Evaluation of Antibacterial Efficacy of MTA with and without Additives Like Silver Zeolite and Chlorhexidine

Review of carbonaceous nanoparticles for antibacterial uses in various dental infections

The mouth cavity is the second most complex microbial community in the human body. It is composed of bacteria, viruses, fungi, and protozoa. An imbalance in the oral microbiota may lead to various conditions, including caries, soft tissue infections, periodontitis, root canal infections, peri-implantitis (PI), pulpitis, candidiasis, and denture stomatitis. Additionally, several locally administered antimicrobials have been suggested for dentistry in surgical and non-surgical applications. The main drawbacks are increased antimicrobial resistance, the risk of upsetting the natural microbiota, and hypersensitivity responses. Because of their unique physiochemical characteristics, nanoparticles (NPs) can circumvent antibiotic-resistance mechanisms and exert antimicrobial action via a variety of new bactericidal routes. Because of their anti-microbial properties, carbon-based NPs are becoming more and more effective antibacterial agents. Periodontitis, mouth infections, PI, dentin and root infections, and other dental diseases are among the conditions that may be treated using carbon NPs (CNPs) like graphene oxide and carbon dots. An outline of the scientific development of multifunctional CNPs concerning oral disorders will be given before talking about the significant influence of CNPs on dental health. Some of these illnesses include Periodontitis, oral infections, dental caries, dental pulp disorders, dentin and dental root infections, and PI. We also review the remaining research and application barriers for carbon-based NPs and possible future problems.

A Comparative Analysis of the Antimicrobial Efficacy of Nisin in Different Vehicles Against Enterococcus faecalis: An In Vitro Study

Aim To evaluate and compare the antimicrobial efficacy of nisin in different carriers against Enterococcus faecalis. Materials and methods Test materials were divided into four groups of five samples each as follows: group 1 = nisin + 17% ethylenediaminetetraacetic acid (EDTA); group 2 = nisin + 2% chitosan; group 3 = nisin + 2% chlorhexidine; group 4 = nisin + distilled water (control). The antimicrobial effectiveness was assessed using the direct contact method, where a standardized E. faecalis suspension was applied to the test materials. Optical density (OD) was assessed using enzyme-linked immunosorbent assay (ELISA) at the end of days one and seven. Data were analyzed using ANOVA and Tukey's post hoc analysis. The level of significance was set at p < 0.05. Results On day one, there was a significant difference in the mean OD values (p < 0.001) with group 3 showing the highest, followed by groups 1, 2, and 4. On day seven, all groups demonstrated antibacterial activity (group 1 > group 3 > group 4 > group 2) but the differences were not statistically significant (p = 0.393). Intragroup analysis showed a decrease in the OD values from day one to day seven, the difference of which was not significant in all groups except group 1, which showed a significant difference (p = 0.035). Conclusion The antibacterial efficacy of nisin was synergistically enhanced with the addition of 17% EDTA and 2% chlorhexidine over seven days against E. faecalis.

Comparative evaluation of the antibacterial efficacy of two experimental calcium silicate-based intracanal medicaments: An in-vitro study

Introduction

Success of endodontic treatment relies on minimizing microbial load by chemo-mechanical preparation and intra-canal medication(ICM). Calcium hydroxide based ICMs have known disadvantages. Calcium silicate-based cements(CSC) exhibit antibacterial activity, thus promoting researchers to experiment with their formulations to use them as ICMs.

Aim

Evaluation and comparison of the antimicrobial efficacy of two experimental CSC (MTA & Biodentine + 2%chlorhexidine) and Bio-C Temp against E.faecalis.

Methods and Material

Test materials were divided into four groups namely Group1-Bio-C Temp, Group2-UltraCAL XS, Group3-Biodentine+2%CHX and Group4-MTA+2%CHX. Direct contact test was done by placing a standardized suspension of E.faecalis on test materials and bacterial growth was assessed spectrophotometrically using ELISA at one, three and seven days.

Statistical Analysis

Data was analysed using one-way ANOVA, Tukey's multiple post hoc test and paired-t test. Results: Intragroup comparison revealed decreased mean optical density(OD) in groups 1, 2, and 4; no significant difference in group 3. Intergroup comparison showed statistical differences in mean OD values between groups (3 and 4); groups (1 and 2) at days one(p-0.018) and three(p-0.035), but no difference individually. Group 4 showed the highest antimicrobial efficacy on day seven.

Conclusion

MTA+2%CHX & Biodentine+2%CHX showed better antimicrobial efficacy and hence could be used as potential ICMs.

The scientific management of deep carious lesions in vital teeth using contemporary materials—A narrative review

Aim

The aim of this article is to review the scientific evidence for deep caries removal in permanent vital teeth and the choice of dentine replacement material and restoration of the teeth to maintain long term tooth vitality and function.

Method

The two position statements namely the European Society of Endodontology and the American Association of Endodontists position statements on vital pulp therapy will be scrutinized and compared with regards to the deep caries removal strategy and assessed for evidence of best practice. The properties of materials used to manage vital pulps and the best way to restore the teeth will be reviewed and guidance on the full management of vital teeth will be suggested.

Conclusions

Promoting new treatment modalities for reversible and irreversible pulpitis allowing for pulp preservation should be considered. Although debatable, cases with deep caries should be managed by complete non-selective caries removal which will allow for pulpal management if needed and a more predictable outcome can be expected when using the new materials and treatment modalities of vital pulp therapy.

Enhancing the Stability of the Resin-Dentin Bonding Interface with Ag+- and Zn2+-Exchanged Zeolite A

Enhancing the stability of the resin-dentin bonding interface via simultaneously improving the antibacterial, mechanical, and adhesive properties of a dental adhesive is the key to prolonging the longevity of dental restoration for caries treatment. Herein, we present the stabilization effect of Ag⁺- and Zn²⁺-exchanged zeolite A (denoted as Ag-A and Zn-A, respectively) on the resin-dentin bonding interface. Ag-A and Zn-A zeolites exhibited sustained ion release capability, outstanding biocompatibility to L929 cells (<2 mg/mL), and excellent antibacterial ability to Streptococcus mutans (minimum inhibitory concentration: 100 μg/mL for Ag-A and 200 μg/mL for Zn-A). One-step self-etching adhesives modified by Ag-A, Zn-A, or Ag-/Zn-A (1/1 in weight) zeolites with an ultralow loading of 0.2 wt % exhibited favorable antibacterial activity with the inhibition of biofilm formation by 70.33, 56.47, and 62.54%, respectively. Compared to the control group, Zn-A- and Ag-/Zn-A-modified adhesives significantly increased the wettability properties of the adhesive and the long-term resin-dentin bond strength (by ∼25%) after 5000 thermocycles of aging. The current data demonstrated that the introduction of 0.2 wt % Zn-A or Ag-/Zn-A into the adhesive remarkably enhanced the stability of the resin-dentin bonding interface. Our findings provide a new strategy to modify the dental adhesive for further optimizing the longevity of dental restorations for caries.

The Effects of Incorporating Ag-Zn Zeolite on the Surface Roughness and Hardness of Heat and Cold Cure Acrylic Resins

One of the most widely used materials for the fabrication of prosthetic dental parts is acrylic resin. Its reasonable mechanical and physical properties make it a popular material for a wide range of dental applications. Recently, many attempts have been made to improve the mechanical and biological properties of this material, such as by adding fibres, nanoparticles, and nanotubes. The current study aimed to evaluate the effects of adding an antimicrobial agent, Ag-Zn zeolite, on the surface roughness and hardness of the denture base resins. Ag-Zn zeolite particles were chemically prepared and added at different concentrations (0.50 wt.% and 0.75 wt.%) to the heat cure (HC) and cold cure (CC) acrylic resins. Zeolite particles were characterized and confirmed using X-ray diffraction (XRD) and Energy-Dispersive X-ray Spectroscopy (EDX) attached with a Scanning Electron Microscope (SEM). Sixty disk shape specimens (40 mm diameter and 2 mm thickness) were fabricated from the HC and CC resins with and without the zeolite. All the specimens were divided into two main groups based on the acrylic resins, then each was subdivided into three groups (n = 10) according to the concentration of the Ag-Zn zeolite. A surface roughness and a hardness tester were used to measure the surface finish and hardness of the specimens. The analysed data showed that the surface roughness values significantly decreased when 0.50 wt.% and 0.75 wt.% zeolite were incorporated in the HC resin specimens compared to the control group. However, this reduction was not significant in the case of CC resin, while the surface hardness was significantly improved after incorporating 0.50 wt.% and 0.75 wt.% zeolite for both the CC and HC resins. Incorporating Ag-Zn zeolite with acrylic resin materials could be beneficial for improving their surface finish and resistance to surface damage as defined by the higher hardness.

Antimicrobial and Mechanical Effects of Zeolite Use in Dental Materials: A Systematic Review

Objective

Ion-incorporated zeolite is a widely used antimicrobial material studied for various dental applications. At present, there is no other systematic review that evaluates the effectiveness of zeolite in all dental materials. The purpose of this study was to review all available literature that analyzed the antimicrobial effects and/or mechanical properties of zeolite as a restorative material in dentistry.

Material and Methods

Following PRISMA guidelines, an exhaustive search of PubMed, Ovid Medline, Scopus, Embase, and the Dentistry & Oral Sciences Source was conducted. No language or time restrictions were used and the study was conducted from June 1, 2020 to August 17, 2020. Only full text articles were selected that pertained to the usage of zeolite in dental materials including composite resin, bonding agents, cements, restorative root material, cavity base material, prosthesis, implants, and endodontics.

Results

At the beginning of the study, 1534 studies were identified, of which 687 duplicate records were excluded. After screening for the title, abstract, and full texts, 35 articles remained and were included in the qualitative synthesis. An Inter-Rater Reliability (IRR) test, which included a percent user agreement and reliability percent, was conducted for each of the 35 articles chosen.

Conclusion

Although ion-incorporated zeolite may enhance the antimicrobial properties of dental materials, the mechanical properties of some materials, such as MTA and acrylic resin, may be compromised. Therefore, since the decrease in mechanical properties depends on zeolite concentration in the restorative material, it is generally recommended to add 0.2-2% zeolite by weight.

Nanomaterials in Dentistry: State of the Art and Future Challenges

Nanomaterials are commonly considered as those materials in which the shape and molecular composition at a nanometer scale can be controlled. Subsequently, they present extraordinary properties that are being useful for the development of new and improved applications in many fields, including medicine. In dentistry, several research efforts are being conducted, especially during the last decade, for the improvement of the properties of materials used in dentistry. The objective of the present article is to offer the audience a complete and comprehensive review of the main applications that have been developed in dentistry, by the use of these materials, during the last two decades. It was shown how these materials are improving the treatments in mainly all the important areas of dentistry, such as endodontics, periodontics, implants, tissue engineering and restorative dentistry. The scope of the present review is, subsequently, to revise the main applications regarding nano-shaped materials in dentistry, including nanorods, nanofibers, nanotubes, nanospheres/nanoparticles, and zeolites and other orders porous materials. The results of the bibliographic analysis show that the most explored nanomaterials in dentistry are graphene and carbon nanotubes, and their derivatives. A detailed analysis and a comparative study of their applications show that, although they are quite similar, graphene-based materials seem to be more promising for most of the applications of interest in dentistry. The bibliographic study also demonstrated the potential of zeolite-based materials, although the low number of studies on their applications shows that they have not been totally explored, as well as other porous nanomaterials that have found important applications in medicine, such as metal organic frameworks, have not been explored. Subsequently, it is expected that the research effort will concentrate on graphene and zeolite-based materials in the coming years. Thus, the present review paper presents a detailed bibliographic study, with more than 200 references, in order to briefly describe the main achievements that have been described in dentistry using nanomaterials, compare and analyze them in a critical way, with the aim of predicting the future challenges.

Effect of the of Zeolite Containing Silver-Zinc Nanoparticles on the Push out Bond Strength of Mineral Trioxide Aggregate in Simulated Furcation Perforation

STATEMENT OF THE PROBLEM

Recently, zeolite has been regarded to improve the properties of dental materials such as mineral trioxide aggregate (MTA).

PURPOSE

The aim of the present study was to evaluate the effect of incorporating zeolite/silver/zinc (Ze/Ag/Zn) composite at 2 wt% to MTA powder on the push-out bond strength in simulated furcation perforations.

MATERIALS AND METHOD

Furcal perforations, measuring 1.3 mm in diameter and 2 mm in height, were simulated in 40 human mandibular first molars. The samples were allocated to two groups (n=20) based on the material used for the repair of perforations. In the group 1, MTA and in the group 2, MTA plus Ze/Ag/Zn (2%) was used. The samples were incubated at 37°C for 1 week. Then the universal testing machine was employed to measure bond strength. The resistance of materials to dislodgment was recorded in MPa. Data were analyzed using t-test. Statistical significance was set at p< 0.05.

RESULTS

The push-out bond strength in the group 1 (6.40±1.98 MPa) was significantly higher than that in the group 2 (2.1±0.6 MPa) with p= 0.001.

CONCLUSION

Under the limitations of the present study, it can be concluded that incorporation of Ze/Ag/Zn at 2 wt% to MTA powder had a negative effect on the push-out bond strength.

Reformulated mineral trioxide aggregate components and the assessments for use as future dental regenerative cements

Mineral trioxide aggregate, which comprises three major inorganic components, namely, tricalcium silicate (C3S), dicalcium silicate (C2S), and tricalcium aluminate (C3A), is promising regenerative cement for dentistry. While mineral trioxide aggregate has been successfully applied in retrograde filling, the exact role of each component in the mineral trioxide aggregate system is largely unexplored. In this study, we individually synthesized the three components, namely, C3S, C2A, and C3A, and then mixed them to achieve various compositions (a total of 14 compositions including those similar to mineral trioxide aggregate). All powders were fabricated to obtain high purity. The setting reaction of all cement compositions was within 40 min, which is shorter than for commercial mineral trioxide aggregate (~150 min). Over time, the pH of the composed cements initially showed an abrupt increase and then plateaued (pH 10-12), which is a typical behavior of mineral trioxide aggregate. The compression and tensile strength of the composed cements increased (2-4 times the initial values) with time for up to 21 days in an aqueous medium, the degree to which largely depended on the composition. The cell viability test with rat mesenchymal stem cells revealed no toxicity for any composition except C3A, which contained aluminum. To confirm the in vivo biological response, cement was retro-filled into an extracted rat tooth and the complex was re-implanted. Four weeks post-operation, histological assessments revealed that C3A caused significant tissue toxicity, while good tissue compatibility was observed with the other compositions. Taken together, these results reveal that of the three major constituents of mineral trioxide aggregate, C3A generated significant toxicity in vitro and in vivo, although it accelerated setting time. This study highlights the need for careful consideration with regard to the composition of mineral trioxide aggregate, and if possible (when other properties are satisfactory), the C3A component should be avoided, which can be achieved by the mixture of individual components.