scholarly journals Effects of Cold-Light Bleaching on Enamel Surface and Adhesion of Streptococcus mutans

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Bo Zhang ◽  
Sibei Huo ◽  
Shiyu Liu ◽  
Ling Zou ◽  
Lei Cheng ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Streptococcus Mutans ◽  
Laser Scanning ◽  
Bacterial Species ◽  
Laser Scanning Microscopy ◽  
Enamel Surface ◽  
Tooth Bleaching ◽  
Confocal Laser ◽  
Tooth Structure ◽  
Force Microscopy

Tooth bleaching is becoming increasingly popular among patients with tooth staining, but the safety of bleaching agents on tooth structure has been questioned. Primarily thriving on the biofilm formation on enamel surface, Streptococcus mutans has been recognized as a major cariogenic bacterial species. The present study is aimed at investigating how cold-light bleaching would change enamel roughness and adhesion of Streptococcus mutans. Human premolars were divided into 72 enamel slices and allocated into 3 groups: (1) control, (2) cold-light bleaching with 35% hydrogen peroxide (Beyond™), and (3) 35% hydrogen peroxide (Beyond™) alone. Biofilms of Streptococcus mutans were cultivated on enamel slices in 5% CO2 ( v / v ) at 37°C for 1 day or 3 days. Enamel surfaces and biofilms were observed using scanning electron microscope (SEM). Atomic force microscopy (AFM) was applied to quantify the roughness of enamel surface, and the amounts of biofilms were measured by optical density of scattered biofilm and confocal laser scanning microscopy (CLSM). Cold-light bleaching significantly increased ( p < 0.05 ) surface roughness of enamel compared to controls, but significantly inhibited ( p < 0.05 ) adhesion of Streptococcus mutans on enamel in the bacterial cultures of both 1 day and 3 days. In conclusion, cold-light bleaching could roughen enamel surface but inhibit Streptococcus mutans adhesion at the preliminary stage after the bleaching treatment.

scholarly journals Genetic and Physiological Effects of Noncoherent Visible Light Combined with Hydrogen Peroxide on Streptococcus mutans in Biofilm

2008 ◽  
Vol 52 (7) ◽  
pp. 2626-2631 ◽  
Author(s):  
Doron Steinberg ◽  
Daniel Moreinos ◽  
John Featherstone ◽  
Moshe Shemesh ◽  
Osnat Feuerstein
Keyword(s):  
Gene Expression ◽  
Hydrogen Peroxide ◽  
Visible Light ◽  
Streptococcus Mutans ◽  
Laser Scanning ◽  
Antibacterial Effect ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Planktonic Bacteria ◽  
Deep Layers

ABSTRACT Oral biofilms are associated with the most common infections of the oral cavity. Bacteria embedded in the biofilms are less sensitive to antibacterial agents than planktonic bacteria are. Recently, an antibacterial synergic effect of noncoherent blue light and hydrogen peroxide (H2O2) on planktonic Streptococcus mutans was demonstrated. In this study, we tested the effect of a combination of light and H2O2 on the vitality and gene expression of S. mutans embedded in biofilm. Biofilms of S. mutans were exposed to visible light (wavelengths, 400 to 500 nm) for 30 or 60 s (equivalent to 34 or 68 J/cm2) in the presence of 3 to 300 mM H2O2. The antibacterial effect was assessed by microbial counts of each treated sample compared with that of the control. The effect of light combined with H2O2 on the different layers of the biofilm was evaluated by confocal laser scanning microscopy. Gene expression was determined by real-time reverse transcription-PCR. Our results show that noncoherent light, in combination with H2O2, has a synergistic antibacterial effect through all of the layers of the biofilm. Furthermore, this treatment was more effective against bacteria in biofilm than against planktonic bacteria. The combined light and H2O2 treatment up-regulated the expression of several genes such as gtfB, brp, smu630, and comDE but did not affect relA and ftf. The ability of noncoherent visible light in combination with H2O2 to affect bacteria in deep layers of the biofilm suggests that this treatment may be applied in biofilm-related diseases as a minimally invasive antibacterial procedure.

scholarly journals Influence of Aging on Corrosion Behaviour of the 6061 Cast Aluminium Alloy

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1821
Author(s):  
Ting He ◽  
Wei Shi ◽  
Song Xiang ◽  
Chaowen Huang ◽  
Ronald G. Ballinger
Keyword(s):  
Aluminium Alloy ◽  
Laser Scanning ◽  
Corrosion Behaviour ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
The Matrix ◽  
6061 Aluminium Alloy

The influence of AlFeSi and Mg2Si phases on corrosion behaviour of the cast 6061 aluminium alloy was investigated. Scanning Kelvin probe force microscopy (SKPFM), electron probe microanalysis (EPMA), and in situ observations by confocal laser scanning microscopy (CLSM) were used. It was found that Mg2Si phases were anodic relative to the matrix and dissolved preferentially without significantly affecting corrosion propagation. The AlFeSi phases’ influence on 6061 aluminium alloy local corrosion was greater than that of the Mg2Si phases. The corroded region width reached five times that of the AlFeSi phase, and the accelerating effect was terminated as the AlFeSi dissolved.

scholarly journals Polymeric Nanoparticles Active against Dual-Species Bacterial Biofilms

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4958
Author(s):  
Jessa Marie V. Makabenta ◽  
Jungmi Park ◽  
Cheng-Hsuan Li ◽  
Aritra Nath Chattopadhyay ◽  
Ahmed Nabawy ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Laser Scanning ◽  
Polymeric Nanoparticles ◽  
Bacterial Species ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Bacterial Biofilms ◽  
Global Public Health ◽  
Bacterial Strains

Biofilm infections are a global public health threat, necessitating new treatment strategies. Biofilm formation also contributes to the development and spread of multidrug-resistant (MDR) bacterial strains. Biofilm-associated chronic infections typically involve colonization by more than one bacterial species. The co-existence of multiple species of bacteria in biofilms exacerbates therapeutic challenges and can render traditional antibiotics ineffective. Polymeric nanoparticles offer alternative antimicrobial approaches to antibiotics, owing to their tunable physico-chemical properties. Here, we report the efficacy of poly(oxanorborneneimide) (PONI)-based antimicrobial polymeric nanoparticles (PNPs) against multi-species bacterial biofilms. PNPs showed good dual-species biofilm penetration profiles as confirmed by confocal laser scanning microscopy. Broad-spectrum antimicrobial activity was observed, with reduction in both bacterial viability and overall biofilm mass. Further, PNPs displayed minimal fibroblast toxicity and high antimicrobial activity in an in vitro co-culture model comprising fibroblast cells and dual-species biofilms of Escherichia coli and Pseudomonas aeruginosa. This study highlights a potential clinical application of the presented polymeric platform.

scholarly journals Intragenic Antimicrobial Peptide Hs02 Hampers the Proliferation of Single- and Dual-Species Biofilms of P. aeruginosa and S. aureus: A Promising Agent for Mitigation of Biofilm-Associated Infections

2019 ◽  
Vol 20 (14) ◽  
pp. 3604 ◽  
Author(s):  
Lucinda J. Bessa ◽  
Julia R. Manickchand ◽  
Peter Eaton ◽  
José Roberto S. A. Leite ◽  
Guilherme D. Brand ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Laser Scanning ◽  
Multidrug Resistant ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Antibiofilm Activity ◽  
Bacterial Cells ◽  
Generalized Polarization ◽  
Force Microscopy ◽  
Atomic Force

Pseudomonas aeruginosa and Staphylococcus aureus are two major pathogens involved in a large variety of infections. Their co-occurrence in the same site of infection has been frequently reported and is linked to enhanced virulence and difficulty of treatment. Herein, the antimicrobial and antibiofilm activities of an intragenic antimicrobial peptide (IAP), named Hs02, which was uncovered from the human unconventional myosin 1H protein, were investigated against several P. aeruginosa and S. aureus strains, including multidrug-resistant (MDR) isolates. The antibiofilm activity was evaluated on single- and dual-species biofilms of P. aeruginosa and S. aureus. Moreover, the effect of peptide Hs02 on the membrane fluidity of the strains was assessed through Laurdan generalized polarization (GP). Minimum inhibitory concentration (MIC) values of peptide Hs02 ranged from 2 to 16 μg/mL against all strains and MDR isolates. Though Hs02 was not able to hamper biofilm formation by some strains at sub-MIC values, it clearly affected 24 h preformed biofilms, especially by reducing the viability of the bacterial cells within the single- and dual-species biofilms, as shown by confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM) images. Laurdan GP values showed that Hs02 induces membrane rigidification in both P. aeruginosa and S. aureus. Peptide Hs02 can potentially be a lead for further improvement as an antibiofilm agent.

Interspecies Interactions in Dual-Species Biofilms Formed by Psychrotrophic Bacteria and the Tolerance of Sessile Communities to Disinfectants

2020 ◽  
Vol 83 (6) ◽  
pp. 951-958 ◽  
Author(s):  
LEI YUAN ◽  
NI WANG ◽  
FAIZAN A. SADIQ ◽  
GUOQING HE
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Hypochlorite ◽  
Peracetic Acid ◽  
Laser Scanning ◽  
Structural Changes ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Interspecies Interactions ◽  
Mixed Species ◽  
Psychrotrophic Bacteria

ABSTRACT Biofilms on the surface of food processing equipment act as potential reservoirs of microbial contamination. Bacterial interactions are believed to play key roles in both biofilm formation and antimicrobial tolerance. In this study, Aeromonas hydrophila, Chryseobacterium oncorhynchi, and Pseudomonas libanensis, which were previously isolated from Chinese raw milk samples, were selected to establish two dual-species biofilm models (P. libanensis plus A. hydrophila and P. libanensis plus C. oncorhynchi) on stainless steel at 7°C. Subsequently, three disinfectants, hydrogen peroxide (100 ppm), peracetic acid (100 ppm), and sodium hypochlorite (100 ppm), were used to treat the developed sessile communities for 10 min. Structural changes after exposure to disinfectants were analyzed with confocal laser scanning microscopy. The cell numbers of both A. hydrophila and C. oncorhynchi recovered from surfaces increased when grown as dual species biofilms with P. libanensis. Dual-species biofilms were more tolerant of disinfectants than were each single-species biofilm. Peracetic acid was the most effective disinfectant for removing biofilms, followed by hydrogen peroxide and sodium hypochlorite. The results expand the knowledge of mixed-species biofilms formed by psychrotrophic bacteria and will be helpful for developing effective strategies to eliminate bacterial mixed-species biofilms. HIGHLIGHTS

scholarly journals Bacterial colonization of enamel in situ investigated using fluorescence in situ hybridization

2009 ◽  
Vol 58 (10) ◽  
pp. 1359-1366 ◽  
Author(s):  
Ali Al-Ahmad ◽  
Marie Follo ◽  
Ann-Carina Selzer ◽  
Elmar Hellwig ◽  
Matthias Hannig ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Bacterial Colonization ◽  
Bacterial Species ◽  
Fusobacterium Nucleatum ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Actinomyces Naeslundii ◽  
Oral Biofilms

Oral biofilms are one of the greatest challenges in dental research. The present study aimed to investigate initial bacterial colonization of enamel surfaces in situ using fluorescence in situ hybridization (FISH) over a 12 h period. For this purpose, bovine enamel slabs were fixed on buccal sites of individual splints worn by six subjects for 2, 6 and 12 h to allow biofilm formation. Specimens were processed for FISH and evaluated with confocal laser-scanning microscopy, using probes for eubacteria, Streptococcus species, Veillonella species, Fusobacterium nucleatum and Actinomyces naeslundii. The number of adherent bacteria increased with time and all tested bacterial species were detected in the biofilm formed in situ. The general percentage composition of the eubacteria did not change over the investigated period, but the number of streptococci, the most frequently detected species, increased significantly with time (2 h: 17.7±13.8 %; 6 h: 20.0±16.6 %; 12 h: 24.7±16.1 %). However, ≤1 % of the surface was covered with bacteria after 12 h of biofilm formation in situ. In conclusion, FISH is an appropriate method for quantifying initial biofilm formation in situ, and the proportion of streptococci increases during the first 12 h of bacterial adherence.

scholarly journals Effects of cigarette smoking on the growth of Streptococcus mutans biofilms: an in vitro study

2021 ◽  
Author(s):  
Ye Han
Keyword(s):  
Treatment Group ◽  
Cigarette Smoking ◽  
Streptococcus Mutans ◽  
Laser Scanning ◽  
Water Soluble ◽  
Laser Scanning Microscopy ◽  
Extracellular Polysaccharides ◽  
Confocal Laser ◽  
Control Group

Abstract This study aimed to investigate the differences in growth and virulence (EPSs and acidogenicity) of Streptococcus mutans biofilms (S. mutans) according to the different times of cigarette smoking (CS) treatment. S. mutans biofilms (74-hour-old) were formed on saliva-coated hydroxyapatite disks. The biofilms were treated with CS at different times per day (one time, three times, and six times/day). The control group did not receive CS treatment. Acidogenicity, dry weight, colony-forming units, water-soluble/insoluble extracellular polysaccharides, and intracellular polysaccharides were analyzed and confocal laser scanning microscopy images were obtained of the 74-h-old biofilms. The 74-h-old biofilms on sHA discs in the 6 times/day CS treatment group showed the lowest biofilm accumulation and extracellular polysaccharide amount compared with the control group and other CS treatment groups. In the CLSM study, the biofilms in the six times/day CS treatment group also showed the lowest bacterial count (live and dead cells) and EPS biovolume. CS has an obvious inhibition on the growth of S. mutans biofilms, the degree of inhibition is proportional to the number of CS treatments.

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