New adhesive system based in metals cross-linking methacrylate

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.

Aspects and Principles of Material Connections in Restorative Dentistry-A Comprehensive Review

The combination of two dissimilar materials has always been a serious problem in dentistry. In order to meet this challenge, it is necessary to combine both chemical methods (treatment with silanes, (meth)acrylic functional monomers) and the development of the surface of the joined material in a physical way, e.g., by sandblasting with alumina, alumina with silica, acid etching, the use of lasers and other means. The purpose of this literature review is to present all methods of joining dental composites with other materials such as ceramics, metal, another composite material. This review covers articles published within the period 2012-2022 in journals indexed in the PubMed database, written in English and describing joining different dental materials to each other. All the critical steps of new joint preparation have been addressed, including proper cleaning of the joint surface, the application of appropriate primers capable of forming a chemical bond between ceramics, zirconium oxide or metals and alloys, and finally, the application of new composite materials.

Novel polymethyl methacrylate modified with metal methacrylate monomers: biological, physicomechanical, and optical properties

This study sought to evaluate the physical and antimicrobial properties of a thermopolymerizable acrylic resin (PMMA) modified with metallic methacrylate monomers -zirconia (ZM), tin (TM), and di-n-butyl (DNTMB) methacrylates. Color stability was evaluated before and after immersion of samples in a staining solution by a digital spectrophotometer. The mechanical brushing test was evaluated by the roughness test. The flexural strength test used a mechanical testing machine. Human keratinocytes were used to assess cell viability and the biofilm formation assay was carried out for 5 days, in a microcosms model after one year of specimen storage. For statistical analysis, the method chosen was based on adherence to the normal distribution model and equality of variances (p < 0.05). The addition of DNTMB to PMMA promoted great antimicrobial action, acceptable cytocompatibility, without hampering the physical-mechanical properties of the commercial material. Therefore, the modified PMMA proved to be a promisor alternative to conventional resins.This study sought to evaluate the physical and antimicrobial properties of a thermopolymerizable acrylic resin (PMMA) modified with metallic methacrylate monomers -zirconia (ZM), tin (TM), and di-n-butyldimethacrylate-tin (DNTMB) methacrylates. Color stability was evaluated before and after immersion of samples in a staining solution using a digital spectrophotometer. The mechanical brushing test was evaluated by the roughness test. The flexural strength test used a mechanical testing machine. Human keratinocytes were used to assess cell viability and the biofilm formation assay was carried out for 5 days in a microcosm model after one year of specimen storage. For statistical analysis, the method chosen was based on adherence to the normal distribution model and equality of variances (p < 0.05). The addition of DNTMB to PMMA promoted great antimicrobial action, acceptable cytocompatibility, without hampering the physical-mechanical properties of the commercial material. Therefore, the modified PMMA proved to be a promising alternative to conventional denture base resins for dental use.

Exploring the use of a Ruthenium complex incorporated into a methacrylate-based dental material for antimicrobial photodynamic therapy

OBJECTIVES

To evaluate the effects of a blue light photosensitizer (PS), Ruthenium II complex (Ru), on the chemical, physical, mechanical, and antimicrobial properties of experimental dental resin blends.

METHODS

The experimental resin (BisEMA, TEEGDMA, HPMA, ethanol, and photoinitiator) was loaded with Ru at 0.00%, 0.07%, 0.14%, 0.28%, 0.56%, 1.12%, 1.2%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% w/w. Samples were evaluated for the degree of conversion (DC) after 30 and 60 s curing-time (n = 6). Selected formulations (0.00%, 0.28%, 0.56%, 1.12%) were further tested for shear bond strength (SBS) (n = 15); flexural strength (FS) (n = 12); and antimicrobial properties (CFUs), in dark and light conditions. These latter tests were performed on specimens stored for 24-h or 2-month in 37°C water. Water sorption (WS) and solubility (SL) tests were also performed (n = 12). Data were analyzed either by a one- or two-factor general linear model (α = 0.05).

RESULTS

Overall, Ru concentration above 1.2% resulted in reduced DC. In SBS results, only the 1.12%Ru resin blend samples had statistically lower values compared to the 0.00%Ru resin blend at 24-h storage (p = 0.004). In addition, no differences in SBS were detected among the experimental groups after 2-month storage in water. Meanwhile, FS increased for all experimental groups under similar aging conditions (p < 0.001). Antimicrobial properties were improved upon inclusion of Ru and application of light (p < 0.001 for both) at 24-h and 2-month storage. Lastly, no detectable changes in WS or SL were observed for the Ru-added resins compared to the 0.00%Ru resin blend. However, the 0.28% Ru blend presented significantly higher WS compared to the 0.56% Ru blend (p = 0.007).

CONCLUSIONS

Stable SBS, improved FS, and sustained antimicrobial properties after aging gives significant credence to our approach of adding the Ruthenium II complex into dental adhesive resin blends intended for an aPDT approach.

Physicomechanical, optical, and antifungal properties of polymethyl methacrylate modified with metal methacrylate monomers

STATEMENT OF PROBLEM

The high recurrence rates of denture stomatitis may be associated with the resistance of biofilms to therapeutics. Therefore, methods that provide biomaterials with antifungal properties are an attractive solution to improving microbial control.

PURPOSE

The purpose of this in vitro study was to modify conventional polymethyl methacrylate (PMMA) through the incorporation of metal methacrylate monomers and to evaluate the physicomechanical and optical properties and antifungal activity of the modified materials.

MATERIAL AND METHODS

Experimental denture base acrylic resins were fabricated through the addition of zirconium methacrylate (ZM), tin methacrylate (TM), and di-n-butyldimethacrylate-tin (DNBMT) to the liquid of a commercially available denture base PMMA resin. Unmodified PMMA resin was used as the control. The degree of conversion of the materials was tested through Fourier transform infrared spectroscopy (n=3). A digital spectrophotometer was used to assess the color change of the modified materials (n=8). Differences in Knoop hardness and roughness between experimental groups were also evaluated (n=8). A biofilm accumulation test with Candida albicans (ATCC 62342) (n=4) was performed for 5 days in Sabouraud broth culture supplemented with 10% sucrose. Data were subjected to analysis of variance and the post hoc Tukey honestly significant difference test (α=.05).

RESULTS

The degree of conversion and color-change values of the experimental materials were statistically similar to those of the control (P=.593). The incorporation of DNBMT significantly increased the hardness of the modified material (P=.014). The ZM, TM, and DNBMT groups had higher antifungal activity against C. albicans (P=.001) and lower roughness than the control group (control 0.65 ±0.05 μm; ZM 0.34 ±0.09 μm, TM 0.34 ±0.11 μm, and DNBMT 0.41 ±0.08 μm).

CONCLUSIONS

The metal-containing methacrylate monomers provided antifungal action to the modified materials without affecting the physicomechanical or optical properties of the denture base resin. ZM, TM, and DNBMT are potential reactive agents for the fabrication of PMMA denture base resins with antifungal properties.

Bibliometric Analysis of Literature Published on Antibacterial Dental Adhesive from 1996-2020

This study aimed to investigate the current state of research on antibacterial dental adhesives. The interest in this field can be drawn from an increasing number of scholarly works in this area. However, there is still a lack of quantitative measurement of this topic. The main aim of this study was to consolidate the research published on the antibacterial adhesive from 1996 to 2020 in Web of Science indexed journals. The bibliometric method, a quantitative study of investigating publishing trends and patterns, was used for this study. The result has shown that a gradual increase in research was found, whereby a substantial increase was observed from 2013. A total of 248 documents were published in 84 journals with total citations of 5107. The highly cited articles were published mainly in Q1 category journals. Most of the published articles were from the USA, China, and other developed countries; however, some developing countries contributed as well. The authorship pattern showed an interdisciplinary and collaborative approach among researchers. The thematic evaluation of keywords along with a three-factor analysis showed that 'antibacterial adhesives' and 'quaternary ammonium' have been used commonly. This bibliometric analysis can provide direction not only to researchers but also to funding organizations and policymakers.

Physico-chemical and antimicrobial properties and the shelf life of experimental endodontic sealers containing metal methacrylates

The objective of this study was to evaluate the physico-chemical and antimicrobial properties of a dual polymerization experimental endodontic sealer (E) and experimental sealers containing dibutyltin methacrylate (Sn²⁺) (ETs) or calcium methacrylate (Ca²⁺) (ECs). The pH and ion release levels of the sealers were measured. The dimensional stability was evaluated in accordance with ISO 6876. Biofilm growth inhibition was evaluated using confocal laser scanning microscopy (CLSM). Biofilm viability analysis was performed using the SYTO 9 technique. The shelf life was evaluated through the degree of conversion and film thickness tests after the sealers had been stored for different periods of time. For statistical analysis, ANOVA and Tukey's post hoc test were used, with a significance level of 5%. ETs revealed better anti-biofilm potential after 15 days than that of the controls. The degree of conversion was reduced after the shelf-life period. The addition of calcium and dibutyltin methacrylate improved the anti-biofilm properties of the experimental endodontic sealer without impairing their physico-chemical properties.

Anti-biofilm activity of a novel pit and fissure self-adhesive sealant modified with metallic monomers

Dental plaque is a biofilm composed of a complex oral microbial community. The accumulation of plaque in the pit and fissures of dental elements often leads to the development of tooth decay (dental caries). Here, potent anti-biofilm materials were developed by incorporating zinc methacrylates or di-n-butyl-dimethacrylate-tin into the light-curable sealant and their physical, mechanical, and biological properties were evaluated. The data revealed that 5% di-n-butyl-dimethacrylate-tin (SnM 5%) incorporated sealant showed strong anti-biofilm efficacy against various single-species (Streptococcus mutans or Streptococcus oralis or Candida albicans) and S. mutans-C. albicans cross-kingdom dual-species biofilms without either impairing the mechanical properties of the sealant or causing cytotoxicities against mouse fibroblasts. The findings indicate that the incorporation of SnM 5% in the experimental pit and fissure self-adhesive sealant may have the potential to be part of current chemotherapeutic strategies to prevent the formation of cariogenic oral biofilms that cause dental caries.

Evaluation of physical-mechanical properties, antibacterial effect, and cytotoxicity of temporary restorative materials

The objective of this study was to compare selective physical-mechanical properties, antibacterial effects and cytotoxicity of seven temporary restorative materials (TRM): five resin-based materials [Bioplic (B), Fill Magic Tempo (FM), Fermit inlay (F), Luxatemp LC (L) and Revotek LC (R)], and zinc oxide-eugenol cement (IRM) and glass ionomer cement (GIC) as the controls. Material and methods The physical-mechanical properties were evaluated by determining microleakage (ML), ultimate tensile strength (UTS) and Shore D hardness (SDH). In addition, the polymerization rate (Pr-1), depth of cure (DC), water sorption and solubility (WS/SL) were evaluated. The antimicrobial effects of the materials were assessed by biofilm accumulation of Streptococcus mutans (BT) and the direct contact test (DCT) by exposure to Enterococcus faecalis for 1 and 24 h, and cytotoxicity by MTT assay. The data were analyzed by ANOVA or Kruskall-Wallis tests, and a complementary post-hoc method (p<0.05). Results Group B, followed by FM and GIC had significantly lower percentages of microleakage in comparison with the other groups; Groups FM and L showed the highest WS, while Groups R and FM showed the significantly lowest SL values (p<0.05). Group R showed the statistically highest UTS mean and the lowest DC mean among all groups. Group F showed the lowest S. mutans biofilm accumulation (p=0.023). Only the Group L showed continued effect against E. faecalis after 1 h and 24 h in DCT. The L showed statistically lower viability cell when compared to the other groups. Conclusions These findings suggest the antibacterial effect of the temporary materials Fill Magic and Bioplic against S. mutans, while Luxatemp showed in vitro inhibition of S. mutans biofilm accumulation and E. faecalis growth. Regarding the cell viability test, Luxatemp was the most cytotoxic and Fill Magic was shown to be the least cytotoxic.