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Materials (Basel, Switzerland) Mar 2024Invisible orthodontic aligners are having a great impact on tooth movement in an aesthetic and effective way. Different techniques, models, and clinical aspects have...
Invisible orthodontic aligners are having a great impact on tooth movement in an aesthetic and effective way. Different techniques, models, and clinical aspects have been studied for their proper use. However, the aim of this research has been to determine the effect of the shaping process on mechanical properties and their bacterial behavior. For this study, 40 original polyurethane plates and 40 identical models, obtained by hot forming the original plates, were used. The static tensile mechanical properties were studied with a Zwick testing machine using testing speeds of 5 mm/min at a temperature of 37 °C. The original plate and the aligner have been studied with a creep test by subjecting the samples to a constant tension of 30 N, and determining the elongation using a long-distance, high-resolution microscope at different time periods between 1 and 720 h. Studies of water absorption has been realized with artificial saliva for 5 h. Bacterial cultures of and strains were grown on the original plates and on new and used models, to determine the proliferation of each bacterium through metabolic activity, colony-forming units, and LIVE/DEAD assays. The mechanical results showed an increase in the strength of the inserts with respect to the models obtained from 3.44 to 3.95 MPa in the elastic limit and a lower deformation capacity. It has been proven that the transition zone in the creep curves lasts longer in the original plate, producing the rapid increase in deformation at a shorter time (400 h) in the aligner. Therefore, the shaping process reduces the time of dental correction exerted by the aligner. The results of the bacterial culture assays show an increase in the number of bacterial colonies when the aligners have been used and when the polyurethane is conformed due to the internal energy of the model, with respect to the original polyurethane. It has been observed that between the original plate and the aligner there are no statistically significant differences in water absorption and therefore the forming process does not affect water absorption. A slight increase in water absorption can be observed, but after five hours of exposure, the increase is very small.
PubMed: 38541514
DOI: 10.3390/ma17061360 -
Applied and Environmental Microbiology Aug 2020This study compares the metabolic properties of kojibiose, trehalose, sucrose, and xylitol upon incubation with representative oral bacteria as monocultures or synthetic...
This study compares the metabolic properties of kojibiose, trehalose, sucrose, and xylitol upon incubation with representative oral bacteria as monocultures or synthetic communities or with human salivary bacteria in a defined medium. Compared to sucrose and trehalose, kojibiose resisted metabolism during a 48-h incubation with monocultures, except for Incubations with -based communities, as well as salivary bacteria, displayed kojibiose metabolism, yet to a lesser extent than sucrose and trehalose. Concurring with our findings, screening for carbohydrate-active enzymes revealed that only spp. and possess enzymes from glycohydrolase (GH) families GH65 and GH15, respectively, which are associated with kojibiose metabolism. Donor-dependent differences in salivary microbiome composition were noted, and differences in pH drop during incubation indicated different rates of sugar metabolism. However, functional analysis indicated that lactate, acetate, and formate evenly dominated the metabolic profile for all sugars except for xylitol. 16S rRNA gene sequencing analysis and α-diversity markers revealed that a significant shift of the microbiome community by sugars was more pronounced in sucrose and trehalose than in kojibiose and xylitol. In spp., a taxon linked to cariogenesis dominated in sucrose (mean ± standard deviation, 91.8 ± 6.4%) and trehalose (55.9 ± 38.6%), representing a high diversity loss. In contrast, (5.1 ± 3.7%) was less abundant in kojibiose, which instead was dominated by (26.8 ± 19.6%), while for xylitol, (29.4 ± 19.1%) was most abundant. Overall, kojibiose and xylitol incubations stimulated cariogenic species less yet closely maintained an abundance of key phyla and genera of the salivary microbiome, suggesting that kojibiose has low cariogenic properties. This study provides a detailed scientific insight on the metabolism of a rare disaccharide, kojibiose, whose mass production has recently been made possible. While the resistance of kojibiose was established with monocultures, delayed utilization of kojibiose was observed with communities containing lactobacilli and as well as with complex communities of bacteria from human saliva. Kojibiose is, therefore, less metabolizable than sucrose and trehalose. Moreover, although conventional sugars cause distinct shifts in salivary microbial communities, our study has revealed that kojibiose is able to closely maintain the salivary microbiome composition, suggesting its low cariogenic properties. This study furthermore underscores the importance and relevance of microbial culture and mixed cultures to study cariogenicity and substrate utilization; this is in sharp contrast with tests that solely rely on monocultures such as , which clearly fail to capture complex interactions between oral microbiota.
Topics: Bacteria; Disaccharides; Humans; Kinetics; Microbiota; Mouth; RNA, Bacterial; RNA, Ribosomal, 16S; Sucrose; Sugars; Trehalose; Xylitol
PubMed: 32561577
DOI: 10.1128/AEM.01170-20 -
Scientific Reports Jul 2023We evaluated the anti-cariogenic effect of an experimental synbiotic compound containing probiotic Lacticaseibacillus rhamnosus (NRRL B-442)-based jelly candy...
We evaluated the anti-cariogenic effect of an experimental synbiotic compound containing probiotic Lacticaseibacillus rhamnosus (NRRL B-442)-based jelly candy supplemented with natural prebiotic grape seed extract (GSE) in a nanoemulsion formula on the colonization and establishment of Streptococcus mutans (ATCC 25175) and Actinomyces viscosus (ATTCC 19246) biofilms through counting colony forming units, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). We were then analysing the remineralizing effect of synbiotic jelly candy on human enamel surface lesions using Vickers microhardness testers, atomic force microscopy (AFM), SEM, energy-dispersive X-ray spectroscopy (EDAX), and confocal laser scanning microscopy (CLSM) at three stages (sound, after demineralization, and after pH cycling). We found after 21 days of treatment of the pH-cycled enamel discs with jelly candy for 10 min twice daily, a 68% decrease in S. mutans colony formation, reducing biofilm development, trapping S. mutans visualized in jelly candy under SEM examination, and significantly altering the morphological structure of these bacteria under TEM analysis. For remineralization measurements, statistically significant differences in microhardness integrated mineral loss, and lesion depth through CLSM between demineralization and treatment stages. These findings provide an effective anti-cariogenic synbiotic compound of grape seed extract and probiotic jelly candy with potential remineralizing activity.
Topics: Humans; Grape Seed Extract; Prebiotics; Streptococcus mutans; Probiotics; Candy; Biofilms; Tooth Remineralization; Dental Caries
PubMed: 37414826
DOI: 10.1038/s41598-023-37645-5 -
Molecules (Basel, Switzerland) Dec 2022For dental caries and periodontal diseases initiated by dental plaque (as bacterial communities) and to inhibit the growth of oral pathogenic bacteria, oral care...
For dental caries and periodontal diseases initiated by dental plaque (as bacterial communities) and to inhibit the growth of oral pathogenic bacteria, oral care products containing antiseptic active ingredients are highly recommended, nonetheless, side effects of such actives are a concern (teeth discoloration/staining and taste perception, for example). In this context, we challenged xylityl sesquicaprylate, an antiseptic compound from natural resources, as an active ingredient to be used in an alcohol-free mouthwash formulation. The xylityl sesquicaprylate sample was compared to a respective blank mouthwash formulation and one containing triclosan. The in vitro efficacy was screened by the time-kill assay against eight microorganisms. The xylityl sesquicaprylate-containing mouthwash (0.45% w/w) presented a particularly interesting profile of efficacy against Actinomyces viscosus, Fusobacterium nucleatum, Porphyromonas gingivalis, and Tannerella forsythia, with results of greater magnitude to reduce the log10 of those microorganisms in comparison with the triclosan sample.
Topics: Humans; Anti-Infective Agents, Local; Mouthwashes; Triclosan; Dental Caries; Porphyromonas gingivalis
PubMed: 36615226
DOI: 10.3390/molecules28010028 -
International Journal of Dentistry 2022The application of herbal and/or chemical antimicrobial mouthwashes in addition to the mechanical methods of bacteria removal helps reduce the periopathogens and thus...
BACKGROUND
The application of herbal and/or chemical antimicrobial mouthwashes in addition to the mechanical methods of bacteria removal helps reduce the periopathogens and thus increase the periodontal tissues' health. The present study aimed to evaluate the antibacterial effect of Thymex (TMX) syrup on three periodontal facultative anaerobes in vitro and compare it with 0.2% chlorhexidine (CHX) mouthwash.
METHODS
In this in vitro experiment, the disc diffusion method was used to measure the inhibitory halo diameter (IhD) of , , and . The paper discs containing TMX and CHX were placed on Mueller-Hinton agar media and cultured with the mentioned bacteria. Moreover, a blank disc containing distilled water was used as a control. From each of the three bacterial species, five samples were taken, and after 18 hours of storage in the incubator, the IhDs were measured in millimeters. A one-way ANOVA test and an independent sample -test were used to compare the mean differences of IhDs between groups. The significance level was considered to be 0.05.
RESULTS
The IhDs ranged between 6.2-8.8 mm and 12.3-34 mm for TMX and CHX, respectively. CHX showed a more inhibitory effect on all three species of bacteria compared to TMX mouthwash ( < 0.001).
CONCLUSIONS
Despite the inhibitory effect of TMX on bacterial growth, CHX showed significantly more antibacterial activity than TMX against three studied bacterial species.
PubMed: 36620479
DOI: 10.1155/2022/6359841 -
Microbiology Spectrum Apr 2024Antimicrobial resistance is one of the greatest challenges to global health. While the development of new antimicrobials can combat resistance, low profitability reduces...
Antimicrobial resistance is one of the greatest challenges to global health. While the development of new antimicrobials can combat resistance, low profitability reduces the number of new compounds brought to market. Elucidating the mechanism of action is crucial for developing new antimicrobials. This can become expensive as there are no universally applicable pipelines. Phenotypic heterogeneity of microbial populations resulting from antimicrobial treatment can be captured through flow cytometric fingerprinting. Since antimicrobials are classified into limited groups, the mechanism of action of known compounds can be used for predictive modeling. We demonstrate a cost-effective flow cytometry approach for determining the mechanism of action of new compounds. Cultures of and were treated with different antimicrobials and measured by flow cytometry. A Gaussian mixture mask was applied over the data to construct phenotypic fingerprints. Fingerprints were used to assess statistical differences between mechanism of action groups and to train random forest classifiers. Classifiers were then used to predict the mechanism of action of cephalothin. Statistical differences were found among the different mechanisms of action groups. Pairwise comparison showed statistical differences for 35 out of 45 pairs for and for 32 out of 45 pairs for after 3.5 h of treatment. The best-performing random forest classifier yielded a Matthews correlation coefficient of 0.92 and the mechanism of action of cephalothin could be successfully predicted. These findings suggest that flow cytometry can be a cheap and fast alternative for determining the mechanism of action of new antimicrobials.IMPORTANCEIn the context of the emerging threat of antimicrobial resistance, the development of novel antimicrobials is a commonly employed strategy to combat resistance. Elucidating the mechanism of action of novel compounds is crucial in this development but can become expensive, as no universally applicable pipelines currently exist. We present a novel flow cytometry-based approach capable of determining the mechanism of action swiftly and cost-effectively. The workflow aims to accelerate drug discovery and could help facilitate a more targeted approach for antimicrobial treatment of patients.
Topics: Humans; Cephalothin; Flow Cytometry; Cost-Benefit Analysis; Anti-Infective Agents; Drug Development; Anti-Bacterial Agents
PubMed: 38483479
DOI: 10.1128/spectrum.03931-23 -
Journal of Ayurveda and Integrative... 2020Dental caries is a biofilm-related infectious disease with a multifactorial etiology, over five billion inhabitants have affected worldwide due to this disease.
BACKGROUND
Dental caries is a biofilm-related infectious disease with a multifactorial etiology, over five billion inhabitants have affected worldwide due to this disease.
OBJECTIVE
Antimicrobial efficacy of a mixed herbal powder extract (MHPE) against cariogenic microorganisms was investigated.
MATERIALS AND METHODS
MIC, MBC, kinetics of killing, biofilm disruption and anticaries effect of MHPE were determined. For biofilm disruption, biofilms of Streptococcus mutans, Lactobacillus casei, Actinomyces viscosus and Candida albicans were treated with MHPE for 30 min and attached cells were quantified after staining. For live/dead staining biofilm assay, S. mutans biofilm treated with MHPE for 1min, 5min and 1 h was examined with confocal laser scanning system after live/dead staining. Efficacy was experimented by structural quality using Scanning Electron Microscope (SEM). Anticaries effect was determined by formation of caries-like lesion in continuous flow biofilm model.
RESULTS
MHPE exhibited inhibition zones ranging from 12.5 to 24.0 mm. The highest inhibition zone was recorded at concentration of 50 μg/ml. MIC for S. mutans was between 12.23 and 36.7 μg/ml, while the MBC values ranged from 36.7 to 110.65 μg/ml. Inhibitory concentration of MHPE was three fold higher than CHLX. Significant reduction of cell count (49-95%) was observed with increasing time and higher concentration. Percentage biofilm reduction compare with negative control was 96.9% (A. viscosus), 94% (C. albicans), 99.8% (L. casei) and 91.7% (S. mutans). For MHPE-treated biofilm, live/dead staining demonstrated significant (p < 0.05) higher in deceased red fluorescence areas in all kinetics points from 53.6% (1min) to 85% (1h). SEM confirmed the damage in the outer layers of S. mutans. MHPE has components with effective antibacterial activity against caries-inducing microorganisms.
CONCLUSION
The anti-adherence and anti-biofilm effect as well as the faster killing activity suggests that MHPE formula has effective antibacterial activity and could be a useful source of anti-cariogenic agents in near future.
PubMed: 30389224
DOI: 10.1016/j.jaim.2018.01.005 -
Infection and Immunity Oct 2022Root caries in geriatric patients is a growing problem as more people are maintaining their natural teeth into advanced age. We determined the levels of various...
Root caries in geriatric patients is a growing problem as more people are maintaining their natural teeth into advanced age. We determined the levels of various bacterial species previously implicated in root caries disease or health using quantitative real-time PCR in a pilot study of 7 patients with 1 to 4 root caries lesions per person. Levels of 12 different species on diseased roots compared to healthy (contralateral control) roots were measured. Four species were found at significantly higher levels on diseased roots (Streptococcus mutans, Veillonella parvula/dispar, Actinomyces naeslundii/viscosus, and Capnocytophaga granulosa) compared across all plaque samples. The level of colonization by these species varied dramatically (up to 1,000-fold) between patients, indicating different patients have different bacteria contributing to root caries disease. Neither of the two species previously reported to correlate with healthy roots (C. granulosa and Delftia acidovorans) showed statistically significant protective roles in our population, although D. acidovorans showed a trend toward higher levels on healthy teeth (0.08). There was a significant positive correlation between higher levels of S. mutans and V. parvula/dispar on the same diseased teeth. mixed biofilm studies demonstrated that co-culturing S. mutans and V. parvula leads to a 50 to 150% increase in sucrose-dependent biofilm mass compared to S. mutans alone, depending on the growth conditions, while V. parvula alone did not form biofilms. The presence of V. parvula also decreased the acidification of S. mutans biofilms when grown in artificial saliva and enhanced the health of mixed biofilms.
Topics: Humans; Aged; Streptococcus mutans; Root Caries; Saliva, Artificial; Pilot Projects; Veillonella; Biofilms; Sucrose; Dental Caries
PubMed: 36129298
DOI: 10.1128/iai.00355-22 -
Scanning 2021To compare the effects of bleaching associated with Er:YAG and Nd:YAG laser on enamel structure and mixed biofilm formation on teeth surfaces.
OBJECTIVE
To compare the effects of bleaching associated with Er:YAG and Nd:YAG laser on enamel structure and mixed biofilm formation on teeth surfaces.
MATERIALS AND METHODS
Sixty-eight enamel samples were randomly divided into four groups ( = 17), control, Opalescence Boost only, Opalescence Boost plus Er: YAG laser, and Opalescence Boost plus Nd:YAG laser. The structure was observed using SEM after bleaching. Subsequently, the treated enamel samples were also cultured in suspensions of , , , and () for 24 and 48 h. Biofilm formation was quantified by crystal violet staining, and the structure was visualized by confocal laser scanning microscopy. The data were analyzed using the Kruskal-Wallis method.
RESULTS
The enamel structure significantly changed after bleaching. There was no obvious difference in the biofilm formation after 24 h; however, after 48 hours, the amount of biofilm increased significantly. Remarkably, the amount was significantly higher on enamel bleached only, however, there was no significant difference between samples bleached with Er:YAG or Nd:YAG laser compared to the control.
CONCLUSIONS
Bleaching only appeared to markedly promote biofilm formation after 48 h, and the biofilms on samples bleached with Er:YAG or Nd:YAG laser did not change significantly, showing that bleaching with Er:YAG or Nd:YAG laser can be safely applied in clinical practice.
Topics: Biofilms; Dental Enamel; Lasers, Solid-State; Tooth Bleaching; Humans
PubMed: 35003484
DOI: 10.1155/2021/6400605 -
Scientific Reports Apr 2020Bacterial extracellular polymeric substances (EPSs) present diverse properties of biotechnological interest, such as surface modification, metal adsorption and...
Bacterial extracellular polymeric substances (EPSs) present diverse properties of biotechnological interest, such as surface modification, metal adsorption and hydrophobic substances solubilization through surface tension reduction. Thus, there is a growing demand for new producing strains and structurally variable biomolecules with different properties. One approach for scanning this biodiversity consists of exploring environments under selective pressures. The aim of this study was to evaluate the composition of culturable heterotrophic bacterial communities from five different sites from a copper mine in the Amazon biome by an enrichment technique to obtain metal resistant bacteria (lead, arsenic, cadmium, copper and zinc) capable of producing EPSs. The bacterial densities at the sites varied from 2.42 × 10 to 1.34 × 10 NMP mL and the 77 bacterial isolates obtained were classified in four divisions, β-Proteobacteria (16.88%), γ-Proteobacteria (7.29%), Firmicutes (61%) and Actinobacteria (12.98%). Bacillus, Alcaligenes, and Lysinibacillus were the most dominant among the 16 observed genera, but the relative frequency of each varied according to the sample and the metal used in the enrichment culture. 58% of the bacterial strains (45) could produce EPSs. From these, 33 strains showed emulsifying activity (E), and 9 of them reached values higher than 49%. Only Actinomyces viscosus E3.Pb5 and Bacillus subtilis group E3.As2 reduced the medium surface tension to values lower than 35 mN m. It was possible to confirm the high presence of bacteria capable of producing EPSs with tensoactive properties in Amazon copper mines and the evolutionary pressure exerted by the heavy metals during enrichment. These molecules can be tested as an alternative for use in processes that involve the removal of metals, such as the bioremediation of contaminated environments.
Topics: Arsenic; Bacteria; Biodegradation, Environmental; Brazil; Cadmium; Copper; Environmental Pollutants; Environmental Pollution; Extracellular Polymeric Substance Matrix; Heterotrophic Processes; Microbiota; Mining; RNA, Ribosomal, 16S; Soil Microbiology; Zinc
PubMed: 32277075
DOI: 10.1038/s41598-020-62780-8