| 1. |
- Dahlén, Gunnar, 1944, et al.
(författare)
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Rapid urease test (RUT) for evaluation of urease activity in oral bacteria in vitro and in supragingival dental plaque ex vivo
- 2018
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Ingår i: BMC Oral Health. - : Springer Science and Business Media LLC. - 1472-6831. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Urease is an enzyme produced by plaque bacteria hydrolysing urea from saliva and gingival exudate into ammonia in order to regulate the pH in the dental biofilm. The aim of this study was to assess the urease activity among oral bacterial species by using the rapid urease test (RUT) in a micro-plate format and to examine whether this test could be used for measuring the urease activity in site-specific supragingival dental plaque samples ex vivo. Methods: The RUT test is based on 2% urea in peptone broth solution and with phenol red at pH 6.0. Oral bacterial species were tested for their urease activity using 100 μl of RUT test solution in the well of a micro-plate to which a 1 μl amount of cells collected after growth on blood agar plates or in broth, were added. The color change was determined after 15, 30 min, and 1 and 2 h. The reaction was graded in a 4-graded scale (none, weak, medium, strong). Ex vivo evaluation of dental plaque urease activity was tested in supragingival 1 μl plaque samples collected from 4 interproximal sites of front teeth and molars in 18 adult volunteers. The color reaction was read after 1 h in room temperature and scored as in the in vitro test. Results: The strongest activity was registered for Staphylococcus epidermidis, Helicobacter pylori, Campylobacter ureolyticus and some strains of Haemophilus parainfluenzae, while known ureolytic species such as Streptococcus salivarius and Actinomyces naeslundii showed a weaker, variable and strain-dependent activity. Temperature had minor influence on the RUT reaction. The interproximal supragingival dental plaque between the lower central incisors (site 31/41) showed significantly higher scores compared to between the upper central incisors (site 11/21), between the upper left first molar and second premolar (site 26/25) and between the lower right second premolar and molar (site 45/46). Conclusion: The rapid urease test (RUT) in a micro-plate format can be used as a simple and rapid method to test urease activity in bacterial strains in vitro and as a chair-side method for testing urease activity in site-specific supragingival plaque samples ex vivo. © 2018 The Author(s).
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| 2. |
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| 3. |
- Hassan, Haidar, et al.
(författare)
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Plaque pH in Caries-Free and Caries-Active Young Individuals before and after Frequent Rinses with Sucrose and Urea Solution.
- 2015
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Ingår i: Caries research. - : S. Karger AG. - 1421-976X .- 0008-6568. ; 49:1, s. 18-25
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To examine pH in the approximal dental biofilm after acid and alkali formation from sucrose and urea, after an adaptation period to these substances, in caries-free (CF) and caries-active (CA) individuals. Saliva flow and buffer capacity, and aciduric bacteria in saliva and plaque were also examined. Material and Methods: Twenty adolescents and young adults (15-21 years) with no caries (n = 10, Dm + iMFS = 0) or ≥1 new manifest lesions/year (n = 10, DmMFS = 3.4 ± 1.8) participated. After plaque sampling, interproximal plaque pH was measured using the strip method before (baseline) and up to 30 min (final pH) after random distribution of a 1-min rinse with 10 ml of 10% sucrose or 0.25% urea. This procedure was repeated after a 1-week adaptation period of rinsing 5 times/day with 10 ml of the selected solution. After a 2-week washout period the second solution was similarly tested. Mutans streptococci, lactobacilli and pH 5.2-tolerant bacteria were analyzed by culturing. Results: In the CF group, acid adaptation resulted in lowering of baseline and final plaque pH values after a sugar challenge, and in increased numbers of bacteria growing at pH 5.2, which was increased also after alkali adaptation. In the CA group, the final pH was decreased after acid adaptation. No clear effects of alkali adaptation were seen in this group. Conclusion: One-week daily rinses with sucrose and urea had the most pronounced effect on the CF group, resulting in increased plaque acidogenicity from the sugar rinses and increased number of acid-tolerant plaque bacteria from both rinses. © 2014 S. Karger AG, Basel.
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| 4. |
- Lingström, Peter, 1960, et al.
(författare)
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The anticaries effect of a food extract (shiitake) in a short-term clinical study.
- 2012
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Ingår i: Journal of biomedicine & biotechnology. - : Hindawi Limited. - 1110-7251 .- 1110-7243. ; 2012
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Tidskriftsartikel (refereegranskat)abstract
- The main objective was to investigate whether low-molecular-weight fraction of edible mushroom shiitake extract (Lentinus edodes) possesses caries-preventive properties. The study was designed as a double-blind, three-leg, cross-over, randomized, controlled clinical trial carried out on two series of volunteers at the University of Gothenburg, and the Academic Centre for Dentistry Amsterdam. Volunteers rinsed twice daily with a solution containing low-molecular-weight fraction of edible mushroom, placebo (negative control without active ingredients), or Meridol (positive control, AmF-SnF(2)) for two weeks, with a two-week washout period between each rinsing period. Changes in the acidogenicity of dental plaque before and after a sucrose challenge, shifts in microbial composition, and plaque scores were determined. Frequent rinses with shiitake reduced the metabolic activity of dental plaque. No reduction of plaque scores and no inhibition of the production of organic acids in plaque was found. Minor differences in microbial composition between test sessions were found. To conclude, the results indicate that shiitake extract has anticariogenic potential, but not to the same extent as the positive control.
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| 5. |
- Piwat, S, et al.
(författare)
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Site-specific dental plaque pH in 13-year-old Thai schoolchildren.
- 2015
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Ingår i: Clinical oral investigations. - : Springer Science and Business Media LLC. - 1436-3771 .- 1432-6981. ; 19:9, s. 2179-2186
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this paper was to study pH conditions between dental sites, taking account the presence of caries, calculus, and microbial composition and alkali production.
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| 6. |
- Raner, Elisabeth, et al.
(författare)
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pH and bacterial profile of dental plaque in children and adults of a low caries population
- 2014
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Ingår i: Anaerobe. - : Elsevier BV. - 1075-9964 .- 1095-8274. ; 27, s. 64-70
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Tidskriftsartikel (refereegranskat)abstract
- Objective: This study compares pH and microbiological profile of dental plaque in children and adults of a low caries population. Material and methods: Thirty-nine children, 12-14 years of age and 45 adults between 20 and 39 years of age in 5 Karen villages of the Tak province, Northern Thailand were examined for plaque, calculus, caries (DMFT) and pH measurements in resting plaque and after a sucrose rinse. Information on dietary and oral hygiene habits was obtained through interviews using a fixed questionnaire. Microbiological profile of plaque samples was analyzed with DNA-DNA checkerboard technique. Results: Mean DMFT was 0.77 +/- 1.56 and 87% of the adults and 67% of the children were caries free (p < 0.05). The mean resting pH was for both age groups in the range of 7.0-7.1 and significantly higher than a Swedish caries free reference group. Karen adult men had significantly lower pH minimum than females and children (p < 0.05). Supragingival plaque samples showed high levels of low acidogenic and anaerobic species, which dominated over strong acid producers such as streptococci. Conclusion: The study indicates that the Karen children and adults has a plaque physiology and microbiology predominating by low acidogenic anaerobes, which in addition to the low sucrose intake explains the low caries prevalence in this population. (C) 2014 Elsevier Ltd. All rights reserved.
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