Showing papers in "Caries Research in 1975"
TL;DR: The results suggest that there is no one specific etching pattern produced in human dental enamel by the action of acid solutions, and differences produced by acids are difficult to explain on the basis of variation in chemical composition, and crystallite orientation.
Abstract: This study has shown that the exposure of human dental enamel to acid solutions in vitro produces three basic etching patterns. In the most common, called type 1 etching pattern, prism core material was preferentially removed leaving the prism peripheres relatively intact. In the second, type 2 etching pattern, the reverse pattern was observed. The peripheral regions of prisms were removed preferentially, leaving prism cores remaining relatively unaffected. In the type 3 etching pattern, there was a more random pattern, areas of which corresponded to types 1 and 2 damage together with regions in which the pattern of etching could not be related to prism morphology. These findings differ from previous studies in which the type 1 pattern was ascribed to acid action and type 2 etching pattern to attack by chelators. The results therefore suggest that there is no one specific etching pattern produced in human dental enamel by the action of acid solutions. Such differences produced by acids are difficult to explain on the basis of variation in chemical composition, and crystallite orientation. This further highlights the variation in structure that can occur in enamel not only from tooth to tooth, or surface to surface, but also from site to site on a single tooth surface.
400 citations
TL;DR: The oral establishment of various species of streptococci and lactobacilli has been studied on 25 infants during a period of 5 years and the composition of the flora was significantly different from that which has previously been described for adults.
Abstract: The oral establishment of various species of streptococci and lactobacilli has been studied on 25 infants during a period of 5 years. When the children were 3, 4 and 5 years old, their caries and gingival status were recorded. Streptococcus salivarius becomes established within a day of birth, and Streptococcus sanguis after the eruption of the teeth during the first year. Streptococcus mutans was recovered from the infants significantly later and had only become established in half the number of the infants when they had reached 5 years. Lactobacilli were only recovered in low numbers and below 2 years of age they seemed to be mostly transients in the mouth of the infants. The lactobacillus flora which was then isolated, was dominated by Lactobacillus casei and the composition of the flora was significantly different from that which has previously been described for adults.
211 citations
TL;DR: The pH of plaque and concentration of lactic and volatile acids present before and after exposure in vivo to sugar has been investigated.
Abstract: The pH of plaque and concentration of lactic and volatile acids present before and after exposure in vivo to sugar has been investigated. Plaque was weighed and the acids quantitati
185 citations
TL;DR: Consideration of the results indicates that each of the sites represents a distinct ecological niche that should be looked at in isolation, and that the following parameters may be important in relating the bacterial population of a site to the formation of a carious lesion.
Abstract: Three sequential samples from the distal surface of the upper first premolars of ten 13- to 14-year-old children were collected over a period of 12 weeks. Viable bacterial counts were made on each sample and representative strains of the genera Streptococcus, Actinomyces, Veillonella, Neisseria, Fusobacterium, Rothia, Lactobacillus, Bacterionema, Eubacteria and Arachnia were identified on the basis of morphology, physiological tests, cell wall and acid end product analysis and serology. The qualitative composition of the 58 samples obtained from the 20 sampled areas examined was similar, although some surfaces were consistently free of specific organisms during the test period, this was particularly evident with the lactobacilli. The mean percentages of the predominant genera were Actinomyces 34.92, Streptococcus 22.9, Veillonella 13.07, and ‘bacteroides’ 7.97. Streptococcus mutans mean percentage was 2.17, Strep. sanguis 5.9, Strep. salivarius 0.67, Strep. milleri 0.51, A. israelii 16.5 and A. viscosus together with A. naeslundii 19.05. Consideration of the results indicates that each of the sites represents a distinct ecological niche that should be looked at in isolation, and that the following parameters may be important in relating the bacterial population of a site to the formation of a carious lesion: (a) qualitative composition; (b) persistence of specific bacteria; (c) concentration of specific bacteria, and (d) the stability of the numerical concentration of specific bacteria.
125 citations
TL;DR: The ability of an epidemiological diagnostic system to distinguish tooth sites with carious cavities from those without was investigated and the concurrent validity of clinical diagnosis of pits and fissures and the radiological diagnosis of posterior approximal surfaces was estimated.
Abstract: The ability of an epidemiological diagnostic system to distinguish tooth sites with carious cavities from those without was investigated. The diagnostic data were obtained during annual clinical and bitewing radiographical examinations of 551 teenage clinical trial subjects. 109 premolars and permanent molars, extracted during subsequent treatment of the subjects, were kept. Undecalcified serial sections of these teeth were examined in water at × 2.5 magnification under incident light, to compare the original diagnostic findings with the histological extent of caries. Quantitative methods were used to estimate the concurrent validity of clinical diagnosis of pits and fissures and the radiological diagnosis of posterior approximal surfaces. For fissure diagnosis a validity coefficient (rt) of 0.83 was obtained. 84% of cavities were detected while 22% of sites without cavitation were wrongly diagnosed as having cavities. For radiological diagnosis the validity coefficient (rt) was 0.95. Although 97% of surfaces without cavitation were correctly identified, only 73% of approximal cavities were detected radiologically. The effect of different factors on the validity findings is considered.
122 citations
98 citations
TL;DR: The results indicate that one treatment with the F–– containing lacquer introduces an amount of permanently deposited fluoride comparable to that of a great number of applications by the other solutions mentioned.
Abstract: The purpose of this study was to compare the F–– acquisition of enamel of APF solutions, NH4F containing solutions, organic fluoride solutions and a urethane lacquer-containing silane fluoride. The F–– content as a function of the distance from the anatomical surface was studied after one application, after 24 h of washing in tap water and after 1 week of washing. The results indicate that one treatment with the F–– containing lacquer introduces an amount of permanently deposited fluoride comparable to that of a great number of applications by the other solutions mentioned. The silane fluoride-containing lacquer introduces about 2,000 ppm of permanently bonded F–– in an average surface of 8 μm thickness.
81 citations
TL;DR: Signs of an adaptation to metabolize other compounds (for example, amino acids or peptides) were obtained and xylitol had no strong effect on the uptake of glucose by the cells which were adapted to tolerate this polyol.
Abstract: Cells of cariogenic Streptococcus mutans (Ingbritt) were maintained and grown in a Trypticase-Phytone-based medium which contained either glucose, xylitol or their combinations as the added carbohydrate. 2.5% xylitol retarded the growth of the cells in the presence of 0.25% glucose, but during 2.5 months adaptive period the cells were able to tolerate the presence of xylitol. However, no evidence was obtained in 10 months of a possible adaptation to metabolize xylitol. Instead, indications of an adaptation to metabolize other compounds (for example, amino acids or peptides) were obtained. Xylitol had no strong effect on the uptake of glucose by the cells which were adapted to tolerate this polyol. 3% xylitol inhibited by 40–50% the activity of dextran-hydrolyzing extracellular enzyme(s) in the growth medium of the above cells in the conditions used. The extracellular polysaccharide-forming activity by the cells was increased 60–80% by low concentrations of xylitol (up to 55 mg/ml growth medium). Higher concentrations were inhibitory.
70 citations
TL;DR: The percentage of Streptococcus mutans and StrePTococcus sanguis in pooled occlusal plaque and in pooled approximal plaque following 8–10 daily applications of ei decreases with increasing number of applications.
Abstract: The percentage of Streptococcus mutans and Streptococcus sanguis in pooled occlusal plaque and in pooled approximal plaque following 8–10 daily applications of ei
66 citations
TL;DR: The histological features of enamel in teeth showing either mild or severe fluorosis are described, and sections were examined in transmitted and polarized light after imbibition in aqueous.
Abstract: The present study describes the histological features of enamel in teeth showing either mild or severe fluorosis. Sections were examined in transmitted and polarized light after imbibition in aqueous
65 citations
TL;DR: An investigation into occurrence of dextranase in human oral streptococci revealed that cell extracts of 8 out of 25 strains contained an enzyme, α-1,6-glucan glucohydrolase, that hydrolyzed the α-(1 → 6)-glucosidic linkages in Dextran and isomaltose.
Abstract: An investigation into occurrence of dextranase in human oral streptococci revealed that cell extracts of 8 out of 25 strains contained an enzyme, α-1,6-glucan glucohydrolase, that hydrolyzed the α-(1 → 6)-glucosidic linkages in dextran and isomaltose. Glucose was the only product of low molecular weight released by this enzyme. Six strains contained a different dextranase that released oligosaccharides of the isomaltose series from dextran. In the case of Streptococcus mutans IB16, it was established that the main oligosaccharide products were isomaltotetraose and isomaltopentaose. Cell-free filtrates from 14 of the 25 strains synthesized extracellular polysaccharides from sucrose, and eleven of the filtrates produced water-insoluble glucans. Dextranase occurred in five of the strains that synthesized glucan and in five strains that were unable to synthesize extracellular polysaccharides. All the insoluble glucans were partially hydrolyzed by a fungal α-(1 → 3)-glucanase. None of the cell-extracts or cell-free filtrates was able to hydrolyze α-1,3-glucan.
TL;DR: The present experiments showed that fluoride and monofluorophosphate in low concentrations could desorb albumin and salivary glycoprotein adsorbed to hydroxyapatite in vitro, indicating a similar mechanism for desorption of pellicle protein and bacteria.
Abstract: The present experiments showed that fluoride and monofluorophosphate in low concentrations could desorb albumin and salivary glycoprotein adsorbed to hydroxyapatite in vitro. It is suggested that the principle involved is competitive inhibition, the fluoride and monofluorophosphate ions replacing acidic protein groups adsorbed to calcium ‘sites’ on the mineral surface. Bacteria adsorbed to hydroxyapatite could be desorbed in the same way indicating a similar mechanism. The adsorption of biological material to teeth seems to be strongly dependent on the surface chemistry of the teeth. Desorption of pellicle protein and bacteria may be one of the mechanisms by which fluoride and monofluorophosphate exert their cariostatic effect in vivo.
TL;DR: In this paper, sound premolars were demineralized for 4, 6, 9, and 11 days in buffer solutions of either pH 4, 4.5, or 5.
Abstract: Sound premolars were demineralized for 4, 6, 9, and 11 days in buffer solutions of either pH 4, 4.5, or 5. Lesions were examined by quantitative microradiography. The thickness of the surface layer, depth of the lesion and degree of demineralization were studied as a function of pH and demineralization time.
TL;DR: The findings that both the plaque-inhibiting property of chlorhexidine and the retention of the drug in the oral cavity were pH-dependent support the hypothesis that the drug’s clinical effect is related to its retention in the mouth.
Abstract: Two clinical trials have been performed. In the first series the oral retention of chlorhexidine after mouth rinses of various pH values was determined, employing 14C-ring-labelled chlorhexidine for quantitation. The amount of chlorhexidine retained in the mouth was found to be considerably less when the mouth rinses were adjusted to low pH values (1.5 and 3.0) than when the pH was neutral or alkaline (6.4 and 9.0). In another series the plaque formation during a 3-day period without oral hygiene was estimated, employing chlorhexidine mouth rinses of various pH values. The plaque-inhibiting capacity of chlorhexidine was almost eliminated by lowering the pH of the mouth rinses to 1.5 or 3.0. Bacteriologic in vitro tests, employing a cariogenic streptococcus as the target bacteria, failed to demonstrate differences between the bactericidal effect of the drug at low and high pH. The findings that both the plaque-inhibiting property of chlorhexidine and the retention of the drug in the oral cavity were pH-dependent support the hypothesis that the drug’s clinical effect is related to its retention in the mouth.
TL;DR: The plaque calcium and phosphorus levels were inversely related to both the new DMFS developing during the 2-year period and the total caries experience of the subjects at the end of the study.
Abstract: In a 2-year study of the calcium and phosphorus levels of mature plaque collected from male subjects aged 11–12 years at the commencement of the study, the plaque calcium and phosphorus levels were inversely related to both the new DMFS developing during the 2-year period and the total caries experience of the subjects at the end of the study.
TL;DR: Carious dentinal lesions in which a remineralized surface layer covers the decalcified region were subjected to electron-probe and electron microscope studies.
Abstract: Carious dentinal lesions in which a remineralized surface layer covers the decalcified region were subjected to electron-probe and electron microscope studies. The remineralized surface layer containe
TL;DR: It was found that NH4F produced an initial enamel fluoride level much higher than that produced by APF, and both groups, however, were observed to have lower fluoride concentrations than before treatment.
Abstract: A microsampling technique was used to measure enamel fluoride concentrations before, immediately after, 1 week after, and 3 months after an application of an APF or NH4F solution on the maxillary anterior teeth of 63 children. The fluoride treatments were preceded by a 1-min application of 0.05 m H3PO4. It was found that NH4F produced an initial enamel fluoride level much higher than that produced by APF. One week after treatment, the fluoride concentrations produced by NH4F were still higher than those obtained with APF. Three months after treatment there was no difference between the NH4F and APF groups. Both groups, however, were observed to have lower fluoride concentrations than before treatment.
TL;DR: It was noted that a combination of low fluoride level in the enamel and high prevalence or incidence of dental caries was observed in only very few individuals.
Abstract: A follow-up study of 66 children, examined for dental caries at the age of 3, was carried out when these children had reached the age of 6. Caries prevalence in the primary dentition at the final examination as well as caries incidence during the 3-year period was compared to the fluoride content of the enamel measured by an abrasive biopsy technique on the buccal surfaces of the upper primary cuspids. No statistically significant correlation between the two parameters could be established. It was noted that a combination of low fluoride level in the enamel and high prevalence or incidence of dental caries was observed in only very few individuals.
TL;DR: The effects of Actinomyces viscosus on the establishment and symbiosis of Streptococcus mutans and StrePTococcus sanguis and of the sucrose con are studied.
Abstract: The effects of Actinomyces viscosus on the establishment and symbiosis of Streptococcus mutans and Streptococcus sanguis and of the sucrose con
TL;DR: It may be concluded from the correlation between the lesion depth and the thickness of the surface layer that, when more material is dissolved in the lesions, more precipitation can take place near the intact surface, thus increasing the thickness Of The surface layer.
Abstract: The influence of the original mineral content on the effect of one and two periods of acid attack was studied using quantitative microradiography. The maximum mineral content and the thickness of the surface layer, the minimum mineral content and the depth of the lesion were depicted as a function of the original mineral content. A linear relationship was found in all cases except in those groups with the highest original mineral content, where a flattening of the curve was seen. It may be concluded from the correlation between the lesion depth and the thickness of the surface layer that, when more material is dissolved in the lesion, more precipitation can take place near the intact surface, thus increasing the thickness of the surface layer.
TL;DR: The source of fluoride ions in sodium monofluorophosphate dentifrices and their importance in the fluoridation of enamel relative to MFP anions has been investigated.
Abstract: The source of fluoride ions (F––) in sodium monofluorophosphate (MFP) dentifrices and their importance in the fluoridation of enamel relative to MFP anions has been investigated. Commercial
TL;DR: It is suggested that acidic environments would be prolonged at the tooth interface, through the catabolism of the polysaccharide, and the filamentous forms, although numerically few, probably contribute significantly to this environment during the absence of exogenous sugars.
Abstract: The localization and distribution of organisms actively synthesizing intracellular polysaccharide from labelled glucose has been studied in plaque in situ, using electron microscope autoradiography Freshly extracted teeth were in contact with one of three different glucose concentrations for varying periods of time After fixation the teeth were prepared for electron microscopy, sectioned, covered with Ilford L4 emulsion and ‘exposed’ for 10 weeks Electron micrographs revealed that coccal-shaped organisms predominated in the plaques (ages unknown) and that approximately 30% of the total number of organisms were labelled, thus signifying active polysaccharide synthesis Although fewer in number than the coccal forms, a greater proportion of the filamentous forms were labelled Regional examination revealed that the proportion of polysaccharide synthesizing organisms was relatively low at the saliva interface (16%) but increased to 52% in the plaque adjacent to the tooth Plaques subjected to low glucose concentrations failed to exhibit polysaccharide synthesis in cocci beneath the outer microbial layer at the saliva interface Filamentous forms continued to be labelled much deeper in the plaque These observations demonstrate that the proportion of organisms actively synthesizing intracellular polysaccharide in mature plaque is much greater adjacent to the tooth than at the saliva interface It is suggested that acidic environments would be prolonged at the tooth interface, through the catabolism of the polysaccharide The filamentous forms, although numerically few, probably contribute significantly to this environment during the absence of exogenous sugars It is further suggested that the low glucose concentration of saliva would be unlikely to provide sufficient energy for microbial metabolism in organisms situated in the deeper regions of the plaque
TL;DR: Washed cells of the FA-1 and K-1 strains of Streptococcus mutans were incubated in buffered solutions, pH 5.9, that were initially either saturated or slightly undersaturated by add.
Abstract: Washed cells of the FA-1 and K-1 strains of Streptococcus mutans were incubated in buffered solutions, pH 5.9, that were initially either saturated or slightly undersaturated by add
TL;DR: 14 children aged 8–12 years participated in a double-blind clinical study to determine the effect of Ca and P concentrations in dental plaque and on plaque weight of consuming milk-cereal tablets in children.
Abstract: 14 children aged 8–12 years participated in a double-blind clinical study to determine the effect of Ca and P concentrations in dental plaque and on plaque weight of consuming milk-cereal tablets in w
TL;DR: The mechanisms of action of fluoride ions in saliva-sucrose solutions were studied when half crowns of premolars were employed in an in vitro system.
Abstract: The mechanisms of action of fluoride ions in saliva-sucrose solutions were studied when half crowns of premolars were employed in an in vitro system. The fluoride ion concentration
TL;DR: A new acid etch enamel microsampling technique was employed to study the effect of artificially produced acquired pellicle on fluoride uptake and the results showed less variance of parts per million flu.
Abstract: A new acid etch enamel microsampling technique was employed to study the effect of artificially produced acquired pellicle on fluoride uptake. The results showed less variance of parts per million flu
TL;DR: A sedimentation method for studying adsorption of microorganisms onto hydroxyapatite is described and compared with batch adsorptive experiments, which demonstrate the feasibility and the high quality of the results.
Abstract: A sedimentation method for studying adsorption of microorganisms onto hydroxyapatite is described and compared with batch adsorption experiments. Data, which demonstrate the feasibility and the high r
TL;DR: Investigation of the ultra structural changes in human enamel – untreated and pre-treated with Na2FPO3 – after an artificial carious attack indicated that most likely FPO32–– ions influence both transport of ions in the lesion and in the surface layer.
Abstract: The purpose of this study was to investigate the ultra structural changes in human enamel – untreated and pre-treated with Na2FPO3 – after an artificial carious attack. With the scanning electronmicroscope the influence of local fluoride application on surface topography and on the caries lesions in cross-sections was investigated. The results show that in Na2FPO3 pre-treated specimen the prism core dissolved faster than the interprismatic areas. The experiments indicated forthermore that most likely FPO32–– ions influence both transport of ions in the lesion and in the surface layer; FPO32–– application caused a considerable ‘clogging’ of the interprismatic areas. A preparation method is outlined by which a detailed comparison of pre-treated and untreated enamel originally located less than 0.25 mm apart is possible.