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Korean Journal of Orthodontics Jun 2024The clinical application of aligners is accompanied by the ageing of the polymer appliances and the attachments used, which may result in inefficiency in reaching the... (Review)
Review
The clinical application of aligners is accompanied by the ageing of the polymer appliances and the attachments used, which may result in inefficiency in reaching the predicted range of tooth movement, and release of compounds and microplastics in the oral cavity as a result of the friction, wear and attrition of the aligner and composite attachment. The purpose of this review is to present the mechanism and effects of ageing; describe the hydrolytic degradation of aligners and enzymatic degradation of composite attachments; examine the ageing pattern of aligners , under actual clinical scenarios; and identify a link to the discrepancy between predicted and actual clinical outcome. Lastly, strategies to deal with three potentially critical issues associated with the use of aligners, namely the necessity of weekly renewal, the dissimilar mechanical properties of aligner and attachment resulting in wear and plastic deformation of the aligner, and the development of integuments and biofilms with microbial colonization of the appliance, are discussed.
PubMed: 38926752
DOI: 10.4041/kjod24.085 -
European Respiratory Review : An... Apr 2024Lower respiratory tract infections (LRTIs) present a significant global health burden, exacerbated by the rise in antimicrobial resistance (AMR). The persistence and... (Review)
Review
Lower respiratory tract infections (LRTIs) present a significant global health burden, exacerbated by the rise in antimicrobial resistance (AMR). The persistence and evolution of multidrug-resistant bacteria intensifies the urgency for alternative treatments. This review explores bacteriophage (phage) therapy as an innovative solution to combat bacterial LRTIs. Phages, abundant in nature, demonstrate specificity towards bacteria, minimal eukaryotic toxicity, and the ability to penetrate and disrupt bacterial biofilms, offering a targeted approach to infection control. The article synthesises evidence from systematic literature reviews spanning 2000-2023, and studies, case reports and ongoing clinical trials. It highlights the synergistic potential of phage therapy with antibiotics, the immunophage synergy in animal models, and the pharmacodynamics and pharmacokinetics critical for clinical application. Despite promising results, the article acknowledges that phage therapy is at a nascent stage in clinical settings, the challenges of phage-resistant bacteria, and the lack of comprehensive cost-effectiveness studies. It stresses the need for further research to optimise phage therapy protocols and navigate the complexities of phage-host interactions, particularly in vulnerable populations such as the elderly and immunocompromised. We call for regulatory adjustments to facilitate the exploration of the long-term effects of phage therapy, aiming to incorporate this old-yet-new therapy into mainstream clinical practice to tackle the looming AMR crisis.
Topics: Humans; Phage Therapy; Respiratory Tract Infections; Animals; Anti-Bacterial Agents; Bacteriophages; Treatment Outcome; Bacterial Infections; Bacteria; Host-Pathogen Interactions
PubMed: 38925791
DOI: 10.1183/16000617.0029-2024 -
Ultrasonics Sonochemistry Jun 2024In recent years, researchers have increasingly focused on the development of multiphase trimetallic nanocomposites (TMNC) incorporating ternary metals or metal oxides,...
In recent years, researchers have increasingly focused on the development of multiphase trimetallic nanocomposites (TMNC) incorporating ternary metals or metal oxides, which hold significant potential as alternatives for combatting biofilms and bacterial infections. Enhanced oral health is ensured by the innovative techniques used to effectively prevent bacterial adherence and formation of biofilm on dental sutures. In this investigation, TMNC, which consists of Pb, Ag, and Cu, was synthesized using an autoclave-assisted sonochemical technique. Following synthesis, TMNC were characterized using FTIR, XRD, BET, XPS, TGA, and Raman spectroscopy to analyze their shape and microstructure. Subsequent evaluations, including MTT assay, antibacterial activity testing, and biofilm formation analysis, were conducted to assess the efficiency of the synthesized TMNC. Cytotoxicity and anti-human oral squamous cell carcinoma activities of TMNC were evaluated using the Human Oral Cancer cell line (KB) cell line through MTT assay, demonstrating a dose-dependent increase in anti-human oral squamous cell carcinoma activity against the KB cell line compared to the normal cell line, resulting in notably high cell viability. Furthermore, an ultrasonic probe was employed to incorporate TMNC onto dental suturing threads, with different concentrations of TMNC, ultrasonic power levels, and durations considered to determine optimal embedding conditions that result in the highest antibacterial activity. The inhibitory effects of TMNC, both in well diffusion assays and when incorporated into dental suturing threads, against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria on Mueller-Hinton agar (MHA) were assessed using various concentrations of TMNC. The results of the study indicated that the efficacy of TMNC in inhibiting bacterial growth on dental suturing threads remained impressive, even at low concentrations. Moreover, an evaluation of their potential to destabilize biofilms formed by S. aureus and E. coli, the two pathogens in humans, indicated that TMNC would be a promising anti-biofilm agent.
PubMed: 38924854
DOI: 10.1016/j.ultsonch.2024.106966 -
Environmental Microbiology Reports Jun 2024Microorganisms, including potential pathogens, can colonise plastic surfaces in aquatic environments. This study investigates the colonisation of plastic pellets by...
Microorganisms, including potential pathogens, can colonise plastic surfaces in aquatic environments. This study investigates the colonisation of plastic pellets by Escherichia coli (E. coli) as a proxy for faecal pathogens in aquatic environments. Plastic pellets from a polluted beach were placed in seawater aquaria spiked with E. coli. Diverse bacteria, primarily from the Proteobacteria phylum, rapidly colonised the pellets within 24 h, with notable species known for plastic or hydrocarbon degradation. Over 26 days, biofilms formed on the plastic surfaces, reaching bacterial populations of up to 6.8·10 gene copies (gc) of the 16S rRNA mm. E. coli, was detected in the pellets for up to 7 days using culture methods, exhibiting varying attachment densities regardless of source or environmental factors. The study highlights plastic biofilms as reservoirs for E. coli, contributing to the survival and persistence of faecal bacteria in aquatic systems. These findings deepen our understanding of the risks associated with plastic pollution in marine settings, offering insights into the behaviour of faecal indicators and their implications for water quality assessments, while providing valuable information on potential pathogen dissemination within plastic-associated microbial communities.
Topics: Biofilms; Escherichia coli; Plastics; Seawater; RNA, Ribosomal, 16S; Water Microbiology
PubMed: 38924372
DOI: 10.1111/1758-2229.13308 -
Environmental Microbiology Reports Jun 2024The global landscape of Candida infections has seen a significant shift. Previously, Candida albicans was the predominant species. However, there has been an emergence... (Comparative Study)
Comparative Study
The global landscape of Candida infections has seen a significant shift. Previously, Candida albicans was the predominant species. However, there has been an emergence of non-albicans Candida species, which are often less susceptible to antifungal treatment. Candida kefyr, in particular, has been increasingly associated with infections. This study aimed to investigate the profiles of enzymatic activity and biofilm formation in both clinical and non-clinical isolates of C. kefyr. A total of 66 C. kefyr isolates were analysed. The activities of proteinase and phospholipase were assessed using bovine serum albumin and egg yolk agar, respectively. Haemolysin, caseinolytic and esterase activities were evaluated using specific methods. Biofilm formation was investigated using crystal violet staining. The findings indicated that biofilm and proteinase activity were detected in 81.8% and 93.9% of all the isolates, respectively. Haemolysin activity was observed with the highest occurrence (95.5%) among normal microbiota isolates. Esterase activity was predominantly identified in dairy samples and was absent in hospital samples. Caseinase production was found with the highest occurrence (18.2%) in normal microbiota and hospital samples. Phospholipase activity was limited, found in only 3% of all the isolates. These findings reveal variations in enzyme activity between clinical and non-clinical C. kefyr isolates. This sheds light on their pathogenic potential and has implications for therapeutic strategies.
Topics: Biofilms; Candida; Humans; Candidiasis; Phospholipases; Esterases; Hemolysin Proteins; Peptide Hydrolases; Environmental Microbiology
PubMed: 38923398
DOI: 10.1111/1758-2229.13282 -
Journal of Applied Oral Science :... 2024To evaluate the protective effect of an experimental solution containing TiF4/NaF on the development of radiation-induced dentin caries lesions.
OBJECTIVE
To evaluate the protective effect of an experimental solution containing TiF4/NaF on the development of radiation-induced dentin caries lesions.
METHODOLOGY
bovine root samples were irradiated (70Gy) and distributed as following (n=12/group): Commercial Saliva (BioXtra), NaF (500 ppm F-), TiF4 (500 ppm F), TiF4/NaF (TiF4: 300 ppm F-, NaF: 190 ppm F-), and Phosphate buffer solution (PBS, negative control). Biofilm was produced using biofilm from irradiated patients and McBain saliva (0.2% of sucrose, at 37oC and 5% CO2) for five days. The treatments were applied 1x/day. Colony-forming units (CFU) were counted and demineralization was quantified by transversal microradiography. The ANOVA/Tukey test was applied for all parameters.
RESULTS
All treatments reduced CFU for total microorganisms. TiF4 reduced Lactobacillus sp. (7.04±0.26 log10 CFU/mL) and mutans streptococci (7.18±0.28) CFU the most, when compared to PBS (7.58±0.21 and 7.75±0.17) and followed by NaF (7.12±0.31 and 7.34±0.22) and TiF4/NaF (7.16±0.35 and 7.29± 0.29). TiF4 and Commercial saliva showed the lowest integrated mineral loss (ΔZ-vol%.mm) (1977±150 and 2062±243, respectively) when compared to PBS (4540±335), followed by NaF (2403±235) and TiF4/NaF (2340±200). Commercial saliva was the only to significantly reduce mineral loss (LD-µm) (111±25) compared to PBS (153±24).Mean mineral loss (R-vol%) decreased by 35.2% for TiF4 (18.2±3.3) when compared to PBS (28.1±2.9) Conclusion: TiF4/NaF has a comparable anti-cariogenic effect to TiF4 and Commercial saliva under the model in this study.
Topics: Sodium Fluoride; Cattle; Animals; Dentin; Dental Caries; Biofilms; Fluorides; Saliva; Streptococcus mutans; Time Factors; Analysis of Variance; Microradiography; Cariostatic Agents; Reproducibility of Results; Lactobacillus; Colony Count, Microbial; Tooth Demineralization; Humans; Materials Testing; Reference Values; Treatment Outcome; Statistics, Nonparametric; Titanium
PubMed: 38922242
DOI: 10.1590/1678-7757-2024-0024 -
Journal of Applied Oral Science :... 2024This study compared three protocols for developing artificial white spot lesions (WSL) using biofilm models. (Comparative Study)
Comparative Study
OBJECTIVE
This study compared three protocols for developing artificial white spot lesions (WSL) using biofilm models.
METHODOLOGY
In total, 45 human enamel specimens were sterilized and allocated into three groups based on the biofilm model: Streptococcus sobrinus and Lactobacillus casei (Ss+Lc), Streptococcus sobrinus (Ss), or Streptococcus mutans (Sm). Specimens were incubated in filter-sterilized human saliva to form the acquired pellicle and then subjected to the biofilm challenge consisting of three days of incubation with bacteria (for demineralization) and one day of remineralization, which was performed once for Ss+Lc (four days total), four times for Ss (16 days total), and three times for Sm (12 days total). After WSL creation, the lesion fluorescence, depth, and chemical composition were assessed using Quantitative Light-induced Fluorescence (QLF), Polarized Light Microscopy (PLM), and Raman Spectroscopy, respectively. Statistical analysis consisted of two-way ANOVA followed by Tukey's post hoc test (α=0.05). WSL created using the Ss+Lc protocol presented statistically significant higher fluorescence loss (ΔF) and integrated fluorescence (ΔQ) in comparison to the other two protocols (p<0.001).
RESULTS
In addition, Ss+Lc resulted in significantly deeper WSL (137.5 µm), followed by Ss (84.1 µm) and Sm (54.9 µm) (p<0.001). While high mineral content was observed in sound enamel surrounding the WSL, lesions created with the Ss+Lc protocol showed the highest demineralization level and changes in the mineral content among the three protocols.
CONCLUSION
The biofilm model using S. sobrinus and L. casei for four days was the most appropriate and simplified protocol for developing artificial active WSL with lower fluorescence, higher demineralization, and greater depth.
Topics: Biofilms; Humans; Streptococcus mutans; Dental Caries; Dental Enamel; Lacticaseibacillus casei; Time Factors; Reproducibility of Results; Streptococcus sobrinus; Spectrum Analysis, Raman; Analysis of Variance; Microscopy, Polarization; Statistics, Nonparametric; Tooth Remineralization; Reference Values; Saliva; Tooth Demineralization; Fluorescence
PubMed: 38922241
DOI: 10.1590/1678-7757-2023-0458 -
Journal of Functional Biomaterials Jun 2024Root caries caused by cariogenic bacteria are a burden on a large number of individuals worldwide, especially the elderly. Applying a protective coating to exposed root...
Root caries caused by cariogenic bacteria are a burden on a large number of individuals worldwide, especially the elderly. Applying a protective coating to exposed root surfaces has the potential to inhibit the development of caries, thus preserving natural teeth. This study aimed to develop a novel antibacterial coating to combat root caries and evaluate its effectiveness using the antibacterial monomer dimethylaminohexadecyl methacrylate (DMAHDM). DMAHDM was synthesized and incorporated into a resin consisting of 55.8% urethane dimethacrylate (UDMA) and 44.2% TEG-DVBE (UV) at a 10% mass fraction of glass filler. Multiple concentrations of DMAHDM were tested for their impact on the resin's mechanical and physical properties. biofilms grown on resin disks were analyzed for antibacterial efficacy. Cytotoxicity was assessed against human gingival fibroblasts (HGFs). The results showed an 8-log reduction in colony-forming units (CFUs) against biofilm (mean ± sd; n = 6) ( < 0.05) when 5% DMAHDM was incorporated into the UV resin. There was a 90% reduction in metabolic activity and lactic acid production. A low level of cytotoxicity against HGF was observed without compromising the physical and mechanical properties of the resin. This coating material demonstrated promising physical properties, potent antibacterial effects, and low toxicity, suggesting its potential to protect exposed roots from caries in various dental procedures and among elderly individuals with gingival recession.
PubMed: 38921541
DOI: 10.3390/jfb15060168 -
Biosensors Jun 2024Microbial biofilms present one of the most widespread forms of life on Earth. The formation of microbial communities on various surfaces presents a major challenge in a... (Review)
Review
Microbial biofilms present one of the most widespread forms of life on Earth. The formation of microbial communities on various surfaces presents a major challenge in a variety of fields, including medicine, the food industry, shipping, etc. At the same time, this process can also be used for the benefit of humans-in bioremediation, wastewater treatment, and various biotechnological processes. The main direction of using electroactive microbial biofilms is their incorporation into the composition of biosensor and biofuel cells This review examines the fundamental knowledge acquired about the structure and formation of biofilms, the properties they have when used in bioelectrochemical devices, and the characteristics of the formation of these structures on different surfaces. Special attention is given to the potential of applying the latest advances in genetic engineering in order to improve the performance of microbial biofilm-based devices and to regulate the processes that take place within them. Finally, we highlight possible ways of dealing with the drawbacks of using biofilms in the creation of highly efficient biosensors and biofuel cells.
Topics: Biofilms; Biosensing Techniques; Bioelectric Energy Sources
PubMed: 38920606
DOI: 10.3390/bios14060302 -
International Journal of Nanomedicine 2024This research was to innovate a nanozyme-based therapeutic strategy that combines aggregation-induced emission (AIE) photosensitizers with copper nanozymes. This...
PURPOSE
This research was to innovate a nanozyme-based therapeutic strategy that combines aggregation-induced emission (AIE) photosensitizers with copper nanozymes. This approach is designed to address the hypoxic conditions often found in bacterial infections and aims to boost the effectiveness of photodynamic therapy (PDT) by ensuring sufficient oxygen supply for reactive oxygen species (ROS) generation.
METHODS
Our approach involved the synthesis of dihydroxyl triphenyl vinyl pyridine (DHTPY)-Cu@zoledronic acid (ZOL) nanozyme particles. We initially synthesized DHTPY and then combined it with copper nanozymes to form the DHTPY-Cu@ZOL composite. The nanozyme's size, morphology, and chemical properties were characterized using various techniques, including dynamic light scattering, transmission electron microscopy, and X-ray photoelectron spectroscopy. We conducted a series of in vitro and in vivo tests to evaluate the photodynamic, antibacterial, and wound-healing properties of the DHTPY-Cu@ZOL nanozymes, including their oxygen-generation capacity, ROS production, and antibacterial efficacy against methicillin-resistant Staphylococcus aureus (MRSA).
RESULTS
The DHTPY-Cu@ZOL exhibited proficient HO scavenging and oxygen generation, crucial for enhancing PDT in oxygen-deprived infection environments. Our in vitro analysis revealed a notable antibacterial effect against MRSA, suggesting the nanozymes' potential to disrupt bacterial cell membranes. Further, in vivo studies using a diabetic rat model with MRSA-infected wounds showed that DHTPY-Cu@ZOL markedly improved wound healing and reduced bacterial presence, underscoring its efficacy as a non-antibiotic approach for chronic infections.
CONCLUSION
Our study suggests that DHTPY-Cu@ZOL is a highly promising approach for combating antibiotic-resistant microbial pathogens and biofilms. The biocompatibility and stability of these nanozyme particles, coupled with their improved PDT efficacy position them as a promising candidate for clinical applications.
Topics: Photochemotherapy; Animals; Methicillin-Resistant Staphylococcus aureus; Copper; Anti-Bacterial Agents; Photosensitizing Agents; Wound Infection; Staphylococcal Infections; Reactive Oxygen Species; Imidazoles; Pyridines; Rats; Wound Healing; Male; Humans; Rats, Sprague-Dawley
PubMed: 38919773
DOI: 10.2147/IJN.S458520