Biomedical subjects

S Edwardsson

Publications and source records attributed to S Edwardsson.

At least 37 records · Page 2Linked to original sources

PubMed1995

The effect of a low fluoride containing toothpaste on the development of dental caries and microbial composition using a caries generating model device in vivo.

The purpose of the study was to evaluate the effect of daily use of a low fluoride containing toothpaste (250 ppm F) on the uptake of fluoride and development of enamel lesions as well as the prevalence of lactobacilli and mutans streptococci in dental plaque compared to the use of placebo toothpaste. 16 children were selected with homologous premolar teeth. The teeth were cemented with orthodontic bands ad modum Ogaard for plaque accumulation and enamel lesion development. The plaque accumulated during 4 weeks was collected and analysed for lactobacilli and mutans streptococci. The teeth were further analysed by secondary ion mass spectrometry (SIMS), determining the concentration profiles of fluoride and other elements in the outermost enamel and in the lesion. The results show that although significant amounts of fluoride were taken up in the surface enamel from the fluoride toothpaste, the extent of the lesions was not influenced compared to teeth brushed with a non F-toothpaste. Neither were microbiological differences in the dental plaque found between the groups. An interesting observation was that early demineralization of enamel took place without detectable levels of mutans streptococci in the overlaying dental plaque. The conclusion is that fluoride taken up in enamel from F-toothpaste has no significant influence on enamel lesion development if a cariogenic dental plaque with high levels of acid producing microorganisms is continuously attached to the enamel surface.

Adolescent↗

PubMed1994

Effect of lactoferrin on interaction of Prevotella intermedia with plasma and subepithelial matrix proteins.

A lactoferrin-binding protein with an estimated molecular mass of 57 kDa was identified in the cell envelope of Prevotella intermedia by gel electrophoresis and Western-blot analysis. Peroxidase-labeled bovine lactoferrin and human lactoferrin showed similar specific binding to this protein. Whole cells of P. intermedia were also examined for interactions with 5 125I-labeled plasma and subepithelial matrix proteins. A high degree of binding was found with fibronectin, collagen type I and type IV and laminin, whereas a moderate interaction was detected with fibrinogen. The ability of bovine lactoferrin to affect the interactions of the above proteins with P. intermedia was examined. In the presence of unlabeled bovine lactoferrin, a dose-dependent inhibition of binding was observed with all 5 proteins tested. Unlabeled bovine lactoferrin also dissociated the bacterial complexes with these proteins. The complexes with laminin or collagen type I were more effectively dissociated than fibronectin or fibrinogen, whereas the interaction with collagen type IV was affected to a lesser extent. A strain-dependent variation in the effect of bovine lactoferrin was observed. These data establish the presence of a specific lactoferrin-binding protein in the cell envelope of P. intermedia. The ability of lactoferrin to inhibit the binding of some plasma and subepithelial matrix proteins to P. intermedia could be a protective mechanism against the establishment of this pathogen in the periodontal pocket.

Animals↗

PubMed1994

Oral microflora of the ferret at the gingival sulcus and mucosa membrane in relation to ligature-induced periodontitis.

The aim of this study was to describe, in the domestic ferret, the composition of the normal gingival sulcus and the near related mucosa microflora and the shift in the composition during an acute periodontal breakdown induced by the placement of ligatures. Five animals were used. At the start of the experiment (day 0) and before the placement of the ligatures, 2 microbiological samples were obtained from the gingival sulcus and the related mucosa at the mid-buccal surface of the right upper P4. The same sites were sampled on the left side, serving as control sites. On day 28, new microbiological samples were taken from the same 4 sites. The samples were analyzed with darkfield microscopy and with viable counts. In the darkfield analysis, on day 0, the predominant bacterial morphotype was cocci, ranging from 88-92%. The viable counts showed that nearly 100% of the total cultivable flora was composed of facultative anaerobic gram-negative and gram-positive rods. Pasteurella spp., Corynebacterium spp. and Rothia spp. were the major components of these bacterial groups. No anaerobic bacteria were detected. On day 28, cocci decreased to approximately 75% in the experimental gingival sulcus sample, and filaments and rods increased significantly. Spirochetes remained largely unchanged during the experiment. The composition of the experimental site samples changed. There was a decrease in the mean numbers of facultative anaerobic gram-positive rods, and approximately one third of the microflora comprised anaerobic gram-negative rods, mainly Porphyromonas gingivalis and Fusobacterium spp. Although the composition of the microflora of the ferret presented few similarities to that described in dogs and monkeys, the anaerobic portion of the gingival sulcus and oral mucosa microflora related to ligature-induced periodontitis presented microorganisms observed in experimental periodontitis both in dogs and monkeys as well as in human periodontal diseases.

Animals↗

PubMed1994

Short-term effect of topical application of delmopinol on salivary microbiology, plaque, and gingivitis.

The aim of this study was to test a possible dose-response effect of topical application of delmopinol HCl on the salivary microbiology, the healing of a pre-established experimental gingivitis, plaque development, and supragingival plaque composition. Forty-eight healthy subjects were enrolled in an oral hygiene program for 2 wk to upgrade their oral health. After professional tooth cleaning, they abstained from all oral hygiene, but applied 2 ml of a placebo with a soft paintbrush onto their teeth twice daily for 2 wk. At the end of this period, the subjects received tooth cleaning and were then assigned to three treatment groups of 16 individuals each. They applied 2 ml of 0.1%, 0.5%, and 1% delmopinol HCl, respectively, twice daily for the next 2 wk and refrained from all other oral hygiene procedures. At the end of the placebo and delmopinol HCl treatment periods, (1) saliva samples were obtained and cultivated on a series of media, (2) the degree of gingivitis was measured with gingival crevicular fluid (GCF) and gingivitis index (GI), (3) the stainable buccal plaque extension was analyzed planimetrically, and (4) the bacterial morphotypes of plaque adjacent to the gingival margin were analyzed. No changes in the salivary microbiologic counts were detected. The amounts of GCF and GI were reduced in all delmopinol groups, as compared with placebo. Mean plaque extension was reduced by 16% for the 0.1%, 56% for the 0.5%, and 58% for the 1% delmopinol group. Cocci appeared to predominate in bacterial dental plaque when 0.5% and 1% delmopinol were used.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Microbiology of early supragingival plaque development after delmopinol treatment.

The aim of this double blind, cross-over, microbiological study was to compare the effect of topical application of the plaque control agent 0.5% delmopinol HCl with placebo on early supragingival plaque formation. Six subjects underwent 7 periods (0.5, 1, 2, 8 and 24 h and 3 and 7 days) of placebo and delmopinol application, respectively. At the start of each study period the teeth were professionally cleaned and 2 ml of placebo and delmopinol 0.5%, respectively, were applied on all teeth (twice daily for periods lasting 24 h or more). At the end of each period, supragingival plaque samples of one upper and one lower buccal tooth surface were collected separately and cultured on anaerobically incubated Brucella blood agar, on aerobically incubated blood agar and on selective media for the enumeration of Streptococcus spp., Haemophilus spp., Actinomyces spp., Veillonella spp., Neisseria spp. and Fusobacterium spp. The total anaerobic cultivable microflora after delmopinol use was 10-100 times lower than after placebo use. Compared with placebo, the proportion of cultivable aerobes (61.3%), Streptococcus spp. (104.8%) and Haemophilus spp. (82.3%) increased and the proportion of Actinomyces spp. (86.1%), Veillonella spp. (60.5%), Neisseria spp. (96.9%) and Fusobacterium spp. (60.6%) decreased after 7 days. Short-term application of 0.5% delmopinol HCl on supragingival dental plaque regrowth resulted in a reduction of the number of cultivable microorganisms in the plaque and produced a shift in the cultivable plaque composition.

Actinomyces↗

PubMed1993

pH changes in human dental plaque from lactose and milk before and after adaptation.

pH changes in human dental plaque in vivo from lactose and milk have been studied in four separate mouthrinse experiments. (1) pH was measured in plaque samples of 12 subjects before and after 6 weeks of frequent daily mouthrinsing with 10% lactose. The pH decreases were significantly more pronounced after the adaptation period than before (p < 0.001), 4 of the 12 subjects showing about the same low plaque pH from lactose as from glucose. (2) Similar to the previous experiment, frequent daily mouthrinsing with low-fat bovine milk in 10 subjects resulted in more pronounced pH decreases in plaque after an adaptation period of 4 weeks (p < 0.001). (3) Single mouthrinses, without any prior adaptation, with bovine standard milk, human breast milk, lactose-hydrolysed bovine standard milk, 5% lactose and 5% sucrose were compared regarding the effect on plaque pH in 7 subjects. All solutions resulted in pH falls. The most pronounced were found with sucrose, followed by the lactose-hydrolysed milk. (4) Bovine standard milk, 5% lactose and 10% sucrose were compared after a single mouthrinse in 5 subjects using interdental plaque pH wire telemetry. Lactose and milk were fermented more slowly than sucrose. In a separate study, acid production from lactose was also measured in two oral strains each of Streptococcus mutans, Streptococcus salivarius and Streptococcus sanguis. The results from these experiments indicated that at least part of the lactose transport and catabolism in all studied streptococcus strains seems to be regulated by inducible enzymes.

Adaptation, Biological↗

PubMed1992

Purification and properties of sorbitol-6-phosphate dehydrogenase from oral streptococci.

The activity of sorbitol-6-phosphate (S6P) dehydrogenase (S6PDH) and the sorbitol transport system were studied in strains of the oral streptococci Streptococcus gordonii, Streptococcus mitis, Streptococcus sanguis and Streptococcus mutans. Genetically transformed (to ferment sorbitol) strains and their DNA donors were included. S6PDH was purified by anion exchange chromatography and gel filtration. The purity of the enzyme was confirmed by polyacrylamide gel electrophoresis. The purified enzyme from all the strains exhibited Michaelis-Menton saturation kinetics. The Km values for nicotinamide-adenine dinucleotide (NAD) and S6P ranged between 0.03 and 0.21 mM and 0.07 and 0.20 mM respectively. The relative molecular weights of the native enzyme were 229,000 for one donor-transformant pair (S. sanguis and S. gordonii), 107,000 for the other pair (S. mitis and S. gordonii) and 129,000 for S. mutans. The molecular weights of the S6PDH subunits ranged from 26,000 to 28,000. The pH optima (greater than 8.5) and the amino acid composition (15 amino acids examined) were similar for the S6PDH from the different strains. However, the chromatographic and electrophoretic patterns as well as the Km values for NAD and S6P were the same only between the S6PDHs from the strains within each donor-transformant pair. Purified S6PDH from S. mutans also exhibited low mannitol-1-phosphate dehydrogenase activity. Sorbitol-grown decryptified cells of all the strains phosphorylated sorbitol in the presence of phosphoenolpyruvate but not in the presence of adenosine triphosphate (ATP). ATP-mediated phosphorylation of glucose was observed with the same strains when grown on glucose. No evidence for a non-phosphotransferase transport system was found for sorbitol in any of the strains.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Transport, Active↗

PubMed1992

The effect of topical metronidazole therapy on experimentally-induced periodontitis in the beagle dog.

The present study was performed to assess the effect of topical metronidazole therapy on ligature-induced periodontitis in beagle dogs. 6 beagle dogs with experimentally-induced periodontitis on the mandibular 2nd, 3rd and 4th premolars were treated with metronidazole 10% dental paste 2 x daily for 4 weeks in an open placebo-controlled study using a split-mouth design. Recordings of probing pocket depth, bleeding on probing and gingival index were performed before commencement of treatment and repeated weekly during the 4-weeks treatment period. Concurrently, samples for microbiological analysis were collected from 2 of the dogs. The results demonstrated that probing pocket depth, bleeding on probing and gingival index had improved significantly in the metronidazole-treated side compared with the placebo-treated side. Black pigmented Bacteroides spp. and Spirochetes, present in all samples before treatment, were eliminated from the metronidazole-treated side after the 1st week of treatment and throughout the treatment period, whereas they were present in all samples from the placebo-treated side. The result of the present study demonstrates that topical application of metronidazole in a dental paste, improves the clinical features of the experimentally-induced periodontitis and eliminates some of the micro-organisms associated with the disease.

Animals↗

PubMed1992

Influence of transient salivary flora on assessment of mutans streptococci level by the "Strip mutans" method.

The Dentocult SM ("Strip mutans") method occasionally shows decoloration of broth and of colonies of mutans streptococci on the plastic strip, thereby making interpretation difficult. In an attempt to explain the phenomenon and to investigate the influence of the salivary flora on the "Strip mutans" method, a total of 46 subjects were sampled. Saliva was analyzed using the "Strip mutans" method and conventional plating techniques to identify mutans streptococci, enterococci, staphylococci, enteric bacteria, and yeasts. Approximately 85% of the "Strip mutans" scores coincided with the conventional MSB-plating method. Two samples showed decolored mutans streptococci colonies on the "Strip mutans" strip. Enterococcus spp. were present in the saliva of these test subjects and could grow in the "Strip mutans" broth. Enterococcus faecalis was able to induce the same type of decoloration under experimental pure culture conditions. Three "Strip mutans" samples showed small colonies of mutans streptococci, visible only under magnification (x 10-20). Staphylococcus epidermidis was present in these saliva samples and showed heavy growth in the broth. Under experimental pure culture conditions S. epidermidis also inhibited the growth of mutans streptococci to some extent.

Adult↗

PubMed1992

Rinsing with delmopinol 0.2% and chlorhexidine 0.2%: short-term effect on salivary microbiology, plaque, and gingivitis.

The aim of this short-term study was to compare the effect of delmopinol HCl 0.2% and chlorhexidine digluconate 0.2% rinses on the development of dental plaque, the healing of experimental gingivitis, and the salivary microbiology. As part of a larger study protocol, 45 healthy males enrolled in an oral hygiene program to upgrade their oral health. For this portion of the study, participants had their teeth professionally cleaned on day 0. The participants then abstained from standard mechanical oral hygiene procedures, but applied a placebo solution twice daily for 2 weeks. At the end of this period the subjects received a second professional cleaning and were then assigned to 2 treatment groups: Group 1 rinsed with 10 ml of delmopinol HCl 0.2% and Group 2 rinsed with 10 ml of chlorhexidine digluconate 0.2% for 1 minute twice daily for the next 2 weeks and continued to refrain from mechanical oral hygiene procedures. At the end of the placebo and active treatment periods 1) saliva samples were taken and cultivated on a series of media; 2) the degree of gingivitis was assessed with gingival crevicular fluid (GCF) and gingivitis index (GI); and 3) the plaque index was assessed and the stainable buccal plaque extension was analyzed planimetrically. No changes in the salivary microbiological counts were detected for the subjects rinsing with delmopinol. Subjects rinsing with chlorhexidine showed significant reductions of anaerobes, aerobes, and S. mutans in saliva. The amounts of GCF and GI were reduced largely to the same extent in both treatment groups. Mean plaque extension was reduced by 52% after delmopinol and 88% after chlorhexidine rinsing.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

Antimicrobial effect of a dental varnish, in vitro.

The effects of a polymer based antimicrobial releasing varnish Cervitec were investigated against different gram-positive and gram-negative bacterial strains as well as a yeast using the agar diffusion inhibitory test (ADT-test in vitro). As positive controls a 1% chlorhexidine gel and 1% aqueous solution of thymol and a placebo polymer varnish without active agents were employed. The test experimental varnish containing 1% chlorhexidine and 1% thymol showed antimicrobial activity against all gram-positive and gram-negative microorganisms tested including one Candida strain. The positive controls were similar in effect compared to the test varnish. No antimicrobial effect was observed with the placebo varnish without active ingredients. Toothpicks and dental floss treated with the test varnish showed an antimicrobial effect against S. mutans even after storing in room temperature up to 12 months. The results from this study support earlier laboratory studies that chlorhexidine and thymol diffuse out of the experimental varnish and that the varnish is active against various of oral pathogens. The possibility to use toothpicks or dental floss impregnated with the varnish with the aim to become chemotherapeutically active against periodontal diseases as well as against dental caries, is promising and should be tested in vivo.

Actinomyces viscosus↗

PubMed1991

Mutans streptococci in saliva and interdental spaces after topical applications of an antibacterial varnish in schoolchildren.

The effect of a chlorhexidine-containing varnish on the levels of mutans streptococci in saliva and in interdental spaces was investigated in 33 15-year-old schoolchildren. Each child was treated with an active (1% chlorhexidine; 1% thymol) and a placebo varnish preparation following the split-mouth technique. The varnishes were applied twice in small amounts into upper interdental areas with a 2-d interval. Mutans streptococci in saliva and interdental plaque was sampled and enumerated during 3 months. The results showed an immediate reduction of the number of interdental mutans streptococci on both test and placebo side after the varnish applications. The levels, however, were significantly lower in the test quadrants compared with the placebo-treated sides after 8, 30 and 90 d. Thus, the findings indicate a slower recolonization in interdental spaces treated with the active preparation. The levels of mutans streptococci in saliva were significantly reduced 1 and 3 months after varnish treatment, suggesting a long-term effect of the antibacterial varnish.

Adolescent↗

PubMed1991

Effect of delmopinol on in vitro dental plaque formation, bacterial acid production and the number of microorganisms in human saliva.

This study investigated the effect of a surface active compound, delmopinol, on plaque formation and established plaque in vitro, on the bacterial acid production from glucose and on the total viable bacterial counts in saliva. The antimicrobial effect was compared with that of chlorhexidine. The plaque-inhibiting effect was evaluated in an artificial mouth system, and the effect on bacterial acid production was registered as a decrease of pH in bacterial suspensions with various concentrations of delmopinol. It was shown that delmopinol is able to prevent plaque formation, to dissolve established plaque in vitro, and that it has 5-125 times higher minimum inhibitory concentrations than chlorhexidine. Saliva samples collected 1 min after rinsing with delmopinol showed on differences in the total number of bacteria in saliva as compared with controls. It was also shown that the bacterial acid production from glucose was reduced successively with increasing concentrations of delmopinol. The results indicate that delmopinol might be as effective as chlorhexidine against plaque formation and that delmopinol is capable of penetrating established plaque, thus promoting a more effective mechanical cleansing.

Anti-Infective Agents, Local↗

PubMed1991

Human lactoferrin binding to Porphyromonas gingivalis, Prevotella intermedia and Prevotella melaninogenica.

Human isolates of Porphyromonas gingivalis (n = 16), Prevotella intermedia n = 82) and Prevotella melaninogenica (n = 18) from diseased periodontal pockets were examined for interaction with human lactoferrin (HLf) in a standardized 125I-labeled protein binding assay. The highest HLf binding was found in P. intermedia strains, followed by P. gingivalis and P. melaninogenica. Further characterization of the interaction was performed with 1 representative strain from each species. HLf binding to P. gingivalis reached a saturation instantly and was optimal at pH 5.0-6.5. The corresponding values for P. melaninogenica were 90 min and pH 3.0-5.5. The HLf binding to the 2 strains seem to be nonspecific. In contrast, P. intermedia demonstrated specific binding, and a time-saturability within 60 min with an optimal uptake at pH 6.0-7.5. Scatchard analysis implied 45,000 receptors per cell with an affinity constant of 5.5 x 10(-7) M on P. intermedia strain 4H. The binding capacity in all 3 strains was affected by the culture medium. HLf binding components in these strains were susceptible to heat or proteases. Binding was eliminated in P. gingivalis and was enhanced in P. intermedia and P. melaninogenica by periodate treatment. Unlabeled HLf or bovine lactoferrin effectively displaced labeled HLf binding. Various proteins and carbohydrates did not inhibit HLf binding. Our data suggest that HLf binds to these periodontitis-associated species and that this mechanism is distinct from the previously known ligand interactions in oral bacteria.

Acute-Phase Proteins↗

PubMed1991

Effect of partial substitution of invert sugar for sucrose in combination with Duraphat treatment on caries development in preschool children: the Malmö Study.

The aim was to study the effect of substitution of invert sugar for sucrose, in combination with fluoride varnish (Duraphat) treatment twice a year, on caries development in preschool children. One hundred and eighty-seven 4-years-olds were divided randomly into four sugar groups: (1) sucrose (S), (2) sucrose-Duraphat (SD), (3) invert sugar (I), and (4) invert sugar-Duraphat (ID). All families were asked to buy beverages, biscuits, breakfast cereals, marmalade, ice cream, jam, ketchup, sweets and table sugar, totally 32 different food items, sweetened with invert sugar or sucrose. The substitution was, thus, restricted to a number of sugar-rich between-meal products. The study was carried out double-blind for 2 years. The children of those parents who did not want to participate in the sugar groups were divided randomly into one of the following two groups: (5) Duraphat (D), and control (C). Because of lack of cooperation, only 114 of the 187 children (61%) were considered to have completed the study. The mean caries increment, including initial lesions, was 3.86 dmfs in the combined groups S and SD (n = 63) and 3.10 dmfs in the combined groups I and ID (n = 51) during the 2 years (p = 0.34). The corresponding values for the 2nd year only were 1.84 and 0.67 dmfs, respectively (p = 0.09). The mean caries increment was 2.86 dmfs in group D (n = 113) and 4.10 dmfs (p = 0.08) in group C (n = 93). If initial caries lesions were excluded from the index, the difference between groups D and C was significant (p = 0.008).(ABSTRACT TRUNCATED AT 250 WORDS)

Cariogenic Agents↗

PubMed1991

Secondary caries related to various marginal gaps around amalgam restorations in vitro.

Secondary caries lesions were produced in vitro by immersing human tooth-blocks with amalgam restorations every third day for 4 weeks in glucose- or sucrose-containing broth inoculated with a strain of Streptococcus mutans. The lesions at the cavity walls were related to various standardized micro-spaces (0, 30, 40, 60 and 80 microns) around the restorations. When a thick, sucrose induced layer of plaque covered the margin, dentine caries was found in all cases where a gap was present (30 microns or more). In the presence of a thin, glucose induced layer of plaque, dentine caries was detected only in the specimens with 60 and 80 microns gap-widths. Caries lesions were detected on the outer free enamel surfaces in all specimens. Lesions in the enamel of the cavity walls were observed with polarized light in 46% in the presence of sucrose- and in 21% in the presence of glucose-induced plaque.

Dental Amalgam↗

PubMed1990

Sorbitol-fermenting predominant cultivable flora of human dental plaque in relation to sorbitol adaptation and salivary secretion rate.

The sorbitol-fermenting predominant flora of human dental plaque was studied in 12 people with low and 11 with normal salivary secretion rates before and after a period of frequent mouth rinses with sorbitol solution. A total of 277 sorbitol-fermenting isolates are described by their morphological and physiological characteristics. The flora was almost exclusively composed of gram-positive bacteria belonging to the genera Streptococcus, Lactobacillus and Actinomyces in people with low secretion rates and Streptococcus and Actinomyces in those with normal salivation. At the species level, Streptococcus mutans predominated in all. The frequent use of sorbitol resulted in an increase of the streptococcal species mainly and particularly of Streptococcus sanguis I in people with normal salivation. The counts of lactobacilli and Actinomyces remained unaffected. Almost all isolates appeared to belong to the resident plaque flora. Succession of new sorbitol-fermenting genera to the plaque community could not be observed as a result of the frequent exposure of the mouth to sorbitol.

Adaptation, Biological↗

PubMed1990

Identification procedures for oral Actinomyces species.

Rapid tests for carbohydrate fermentation, nitrate reduction and enzymic reactions with single reagents were used for species identification of 144 isolates being gram-positive pleomorphic rods and belonging to the genus Actinomyces. The isolates derived from human supragingival and subgingival plaque. The results were compared with those obtained with reference strains as well as other previously identified strains belonging to Actinomyces and to the related genera Arachnia, Bifidobacterium, Propionibacterium and Rothia. The results showed that species identification within the genus Actinomyces was possible with the tests studied. A key for identification work is hereby provided.

Actinomyces↗