Water-Insoluble, Thermostable, Crosslinked Gelatin Matrix for Soft Tissue Implant Development

In this present study, the material science background of crosslinked gelatin (GEL) was investigated. The aim was to assess the optimal reaction parameters for the production of a water-insoluble crosslinked gelatin matrix suitable for heat sterilization. Matrices were subjected to enzymatic degradation assessments, and their ability to withstand heat sterilization was evaluated. The impact of different crosslinkers on matrix properties was analyzed. It was found that matrices crosslinked with butanediol diglycidyl ether (BDDE) and poly(ethylene glycol) diglycidyl ether (PEGDE) were resistant to enzymatic degradation and heat sterilization. Additionally, at 1 v/v % crosslinker concentration, the crosslinked weight was lower than the starting weight, suggesting simultaneous degradation and crosslinking. The crosslinked weight and swelling ratio were optimal in the case of the matrices that were crosslinked with 3% and 5% v/v BDDE and PEGDE. FTIR analysis confirmed crosslinking, and the reduction of free primary amino groups indicated effective crosslinking even at a 1% v/v crosslinker concentration. Moreover, stress-strain and compression characteristics of the 5% v/v BDDE crosslinked matrix were comparable to native gelatin. Based on material science measurements, the crosslinked matrices may be promising candidates for scaffold development, including properties such as resistance to enzymatic degradation and heat sterilization.

Effect of heat application on the physicochemical properties of new endodontic sealers: an in vitro and SEM study

Understanding the properties of endodontic sealers is vital for treatment planning. Calcium silicate-based sealers are important in modern endodontics. This study investigates the effect of heat on the physicochemical properties of new calcium silicate sealers, addressing concerns raised by clinicians seeking to combine their benefits with the gutta-percha obturation technique. Five endodontic sealers (AH Plus Bioceramic®, Total Fill® BC®, One-fil® Bioceramic, K-Biocer, Any-seal®) were evaluated. Each sealer (n = 16/group) was either kept at 37 °C or subjected to heat at 60 or 200 °C for 30 s. ISO 6876-2012 standards were used to measure setting time, flow, film thickness, and dimensional changes over time. SEM and EDS were utilized for surface and chemical analysis. Data analysis employed IBM SPSS Statistics version 26 with a 5% significance level for two-sided tests. The sealers' setting times were shortened by heat, except for Total Fill® BC with extended setting time. All sealers had significantly longer setting times than manufacturer specifications. Film thickness increased with temperature, while flow values decreased. K-Biocer sealer showed the highest flow (16.89 ± 0.57 mm) at 200 °C, while Total Fill® sealer had the lowest (15.32 ± 0.62 mm). Shrinkage was significant at 60 °C and 200 °C, with greater shrinkage at 200 °C. Heat caused surface deformations in all sealers. The 200 °C groups exhibited more voids in AH Plus Bioceramic®, Any-seal®, and One-fil® sealers, and higher void area in Total Fill®, One-fil®, and K-Biocer sealers (p value < 0.001). EDX analysis confirmed heat-induced chemical and elemental changes in all tested sealers. Elevated temperature affects the physicochemical properties and structure of the tested endodontic sealers. The consideration of endodontic sealer compatibility is essential when warm gutta-percha obturation techniques are used.

Calcium gluconate-based flame retardant towards simultaneously high-efficiency fire safety and mechanical enhancement for epoxy resin

Flame retardants containing biomass receive growing interest in environmental friendliness and sustainability but usually face the low flame-retardant efficiency and deterioration on mechanical property of matrix. Herein, a calcium gluconate-based flame retardant (CG@APP) was chemically prepared using calcium gluconate (CG) and ammonium polyphosphate (APP) via ion exchange reaction, and enabled the excellent fire safety and mechanical enhancement for epoxy resin (EP). The resulted EP composites containing 6 wt% CG@APP (EP/CG@APP6) exhibited V-0 ratings in UL-94 test. Furthermore, with respect to EP/APP6, the peak of heat release rate (pHRR) and peak of smoke production rate (pSPR) of EP/CG@APP6 decreased by 70.5 % and 50.0 %, respectively. The well synergistic flame-retardant mechanism of CG@APP between gaseous and solid phases was revealed to generate denser and more continuous charring residuals, which could do well work on insulation for heat transfer and fuel diffusion. In addition, the shell rich in hydroxyl group and Ca2+ on the surface of CG@APP well enhanced the interface compatibility through the hydrogen bond and coordinated bond, thus the tensile strength, flexural strength and impact strength of EP/CG@APP6 increased by 18.2 %, 4.5 % and 9.1 % compared with pure EP, respectively. This work provided a simple and sustainable way to construct excellent fire-safety composites.

An automated method to analyze root filling voids and gaps using confocal microscopy images

This study evaluated the feasibility of an automated method to delimit the required area to quantitatively analyze root filling voids and gaps from cross-sectional confocal laser scanning microscopy (CLSM) images. Root canals of maxillary canines were prepared with rotary instruments and filled by lateral compaction technique using gutta-percha and AH Plus sealer. The roots were stored (100% humidity, 37 °C) for a period of 24 h and then transversally sectioned to obtain 2-mm-thick slices from the apical and middle thirds. The areas corresponding to filling materials, gaps, and voids were manually delimited or automatically demarked by ImageJ software after converting the images to the RGB color system. Based on manual and automatic delimitations, the percentages of voids and gaps were calculated. Data of voids and gaps between middle and apical thirds were individually compared by paired t-test. Pearson`s correlation test was used to assess the correlation of data between the methods. Irrespective of the method of area delimitation, no difference was observed between the root thirds for both voids and gaps, while the p-values calculated for each method were similar. Almost perfect correlations between the methods were observed for both outcomes. The proposed method to automatically delimit the areas corresponding to filling material, voids, and gaps appears to be a valid method to facilitate the quantitative analysis of defects in root canal fillings using topographic CSLM images.

Effect of obturation technique on dentinal tubule penetration of two tricalcium silicate-based sealers: Ex vivo study

The aim of this study was to assess by confocal laser microscope the depth of dentinal tubule penetration of two tricalcium silicate-based sealers promoted by two obturation techniques in curved canals compared with AHPlus. One hundred and twenty canals were divided into six groups (n = 20): BCSC-Bio-C Sealer (BC) and single-cone technique (SC); BCCW-BC and continuous condensation wave (CW); TFSC-Total Fill (TF) and SC; TFCW-TF and CW; AHSC-AH Plus (AH) and SC; AHCW-AH and CW. Data were analysed using the three-way ANOVA and Tukey's test (α = 5%). Penetration depth was significantly greater for TFCW than TFSC and greater for AHCW than AHSC (p < 0.05). There was no significant difference between BCCW and BCSC (p > 0.05). The penetration of TF was significantly greater (p < 0.05). The CW technique promoted greater intratubular penetration, except for the BC sealer.

The Effect of Adding Various Antibiotics on the Push-out Bond Strength of a Resin-based Sealer: An In Vitro Study

AIM

This study aimed to compare the bond strength of AH Plus sealer to root canal dentin when used with or without various antibiotics including amoxicillin, clindamycin, and triple antibiotic mixture (TAM).

MATERIALS AND METHODS

A total of 80 single-rooted extracted human teeth were instrumented and obturated with gutta-percha and four different sealer-antibiotic combinations (n = 20). Group I: AH Plus without any antibiotics, Group II: AH Plus with amoxicillin, Group III: AH Plus with clindamycin, and Group IV: AH Plus with TAM. After seven days, the roots were sectioned perpendicular to their long axis and 1 mm thick slices were obtained from the midroots. The specimens were subjected to a push-out bond strength test and failure modes were also evaluated. Data was analyzed using Kruskal-Wallis and Dunn's post hoc tests.

RESULTS

Group IV had significantly higher bond strength compared to other groups (p ≤ 0.05). No significant differences were found between other groups. While the sealer-antibiotic groups predominantly showed cohesive failure modes, the control group displayed both cohesive and mixed failure modes.

CONCLUSION

Within the limitations of this study, the addition of TAM increased the push-out bond strength of AH Plus.

CLINICAL SIGNIFICANCE

Amoxicillin, clindamycin, or TAM can be added to AH Plus for increased antibacterial efficacy without concern about their effects on the bond strength of the sealer. How to cite this article: Adl A, Shojaei NS, Ranjbar N. The Effect of Adding Various Antibiotics on the Push-out Bond Strength of a Resin-based Sealer: An In Vitro Study. J Contemp Dent Pract 2024;25(3):231-235.

Characterisation and evaluation of physical properties of AH-Plus sealer with and without the incorporation of petasin, pachymic acid, curcumin and shilajit-an invitro study

BACKGROUND

AH Plus, an epoxy resin-based sealer, is widely used in endodontic practice, owing to its good physical properties that confers longstanding dimensional stability and good adhesion to dentin. Nevertheless, its propensity to trigger inflammation, especially in its freshly mixed state, has been extensively documented. Phytochemicals such as Petasin, Pachymic acid, Curcumin, and Shilajit are known for their anti-inflammatory and analgesic effects. This study aimed to analyze and determine the effect of these natural products on the physical properties of AH Plus sealer when incorporated with the sealer.

METHODS

AH Plus (AHR) sealer was mixed with 10% petasin, 0.75% pachymic, 0.5% and 6%shilajit to obtain AHP, AHA, AHC and AHS in the ratio of 10:1 and 5:1 respectively. Five samples of each material were assessed for setting time, solubility, flow, and dimensional stability in accordance with the ISO 6876:2012 standardization. Sealers were characterized through scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. Statistical evaluation involved the Kolmogorov-Smirnov and Shapiro-Wilks tests for normality and the one-way ANOVA test for analysis.

RESULTS

In this investigation, the characterisation analysis revealed a relatively similar microstructure in all the experimental root canal sealers. All experimental groups, excluding the control group, exhibited an increase in flow ranging from 11.9 to 31.4% at a 10:1 ratio. Similarly, for the 5:1 ratio, the increase ranged from 12.02 to 31.83%. In terms of dimensional stability, all groups at the 10:1 ratio showed a decrease compared to the control group. The addition of natural agents to AHR in 10:1 ratio led to a reduction in setting time by 8.9-31.6%, and at a 5:1 ratio, the reduction ranged from 8.1 to 31.5%. However, regarding solubility, the addition of natural agents did not induce any significant alterations.

CONCLUSION

Based on the results of this study, it can be concluded that all tested root canal sealers exhibited properties that met the acceptable criteria outlined in the ISO 6876:2012 standardization.

Evaluation of disposable protective garments against epoxy resin permeation and penetration from anti-corrosion coatings

INTRODUCTION

Epoxy-based resin formulations are a frequent cause of allergic and irritant contact dermatitis in the construction and painting industries. Cases of epoxy resin contact dermatitis continue to persist across many sectors and are likely attributable to the growing use of epoxy products, including epoxy-based anti-corrosion coatings and inadequate skin protection. There are no published performance data against epoxy resins for garment materials and gloves to guide proper material selection in the workplace.

OBJECTIVES

The objective of this study was to evaluate the resistance of 5 protective garment materials against permeation and penetration by bisphenol A diglycidyl ether and its higher oligomers found commonly in epoxy-based anti-corrosion coatings.

METHODS

Five disposable garment materials were evaluated for resistance to bisphenol A diglycidyl ether monomers and oligomers during contact with epoxy-based anti-corrosion coatings, including latex gloves, nitrile gloves, Tyvek coveralls, polypropylene/polyethylene (PP/PE) coveralls, and a cotton T-shirt. A permeation test cell system was used to evaluate each garment material against an epoxy-based zinc-rich primer and an epoxy-based intermediate coating using a realistic application method. Glass fiber filters were used to collect permeating and penetrating epoxy resin during a 120-min test period. Bisphenol A diglycidyl ether quantification was performed with high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. Paint loading, coating thickness, and homogeneity were assessed on polytetrafluoroethylene filters sprayed in series in permeation test cells.

RESULTS

Latex gloves provided the least resistance to permeation by BADGE in coating formulations, with a maximum cumulative permeation over the 2-h test interval of 21.7 ng cm-2 with the primer and 513.8 ng cm-2 with the intermediate coating product. Nitrile gloves were not permeated by either coating formulation. The Tyvek coveralls provided greater protection as compared to the PP/PE coveralls. The cotton T-shirt was penetrated by bisphenol A diglycidyl ether more frequently than any of the tested garment materials and resulted in a maximum cumulative penetration of 128 ng cm-2 with the primer and 28.0 ng cm-2 with the intermediate coating.

CONCLUSION

Although all the garment materials evaluated during this study provided sufficient protection to prevent cumulative permeation in excess of the established acceptable permeation thresholds, the use of nitrile gloves and Tyvek coverall is highly recommended to minimize skin exposure to bisphenol A diglycidyl ether. We recommend cotton T-shirts to be used under Tyvek coveralls as a secondary layer of skin protection and for added comfort, but not as a primary protection layer.

Evaluation of stress distributions of calcium silicate-based root canal sealer in bulk or with main core material: A finite element analysis study

This research aimed to assess the stress distribution in lower premolars that were obturated with BioRoot RCS or AH Plus, with or without gutta percha (GP), and subjected to vertical and oblique forces. One 3D geometric model of a mandibular second premolar was created using SolidWorks software. Eight different scenarios representing different root canal filling techniques, single cone technique with GP and bulk technique with sealer only with occlusal load directions were simulated as follows: Model 1 (BioRoot RCS sealer and GP under vertical load [VL]), Model 2 (BioRoot RCS sealer and GP under oblique load [OL]), Model 3 (AH Plus sealer with GP under VL), Model 4 (AH Plus sealer with GP under OL), Model 5 (BioRoot RCS sealer in bulk under VL), Model 6 (BioRoot RCS in bulk under OL), Model 7 (AH Plus sealer in bulk under VL), and Model 8 (AH Plus sealer in bulk under OL). A static load of 200 N was applied at three occlusal contact points, with a 45° angle from lingual to buccal. The von Mises stresses in root dentin were higher in cases where AH Plus was used compared to BioRoot RCS. Furthermore, shifting the load to an oblique direction resulted in increased stress levels. Replacing GP with sealer material had no effect on the dentin maximum von Mises stress in BioRoot RCS cases. Presence of a core material resulted in lower stress in dentin for AH Plus cases, however, it did not affect the stress levels in dentin for cases filled with BioRoot RCS. Stress distribution in the dentin under oblique direction was higher regardless of sealer or technique used.

Comparative bioactivity and immunomodulatory potential of the new Bioroot Flow and AH Plus Bioceramic sealer: An in vitro study on hPDLSCs

OBJECTIVES

To evaluate the cytocompatibility, bioactivity, and anti-inflammatory potential of the new pre-mixed calcium silicate cement-based sealers Bioroot Flow (BrF) and AH Plus Bioceramic Sealer (AHPbcs) on human periodontal ligament stem cells (hPDLSCs) compared to the epoxy resin-based sealer AH Plus (AHP).

MATERIALS AND METHODS

Standardized discs and 1:1, 1:2, and 1:4 eluates of BrF, AHPbcs and AHP after setting were prepared. The following assays were performed: cell attachment and morphology via SEM, cell viability via a MTT assay, cell migration/proliferation via a wound-healing assay, cytoskeleton organization via immunofluorescence staining; cytokine release via ELISA; osteo/cemento/odontogenic marker expression via RT-qPCR, and cell mineralized nodule formation via Alizarin Red S staining. HPDLSCs were isolated from extracted third molars from healthy patients. Comparisons were made with hPDLSCs cultured in unconditioned (negative control) or osteogenic (positive control) culture media. Statistical significance was established at p < 0.05.

RESULTS

Both BrF and AHPbcs showed significantly positive results in the cytocompatibility assays (cell metabolic activity, migration, attachment, morphology, and cytoskeleton organization) compared with a negative control group, while AHP showed significant negative results. BrF exhibited an upregulation of at least one osteo/cementogenic marker compared to the negative and positive control groups. BrF showed a significantly higher calcified nodule formation than AHPbcs, the negative and positive control groups, while AHPbcs was higher than the negative control group. Both were also significantly higher than AHP group.

CONCLUSION

BrF and AHPbcs exhibit adequate and comparable cytocompatibility on hPDLSCs. BrF also promoted the osteo/cementogenic differentiation of hPDLSCs. Both calcium silicate-based sealers favored the downregulation of the inflammatory cytokine IL-6 and the calcified nodule formation from hPDLSCs. BrF exerted a significantly higher influence on cell mineralization than AHPbcs.

CLINICAL RELEVANCE

This is the first study to elucidate the biological properties and immunomodulatory potential of Bioroot Flow and AH Plus Bioceramic Sealer. The results act as supporting evidence for their use in root canal treatment.

Marginal adaptation and fracture resistance of virgilite-based occlusal veneers with varying thickness

STATEMENT OF PROBLEM

CAD/CAM occlusal veneers have been developed for minimally invasive prosthetic restoration of eroded teeth. Marginal adaptation and fracture resistance are crucial for the long-term survivability and clinical success of such restorations. Virgilite-based lithium disilicate glass-ceramic is a newly introduced material with claims of high strength. However, constructing occlusal veneers from this material of varying thickness has not been investigated.

PURPOSE

The current study aimed to assess the impact of CAD/CAM occlusal veneer thickness and materials on marginal adaptation and fracture resistance.

MATERIALS AND METHODS

Thirty-two occlusal veneers were constructed and divided into two groups (n = 16) based on the CAD/CAM material into Brilliant Crios and CEREC Tessera. Each group was further subdivided into two subgroups (n = 8) according to the thickness: 0.6 and 0.9 mm. Occlusal veneers were bonded to epoxy resin dies. The marginal gap was evaluated before and after thermodynamic aging. Fracture resistance and failure mode were evaluated for the same samples after aging. Marginal adaptation was analyzed using the Mann-Whitney U test. Fracture resistance was analyzed using Weibull analysis (α = 0.05).

RESULTS

The marginal gap was significantly increased following thermodynamic aging for tested groups (P < 0.001). CEREC Tessera showed a significantly higher marginal gap than Brilliant Crios before and after aging for both thicknesses (P < 0.05). CEREC Tessera recorded lower significant fracture load values compared to Brilliant Crios (P < 0.05).

CONCLUSIONS

Both CEREC Tessera and Brilliant Crios demonstrated clinically accepted marginal gap values. All groups showed fracture resistance values higher than the average masticatory forces in the premolar region except for 0.6 mm CEREC Tessera.

CLINICAL IMPLICATIONS

Reinforced composite occlusal veneers demonstrated more favorable outcomes in terms of marginal gap and fracture resistance at both tested thicknesses compared to virgilite-based lithium disilicate glass-ceramic. Additionally, caution should be exercised during the construction of occlusal veneers from virgilite-based lithium disilicate glass-ceramic with reduced thickness.

Bio-based epoxy vitrimer with inherent excellent flame retardance and recyclability via molecular design

The development of biobased fire-safe thermosets with recyclability heralds the switch for a transition towards a circular economy. In this framework, we introduced a novel high-performance bio-epoxy vitrimer (named GVD), which was fabricated by forming a crosslinking network between bio-epoxy glycerol triglycidyl ether (Gte), varying amounts of reactive flame-retardant agent 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) (0-7 wt%) and a vanillin-based hardener (VA) with imine bonds. For instance, the epoxy vitrimer GVD5, featuring a DOPO content of 5 wt%, achieved a V-0 rating in the vertical burning test (UL-94) and obtained a limiting oxygen index (LOI) value of 31 %, surpassing the performance of pristine epoxy. Furthermore, the peak heat release rate and total heat release of GVD5 were reduced by 38.2 % and 26.3 %, respectively, compared to pristine epoxy. The GVD vitrimers further demonstrated exceptional reprocessability and recyclability, attributed to the presence of dynamic imine bonds within the topological crosslinking network. Remarkably, the epoxy vitrimers maintained the mechanical properties of the parent epoxy. Therefore, this work provides a facile strategy for fabricating high-performance and multi-functional bio-epoxy thermosets.

Flame retardant, high mechanical strength, transparent and water-resistant epoxy composites modified with chitosan derivatives

Adding bio-based flame retardants to improve the flame retardancy of polymer materials without sacrificing other properties is a great challenge. Herein, a novel flame-retardant CS-DOPA was prepared from chitosan and 10-hydroxy-9,10-dihydro-9-oza-10-phosphaphenanthrene-10-oxide by acid-base neutralization reaction and fully characterized. The 4 wt% CS-DOPA modified EP showed good flame retardancy in both gaseous and condensed phase. The peak heat release rate, total smoke production, CO production, and smoke production rate of EP composites containing 4 wt% CS-DOPA were reduced by 55 %, 34 %, 45 %, and 46 %, respectively, to pass the UL-94 V-1 rating with a limiting oxygen index of 34.1 %. The CS-DOPA contributes to the formation of the condensed phase of the thermo-oxidation-resistant high-quality char layer with non-flammable other and phosphorus-containing free radicals released in the gas phase. In addition, EP/4CS-DOPA has good water resistance, mechanical properties, and transparency, with tensile and flexural strength improved by 12.7 % and 13.9 %, respectively, and still has high strength even after water treatment. The present work provides a green and facile strategy to use chitosan as a main raw material to manufacture EP materials with high performance.

A reactive compatibilization with the compound containing four epoxy groups for polylactic acid/poly(butylene adipate-co-terephthalate)/thermoplastic starch ternary bio-composites

How to effectively improve the poor interfacial adhesion between polylactic acid/poly(butylene adipate-co-terephthalate) (PLA/PBAT) matrix and thermoplastic starch (TPS) is still a challenge. Therefore, this work aims to introduce a convenient method to enhance the performance of PLA/PBAT/TPS blend by melt reactive extrusion. Here, using 4,4'-methylene-bis(N,N-diglycidyl-aniline) (MBDG) containing four epoxy groups as a reactive compatibilizer, and respectively using 1-methylimidazole (MI) or triethylenediamine (TD) as a catalyzer, serial PLA/PBAT/TPS ternary bio-composites are successfully prepared via melt reactive extrusion. The results showed that, under the catalysis of organic base, especially MI, the epoxy groups of MBDG can effectively react with hydroxyl and carboxyl groups of PLA/PBAT and hydroxyl groups in TPS to form chain-expanded and cross-linked structures. The tensile strength of the composites is increased by 20.0 % from 21.1 MPa, and the elongation at break is increased by 182.4 % from 17.6 % owing to the chain extension and the forming of cross-linked structures. The molecular weight, thermal stability, crystallinity, and surface hydrophobicity of the materials are gradually improved with the increase of MBDG content. The melt fluidity of the composites is also improved due to the enhancement of compatibility. The obtained PLA/PBAT/TPS materials have the potential to be green plastic products with good properties.

Natural diterpenoid EKO activates deubiqutinase ATXN3 to preserve vascular endothelial integrity and alleviate diabetic retinopathy through c-fos/focal adhesion axis

Diabetic retinopathy (DR) is one of the most prevalent severe diabetic microvascular complications caused by hyperglycemia. Deciphering the underlying mechanism of vascular injury and finding ways to alleviate hyperglycemia induced microvascular complications is of great necessity. In this study, we identified that a compound ent-9α-hydroxy-15-oxo-16-kauren-19-oic acid (EKO), the diterpenoid isolated and purified from Pteris semipinnata L., exhibited good protective roles against vascular endothelial injury associated with diabetic retinopathy in vitro and in vivo. To further uncover the underlying mechanism, we used unbiased transcriptome sequencing analysis and showed substantial impairment in the focal adhesion pathway upon high glucose and IL-1β stimulation. EKO could effectively improve endothelial focal adhesion pathway by enhancing the expression of two focal adhesion proteins Vinculin and ITGA11. We found that c-fos protein was involved in regulating the expression of Vinculin and ITGA11, a transcription factor component that was downregulated by high glucose and IL-1β stimulation and recovered by EKO. Mechanically, EKO facilitated the binding of deubiquitylation enzyme ATXN3 to c-fos protein and promoted its deubiquitylation, thereby elevating its protein level to enhance the expression of Vinculin and ITGA11. Besides, EKO effectively suppressed ROS production and restored mitochondrial function. In vivo studies, we confirmed EKO could alleviate some of the indicators of diabetic mice. In addition, protein levels of ATXN3 and focal adhesion Vinculin molecule were also verified in vivo. Collectively, our findings addressed the endothelial protective role of natural diterpenoid EKO, with emphasize of mechanism on ATXN3/c-fos/focal adhesion signaling pathway as well as oxygen stress suppression, implicating its therapeutic potential in alleviating vascular endothelium injury and diabetic retinopathy.

Epoxy resin-based root canal sealers: An integrative literature review

The correct obturation of the root canal system achieved by means of a core and a cement is essential for the success of endodontic treatment. There are several root canal cements (RCCs) on the market; however, because of their excellent characteristics, epoxy resin-based sealers (ERBSs) have been widely used. The main aim of this review was to analyze and integrate the available information on different ERBSs. An electronic search was performed in the PubMed and Scopus databases, using "epoxy resin" AND "root canal treatment", and "epoxy resin" AND "endodontics" as search terms. In general, ERBSs have good flow properties, film thickness, solubility, dimensional stability, sealing capacity, and radiopacity. They are also able to adhere to dentin while exhibiting low toxicity and some antibacterial effects. However, their main disadvantage is the lack of bioactivity and biomineralization capability. A large number of ERBSs are available on the market, and AH Plus keeps being the gold standard RCC. Yet, information on many of them is limited or non-existent, which could be due to the fact that some of them are relatively new. The latter emphasizes the need for relevant research on the physicochemical and biological properties of some ERBSs, with the aim of supporting their clinical use with sufficient evidence via prospective and long-term studies.

Biodegradable reactive compatibilizers for efficient in-situ compatibilization of poly (lactic acid)/poly (butylene adipate-terephthalate) blends

The wide application of fully biodegradable polylactic acid/polybutylene terephthalate (PLA/PBAT) blends in environmentally friendly packaging were limited because of poor compatibility. Normal compatibilizers suffer from poor thermal stability and non-biodegradability. In this work, epoxy copolymer (MDOG) with different molecular structures were made of 2-methylene-1, 3-dioxoheptane, and glycidyl methacrylate as raw materials by free radical copolymerization. MDOG copolymers have good biodegradability and a high thermal decomposition temperature of 361 °C. The chemical reaction of the epoxy groups in MDOG with PLA and PBAT during the melting reaction improved the interfacial bonding by decreasing the particle size of PBAT. Compared to the PLA/PBAT blends, the tensile strength and fracture toughness of PLA/PBAT/MDOG blends were enhanced to 34.6 MPa and 115.8 MJ/m3, which are 25 % and 81 % higher, respectively. As a result, this work offers new methods for developing thermally stable and biodegradable compatibilizers, which will hopefully promote the development of packaging industry.

Analysis of the cytotoxicity and bioactivity of CeraSeal, BioRoot™ and AH Plus® sealers in pre-osteoblast lineage cells

BACKGROUND

The objective of the present study was to evaluate in vitro the cytotoxicity and bioactivity of various endodontic sealers (CeraSeal, BioRoot™ and AH Plus®) in pre-osteoblast mouse cells (MC3T3 cells).

METHODS

MC3T3 cells (ATCC CRL-2594) were plated in 1 × 104 cells/well in 96-well plates in contact with endodontic sealers at concentrations of 1:10 and 1:100. Cell viability was evaluated by MTT assay after 24 and 48 h. In addition, sealer bioactivity was measured by RT-PCR for mediator of inflammation (Tnf, Ptgs2) and mineralization (Runx2, Msx1, Ssp1 and Dmp1) after 24 h and by Alizarin Red S Assay of mineralization after 28 days. Data were analyzed using one-way ANOVA followed by the Tukey's post-test at a significance level of 5%.

RESULTS

BioRoot™ presented 24-hour cytotoxicity (p < 0.05) at 1:10 concentration. In the period of 48 h, no endodontic cement was cytotoxic to the cells compared to the control (p > 0.05). TNF-α gene expression was induced by AH Plus® (p < 0.05), while Ptgs2 was induced by the CeraSeal and BioRoot™ (p < 0.05). The expression of Runx2 was stimulated by BioRoot™ and AH Plus® (p < 0.05). In contrast, the expression of Dmp-1 Dmp1 was higher for the CeraSeal and BioRoot™ (p < 0.05). Nonetheless, the sealers did not impact the formation of mineralization nodules (p > 0.05).

CONCLUSION

CeraSeal, BioRoot™ and AH Plus® sealers were not cytotoxic to MC3T3 cells within 48 h, but differentially induced the expression of genes related to inflammation and mineralization without impacting biomineralization by the cells.

Cellulose nanocrystals-reinforced waterborne epoxy coatings with enhanced corrosion resistance for steel

The practical applications of waterborne epoxy coatings are limited due to their poor barrier properties caused by the formation of numerous micropores and defects during the curing process. Herein, cellulose nanocrystals (CNCs)-reinforced waterborne epoxy coatings were fabricated by the direct addition of 0.2-1.0 wt% CNCs to waterborne epoxy emulsion followed by amine curing agent addition and spray coating. The incorporation of 0.2-0.5 wt% CNCs had no discernible impact on the stability of the waterborne epoxy emulsion. This led to the uniform dispersion of CNCs in the cured coating matrix, as evidenced by differential scanning calorimetry analysis. Because of the good compatibility, 0.2-0.5 wt% CNCs-reinforced epoxy coatings exhibited superior corrosion protection performance for steels. The impedance modulus of these coatings remained at 108 Ω cm2 after being immersed in a 3.5 wt% NaCl solution for 21 d. The hydroxyl groups present on the CNC surface undergo a reaction with the epoxy group, enhancing intermolecular interaction and leading to the formation of a defect-free dense structure that improves coating barrier properties. However, the incorporation of an excessive amount of CNCs (i.e., 0.8 and 1.0 wt%) significantly compromised the corrosion resistance of epoxy coatings due to aggregation-induced coating defects. Overall, this study provides a facile and green strategy for corrosion resistance improvement of waterborne epoxy coatings.

Preparation, characterization, and application of waterborne lignin-based epoxy resin as eco-friendly wood adhesive

A series of novel waterborne lignin-based epoxy resin emulsions (WLEPs) were successfully synthesized, and then the WLEPs were cured with polyamide (PA) to give formaldehyde-free wood adhesives with high-performance. The chemical structures and properties of WLEP emulsions were determined. The effects of the emulsifiers on thermal and mechanical properties of the adhesives were investigated, and the potential application of WLEPs in the formulation of plywood were also evaluated. The results demonstrated that the WLEP dispersions presented excellent storage stability (>180 days) with their viscosities range from 110 mPa·s to 470 mPa·s and particle sizes in the range of 321-696 nm, which were beneficial for the fluidity and permeability of the wood adhesives. Furthermore, the thermal and mechanical properties of adhesives could be tuned effectively by controlling the length of PEG chains. The adhesive bearing PEG 6000 exhibited the highest tensile strength of 24.0 MPa and Young's modulus of 1439 MPa. Notably, the plywood prepared with the resulting adhesives displayed good bonding performance, especially water resistance, which were much higher than the national standard requirement for exterior-grade plywood type I. These results indicated that the WLEPs could be used as sustainable alternatives for traditional formaldehyde-based wood adhesives in practical applications.

The flow behavior and sealing ability of calcium silicate root canal cement containing dimethyl sulfoxide: An in vitro study

INTRODUCTION

To develop a calcium silicate (CaSi)-based cement containing dimethyl sulfoxide (DMSO) and cement deliver device for new root canal filling technique, and to assess the flow behavior, leakage, and root canal filling quality of CaSi containing DMSO.

METHODS

CaSi containing DMSO (CSC-DMSO) and CaSi containing PEG (CSC-PEG) were prepared, and the flow characteristics of both cements were compared in gypsum and resin channels using a high-speed camera. Eight root canals were obturated by CSC-DMSO or CSC-PEG using a cement delivery device, and root canal filling quality was assessed in terms of filling length using periapical radiographs. The filling length was evaluated by 'apico-coronal extension,' measuring length in reference to apical constriction. Microleakage was measured for thirty human molars that were randomly filled with CSC-DMSO, CSC-PEG, or gutta-percha and AH plus. Preliminary obturation of CSC-DMSO with cement delivery device in human teeth was analyzed in terms of filling length and void, using periapical radiographs. Statistical analysis was performed with the Kruskal Wallis test for simulated root canal fillings and one-way ANOVA for leakage test.

RESULTS

The flow speed of CSC-DMSO reduced in gypsum channels compared to resin channels, but CSC-PEG did not exhibit significant differences in the channels. The median absolute value of apico-coronal extension was significantly lower in CSC-DMSO compared to CSC-PEG (p < 0.05). Microleakage did not statistically differ between the groups (p > 0.05). In the preliminary obturation, the mean apico-coronal extension of CSC-DMSO was -0.297 ± 0.724 mm, while CSC-PEG was not feasible due to excess apical extrusions.

CONCLUSIONS

CSC-DMSO could be considered as an alternative filling material for root canal obturation.

Canal disinfection using photo-chemically activated micro-bubble emulsion, Emblica officinalis, and Nd: YAP laser on smear layer and push-out bond strength of resin-based root canal sealer to the radicular dentin

AIMS

Evaluation of the effects of the latest root canal disinfectants i.e., Micro-bubble emulsion (MBE), Neodymium-doped yttrium aluminum perovskite (Nd: YAP), Emblica officinalis (E. officinalis) on the removal of smear layer (SL) and push out bond strength (PBS) of resin-based root canal sealer to the radicular dentin.

METHODS

The coronal portion of sixty single-rooted human mandibular premolar teeth was precisely sectioned at the cementoenamel junction. The canals were prepared to utilize ProTaper universal rotary files till F3. All the study specimens were divided into four groups based on the disinfection regime (n = 15) Group 1: 5.25% NaOCl, Group 2: MBE, Group 3: Nd: YAP laser and Group 4: E. officinalis extract. All the canals were then finally irrigated using 17% EDTA solution as a final disinfecting agent. SL removal assessment was performed on five samples from each group using a scanning electron microscope (SEM). Ten samples from each group were then filled with root canal filling material and the roots were sectioned. Push-out test and failure mode analysis were performed using the universal testing machine (UTM) and stereomicroscope respectively. The mean scores of PBS and SL removal were compared using a one-way analysis of variance (ANOVA) and Post Hoc Tukey's HSD test p = 0.05.

RESULTS

Group-2 (MBE + EDTA) coronal section (1.50 ± 0.23) exhibited the most effective eradication of SL from the canal space. The apical third of Group-1 (NaOCl+EDTA) (2.68 ± 0.82) samples demonstrated the least effective removal of SL from the radicular canal. The maximum score of PBS of AH plus sealer to the canal dentin was exhibited by the coronal section of Group-2 (MBE + EDTA) (9.55 ± 0.45 MPa) samples. However, the apical third of Group-1 (NaOCl+ EDTA) specimens (5.16 ± 0.32 MPa) demonstrated the minimum EBS.

CONCLUSION

MBE+ EDTA displayed better smear layer removal and bond integrity of AH plus sealer to the root canal dentin. Nd: YAP+ EDTA laser and E.officinalis displayed comparable outcomes to that of control NaOCl+ EDTA.

The Effect of Different Obturation Techniques Using Different Root Canal Sealers on the Residual Filling Material After Retreatment Procedures

BACKGROUND

This study aimed to compare the effect of different obturation techniques with root canal sealers on the residual filling material after retreatment using SEM.

MATERIAL AND METHOD

Sixty (60) single rooted mandibular premolars were selected and instrumented with rotary files using the Mtwo system up to file size 30/.05 taper. The samples were randomly divided to two groups based on the type of sealer and three sub-groups (n=10) based on the obturating technique used. The root fillings were removed using the PTUR system files and the specimens were longitudinally sectioned while digital images were obtained from the root canals with SEM. The time required to reach working lenght were recorded.

RESULTS

There was no difference in terms of the smear score when comparing both sealer and obturation technique groups in the apical third. Smear scores were significantly affected by the type of sealer and obturation technique in the medium and coronal thirds of root canals (p<0.05). Higher smear scores were obtained with GFB than AH Plus (p<0.05). The time required to reach working length with GFB was longer than AH Plus (p<0.05).

CONCLUSION

Residual filling material was observed in all samples, regardless of the root canal sealer or the obturation technique used. There was a significantly lower smear scores in the AH Plus groups as compared to the GFB.

Marginal fit and fracture resistance of polyetheretherketone, zirconia, and titanium implant-supported prosthesis frameworks for a partially edentulous arch after thermomechanical aging

STATEMENT OF PROBLEM

Although polyetheretherketone (PEEK) and zirconia (Zir) have been used as implant-supported prosthesis (ISP) frameworks, the long-term effects of thermomechanical aging on the marginal fit and fracture resistance of PEEK and Zir ISP frameworks with titanium (Ti) bases for patients with a partially edentulous arch are not clear.

PURPOSE

The purpose of this in vitro study was to determine the marginal fit and fracture resistance of PEEK and Zir ISP frameworks with Ti bases and Ti ISP frameworks for partially edentulous arches after aging.

MATERIAL AND METHODS

A total of 30 ISP epoxy resin casts were obtained from a typodont with 1 straight implant (Nobel Biocare) in the mandibular right canine region and 1 implant with a 30-degree distal tilt in the mandibular right first molar region. All frameworks (n=10) were fabricated on their own epoxy resin cast with multiunit abutment replicas by using a computer-aided design and computer-aided manufacturing system (exocad-Yenadent). The PEEK and Zir frameworks were fabricated with Ti-bases. Primer (MKZ) and resin cement (DTK adhesive) were used to cement the frameworks to the Ti-bases under a static load of 10 N. After thermomechanical aging (1.2×106 cycles, 120 N, 5 °C-55 °C), marginal gaps between the Ti-bases and cemented frameworks and vertical and passive fits between the Ti-bases and framework and multi-unit abutments were measured by using a stereomicroscope (Euromex) at ×100 magnification. Fracture resistances and types were then determined by using a universal test machine and a stereomicroscope at ×40 magnification. Data were analyzed by using 1-way analysis of variance (ANOVA) and the Tukey HSD and Fisher-Freeman-Halton tests (α=.05).

RESULTS

The marginal gaps of the PEEK and Zir frameworks were respectively 83.5 ±27.1 and 81.8 ±17.8 µm. PEEK (23.7 ±4.6) and Zir (32.9 ±8.7) had a better vertical fit (µm) than Ti (52.5 ±10.6) (P<.001). Zir (49.3 ±16.2) (P<.001) and PEEK (70.9 ±19.6) (P>.05) frameworks had better passive fit (µm) than Ti (91.3 ±24.2). Ti had the highest mean fracture resistance (N) (14800.2 ±3442.3) followed by Zir (7318.7 ±1385.1) and PEEK (3448.9 ±486.6) (P<.001). Fracture types were different in different groups (P<.001).

CONCLUSIONS

The PEEK and Zir frameworks with Ti bases had better vertical and passive fit than the Ti frameworks. All ISP frameworks represented mean marginal fit below 92 µm and withstood physiologic occlusal forces after thermomechanical aging.

Effect of epoxy value on the rheological properties and microcosmic mechanism of WER emulsified asphalt

Waterborne epoxy resin (WER), a cleaning material with exceptional high-temperature resistance, has attracted much attention to modify emulsified asphalt in the pavement material field. Epoxy value is the critical characteristic index of WER. In this research, three WER with the epoxy values of 0.20 eq/100g, 0.44 eq/100g, and 0.51 eq/100g were utilized as asphalt modifiers. The influence of epoxy value on WER-EA was investigated by comparing the rheological properties of three kinds of WER emulsified asphalt (WER-EA). The modification mechanism of WER-EA has been analyzed using FTIR and SEM. The results demonstrate that different WER-EA resulted in significantly different rheological properties. WER-EA with the epoxy value of 0.20 eq/100g (E20) performed best at high temperatures, with a maximum increase of 17477% in G*/sinδ compared to the neat asphalt and a maximum increase of 66.3% in G*/sinδ compared to the other two WER-EA. WER-EA with 0.44 eq/100g epoxy value (E44) performed best at low temperatures, with a maximum increase in m value of 39.4% and a maximum decrease in S value of 33.3% compared to the other two WER-EA. In addition, the interpenetrating polymer network (IPN) in E20 was observed to be more solid and stable, and IPN in E44 was more uniform. To summarize, lower epoxy value led to a higher degree of WER reaction and higher content of rigid groups, which is more conducive to optimizing the high-temperature property of WER-EA. WER with moderate epoxy value resulted in a low content of polar bonds and thus high content of flexible segments, which helps emulsified asphalt to form a more uniform IPN.

Effect of the Addition of Naringenin Derived from Citrus on the Properties of Epoxy Resin Compositions

This research concerns the modification of commercially available epoxy resin with flame retardants in order to obtain aging-resistant and antimicrobial polymeric materials with a plant stabilizer dedicated to use in rail transport. Polymer compositions based on epoxy resin, fiberglass fabric, and naringenin were prepared. Naringenin was added as a natural stabilizer at 2, 4, and 8 phr. The materials were subjected to solar aging lasting 800 h. The hardness of the samples, surface energy, and carbonyl indexes were determined, and the color change in the composition after aging was analyzed. In addition, microscopic observations, analyses of mechanical properties, and microbiological tests were performed. The hardness determination showed that the samples retained their functional properties after solar aging. The increase in the polar component of the surface energy of all materials indicated the beginning of the degradation process of the composites. The tensile one-directional tests were carried out for plane samples taken in three directions (0, 90, and 45 degrees referred to a plate edge) before and after the aging process. The addition of naringenin did not affect the functional and surface properties of the epoxy resin-based materials. Polyphenol stabilized polymer composites, as evidenced by the results of carbonyl indexes. Moreover, the obtained samples showed good antimicrobial properties for E. coli and C. albicans in the field of testing the viability of microbial cells in contact with the tested surfaces.

Efficient expression of γ-glutamyl transpeptidase in Bacillus subtilis via CRISPR/Cas9n and its immobilization

In this study, we successfully applied the strategy of combining tandem promoters and tandem signal peptides with overexpressing signal peptidase to efficiently express and produce γ-glutamyl peptidase (GGT) enzymes (BsGGT, BaGGT, and BlGGT) from Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus licheniformis in Bacillus subtilis ATCC6051Δ5. In order to avoid the problem of instability caused by duplicated strong promoters, we assembled tandem promoters of different homologous genes from different species. To achieve resistance marker-free enzyme in the food industry, we first removed the replication origin and corresponding resistance marker of Escherichia coli from the expression vector. The plasmid was then transformed into the B. subtilis host, and the Kan resistance gene in the expression plasmid was directly edited and silenced using the CRISPR/Cas9n-AID base editing system. As a result, a recombinant protein expression carrier without resistance markers was constructed, and the enzyme activity of the BlGGT strain during shake flask fermentation can reach 53.65 U/mL. The recombinant BlGGT was immobilized with epoxy resin and maintained 82.8% enzyme activity after repeated use for 10 times and 87.36% enzyme activity after storage at 4 °C for 2 months. The immobilized BlGGT enzyme was used for the continuous synthesis of theanine with a conversion rate of 65.38%. These results indicated that our approach was a promising solution for improving enzyme production efficiency and achieving safe production of enzyme preparations in the food industry. KEY POINTS: • Efficient expression of recombinant proteins by a combination of dual promoter and dual signal peptide. • Construction of small vectors without resistance markers in B. subtilis using CRISPR/Cas9n-AID editing system. • The process of immobilizing BlGGT with epoxy resin was optimized.

POSS(epoxy)8 reinforced poly (butylene adipate-co-terephthalate)/lignin biodegradable films: Fabrication, enhanced mechanical properties and UV aging resistance

To reduce the white pollution, the eco-friendly biodegradable poly (butylene adipate-co-terephthalate) (PBAT)-based films had attracted increasing interests worldwide. However, the high-cost of the PBAT had limited the large-scale development and application. In this work, 10 wt% low-cost lignin was introduced into the PBAT to prepare composite films by melt blending and blow molding, and the POSS(epoxy)8 was selected as the compatibilizer to improve the compatibility of PBAT and lignin. The maximum tensile strength and the nominal strain at break subsequently increased by 48.2 % and 21.4 % respectively, while the water vapor permeability enhanced by 9.9 %. Furthermore, the UV aging resistance of PBAT/lignin films were significantly improved, with only 1 wt% POSS(epoxy)8 content. This work provides an efficient strategy to foster the end-user confidence in the low-cost and eco-friendly biodegradable polymer materials with efficient performance.

An in vitro assessment of optimizing implant positions in bilateral distal extension implant-assisted removable partial dentures: A microstress analysis

AIM

The aim of this study was to analyze and compare the stress distribution on dental implants in various positions when used with implant-assisted removable partial dentures.

SETTINGS AND DESIGN

This was an in vitro study.

MATERIALS AND METHODS

A model representing a mandibular bilateral partially edentulous condition, with missing premolars and molars, was fabricated using epoxy resin. Two implants of similar diameter measuring 4.0 mm × 10 mm (Dentium, Korea) were inserted in the second molar and the second premolar region on either side of the model for comparing the biomechanical effect of various implant locations. Two types of loads 100N and 125N were applied vertically using universal testing machines in the premolar and molar regions. The loads on the implants beneath the cast partial denture were measured by physical stress analysis using a microstrain gauge.

STATISTICAL ANALYSIS USED

A comparison of maximum stress observed at the premolar versus molar regions due to the application of the 100N and 125N loads was done using the Mann-Whitney U-test.

RESULTS

In physical stress analysis, obtained results were statistically analyzed, and the result was statistically not significant (P = 0.435 at 100N and P = 0.718 at 125N) in positional changes of implant.

CONCLUSION

In the current study, the statistical analysis of physical stress revealed no significant differences in stress values between the loadings at the premolar and molar regions. This suggests that the implant can be placed in either the premolar or molar region based on the availability of bone without affecting stress distribution.

Comparative Evaluation of Push-out Bond Strength of Three Different Root Canal Sealers: An In Vitro Study

AIM

The aim of this present study was to compare the dislodgement resistance of calcium silicate-based sealer, zinc oxide sealer, and a new sealer combining both zinc oxide and calcium silicate-based sealer in vitro.

MATERIALS AND METHODS

60 single-rooted human teeth were instrumented with F3 Protaper Gold. All endodontic canals were filled using gutta percha cones using the cold lateral condensation technique in combination using one of the mentioned sealers (n = 20 per group). The teeth were divided into three groups: group A consisted of Sealite® Ultra, group B consisted of K-Sealer®, and group C consisted of BioRoot® RC. After 2 months of incubation (37°C, 100% humidity) and after cutting out 2 mm from the most apical portion of the root apex, six slices of 1 mm thickness were generated. Mechanical dislodgement resistance was examined using a universal pressure-testing machine and the push-out bond strength (POBS) was calculated. Specimens were examined under 20× magnification to define the bond failure mode. Statistical analysis was executed using ANOVA, post hoc Turkey test for pairwise comparisons and Kruskal-Wallis tests.

RESULTS

The POBS of BioRoot® was significantly higher than the POBS of the two other sealers with a mean of 10.54 MPa ± 2.10 and 5.73 MPa ± 2.34, respectively (p < 0.001). Sealite® and K-Sealer® showed similar results in the median and coronal part. K-Sealer® revealed highest POBS compared with Sealite® in the apical part (p < 0.05).

CONCLUSION

The POBS of the zinc oxide and calcium silicate-based sealer was significantly lower compared with calcium silicate. Sealite® and K-Sealer® exhibited almost same results. BioRoot showed the highest POBS of all sealers.

CLINICAL SIGNIFICANCE

The current study was needed to evaluate the bond strength of three different cements to dentinal walls, by evaluating their respective POBS in vitro. The findings of this study may provide guidance for the clinician in the selection of an adequate endodontic sealer that guarantees an enhanced adhesive seal between the Gutta-percha and the dentinal canal walls. How to cite this article: Makhlouf MP, El Helou JD, Zogheib CE, et al. Comparative Evaluation of Push-out Bond Strength of Three Different Root Canal Sealers: An In Vitro Study. J Contemp Dent Pract 2024;25(1):15-19.

Biobased, cellulose long filament-reinforced vanillin-derived epoxy composite for high-performance and flame-retardant applications

The development of high-strength and intrinsic flame-retardant natural fiber-reinforced green composite (NFRGC) is a landmark for high-performance structural applications. This paper reports a biobased, high-performance, flame-retardant composite material based on diverse bio-resources. Tough and strong cellulose long filaments (CLFs) are combined with vanillin-derived epoxy (VDE) resin to achieve high strength and flame-retardant NFRGC. The green composite was fabricated using a simple hand lay-up and compression molding technique. The green composite showed a noteworthy increment of 100.9 % flexural strength and 346 % flexural modulus compared to the neat VDE resin. Interestingly, despite the highly flammable nature of CLF, the green composite passes a V-0 rating under the UL-94 test, indicating excellent flame-retardant characteristics. Additionally, the green composite demonstrated outstanding hydrophobicity with a water contact angle of 104.2° and good chemical stability in various acidic and organic solvents. The green composite's excellent mechanical and physical properties show its potential for high-strength and flame-retardant structural applications.

Epoxy resin for solidification/stabilization of soil contaminated with copper (II): Leaching, mechanical, and microstructural characterization

Among different types of heavy metal-contaminated soil, copper (Cu)-contaminated soil is very serious, and the Cu concentration in it is usually very high. It is common to solidify/stabilize Cu-contaminated soil using alkaline cementitious material. However, the remediated Cu-contaminated soil fails to meet the requirements of environmental safety and load-bearing capacity. This dilemma in the remediation of Cu-contaminated soil hinders the effective utilization of land resources. In this study, epoxy resin (EP) was utilized to solidify/stabilize Cu-contaminated soil due to its stable and rapid curing performance and excellent resistance to acid, alkali, and salt erosion. The mechanical properties, environmental effects, and curing mechanism of EP-cured Cu-contaminated soil were investigated. The results showed that the application of EP significantly enhanced the unconfined compressive strength (UCS), cohesion and internal friction angle of Cu-contaminated soil. All specimens met the UCS criterion specified by the United States Environmental Protection Agency (USPEA), namely no less than 0.35 MPa, which indicated that those EP-cured Cu-contaminated soil were qualified for practical engineering applications. According to the toxicity characteristic leaching procedure (TCLP), the application of EP enhanced the stability of Cu in Cu-contaminated soil. The leaching index of Cu ranged from 11 to 14. A high leaching index showed that the S/S treatment was safe and effective and the remediated Cu-contaminated soil satisfied the environmental requirement for heavy metals. This study confirmed the feasibility of utilizing EP in the solidification/stabilization (S/S) technology to convert high-concentration Cu-contaminated soil into secure and stable engineering materials. The remediation of Cu-contaminated soil by EP lays a solid foundation for the safe treatment and reuse of heavy metal-contaminated land resources.

Development of cashew nut shell lignin-acrylonitrile butadiene styrene 3D printed core and industrial hemp/aluminized glass fiber epoxy biocomposite for morphing wing and unmanned aerial vehicle applications

The aim of this study was to develop a lightweight epoxy based biocomposite for morphing wing and unmanned aerial vehicle (UAV) applications. The proposed composite was developed using a 3D printed high stiffness lignin-Acrylonitrile Butadiene Styrene (ABS) core and industrial hemp with aluminized glass fiber epoxy skin. The ABS was reinforced using lignin macromolecule derived from cashew nut shells via twin screw extruder and the core was printed using an industrial grade 3D printer. Furthermore, the composites were prepared by compression moulding with an ABS-lignin core and hemp/aluminized GF surface and characterized according to respective American society of testing and materials (ASTM) standards. The findings indicate that the addition of 30 vol% Al-glass and hemp fiber with lignin strengthened ABS core improved the mechanical properties. The composite material designated as "E2" exhibits the maximum mechanical properties, providing tensile strength, flexural strength, Izod impact, interlaminar shear strength (ILSS), and compression values of, 136 MPa, 168 MPa, 4.82 kJ/m2, 21 MPa, and 155 MPa respectively. The maximal energy absorbed by composite designation "E2," during drop load impact test is 20.6 J. Similarly, the composite designation "E2"gives fatigue life cycles of 33,709, 25,781 and 19,633 for 50 %, 70 % and 90 % of ultimate tensile strength (UTS) and 32.5 (K1c) MPa⋅m and 0.76 (G1c) MJ/m2 in fracture toughness and energy release rate respectively.

A comparative study of biological properties of three root canal sealers

OBJECTIVES

The aim of this study was to evaluate the effects of Hiflow with other two kinds of root canal sealers on the biological behavior of stem cells from the apical papilla (SCAP), the influence on inflammatory cytokines release and its antibacterial effects.

MATERIALS AND METHODS

Material extracts of Hiflow, iRoot SP, and AH Plus were prepared. Then, SCAP was incubated with extracts. The effects were evaluated by CCK-8, wound healing assay, ALP staining, alizarin red staining, and qRT-PCR. Meanwhile, polymorphonuclears (PMNs) and monocytes were isolated and treated with extracts for 4 h and 24 h respectively. Cell viability was analyzed by Annexin-V/PI double staining flow cytometry. The effects on the release of cytokines were observed by ELISA. The antibacterial effects of different sealers were tested against three kinds of bacteria found in chronic apical periodontitis.

RESULTS

A series of results of SCAP showed that Hiflow and iRoot SP could promote cell proliferation, migration, and osteogenesis (p < 0.05). Although Hiflow was associated with greater cell apoptosis and necrosis when incubated with PMNs and monocytes (p < 0.05), it had an approximate release of anti-inflammatory cytokines with iRoot SP, which was higher than AH plus (p < 0.05). The co-culture showed that Hiflow and iRoot SP inhibited the colony formation of F. nucleatum (p < 0.05). However, both sealers had no obvious antibacterial effect on E. faecalis and P. gingivalis (p > 0.05).

CONCLUSIONS

In summary, Hiflow and iRoot SP both had positive biological stimulus on SCAP. Meanwhile, Hiflow showed a better induction on anti-inflammatory cytokines over the others. All the properties mentioned above and its antibacterial effect of F. nucleatum promise Hiflow a bright application prospect in endodontic uses.

CLINICAL RELEVANCE

References for clinical work to use BC Sealer Hiflow as a good biological root canal sealer.

A twelve element dual-band MIMO antenna for 5G smartphones

In this paper, a 12x12 dual-band MIMO antenna for 5G smartphones is proposed. It operates in the sub 6 GHz (2.4GHz and 3.5GHz) frequency bands. The MIMO antenna elements are printed on an FR4 epoxy substrate that has a thickness of 0.8mm. The main substrate measures 150 × 75 × 0.8 mm3, while the side substrates have dimensions of 75 × 6 × 0.8mm3. The twelve dual-band antenna elements are compact in size. Each antenna element size is reduced significantly, which is 11.20 × 5.98 mm2(0.0896λ × 0.04784λ). These antenna elments are arranged in such a way that the MIMO antenna not only provides polarization diversity but also helps in achieving good performance in terms of isolation, which is more than 13.5 dB between two adjacent antenna elements. Another significance of the proposed antenna is that both the frequency bands can be tuned independently by varying the corresponding length of each arm. The performance parameters like efficiency is around 40-56% for the lower band and it is 48-62% for the upper band. The envelope correlation coefficient (ECC) is below 0.04 in both frequency bands for the proposed dual band MIMO antenna.

The Effects of Calcium Silicate- and Calcium Hydroxide-based Root Canal Sealers on Postoperative Pain: A Randomized Clinical Trial

INTRODUCTION

This study aimed to compare the postoperative pain level changes resulting from using calcium silicate- (EndoSeal MTA) and calcium hydroxide-based (Sealapex) root canal sealers in mandibular first and second molar teeth with symptomatic apical periodontitis.

METHODS

A total of 60 patients with symptomatic apical periodontitis in their lower molar teeth were randomly allocated into 2 groups according to sealer type (n = 30). Demographic data, including gender, age, and smoking habit, and preoperative pain measures were recorded. Root canal treatments were performed in a single visit. Postoperative pain measurements and analgesic intake were measured at 6, 12, 24, and 48 hours and after 3, 5, and 7 days using the visual analog scale. The data were statistically analyzed using a chi-squared test (to compare gender, age, smoking habit, analgesic intake, and sealer extrusion), the Mann-Whitney U test (to compare pain levels), Friedman tests (for the evaluations of the reduction in pain levels over time), and Spearman's correlation test (to analyze the relationships of age, gender, smoking habit factors with postoperative pain) (P = .05).

RESULTS

The statistical analysis showed no significant differences between the groups in postoperative pain and analgesic intake at any of the time intervals evaluated (P > .05).

CONCLUSIONS

Patients treated with calcium silicate- and calcium hydroxide-based root canal sealers experienced similar postoperative pain and no statistically significant differences were observed in analgesic intake.

Comparative analysis of thermo-physical and mechanical properties of PALF/CF/epoxy resin with and without nano TiO2 filler

The performance of an engineering material depends on its potentiality and characterization under different mechanical and thermal test environments. The present research study has revealed the performance of a new class of hybrid composites, focused specially on the general trends observed in their impact of fabrication and its properties. To investigate how the mechanical and thermal qualities of the epoxy matrix may be improved, pineapple leaf fibre and carbon fibre were particularly chosen. By embedding the selected filler into the Pineapple leaf Fiber/Carbon Fiber(PALF/CF) reinforced epoxy resin, coordination effects, impact of embedding were achieved in the form of modified mechanical and thermal properties. The present research work is focused to perform the thermal and mechanical properties of pineapple leaf fiber/carbon fiber reinforced epoxy resin(ER) composites with and without particulate nano TiO2 fillers. The comparison of hybrid fibre (carbon and pineapple leaf fibre) reinforced epoxy composites with and without particulate nano TiO2 fillers was done. The results of the mechanical tests demonstrated that, in comparison to all other composites, the inclusion of nano fillers improved the tensile, flexural, and impact strengths. Nano particle reinforced with hybrid composite has a score of 23.4, whereas clean epoxy only gets a score of 4.5. It follows from this example that the presence of nanoparticles raises the residual values.

Cytotoxicity and genotoxicity of various types of endodontic sealers in Chinese hamster ovary (CHO-K1) cells

This study aimed to evaluate the cytotoxicity and genotoxicity of five endodontic sealers (AH Plus, MTA Fillapex, Endoseal MTA, Sealapex, and Zinc oxide eugenol) in Chinese hamster ovary cells. Cytotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay to check cell viability at 1, 3, and 7 days. Genotoxicity was assessed by cytokinesis-block micronucleus, single-cell gel electrophoresis, and γH2AX immunofluorescence assays. Cell viability of all endodontic sealers, except Endoseal MTA, on day 1 was less than 100%. Endoseal MTA showed the highest cell viability on day 7. AH Plus and Endoseal MTA showed less DNA damage than other sealers. After complete setting, AH Plus and Endoseal MTA showed low genotoxicity, which could reduce DNA damage in periapical cells, making them suitable as endodontic sealers.

Evaluation of push-out bond strength, dentinal tubule penetration and adhesive pattern of bio-ceramic and epoxy resin-based root canal sealers

INTRODUCTION

Root canal sealing materials play a crucial role in an endodontic procedure by forming a bond between the dentinal walls and the gutta-percha. The current study aims to analyse the dentinal tubule penetration and adhesive pattern, including the push-out bond strength of six commercially available root canal sealers.

METHODOLOGY

Eighty-four mandibular first premolars were split into seven groups (and n = 12), Group 1: Dia-Root, Group 2: One-Fil, Group 3: BioRoot RCS, Group 4: AH Plus, Group 5: CeraSeal, Group 6: iRoot SP, Group 7: GP without sealer (control). Two groups were made, one for dentinal tubule penetration and the other for push-out bond strength; the total sample size was one hundred sixty-eight. Root canal treatment was performed using a method called the crown down technique, and for obturation, the single cone technique was used. A confocal laser scanning microscope (Leica, Microsystem Heidel GmbH, Version 2.00 build 0585, Germany) was used to evaluate dentinal tubule penetration, and Universal Testing Machine was utilised to measure the push-out bond strength (Shimadzu, Japan) using a plunger size of 0.4 mm and speed of 1mm/min. Finally, the adhesive pattern of the sealers was analysed by HIROX digital microscope (KH-7700). Statistical analysis was carried out by a one-way Anova test, Dunnet's T3 test, and Chi-square test.

RESULTS

Highest dentinal tubule penetration was noticed with One-Fil (p<0.05), followed by iRoot SP, CeraSeal, AH Plus, Dia-Root also, the most negligible value was recorded for BioRoot RCS. Meanwhile, BioRoot RCS (p<0.05) demonstrated the greater value of mean push-out bond strength, followed by One-fil, iRoot SP, CeraSeal, AH Plus and Dia-Root. Regarding adhesive pattern, most of the samples were classified as type 3 and type 4 which implies greater sealing ability and better adherence to the dentinal wall. However, BioRoot RCS revealed the most type 4 (p<0.05), followed by AH Plus, One-Fil, CeraSeal and Dia-Root.

CONCLUSION

The highest dentinal tubule penetration was shown by One-Fil compared to other groups. Meanwhile, BioRoot RCS had greater push-out bond strength and more adhesive pattern than other tested materials.

Eco-Friendly One-Pot Supramolecular-Assembly of P-N Flame Retardant for Fire-Safe Epoxy Resin

Flame retardant treatment of epoxy resins (EP) to reduce their flammability for extending their range of applications attracts considerable attention. However, the synthesis process of conventional flame retardants is complicated and involves organic hazardous solvents. Meanwhile, how to ensure both the flame-retardant and mechanical properties is a long-standing and actual difficult problem. In this work, a supramolecular flame retardant (named ATPFR) is facilely created by one-pot reaction, using cheap and accessible raw materials in an ecologically benign aqueous solvent. ATPFR is applied to improve the fire safety of EP. With only 5 wt% ATPFR addition, EP can reach the limiting oxygen index of 28.5% and the UL-94 V-0 rating with a significant "blow-out effect." The cone calorimetry test reveals that the EP thermoset with 5 wt% ATPFR has a 75.8% reduction in the peak heat release rate (p-HRR) and a 67.3% reduction in the peak smoke production rate (p-SPR), respectively, compared with the pure EP. Additionally, EP composites with the small amount of ATPFR exhibit a slight decrease and maintain good mechanical properties. Therefore, the facile synthesis and application of this supramolecular flame retardant provide a reliable way for the construction of polymer materials with environment-friendly and effective flame-retardant system.

Construction of hierarchical SiO2 microcapsule towards flame retardation, low toxicity and mechanical enhancement of epoxy resins

A novel approach for improving the flame retardancy, smoke suppression and mechanical properties of epoxy resins (EPs) has been proposed by incorporating functionalized hollow mesoporous silica microcapsules (SHP) loaded with phosphorous silane flame retardants (SCA) and coated with polydopamine (PDA) and transition metals. The proposed approach involves a multi-level structure that combines several mechanisms to enhance the flame-retardant properties of EP. The physical barrier provided by silica serves to impede heat and mass transfer during combustion, while the catalytic carbonization effect of phosphorus and transition metals promotes the formation of a protective char layer, which acts as a barrier to further flame propagation. Incorporating a low loading amount of 3 wt% SHP into the epoxy matrix resulted in EP/SHP-3 composites with significantly improved flame retardancy, as evidenced by a limiting oxygen index of 31.5% and a V-1 rating, in contrast to the values obtained for unmodified EP, which were 23.8% and no rating, respectively. In addition, cone calorimeter test (CCT) results indicated that the total heat release, peak heat release rate and total smoke production of EP/SHP-3 decreased by 18.2%, 25.2% and 18.4%, respectively. Moreover, the improved interfacial compatibility facilitated by polydopamine assists in the dispersion and compatibility of the SHP with the epoxy matrix, leading to better mechanical properties. Herein, the addition of 1 wt% SHP to EP significantly improved its mechanical performance, with a 16.7% increase in tensile strength and a 19.2% increase in impact strength. The design of the multi-level structural approach has the potential to provide new ideas for the simultaneous improvement of fire safety as well as mechanical properties of polymers.

Tooth discoloration induced by endodontic sealers and cervical limit: 1-year in vitro evaluation

This laboratory study aimed to evaluate the influence of endodontic sealer and cervical limit of root filling on the discoloration of root canal treated teeth. Bovine incisors were randomly distributed into six experimental groups and control (n=21/group), according to the endodontic sealer used [AH Plus (AP); MTA Fillapex (MF) and Sealer Plus BC (SPB)] and the cervical limit of root filling [dental cervix (DC) or 2 mm in apical direction (2mm-AD)]. Tooth discoloration (ΔE) was evaluated by a digital spectrophotometer using the CIED2000 method. Color assessments were performed immediately before (baseline), 1 week, 1, 3, 6 months, and 1 year after obturation. Data were analyzed by ANOVA and Tukey's post-hoc tests (α=5%). Teeth filled with the three sealers showed perceptible tooth discoloration (ΔE≥2.7) in 1 week, maintaining similar values over time. There was a significant difference between MF and SPB sealers in the 2mm-AD groups. In addition, 2mm-AD groups promoted significantly lower discoloration than DC groups for AH (3 months) and SPB (1 and 3 months) sealer,s. Teeth filled with AP, MF, and SPB sealers displayed discoloration from 1 week to one year, with differences between MF and SPB sealers. A cervical limit of filling material at 2 mm from the dental cervix seems more advisable, promoting lower crown discoloration.

Carbon dioxide capture with aqueous calcium carbide residual solution for calcium carbonate synthesis and its use as an epoxy resin filler

Calcium carbide residue (CCR) is a waste obtained from the production of acetylene gas by the hydration reaction of calcium carbide. This residue is generated in large quantities annually and requires appropriate disposal. The main composition of the residue is calcium hydroxide (Ca(OH)2). Ca(OH)2 can react with CO2 gas and form CaCO3 particles. This process is well known but not very attractive since Ca(OH)2 is obtained from limestone using an energy-intensive thermal conversion process. This paper examined the synthesis of CaCO3 from CCR solutions by capturing CO2 with the aid of triethanolamine (TEA) solutions at doses of 0, 5, 10 and 20% w/w. The precipitated CaCO3 was characterized, and the application of CaCO3 as a filler in epoxy resin was tested. The results showed that the precipitated CaCO3 was mainly calcite, with a 76.6% yield. Cubic calcite was primarily obtained in TEA solutions, whereas small and agglomerated spherical vaterite and cubic calcite particles were formed in non-TEA solutions. The CaCO3-filled epoxy composites showed higher compressive strength than the neat resin. However, the transparency of specimen plates was reduced. These results can serve as guidelines for the application of CCR slurry filtrate obtained from the sedimentation ponds of acetylene plants and help to reduce the amount of wastewater that needs to be treated. CO2 gas from industrial flue gas combined with TEA solution could be applied to precipitate CaCO3 for carbon-neutral manufacturing.

Leaching behavior of copper tailings solidified/stabilized using hydantoin epoxy resin and red clay

Tailings produced by mining engineering and metal smelting industries have become a major challenge to the ecological environment and human health. Environmental compatibility, mechanical stability, and economic feasibility have restricted the treatment and reuse of tailings. A novel solidification/stabilization technology using hydantoin epoxy resin (HER) and red clay for copper tailing treatment was developed, and the leaching behaviors of solidified/stabilized copper tailings were investigated in this paper. The leaching characteristics were analyzed by toxicity characteristic leaching procedure (TCLP) leaching tests. Besides, the influence of red clay content and acid rain on the permeability characteristics and leaching characteristics were investigated based on flexible-wall column tests and microstructure tests. The results showed that the copper tailings solidification/stabilization technology with HER and red clay had excellent performances in toxicity stabilization. The leaching concentration of Cu in TCLP tests and flexible wall column tests remained within the limit specified by the Chinese national standard, and the concentration of Cu decreased significantly with the increase of the red clay content. Moreover, acid rain leaching changed the mineral composition and microstructure of solidified tailings, and the porosity of the samples increased with the dissolution of soluble minerals. Additionally, the hydraulic conductivities decreased slightly with the increase in the pH value of acid rain, and the solidified sample with 5% red clay had the lowest hydraulic conductivity.

Effect of the alumina micro-particle sizes on the thermal conductivity and dynamic mechanical property of epoxy resin

Epoxy thermal conductive adhesives with high thermal conductivity and dynamic mechanical properties are important thermally conductive materials for fabricating highly integrated electronic devices. In this paper, micro-Al2O3 is used as a thermally conductive filler for the epoxy resin composite and investigated the effect of micron-sized alumina particle size on the thermal conductivity and dynamic mechanical property of epoxy resin by the transient planar hot plate method and DMA (Dynamic mechanical analysis). The experimental results show that with the same amount of alumina filling, the thermal conductivity and Tg (glass transition temperature) of epoxy/Al2O3 composite material decrease with the increase of alumina particle size. The maximum thermal conductivity of the composite material is 0.679 (W/mK), while the energy storage modulus of epoxy/Al2O3 composite material increases with the increase of alumina particle size, and the maximum energy storage modulus of the composite material is 160MPa. Compared with pure epoxy resin, the thermal conductivity and energy storage modulus have increased by 2.7 and 3.2 times, respectively. The epoxy/Al2O3 composite was applied to the COB (Chips On Board) type LED package, and the substrate temperature of the LED dropped to the lowest after 1.5 hours of operation using EP-A5 composite, and the temperature was stabilized at 38.2°C, indicating that the addition of 5-micron alumina composite has the best heat dissipation in the COB type LED package. These results are critical for the implementation of particulate-filled polymer composites in practical applications because relaxed material specifications and handling procedures can be incorporated in production environments to improve efficiency.

Recent advances in in-resin correlative light and electron microscopy of Epon-embedded cells

Correlative fluorescent and electron microscopic images of the same section of epoxy (or other polymer)-embedded samples, hereafter referred to as 'in-resin CLEM', have been developed to improve the positional accuracy and Z-axis resolution limitations of conventional correlative light and electron microscopy (CLEM). High-pressure freezing and quick-freezing substitution result in in-resin CLEM of acrylic-based resin-embedded cells expressing green fluorescent protein, yellow fluorescent protein, mVenus and mCherry, which are sensitive to osmium tetroxide. The identification of osmium-resistant fluorescent proteins leads to the development of in-resin CLEM of Epon-embedded cells. Using subtraction-based fluorescence microscopy with a photoconvertible fluorescent protein, mEosEM-E, its green fluorescence can be observed in thin sections of Epon-embedded cells, and two-color in-resin CLEM using mEosEM-E and mScarlet-H can be performed. Green fluorescent proteins, CoGFP variant 0 and mWasabi, and far-red fluorescent proteins, mCherry2 and mKate2, are available for in-resin CLEM of Epon-embedded cells using the standard procedure for Epon-embedding with additional incubation. Proximity labeling is applied to in-resin CLEM to overcome the limitations of fluorescent proteins in epoxy resin. These approaches will contribute significantly to the future of CLEM analysis.

Enhancement of Antimicrobial Effect of Endodontic Sealers Using Nanoparticles: A Systematic Review

INTRODUCTION

The elimination of biofilms during root canal therapy continues to pose a challenge due to complex anatomies and uninstrumented portions of the root canal system. The incorporation of nanoparticles in endodontic sealers is an area of interest for potentially enhancing antimicrobial activity and improving treatment outcomes. This systematic review evaluated the antimicrobial effects of various nanoparticles in endodontic sealers.

METHODS

Comprehensive literature review was conducted using the electronic Embase, Web of Science, and PubMed databases followed by citation searching for articles eligible per the inclusion criteria.

RESULTS

A total of 1845 citations were screened, of which 13 articles met the inclusion criteria and were included in this review. All included articles were in vitro studies with low-to-moderate quality assessment scores. The incorporation of select nanoparticles was associated with significant enhancement of antibacterial effects in planktonic and/or biofilm forms, whereas other nanoparticles were not.

CONCLUSIONS

The incorporation of certain types and concentrations of nanoparticles into endodontic sealers displayed antimicrobial effects in vitro. The need for well-designed clinical studies translating in vitro findings into clinical practice is warranted. The incorporation of nanoparticles may enhance the antimicrobial properties of endodontic sealers and may improve treatment outcomes.

Mechanical, tribological, and surface morphological studies on the effects of hybrid ilmenite and silicon dioxide fillers on glass fibre reinforced epoxy composites

Recently, researchers have been attempting to enhance the mechanical and tribological characteristics of thermosetting epoxy composites by incorporating inorganic nanoparticles and ensuring their uniform distribution throughout the matrix. This study characterises ball-milled ilmenite (FeTiO3-size of 63 nm) and silicon dioxide (SiO2-size of 67.5 nm) fillers added to epoxy in proportions of 0:0, 2.5:2.5, 5:5, and 7.5:7.5% by weight. A liquid ultrasonic technique is used to blend the fillers with the epoxy, and compression moulding is used to fabricate the composite. Mechanical tests were performed based on ASTM standards. Tensile strength, tensile modulus, flexural strength, flexural modulus and elongations at break(tensile and flexural test) of 5:5 wt % are 30.54%, 12.2%, 32.22%, 28.98%,23.78% and 23.53% higher than neat sample respectively. Shore "D" hardness and Izod's impact strength are 4.65% and 98.93% higher at 5:5 wt % than neat sample respectively. Specific wear rate decreased from 2.6 × 10-11 m3/Nm (neat GFRP: 0 wt % glass fibre reinforced polymer composite) to 0.7 × 10-11 m3/Nm at 5:5 wt % filler. Nanoparticles lowered the coefficient of friction by around 16.66%, 60.42%, and 33.33% at sliding distances of 100 m for 2.5:2.5, 5:5, and 7.5:7.5 wt % respectively with the neat sample. A 5:5 wt percent resulted in 76.68% less wear volume loss than pure GFRP. Field emission scanning electron microscopy (FESEM) analysis revealed element distributions, particle size, pullout of fibers, damaged interfaces, filler dispersion, voids, wear debris, interfacial debonding, and cavities. Thus, this approach enhances GFRP composite's mechanical, tribological, and structural properties.