| 1. |
- Appelgren, Linnea, et al.
(författare)
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Dental plaque pH and ureolytic activity in children and adults of a low caries population
- 2014
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Ingår i: Acta Odontologica Scandinavica. - : Informa UK Limited. - 0001-6357 .- 1502-3850. ; 72:3, s. 194-201
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. The aim of this study was to evaluate the plaque pH level and ureolytic activity among children and adults of Karen Hill tribes. Methods. Thirty-four children aged 6-10 years and 46 adults aged 20-38 years were interviewed regarding oral hygiene practices, sucrose intake and betel chewing. Caries experience (DMFT and DT), calculus, bleeding on probing (BoP) and Plaque index (PlI) were registered. Ureolytic activity in supragingival plaque was tested at two interproximal sites (11/12 and 41/42) with the rapid urease test (RUT). Registration of plaque pH was performed at two interproximal sites (15/ 16 and 31/41) before, during and 30 min after rinsing with an urea solution (0.25%). Four interproximal plaque samples (one from each quadrant) per individual were collected to test the bacterial composition using the checkerboard technique. Results. Children and adults had similarly low DMFT and DT values. Children had a higher baseline pH and a higher ureolytic activity in the maxilla (p < 0.05) compared with adults. A significant correlation (r(2) = 0.63) was found between baseline pH and urease activity in the mandibular anterior teeth. Caries-free individuals had a higher baseline pH compared with caries active individuals in the anterior mandibular region (p < 0.01). The microbiological composition was characterized by an anaerobic low acidiogenic microbiota. Conclusions. Dental plaque pH is related to the ureolytic activity, which explains the low acidogenic plaque microflora and the low caries levels in the Karen population.
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| 2. |
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| 3. |
- Bergenholtz, Gunnar, 1939, et al.
(författare)
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Sveriges ledande position inom odontologisk forskning hotas
- 2003
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Ingår i: Tandläkartidn. ; 9, s. 60-61
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Nationella samordningsgruppens aktiviteter syftar till att: - identifiera forskningsmiljöer som kan stärkas genom nationell koordinering - sammanföra yngre forskare från olika forskningsmiljöer - sammanföra etablerade forskare men yngre forskare - stimulera till forskningssamarbete på ett nationellt plan
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| 4. |
- Chávez de Paz, Luis, 1974, et al.
(författare)
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Response to alkaline stress by root canal bacteria in biofilms. : Viability and mechanisms of response to alkaline stress by selected root canal bacteria.
- 2007
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Ingår i: International endodontic journal. - : Wiley. - 0143-2885 .- 1365-2591. ; 40:5, s. 344-55
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To determine whether bacteria isolated from infected root canals survive alkaline shifts better in biofilms than in planktonic cultures. METHODOLOGY: Clinical isolates of Enterococcus faecalis, Lactobacillus paracasei, Olsenella uli, Streptococcus anginosus, S. gordonii, S. oralis and Fusobacterium nucleatum in biofilm and planktonic cultures were stressed at pH 10.5 for 4 h, and cell viability determined using the fluorescent staining LIVE/DEAD BacLight bacterial viability kit. In addition, proteins released into extracellular culture fluids were identified by Western blotting. RESULTS: Enterococcus faecalis, L. paracasei, O. uli and S. gordonii survived in high numbers in both planktonic cultures and in biofilms after alkaline challenge. S. anginosus, S. oralis and F. nucleatum showed increased viability in biofilms compared with planktonic cultures. Alkaline exposure caused all planktonic cultures to aggregate into clusters and resulted in a greater extrusion of cellular proteins compared with cells in biofilms. Increased levels of DnaK, HPr and fructose-1,6-bisphosphate aldolase were observed in culture fluids, especially amongst streptococci. CONCLUSIONS: In general, bacteria isolated from infected roots canals resisted alkaline stress better in biofilms than in planktonic cultures, however, planktonic cells appeared to use aggregation and the extracellular transport of specific proteins as survival mechanisms.
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| 5. |
- Chávez de Paz, Luis, 1974, et al.
(författare)
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Streptococci from root canals in teeth with apical periodontitis receiving endodontic treatment.
- 2005
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Ingår i: Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics. - : Elsevier BV. - 1528-395X .- 1079-2104. ; 100:2, s. 232-41
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The object of this study was to investigate the diversity among streptococcal species isolated from root canals in conjunction with endodontic therapy and to characterize their production of extracellular proteins. STUDY DESIGN: Consecutive root canal samples (RCS) taken as bacteriological controls during root canal treatment of teeth with apical periodontitis were analyzed in a total of 100 clinical cases. Bacteria were isolated and classified by selective media and gas liquid chromatography. Streptococcal strains were identified by carbohydrate fermentation, hydrolysis of aesculin/arginine, and production of enzymes. Releases of extracellular proteins by streptococci and Enterococcus spp in fluid culture media were examined with SDS-PAGE and 2-dimension gel electrophoresis (2 DE). Extracellular proteins produced were quantified and qualitatively analyzed. Specific proteins were targeted with Western immunoblot assays. Comparisons were made with type strains. RESULTS: Of a total of 241 bacterial strains recovered in the first samples submitted, Streptococcus gordonii, S anginosus, and S oralis were the most frequently isolated streptococci. In 49 of 89 resubmitted samples showing bacterial growth, S gordonii and S oralis still predominated among streptococci. Other common bacterial isolates were Enterococcus spp, Lactobacillus paracasei, and Olsenella uli. Quantitative and qualitative differences in extracellular protein production were observed among clinical isolates and laboratory streptococcal strains. In similar conditions for growth, S intermedius, S anginosus, S oralis, and S gordonii were strong producers of extracellular proteins (>3.0 microg/mL), while Enterococcus spp and S mutans were weak. Whole cell protein extracts showed a different profile from that of extracellular proteins. The chaperone protein DnaK was recognized to be produced extracellularly by S gordonii, S oralis, S anginosus, and S parasanguis. CONCLUSIONS: Being strong producers of extracellular proteins and by virtue of common presence in teeth undergoing endodontic therapy, S gordonii, S anginosus, and S oralis may be of pathogenic significance in posttreatment apical periodontitis.
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| 6. |
- Ernberg, M, et al.
(författare)
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Examina och utbildning inom svensk odontologisk forskning
- 2003
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Ingår i: Tandläkartidn. ; 95:9, s. 54-59
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- En internationell utvärdering visade för några år sedan att Sverige riskerar att förlora sin position som världsledande nation inom odontologisk forskning. För att få en uppfattning om förändringarna inom forskarutbildningen och den postdoktorala meriteringen samlades data för 1990-2001 in från fakulteterna, Statistiska Centralbyrån samt Högskoleverket. Avsikten var att undersöka antalet forskarutbildade tandläkare, mångfalden bland doktoranderna och de som disputerat samt deras nuvarande anställningsform. Materialet jämfördes sedan med tidigare data. I medeltal avlade 25 personer per år doktorsexamen åren 1990-2001. Antalet har minskat under senare år. En majoritet av dem som avlade doktorsexamen hade odontologisk bakgrund. Relativt få har meriterat sig för en fortsatt akademisk karriär. 32 studerande påbörjade forskarutbildning åren 1991-2001. Andelen doktorander med annan akademisk grundexamen än odontologisk ökar. Sedan 1999 har forskningsvolymen minskat med motsvarande en hel fakultets forskningsvolym. Vi drar därför slutsatsen att kunskapsutvecklingen inom svensk odontologi riskerar att stagnera samt att fakulteternas behov av lärare till högre akademiska tjänster liksom folktandvårdens behov av handledare inom specialistutbildningen inte kommer att kunna tillgodoses i framtiden.
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| 7. |
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| 8. |
- Malmberg, E, et al.
(författare)
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Microorganisms on toothbrushes at day-care centers.
- 1994
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Ingår i: Acta odontologica Scandinavica. - 0001-6357. ; 52:2, s. 93-8
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Tidskriftsartikel (refereegranskat)abstract
- The microflora on 44 toothbrushes at 4 day-care centers in the city of Göteborg have been investigated as a presumptive risk factor for transmission of microorganisms by children. Non-supervised toothbrushing without the use of toothpaste was performed at the day-care centers twice a day. Streptococci, predominantly S. salivarius, S. sanguis, and S. mitis, were the most frequently recorded group of microorganisms and generally constituted the greatest part of the flora (on average, 50%). Beta-hemolytic streptococci were not found in any sample. Haemophilus species were noted in 82% of the samples. H. parainfluenzae being the most frequent, and H. influenzae being identified in only one sample. Anaerobes constituted on average a third of the microflora. Staphylococci were identified in 86% of the samples, S. epidermidis dominating. Fungi including molds were found in 50% of the samples, and from one day-care center large numbers of enteric organisms were identified. Thus this study shows that unsupervised toothbrushing at day-care centers can be questioned, more from a general hygienic point of view than from the risk of transmitting serious pathogens.
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| 9. |
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| 10. |
- Subramani, Durai B, et al.
(författare)
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Lactobacillus and Bifidobacterium species do not secrete protease that cleaves the MUC2 mucin which organises the colon mucus.
- 2010
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Ingår i: Beneficial microbes. - 1876-2891. ; 1:4, s. 343-50
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Tidskriftsartikel (refereegranskat)abstract
- The colon epithelium is covered by two layers of mucus built around the MUC2 mucin. An inner dense and attached mucus layer does not allow bacteria to penetrate, thus keeping the epithelial cell surface free from bacteria. An outer loose mucus layer is the habitat for the commensal bacterial microbiota. The inner mucus layer is renewed from the epithelial side and gets converted into the outer layer due to proteolytic cleavages by host proteases. We have now analysed if potential probiotic bacteria, namely Lactobacillus brevis, Lactobacillus plantarum, Lactobacillus bulgaricus and Bifidobacterium lactis, can secrete protease that cleaves the MUC2 mucin. We found that none of the potential probiotic bacteria Lactobacillus and Bifidobacterium could cleave the MUC2 core protein in the form of recombinant MUC2 N and C-termini although they secreted active proteases. This was in contrast to crude mixtures of oral and faecal bacteria that cleaved the MUC2 mucin. This observation further supports the view that these potential probiotic bacteria are of no harm to the host, as these bacteria cannot disrupt the mucin organised mucus as long as they are covered by glycans.
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