyes and their appropriate blocking agents. The sclerotic layer was richer in histidine than normal dentine. Lower amounts of arginine, lysine and histidine were observed in areas of active destruction by several techniques. In highly pigmented carious dentine, arginine was found to be higher than in the rest of the carious dentine. All of these data compared favorably with previously published biochemical data, particularly that of Armstrong though we were able to localize the changes more precisely.
Hals, E.; Höyer Andreassen, B.; Bie, T.
doi: 10.1159/000260123pmid: 4525801
The histopathology of natural secondary caries associated with silver amalgam fillings was studied and compared with the histopathology of experimental in vitro and in vivo secondary caries described in previous publications. The material consisted of 49 extracted human permanent teeth with a total of 55 silver amalgam, mostly class V, fillings. On macroscopical examination, about 75% of the teeth showed initial secondary caries, whilst 25% revealed no change of the tooth surface adjacent to the filling. The teeth were cut into longitudinal sections, 60–120 µm thick, which were examined by polarized light and microradiography. Because every complete section included an occlusal/incisal and a cervical cavity wall with an adjacent area of the tooth surface, it offered two ‘secondary caries risks’ for histological examination. However, the original number of risks was somewhat reduced during processing of sections. In principle, the histopathology of the lesions corresponded closely to that of the experimental secondary caries, but certain differences are described. In the enamel the frequency of outer lesions was 79.5%, in the cementum 90.9%. The frequency of cavity wall lesions in enamel and dentine/cementum was 69.5 and 86.7%, respectively. Outer lesions associated with a wall lesion were almost three times more frequent than outer lesions without a wall lesion. Increased radiopacity of the dentinal wall occurred in 27.8% of the risks, whilst no such change could be registered in the enamel walls. In the 21 risks of the group that had shown little or no macroscopical lesions, the microscopical changes were surprisingly frequent.
doi: 10.1159/000260124pmid: 4525802
The effect of fluoride administration on skeletal fluoride retention was studied in the unilaterally nephrectomized rat. In series I, fluoride (as NaF) was administered by stomach tube for 30 days in daily doses of 0 (control), 0.5, 1.0 and 2.0 mg F<sup>––</sup>. In series II, fluoride was administered in drinking water ad libitum for 106 days at concentrations of 0 (controls), 25 and 100 ppm F<sup>––</sup>. Each dosage group of rats consisted of: (1) unoperated animals, (2) sham-operated rats and (3) unilaterally nephrectomized rats. There were 8 rats in each subgroup. The fluoride retention in the femora and in the whole carcasses of series I animals was found to be without significant differences between the subgroups of unoperated, sham-operated and nephrectomized rats within the respective fluoride dosage levels. The fluoride administration in drinking-water at the 25- and 100-ppm F<sup>––</sup> levels over a longer period of 106 days, however, resulted in significant increases of skeletal fluoride retention in unilaterally nephrectomized rats as compared to sham-operated rats.
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