Antifungal and Surface Properties of Chitosan-Salts Modified PMMA Denture Base Material

In vitro antifungal and physicochemical properties of polymerized acrylic resin containing strontium-modified phosphate-based glass

Acrylic resins are widely used as the main components in removable orthodontic appliances. However, poor oral hygiene and maintenance of orthodontic appliances provide a suitable environment for the growth of pathogenic microorganisms. In this study, strontium-modified phosphate-based glass (Sr-PBG) was added to orthodontic acrylic resin at 0% (control), 3.75%, 7.5%, and 15% by weight to evaluate the surface and physicochemical properties of the novel material and its in vitro antifungal effect against Candida albicans (C. albicans). Surface microhardness and contact angle did not vary between the control and 3.75% Sr-PBG groups (p > 0.05), and the flexural strength was lower in the experimental groups than in the control group (p < 0.05), but no difference was found with Sr-PBG content (p > 0.05). All experimental groups showed an antifungal effect at 24 and 48 h compared to that in the control group (p < 0.05). This study demonstrated that 3.75% Sr-PBG exhibits antifungal effects against C. albicans along with suitable physicochemical properties, which may help to minimize the risk of adverse effects associated with harmful microbial living on removable orthodontic appliances and promote the use of various materials.

Structure-properties correlation of acrylic resins modified with silver vanadate and graphene

This study aimed to incorporate β-AgVO3 and rGO into self-curing (SC) and heat-curing (HC) acrylic resins and to evaluate their physicochemical, mechanical, and antimicrobial properties while correlating them with the characterized material structure. Acrylic resin samples were prepared at 0 % (control), 0.5 %, 1 %, and 3 % for both nanoparticles. The microstructural characterization was assessed by scanning electron microscopy (SEM) (n = 1) and energy dispersive X-ray spectroscopy (EDS) (n = 1). The physicochemical and mechanical tests included flexural strength (n = 10), Knoop hardness (n = 10), roughness (n = 10), wettability (n = 10), sorption (n = 10), solubility (n = 10), porosity (n = 10), and color evaluation (n = 10). The microbiological evaluation was performed by counting colony-forming units (CFU/mL) and cell viability (n = 8). The results showed that the β-AgVO3 samples showed lower counts of Candida albicans, Pseudomonas aeruginosa, and Streptococcus mutans due to their promising physicochemical properties. The mechanical properties were maintained with the addition of β-AgVO3. The rGO samples showed higher counts of microorganisms due to the increase in physicochemical properties. It can be concluded that the incorporation of β-AgVO3 into acrylic resins could be an alternative to improve the antimicrobial efficacy and performance of the material.

Applications of selected polysaccharides and proteins in dentistry: A review

In the last ten years, remarkable characteristics and a variety of functionalities have been created in biopolymeric materials for clinical dental applications. This review gives an overview of current knowledge of natural biopolymers (biological macromolecules) in terms of structural, functional, and property interactions. Natural biopolymers such as polysaccharides (chitosan, bacterial cellulose, hyaluronic acid, and alginate) and polypeptides (collagen and silk fibroin) have been discussed for dental uses. These biopolymers exhibit excellent properties alone and when employed with other composite molecules making them ideal for treatment of periodontitis, endodontics, dental pulp regeneration and oral wound healing. These biopolymers together with the composite materials exhibit better biocompatibility, inertness, elasticity and flexibility which makes them a leading candidate to be used for other dental applications like caries management, oral appliances, dentures, dental implants and oral surgeries.

The prescription design and key properties of nasal gel for CNS drug delivery: A review

Central nervous system (CNS) diseases are among the major health problems. However, blood-brain barrier (BBB) makes traditional oral and intravenous delivery of CNS drugs inefficient. The unique direct connection between the nose and the brain makes nasal administration a great potential advantage in CNS drugs delivery. However, nasal mucociliary clearance (NMCC) limits the development of drug delivery systems. Appropriate nasal gel viscosity alleviates NMCC to a certain extent, gels based on gellan gum, chitosan, carbomer, cellulose and poloxamer have been widely reported. However, nasal gel formulation design and key properties for alleviating NMCC have not been clearly discussed. This article summarizes gel formulations of different polymers in existing nasal gel systems, and attempts to provide a basis for researchers to conduct in-depth research on the key characteristics of gel matrix against NMCC.

Impact of chitosan-incorporated toothpaste on roughness, gloss, and antifungal potential of acrylic resin

This study aimed to test the efficacy of different silica-based toothpastes with or without chitosan, as a method of cleaning the acrylic surfaces of denture prostheses. Acrylic resin specimens were prepared to evaluate surface roughness and gloss (n = 10), and Candida albicans adhesion/inhibition (n = 2). Two toothpastes with different degrees of abrasiveness were used: Colgate (CT) and Elmex (EX), with or without 0.5% chitosan (Ch) microparticles (CTCh or EXCh, respectively). The negative control was brushed with distilled water. Brushing was simulated with a machine. Surface roughness and gloss were analyzed before and after brushing. Candida albicans incidence/inhibition was tested qualitatively to determine the acrylic resin antifungal activity. The roughness and gloss data were analyzed with a generalized linear model, and the Kruskal Wallis and Dunn tests, respectively (α = 5%). Brushing with toothpastes increased roughness and reduced gloss, compared with the negative control (p < 0.05). CT showed a more significantly different change in roughness and gloss, in relation to the other groups (p < 0.05). Addition of chitosan to CT reduced its abrasive potential, and yielded results similar to those of EX and EXCh. Specimens brushed with CT showed a higher potential for Candida albicans adherence, despite its higher antifungal action. Addition of chitosan to the toothpaste made both toothpaste and brushing more effective in inhibiting Candida albicans. CT had the potential to increase roughness, reduce gloss, and increase Candida albicans adherence. In contrast, chitosan added to CT showed greater antifungal potential, and a higher synergistic effect than EX.

Action of chitosan-based solutions against a model four-species biofilm formed on cobalt-chromium and acrylic resin surfaces

OBJECTIVE

To evaluate the anti-biofilm action of chitosan, nanoparticulate chitosan, and denture cleanser Nitradine™ against biofilms comprising Candida albicans, Candida glabrata, Staphylococcus aureus, and Streptococcus mutans.

BACKGROUND

Biofilm removal from removable partial dentures (RPD) is important for success in prosthetic rehabilitation.

MATERIALS AND METHODS

The anti-biofilm action of the experimental chitosan-based solutions and Nitradine™ was evaluated on acrylic resin and cobalt-chromium alloy through assessing cell viability, cell metabolism, residual aggregated biofilm, and extracellular polymeric substance and biofilm morphology.

RESULTS

Only chitosan reduced the viability of C. albicans on cobalt-chromium alloy surface, by 98% (a 1.7 log10 reduction in cfu). Chitosan-based solutions neither promoted substantial alteration of the metabolic activity of the four-species biofilm nor reduced the amount of the aggregated biofilm. After immersion in chitosan and nanoparticulate chitosan, viable microorganisms and extracellular polymeric substances distributed over the entire specimens' surfaces were observed. Nitradine™ reduced the viability and metabolic activity of biofilm grown on both surfaces, but it did not remove all aggregated biofilm and extracellular polymeric substances. After immersion in Nitradine™, approximately 35% of the specimens' surfaces remained covered by aggregated biofilm, mainly composed of dead cells.

CONCLUSION

Although chitosan and Nitradine™ promoted changes in the viability of microorganisms, neither solution completely removed the four-species biofilm from the Co-Cr and acrylic resin surfaces. Thus, isolated use of hygiene solutions is not indicated for biofilm control on RPDs; this requires complementary mechanical removal.

Biomaterials with antifungal strategies to fight oral infections

Oral fungal infections pose a threat to human health and increase the economic burden of oral diseases by prolonging and complicating treatment. A cost-effective strategy is to try to prevent these infections from happening in the first place. With this purpose, biomaterials with antifungal properties are a crucial element to overcome fungal infections in the oral cavity. In this review, we go through different kinds of biomaterials and coatings that can be used to functionalize them. We also review their potential as a therapeutic approach in addition to prophylaxis, by going through traditional and alternative antifungal compounds, e.g., essential oils, that could be incorporated in them, to enhance their efficacy against fungal pathogens. We aim to highlight the potential of these technologies and propose questions that need to be addressed in prospective research. Finally, we intend to concatenate the key aspects and technologies on the use of biomaterials in oral health, to create an easy to find summary of the current state-of-the-art for researchers in the field.

Chitosan-Based Composites: Development and Perspective in Food Preservation and Biomedical Applications

Chitin, which may be the second-most common polymer after cellulose, is the raw material of chitosan. Chitosan has been infused with various plant extracts and subsidiary polymers to improve its biological and physiological properties. Chitosan's physicochemical properties are enhanced by blending, making them potential candidates that can be utilized in multifunctional areas, including food processing, nutraceuticals, food quality monitoring, food packaging, and storage. Chitosan-based biomaterials are biocompatible, biodegradable, low toxic, mucoadhesive, and regulate chemical release. Therefore, they are used in the biomedical field. The present manuscript highlights the application of chitosan-based composites in the food and biomedical industries.

Antifungal efficiency and cytocompatibility of polymethyl methacrylate modified with zinc dimethacrylate

Objectives

Considering the high incidence rates of denture stomatitis, research that providing dental biomaterials with antifungal property are essential for clinical dentistry. The objectives of the present study were to investigate the effect of zinc dimethacrylate (ZDMA) modification on the antifungal and cytotoxic properties, as well as the variance in surface characteristics and other physicochemical properties of polymethyl methacrylate (PMMA) denture base resin.

Methods

PMMA with various mass fraction of ZDMA (1 wt%, 2.5 wt% and 5 wt%) were prepared for experimental groups, and unmodified PMMA for the control. Fourier-transform infrared spectroscopy (FTIR) was applied for characterization. Thermogravimetric analysis, atomic force microscopy and water contact angle were performed to investigate the thermal stability and surface characteristics (n=5). Antifungal capacities and cytocompatibility were evaluated with Candida albicans (C. albicans) and human oral fibroblasts (HGFs), respectively. Colony-forming unit counting, crystal violet assay, live/dead biofilm staining and scanning electron microscopy observation were performed to assess antifungal effects, and the detection of intracellular reactive oxygen species production was applied to explore the possible antimicrobial mechanism. Finally, the cytotoxicity of ZDMA modified PMMA resin was evaluated by the 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay and live/dead double staining.

Results

The FTIR analyses confirmed some variation in chemical bonding and physical blend of the composites. Incorporation of ZDMA significantly enhanced the thermal stability and hydrophilicity compared with unmodified PMMA (p < 0.05). The surface roughness increased with the addition of ZDMA while remained below the suggested threshold (≤ 0.2 µm). The antifungal activity significantly improved with ZDMA incorporation, and cytocompatibility assays indicated no obvious cytotoxicity on HGFs.

Conclusions

In the present study, the ZDMA mass fraction up to 5 wt% in PMMA performed better thermal stability, and an increase in surface roughness and hydrophilicity without enhancing microbial adhesion. Moreover, the ZDMA modified PMMA showed effective antifungal activity without inducing any cellular side effects.

Antimicrobial surface processing of polymethyl methacrylate denture base resin using a novel silica-based coating technology

OBJECTIVES

This study investigated the surface characteristics of denture base resin coatings prepared using a novel silica-based film containing hinokitiol and assessed the effect of this coating on Candida albicans adhesion and growth.

METHODS

Silica-based coating solutions (control solution; CS) and CS containing hinokitiol (CS-H) were prepared. C. albicans biofilm formed on denture base specimens coated with each solution and these uncoated specimens (control) were analyzed using colony-forming unit (CFU) assay, fluorescence microscopy, and scanning electron microscopy (SEM). Specimen surfaces were analyzed by measuring the surface roughness and wettability and with Fourier-transform infrared (FT-IR) and proton nuclear magnetic resonance (¹H NMR). Stability of coated specimens was assessed via immersion in water for 1 week for each group (control-1w, CS-1w, and CS-H-1w) followed by CFU assay, measurement of surface roughness and wettability, and FT-IR.

RESULTS

CS-H and CS-H-1w contained significantly lower CFUs than those present in the control and control-1w, which was also confirmed via SEM. Fluorescence microscopy from the CS-H group identified several dead cells. The values of surface roughness from coating groups were significantly less than those from the control and control-1w. The surface wettability from all coating groups exhibited high hydrophobicity. FT-IR analyses demonstrated that specimens were successfully coated, and ¹H NMR analyses showed that hinokitiol was incorporated inside CS-H.

CONCLUSIONS

A silica-based denture coating that incorporates hinokitiol inhibits C. albicans growth on denture.

CLINICAL RELEVANCE

We provide a novel antifungal denture coating which can be helpful for the treatment of denture stomatitis.

Anti-fungal efficacy of Miswak Extract (Salvadora Persica) and commercial cleaner against Candida albicans on heat cured polymethylmethacrylate denture base

AIM

The aim of the study was to compare the antifungal efficacy between commercial cleaner (Corega) and Miswak extract (Salvadora persica) against Candida albicans on heat cured Polymethyl methacrylate (PMMA) acrylic denture base resin.

MATERIALS AND METHODS

Forty-eight samples of heat cured PMMA acrylic denture base resin were fabircated in the study. The sterile acrylic resin specimens were immersed in standardized cell suspension of Candida albicans and incubated for 60 min at 370°C for cell adhesion and 2 h at 370°C for biofilm formation. After 24 h biofilm was evaluated by cell viability (CFUs) on SDA and cell counting of Candida albicans under light microscope at 400× magnification. The fungicidal effect of commercial cleaner and Miswak extract on Candida albicans biofilm was then evaluated by colony-forming units on SDA and cell counting under light microscope at 400× magnification.

RESULTS

Screening test agar disk-diffusion assay showed mean inhibitory zone of 3 mm for commercial cleaner as compared to Miswak extract, which showed mean inhibitory zone of 2 and 1 mm for different concentrations. Broth microdilution method showed 31 mg/ml MIC and 62.5 mg/ml Minimal Fungicidal Concentration (MFC) values for commercial cleaner as compared to Miswak extract that showed 125 mg/ml MIC and 250 mg/ml MFC values against Candida albicans. A significant difference (p < 0.05) was observed between pre and post treatment of both commercial cleaner and Miswak extract, for CFUs and cell count for Candida albicans.

CONCLUSION

Commercial denture cleaner (Corega) showed better antifungal (C albicans) activity than Miswak extract (Salvadora persica) on heat cured PMMA acrylic denture base resin.

Mycosynthesis of Metal-Containing Nanoparticles-Fungal Metal Resistance and Mechanisms of Synthesis

In the 21st century, nanomaterials play an increasingly important role in our lives with applications in many sectors, including agriculture, biomedicine, and biosensors. Over the last two decades, extensive research has been conducted to find ways to synthesise nanoparticles (NPs) via mediation with fungi or fungal extracts. Mycosynthesis can potentially be an energy-efficient, highly adjustable, environmentally benign alternative to conventional physico-chemical procedures. This review investigates the role of metal toxicity in fungi on cell growth and biochemical levels, and how their strategies of resistance, i.e., metal chelation, biomineral formation, biosorption, bioaccumulation, compartmentalisation, and efflux of metals from cells, contribute to the synthesis of metal-containing NPs used in different applications, e.g., biomedical, antimicrobial, catalytic, biosensing, and precision agriculture. The role of different synthesis conditions, including that of fungal biomolecules serving as nucleation centres or templates for NP synthesis, reducing agents, or capping agents in the synthesis process, is also discussed. The authors believe that future studies need to focus on the mechanism of NP synthesis, as well as on the influence of such conditions as pH, temperature, biomass, the concentration of the precursors, and volume of the fungal extracts on the efficiency of the mycosynthesis of NPs.

Recent advances of chitosan-based polymers in biomedical applications and environmental protection

Interest in polymer-based biomaterials such as chitosan and its modifications and also the methods of their application in various fields of science is uninterruptedly growing. Owing to unique physicochemical, biological, ecological, physiological properties, such as biocompatibility, biodegradability, stability in the natural environment, non-toxicity, high biological activity, economic affordability, chelating of metal ions, high sorption properties, chitosan is used in various biomedical and industrial processes. The reactivity of the amino and hydroxyl groups in the structure makes it more interesting for diverse applications in drug delivery, tissue engineering, wound healing, regenerative medicine, blood anticoagulation and bone, tendon or blood vessel engineering, dentistry, biotechnology, biosensing, cosmetics, water treatment, agriculture. Taking into account the current situation in the world with COVID-19 and other viruses, chitosan is also active in the form of a vaccine system, it can deliver antibodies to the nasal mucosa and load gene drugs that prevent or disrupt the replication of viral DNA/RNA, and deliver them to infected cells. The presented article is an overview of the nowaday state of the application of chitosan, based on literature of recent years, showing importance of fundamental and applied studies aimed to expand application of chitosan-based polymers in many fields of science.

Denture Acrylic Resin Material with Antibacterial and Protein-Repelling Properties for the Prevention of Denture Stomatitis

Denture stomatitis is a multifactorial pathological condition of the oral mucosa that affects up to 72% of denture wearers. It is commonly seen on the palatal mucosa and characterized by erythema on the oral mucosa that are in contact with the denture surface. The aim of this study was to incorporate 2-methacryloyloxyethyl phosphorylcholine (MPC) and dimethylaminohexadecyl methacrylate (DMAHDM) into a high impact polymethylmethacrylate heat-cured denture base acrylic resin as a potential treatment for denture stomatitis. We used a comparative study design to examine the effect of incorporating MPC as a protein repellent agent and DMAHDM as an antifungal agent to prevent the adherence of Candida albicans to the denture base material. The dual incorporation of MPC and DMAHDM reduced C. albicans biofilm colony-forming unit by two orders of magnitude when compared to the control group devoid of the bioactive agents. Although the addition of MPC and DMAHDM alone or in combination significantly reduced the flexural strength of the material, they showed reduced roughness values when compared to control groups. This new denture acrylic resin provides the benefit of enhancing C. albicans biofilm elimination through dual mechanisms of action, which could potentially reduce the prevalence of denture stomatitis.

Natural Polymers for the Maintenance of Oral Health: Review of Recent Advances and Perspectives

The success of modern dental treatment is strongly dependent on the materials used both temporarily and permanently. Among all dental materials, polymers are a very important class with a wide spectrum of applications. This review aims to provide a state-of-the-art overview of the recent advances in the field of natural polymers used to maintain or restore oral health. It focuses on the properties of the most common proteins and polysaccharides of natural origin in terms of meeting the specific biological requirements in the increasingly demanding field of modern dentistry. The use of naturally derived polymers in different dental specialties for preventive and therapeutic purposes has been discussed. The major fields of application cover caries and the management of periodontal diseases, the fabrication of membranes and scaffolds for the regeneration of dental structures, the manufacturing of oral appliances and dentures as well as providing systems for oral drug delivery. This paper also includes a comparative characteristic of natural and synthetic dental polymers. Finally, the current review highlights new perspectives, possible future advancements, as well as challenges that may be encountered by researchers in the field of dental applications of polymers of natural origin.

Formulation and Antibacterial Activity Evaluation of Quaternized Aminochitosan Membrane for Wound Dressing Applications

Much attention has been paid to chitosan biopolymer for advanced wound dressing owing to its exceptional biological characteristics comprising biodegradability, biocompatibility and respectable antibacterial activity. This study intended to develop a new antibacterial membrane based on quaternized aminochitosan (QAMCS) derivative. Herein, aminochitosan (AMCS) derivative was quaternized by N-(2-Chloroethyl) dimethylamine hydrochloride with different ratios. The pre-fabricated membranes were characterized by several analysis tools. The results indicate that maximum surface potential of +42.2 mV was attained by QAMCS3 membrane compared with +33.6 mV for native AMCS membrane. Moreover, membranes displayed higher surface roughness (1.27 ± 0.24 μm) and higher water uptake value (237 ± 8%) for QAMCS3 compared with 0.81 ± 0.08 μm and 165 ± 6% for neat AMCS membranes. Furthermore, the antibacterial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus cereus. Superior antibacterial activities with maximum inhibition values of 80–98% were accomplished by QAMCS3 membranes compared with 57–72% for AMCS membrane. Minimum inhibition concentration (MIC) results denote that the antibacterial activities were significantly boosted with increasing of polymeric sample concentration from 25 to 250 µg/mL. Additionally, all membranes unveiled better biocompatibility and respectable biodegradability, suggesting their possible application for advanced wound dressing.

An Approach to the Use of Glycol Alkoxysilane-Polysaccharide Hybrids in the Conservation of Historical Building Stones

Stone consolidants have been widely used to protect historical monuments. Consolidants and hydrophobic formulations based on the use of tetraethoxysilane (TEOS) and alkylalkoxysilanes as precursors have been widely applied, despite their lack of solubility in water and requirement to be applied in organic media. In the search for a “greener” alternative based on silicon that has potential use in this field, the use of tetrakis(2-hydroxyethyl)silane (THEOS) and tris(2-hydroxyethyl)methyl silane (MeTHEOS) as precursors, due their high water solubility and stability, is proposed in this paper. It is already known that THEOS and MeTHEOS possess remarkable compatibility with different natural polysaccharides. The investigated approach uses the water-soluble silanes THEOS–chitosan and MeTHEOS–chitosan as a basis for obtaining hybrid consolidants and hydrophobic formulations for the conservation of siliceous and calcareous stones. In the case of calcareous systems, their incompatibility with alkoxysilanes is known and is expected to be solved by the developed hybrid consolidant. Their application in the conservation of building stones from historical and archeological sites from Guanajuato, México was studied. The evaluation of the consolidant and hydrophobic formulation treatment was mainly conducted by determining the mechanical properties and contact angle measurements with satisfactory results in terms of the performance and compatibility with the studied stones.