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This study aimed to evaluate the shear bond strength (SBS) when bonding a universal resin cement to a disilicate glass‐ceramic using different adhesive protocols. Sixty specimens were etched with 10% hydrofluoric acid (HF) for 20 s and assigned to one of four treatment protocols (n = 15): The Positive control protocol comprised use of a universal adhesive system + adhesive resin cement; the Test1 protocol comprised use of a new universal adhesive system + universal resin cement; the Test2 protocol comprised use of a silane coupling agent + universal resin cement; and the use of a universal resin cement without adhesive and silane served as the Negative control. One of the two resin cement cylinders built on each specimen in each group was used to test for 24‐h SBS, while the other was thermocycled and then tested for SBS. Data were submitted to two‐way ANOVA, Tukey's test, and Weibull analysis. The negative control (24 h) showed the lowest SBS mean value. The Test2 protocol resulted in the highest SBS mean value after thermocycling. Adhesive and mixed failures were prevalent in all groups. No statistical difference in m values was observed among the groups at 24 h. After thermocycling, the two Test protocols showed the highest m values. The m values were significantly lower after thermocycling than at 24 h for all groups. After thermal aging, The Test2 protocol resulted in a statistically significantly higher SBS mean value after thermal aging than seen for the other groups. [ABSTRACT FROM AUTHOR]

Statement of the Problem: The creation of a proper seal of the root canal with canal-filling materials, such as gutta-percha and sealer, is one of the essential factors in the success of root canal treatment. In addition, the penetration depth of the sealer is one of the influential factors in creating a proper seal, which improves the sealing ability of the canal and the burial of microorganisms. Purpose: This study aimed to investigate the effect of cold atmospheric plasma on the depth of tubular penetration of two types of resin sealer: AH26 and Beta RCS sealers. Materials and Method: In this experimental study, thirty-two premolar teeth with single root and single canal were selected as samples and after cutting their crowns from the apex distance of 15mm, the canals were prepared with rotary files. Samples were divided into four groups of eight, according to the type of sealer and plasma application: AH26 sealer (AH), plasma+AH26 sealer (PAH), Beta RCS sealer (Beta), and plasma+Beta RCS sealer (PBeta). The cold lateral condensation technique was used for the obturation of canals. The maximum penetration depth and the percentage of sealer penetration were obtained from microscopic images at three coronal, middle, and apical sections. Due to the non-normal distribution of data, the Mann-Whitney U test was used for statistical analysis (p< 0.05). Results: No significant difference was observed between the study groups in the penetration percentage and maximum penetration depth of AH and Beta in the presence and absence of plasma. However, in the coronal section, the depth of maximum sealer penetration was significantly higher in the AH group than in the Beta group (p< 0.05). Conclusion: The use of plasma did not affect the maximum penetration depth and penetration percentage of AH26 sealer and Beta RCS sealer. [ABSTRACT FROM AUTHOR]

Background: This in vitro study aimed to evaluate the effect of sodium hypochlorite (NaOCl) and ethylene diamine tetraacetic acid (EDTA) as pretreatments on the resin infiltration efficacy and acid resistance of enamel white spot lesions (WSLs). Methods: Enamel blocks prepared from the buccal surfaces of sound human premolars were placed in a demineralisation solution for 3 days to establish artificial enamel WSLs. All the blocks with WSLs were randomly divided into four groups (n = 40 per group): RI (Control): resin infiltration only. N/RI: 5.25% NaOCl pretreatment + resin infiltration; E/RI: 17% EDTA pretreatment + resin infiltration; NE/RI: combined pretreatment of 5.25% NaOCl with 17% EDTA + resin infiltration; Enamel pore exposure was measured by using SEM observation and Image J software in each group after pretreatment prior to resin infiltration (n = 8 per group). Resin penetration depth and enamel surface microhardness were assessed after resin infiltration (n = 8 per group for each test) by a confocal laser scanning microscope and a Vickers' microhardness test respectively. The remaining specimens were subjected 7 days of pH cycling after which surface enamel roughness and microhardness were assessed by an atomic force microscope and a microhardness test respectively. Results: Compared to the control group, the enamel surface pore exposure (p = 0.007), resin penetration depth (p = 0.011) and enamel surface microhardness (p < 0.001) were all significantly increased after the pretreatment of 5.25% NaOCl alone or combined with 17% EDTA by one-way ANOVA. After pH cycling, no significant differences were found in enamel surface roughness or microhardness among the four groups (p = 0.55) by two-way ANOVA. Conclusions: Enamel surface pretreatment of 5.25% NaOCl or combined with 17% EDTA improved the efficacy of the resin infiltration of WSLs, but might be useless in enhancing the acid resistance of resin-infiltrated WSLs. [ABSTRACT FROM AUTHOR]

Background: This clinical study aims to compare postoperative pain after single-visit root canal treatment of teeth with asymptomatic apical periodontitis using epoxy-resin-based AH Plus and calcium silicate-based Endosequence BC sealers with or without sonic activation. Methods: This study included 72 individuals with one first or second mandibular premolar tooth with asymptomatic apical periodontitis. They were randomly divided into four groups according to the root canal sealer (AH Plus or Endosequence BC) and activation protocol (sonic activation or non-activation) (n = 18). The participants were ask to rate their postoperative pain intensity on a NRS scale as none, minimal, moderate, or severe after 24 h, 48 h, 72 h, and 7 days following treatment. Patients were also asked to record the number of prescribed analgesic medication tablets (400 mg of ibuprofen) taken. Statistical analysis were performed using the Mann-Whitney U test, the Friedman test, the Spearman's correlation test, the Chi-square test. Significance level was established at 0.05. Results: There was no statistically significant difference in postoperative pain scores or analgesic intake between AH Plus and Endosequence BC sealers regardless of the activation protocol (p > 0.05). There was no statistically significant difference in postoperative pain scores between the sonic activation and non-activation groups (p > 0.05). A weak positive correlation was detected between Endoactivator sonic activation and sealer extrusion (r = 0.36). Conclusions: AH Plus and EndoSequence BC root canal sealers showed similar results in terms of prevalance and intensity of postoperative pain. Sonic activation and non-activation groups had similar postoperative pain scores. Clinical trial registration: The study was retrospectively registered with ClinicalTrials.gov (NCT06403293). Date of Registration: 07/05/24. [ABSTRACT FROM AUTHOR]

AbstractBisphenol A (BPA), a synthetic chemical widely used in the production of polycarbonate plastic and epoxy resins, has been associated with a variety of adverse effects in humans including metabolic, immunological, reproductive, and neurodevelopmental effects, raising concern about its health impact. In the EU, it has been classified as toxic to reproduction and as an endocrine disruptor and was thus included in the candidate list of substances of very high concern (SVHC). On this basis, its use has been banned or restricted in some products. As a consequence, industries turned to bisphenol alternatives, such as bisphenol S (BPS) and bisphenol F (BPF), which are now found in various consumer products, as well as in human matrices at a global scale. However, due to their toxicity, these two bisphenols are in the process of being regulated. Other BPA alternatives, whose potential toxicity remains largely unknown due to a knowledge gap, have also started to be used in manufacturing processes. The gradual restriction of the use of BPA underscores the importance of understanding the potential risks associated with its alternatives to avoid regrettable substitutions. This review aims to summarize the current knowledge on the potential hazards related to BPA alternatives prioritized by European Regulatory Agencies based on their regulatory relevance and selected to be studied under the European Partnership for the Assessment of Risks from Chemicals (PARC): BPE, BPAP, BPP, BPZ, BPS-MAE, and TCBPA. The focus is on data related to toxicokinetic, endocrine disruption, immunotoxicity, developmental neurotoxicity, and genotoxicity/carcinogenicity, which were considered the most relevant endpoints to assess the hazard related to those substances. The goal here is to identify the data gaps in BPA alternatives toxicology and hence formulate the future directions that will be taken in the frame of the PARC project, which seeks also to enhance chemical risk assessment methodologies using new approach methodologies (NAMs). [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is a plasticizer used to synthesize polycarbonate plastics and epoxy resins and is well-known for its endocrine-disrupting action. BPA occurrence in the environment is widespread, and there is a growing concern regarding exposure to this chemical during childhood, given the findings indicating the long-lasting hazards associated with exposure during early life compared to adulthood. We examined urinary BPA concentrations from 319 elementary school-aged Brazilian children, using high-performance liquid chromatography coupled to high-resolution mass spectrometry. We found that urinary BPA was detectable in the majority of children, and that urinary BPA levels were higher among children with lower family income and lower maternal educational levels. BPA levels found herein were compared with those from countries with different regulation policies concerning exposure to BPA. They were similar to those reported from studies conducted in Egypt and Australia. Despite more protective regulatory policies in the European Union, they were similar or lower than those reported in European studies. Our findings indicate that exposure of Brazilian children to BPA is widespread and comparable to or even lower than that of countries with stricter regulatory policies. [ABSTRACT FROM AUTHOR]

A brief overview of chromatographic methods for determining free bisphenol A (BPA) in technical and food products is presented. Bisphenol A is used as a monomer in the production of some plastics and epoxy resins. The concentration of free BPA may exceed the permissible level in food plastic containers and in food products packaged in these containers. The maximum permissible concentration of BPA in water, in water bodies of domestic and drinking water and in cultural and household water use is 0.1 mg/dm3. In European countries, the migration value of BPA for plastics in contact with food products is 0.6 mg/kg. Gas chromatography with preliminary derivatization by the silylation or acylation of the analyte is most often used to determine BPA in plastics, food products, and biological fluids. Direct determination methods have been developed using gas-liquid chromatography on heat-resistant columns. Flame ionization, fluorometric, and mass-selective detectors are used as detection devices. HPLC with optical and mass-selective detectors is used to determine BPA. Thin-layer chromatography has also been used for determining BPA. Solid-phase extraction, liquid−liquid extraction, dispersive liquid−liquid microextraction, and a combined extraction method with separation in acetonitrile (QuEChERS) are used in BPA sample preparation. [ABSTRACT FROM AUTHOR]

Indoor radon is one of the most significant contributors to lung cancer after smoking. Mitigation strategies based on protecting buildings with radon barrier materials, combined with home ventilation or room pressurization, are regularly used. A scale model room made from a porous ignimbrite rich in radon precursors was used as an analogue to test the efficiency of fifteen airtight membranes to reduce radon levels, also in combination with room pressurization. The results of these experiments were considered together with previous ones to propose the scale model room approach as a tool for rapidly evaluating the performance of specially designed radon barrier materials, and for radiation exposure assessment. Relative reduction of indoor radon (RIR) ranges from −20 to −94%. The most effective materials were FPO membrane, single-component silane-terminated polymer membranes and synthetic resins. The presence of additives likely modified the composition and structure of some products, improving their radon barrier capacity. The introduction of room pressurization further reduced radon levels in the model room where the membranes were applied. The overpressure necessary to reach RIRs of the order of 85–90% is very low for materials that powerfully stop radon even without ventilation, but necessarily higher for poorer membranes. [ABSTRACT FROM AUTHOR]

Copyright of Materiały Budowlane is the property of Wydawnictwo SIGMA-NOT and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper experimentally investigates the behavior of innovative sustainable Low-Cost Bamboo Composite (LCBC) structural columns under compressive loading. The LCBC columns are manufactured from bamboo culms in combination with bio-based resins to form composite structural columns. Different LCBC cross-sectional configurations are investigated in this study, including the Russian doll (RD), Big Russian doll (BRD), Hawser (HAW), and Scrimber (SCR). Two bio-based resins, including one bio-epoxies and one furan-based resin, in addition to a soft bio-based filler and a synthetic epoxy resin, are applied. The bamboo species used as the cast-in-place giant bamboo for all configurations include Moso, Guadua, and Tali. Slender LCBC columns showed maximum stress equal to 60 MPa at failure. The study found that the samples with bio-epoxy resin (BE2) exhibited enhanced material stiffness when compared to synthetic epoxy (EPX) and furan-based resin (PF1), while PF1 specimens demonstrated increased ductility. Among the specimens with Moso bamboo and BE2 resin, those with SCR and HAW configurations achieved the highest compressive strengths. [ABSTRACT FROM AUTHOR]

During the Roman age, the southern promontory of the gulf of Baia was the perfect location for the construction of villae maritimae for the Roman élite that decided to spend their summer residences by the sea. One of these residences is now located in the military fortress of the Castello Aragonese di Baia, built in 1495 CE during the Aragonese period (15th century). Here, during restoration works, the ruins of the residential sector of the villa, which historical sources ascribe to Caesar, were unearthed. The most representative evidence of this is the outstanding in situ remain of mosaics, decorated plasters and finely frescoed surfaces decorated according to the repertoire of the II style. This research aims to investigate the polychromy of a wall decoration representing a perspective depiction of architectural scenes en trompe l'oeil analysed by means of a multi-analytical, non-destructive approach performed in situ. The combined use of spectroscopic techniques (portable X-ray fluorescence, Raman and Fourier Transform Infrared Spectroscopy) points out the use of a characteristic Roman palette, quantitatively assessed by colorimetric measurements. It consists of red and yellow ochre, calcite, hematite, organic black pigments, precious materials such as cinnabar and Egyptian blue, green copper compounds. Fourier Transform Infrared Spectroscopy also revealed the presence of synthetic resins, likely used for the conservation of mural paintings. These are, however, damaged by atmospheric humidity, as detected by Infrared Thermography. Gypsum has been identified as the main weathering product. [ABSTRACT FROM AUTHOR]

Considerable efforts have been made to replace formaldehyde-containing adhesives in the manufacturing of wood products, particularly particleboard, with natural alternatives. One promising solution is the liquefaction of lignocellulosic materials such as wood using glycerol (C3H8O3) under sulfuric acid catalysis (H2SO4). The aim of this study was to investigate the chemical composition and properties of spruce and oak biomass after liquefaction and to evaluate its potential as a formaldehyde-free adhesive substitute. All samples were liquefied at 150 °C for 120 min in five different wood–glycerol ratios (1:1 to 1:5). The liquefaction percentage, the insoluble residue, the dry matter and the hydroxyl (OH) number were determined as characteristic values for the polymer properties of the liquefied samples. The results showed the liquefaction percentage was up to 90% for spruce and oak. The insoluble residue ranged from 10 to 29% for spruce and from 10 to 22% for oak, the dry matter ranged from 54 to 70% for spruce and from 51 to 62% for oak, while the highest xydroxyl number was 570 mg KOH/g for spruce and 839 mg KOH/g for oak. Based on these results, liquefied wood was shown to be an effective natural alternative to synthetic resins in particleboard adhesives and a way to reduce formaldehyde emissions. This research not only supports environmentally sustainable practices but also paves the way for various bioproducts derived from liquefied biomass and points to future avenues for innovation and development in this area. [ABSTRACT FROM AUTHOR]

A rapid method is developed for the determination of bisphenol A (BPA) in ethanolic extracts by gas chromatography–mass spectrometry (GC–MS). The GC–MS method has acquired reference status in accredited analytical laboratories in identifying contaminant impurities in food and alcohol products. Bisphenol A is used as a monomer in the production of a number of plastics and epoxy resins; in its free form, it can be contained in quantities exceeding the permissible level in food containers. Bisphenol A can accumulate in a human body and cause harmful health effects. The studies were performed on an Agilent 8890 gas chromatograph equipped with a mass selective detector model 5977B and a 30 m long Ultra ALLOY®-5 UA5-30M-0.25F capillary column. Optimal modes for the determination of bisphenol A in ethanolic extracts were selected. The direct determination of BPA in ethyl solutions without derivatization using GC–MS can be recommended for the development of procedures for monitoring the quality and safety of food packaging, monitoring BPA in alcohol-containing liquids, as well as in forensic medical examination as a reference procedure to confirm the reliability of BPA identification. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, nanocellulose aqueous dispersions were studied as a bio-inspired consolidating agent for the recovery and conservation of ancient wood and compared with two of the most used traditional consolidants: the synthetic resins Paraloid B-72 and Regalrez 1126. The morphology of crystalline nanocellulose (CNC), determined using Scanning Electron Microscopy (SEM), presents with a rod-like shape, with a size ranging between 15 and 30 nm in width. Chemical characterization performed using the Fourier-Transform Infrared Spectroscopy (FT-IR) technique provides information on surface modifications, in this case, demonstrating the presence of only the characteristic peaks of nanocellulose. Moreover, conductometric, pH, and dry matter measurements were carried out, showing also in this case values perfectly conforming to what is found in the literature. The treated wood samples were observed under an optical microscope in reflected light and under a scanning electron microscope to determine, respectively, the damage caused by xylophages and the morphology of the treated surfaces. The images acquired show the greater similarity of the surfaces treated with nanocellulose to untreated wood, compared with other consolidating agents. Finally, a colorimetric analysis of these samples was also carried out before and after a first consolidation treatment, and after a second treatment carried out on the same samples three years later. The samples treated with CNC appeared very homogeneous and uniform, without alterations in their final color appearance, compared to other traditional synthetic products. [ABSTRACT FROM AUTHOR]

Background: No consensus exists on how molar incisor hypomineralisation (MIH) should be covered by the undergraduate dental curricula. Aim: To assess the current teaching and assessment of MIH in the UK. Design: A piloted questionnaire regarding the teaching and assessment of MIH was disseminated to paediatric, restorative and orthodontic teaching leads in each UK dental school (n = 16). Data were analysed using descriptive statistics, chi‐squared and Kruskal–Wallis tests. Results: Response rates from paediatric, restorative and orthodontic teams were 75% (n = 12), 44% (n = 7) and 54% (n = 8), respectively. Prevention of caries, preformed metal crowns, anterior resin composites and vital bleaching were taught significantly more by paediatric teams (p =.006). Quality of life and resin infiltration were absent from restorative teaching. Orthodontic teaching focussed on the timing of first permanent molar extractions. Paediatric teams were mainly responsible for assessment. Risk factors, differential diagnoses for MIH and defining clinical features were more likely to be assessed by paediatric teams than by others (p =.006). All specialities reported that students were prepared to manage MIH. Conclusion: Molar incisor hypomineralisation is primarily taught and assessed by paediatric teams. No evidence of multidisciplinary or transitional teaching/assessment existed between specialities. Developing robust guidance regarding MIH learning in the UK undergraduate curricula may help improve consistency. [ABSTRACT FROM AUTHOR]

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bisphenol A (BPA) has been extensively applied for the production of polycarbonate plastics and epoxy resins, which has gained increasing attention due to its ubiquitous presence and adverse effect on ecosystems and human health. Various biological strategies (such as BPA biodegradation by bacteria, fungi, algae, and plants) have been developed to address BPA contamination issue. This review systematically summarized and analyzed recent advances in biological methods for BPA degradation, including bacterial, fungal, algal, and plants, highlighting the efficiency and mechanisms of BPA degradation. By analyzing the common intermediates of BPA biodegradation by bacteria, fungi, algae and plants reported in previous studies, the typical biodegradation pathways were proposed. The review further addressed the contentious topic of anaerobic BPA degradation, noting the scarcity of definitive evidence endorsing this process. Further, the common enzymes and typical enzymatic reactions involved in the biodegradation process of BPA were summarized. This review will deepen the understanding of BPA biodegradation, leading to the discovery of more efficient microorganisms and highly effective enzymatic catalysts for remediating BPA contamination. [ABSTRACT FROM AUTHOR]

Most traditional adhesives applied in the wood industry are synthetic resins obtained from petroleum. However, the production of these resins raises substantial environmental issues because of formaldehyde release, which leads to detrimental impacts on both human health and the environment. In contrast, bio-based adhesives offer an eco-friendly option that is created by renewable biomass resources. These adhesives can effectively overcome the above problems. Hence, it is crucial to pay more attention to bio-based adhesives. However, the inherent characteristics of the raw materials used in the production of bio-based adhesives result in a number of limitations, including weak bond strength, poor water resistance, and susceptibility to mildew, which restrict their further applications. Most researchers have used physical and chemical methods to modify bio-based adhesives in order to improve their overall performance. The defects of bio-based adhesives, including their limited bond strength, inadequate resistance to water, and vulnerability to mildew, are summarized in this paper, and the investigation of potential modification methods on bio-based adhesives is reviewed. Moreover, we encourage the widespread use of bio-based adhesives in various fields to promote sustainable development due to their eco-friendly characters. [ABSTRACT FROM AUTHOR]

Background: Calcium silicate-based bioceramics have been applied in endodontics as advantageous materials for years, many chemical components and new synthesizing methods were used to improve the base formulation of the materials for positively affecting the sealers properties. Recently, a novel biomaterial formulation, grounded in strontium silicate, has been introduced to the market, offering potential advancements in the field. Objective: To comparatively analyze the cytotoxicity and cell migration effects of a novel strontium silicate-based bioceramic material (CRoot SP) and those of calcium silicate-based (iRoot SP) and epoxide amine resin (AH Plus) sealers on stem cells derived from rat apical papilla(rSCAPs). Methods: rSCAPs were isolated and characterized in vitro and subsequently cultured in the presence of various concentrations of CRoot SP, iRoot SP and AH Plus extracts. Cytotoxicity was assessed by CCK-8 assay, and cell-migration capacity was assessed by using wound healing assays. Results: No significant differences in cell viability were observed in the 0.02 mg/mL and 0.2 mg/mL sealer groups. The cell viability of CRoot SP was consistently greater than that of iRoot SP at concentrations of 5 mg/mL and 10 mg/mL across all time points. Maximum cytotoxic effect was noted on day 5 with 10 mg/mL AH Plus.The scratch was partly healed by cell migration in all groups at 24 h, and the 0.02 mg/mL, and 0.2 mg/mL CRoot SP exerted beneficial effects on rSCAPs migration. Conclusions: CRoot SP exhibited less cytotoxic than the iRoot SP and AH Plus extracts after setting. A lower concentration of CRoot SP thus promotes the cell migration capacity of rSCAPs, and it may achieve better tissue repair during root canal treatment. [ABSTRACT FROM AUTHOR]

Introduction: Resin composites have been commonly used in restorative dentistry over the years. The longevity of restorations depends upon various physical properties like as solubility. Composite solubility can lead to deleterious effects on the polymer structure. Aim: To evaluate and compare the solubility of a single shade resin composite in comparison to a conventional resin composite in artificial saliva. Materials and Methods: In the present in-vitro study, 44 pellets (10 mm x 1 mm) were prepared from each material. The pellets were divided into two groups (n=22) based on the immersion period of two days and seven days. They were incubated, weighed using an analytical balance, and then immersed in artificial saliva. Weighing was done again after the completion of the immersion period, and solubility was calculated. Paired and independent sample t-tests were used to compare the solubility of both materials after two days and seven days. Results: The differences of solubility values for the single shade composite and conventional composite at two and seven-day intervals were (p=0.031) and (p=0.019), respectively, which were statistically significant. On inter-group comparison, the difference in solubility of the single shade composite at two days was significantly lower compared to conventional composites (p=0.024). Whereas, no significant difference was observed in solubility values between both groups at seven days (p=0.102). Conclusion: The performance of the single shade composite in terms of solubility was better in comparison with conventional composite. [ABSTRACT FROM AUTHOR]

Amber has been used to create decorative items for centuries, but its degradation presents challenges for conservators. This study identifies substances historically used to protect amber objects, especially those from 17th and 18th century Gdansk workshops. Despite their historical value, information on amber conservation is scarce. Traditional substances are noted, but their exact compositions and effects on amber remain unclear. Synthetic resins, introduced in the late 19th century, also degrade, complicating conservation due to their removal difficulty and interference with amber identification. This research aimed to develop methods for detecting and analyzing protective coatings on amber objects using macroscopic and microscopic techniques. Initial methods included analytical photography under visible and UV light and reflectance imaging spectroscopy (RIS) to assess the surface. Raman spectroscopy (RS) and X-ray fluorescence spectroscopy (XRF) were used for detailed analysis. RS provided precise layer-specific information but was sensitive to surface conditions, while XRF quickly identified inorganic compounds but not organic materials. Examining amber objects from Polish collections using this methodology revealed various protective substances, including synthetic resins and nitrocellulose varnishes. This research contributes to amber conservation by proposing a comprehensive material analysis approach, essential for developing effective conservation strategies for these historic objects. [ABSTRACT FROM AUTHOR]

Wormwood powder (WP) was used to perform antibacterial modification on traditional thermosetting plastic epoxy resin (EP) to prepare EP with antibacterial function, so as to solve the problems of shortening life span and hygiene caused by bacterial erosion of EP. The dynamics of curing process of antibacterial EP was studied, so as to understand the influence of WP on its curing behavior. It lays a theoretical foundation for selecting reasonable processing conditions. The curing behavior of EP/WP was studied by DSC. The results showed that the antibacterial rate of the composites increased with the addition of WP. When the addition of WP was 20%, the antibacterial rate of the composites against Escherichia coli and Staphylococcus aureus reached 100%. The curing activation energy Ea of pure EP was 74.80 kJ/mol, EP/20% WP was 68.17 kJ/mol, indicating that the addition of WP promoted the curing of EP and reduced its curing activation energy. Through theoretical model analysis, it was found that the curing behavior of EP with WP was consistent with the autocatalytic mechanism. [ABSTRACT FROM AUTHOR]

This research is aimed at analyzing existing plugging compositions and developing a new plugging composition based on phenol-formaldehyde resin. This paper presents the results of studies of a hardening composition based on phenol-formaldehyde resin for repair and insulation work in wells. The plugging composition consists of two parts: Component "A" (resin and additives) and Component "B" (hardener). A resol-type water-soluble phenol-formaldehyde resin was selected for testing. The resin was additionally modified with special additives to improve performance properties. A mixture of acids was chosen as a hardener. Concentrations of resin and hardener were selected to ensure optimal loss of fluidity of the composition for different temperatures. The main physicochemical properties of the plugging composition were determined. The elastic-strength characteristics of the developed composition after curing at various temperatures (Poisson's ratio, Young's modulus, and compressive strength) were assessed. It has been experimentally proven that samples based on phenol-formaldehyde resin do not collapse completely under load but undergo longitudinal and transverse deformations. As the amount of hardener in the system increases, the compressive strength decreases. The presence of the elastic-strength properties of cementing compositions based on synthetic resins distinguishes them favorably from hardening compositions based on cement and microcement. [ABSTRACT FROM AUTHOR]

Fibre-reinforced polymers (FRPs) are widely used in industry due to their impressive strength-to-weight ratio, corrosion resistance and high durability. One of the primary components of FRPs is synthetic resins, specifically epoxy, which has been identified as harmful to the environment. To address this concern, an eco-friendly alternative made from basalt fibres and bio resin has the potential to reduce the environmental impact. This study investigates Basalt Fibre-Reinforced Polymer (BFRP) laminates manufactured using two bio resins, AMPRO™ BIO and Change Climate, comparing them to one conventional epoxy resin, WEST SYSTEM®, in terms of tensile modulus, strength and fracture toughness, as well as shear properties. The results indicate that BFRP laminates made with bio resins exhibit comparable or better mechanical properties to their conventional counterparts with tensile strength being between 6 and 17% more in bio resins compared to the conventional resin, thereby paving the way for further exploration of sustainable FRP laminates in future engineering applications. [ABSTRACT FROM AUTHOR]

This research aims to enhance traditional glass fiber composites by utilizing a mediumreactive unsaturated polyester resin (UPR) synthesized from ortho-phthalic anhydride. The UPR is formulated using unsaturated acids, glycols, and styrene monomers, with the reaction tailored to improve mechanical properties beyond those of standard commercial resins. The liquid resin's properties are evaluated for manufacturing viability, and its solidified form demonstrates superior performance compared to industrial benchmarks. The composite, produced via the hand layup technique, features a reduced resin-to-glass fiber ratio. Mechanical property tests confirm its robustness. Additionally, scanning electron microscopy (SEM) analysis reveals the microstructural characteristics to study the UPR performance. [ABSTRACT FROM AUTHOR]

The primary aim of this research was to explore the feasibility of producing environmentally friendly composite materials by employing diverse hybrid matrices consisting of dammar natural resin, supplemented with small proportions of two synthetic resins: one epoxy and the other acrylic. A blend of paper and chicken feathers served as the reinforcing elements. The fabrication of these composite materials utilized a hand layup technique. Targeted for applications in the furniture industry or interior design, their mechanical properties were assessed through various tests. Specimens were obtained from the manufactured samples and subjected to evaluations for tensile strength, compression, flexure, vibrations, Shore hardness, and water absorption. Results indicated that irrespective of the testing method employed, the mechanical strength properties exhibited a decline with an increase in the percentage of dammar in the hybrid resins, whereas the elasticity properties demonstrated an increase with this percentage. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the fracture load of monolithic, single-tooth implant-supported crowns cemented on solid or Ti-base (Variobase C) abutments. Materials and Methods: Besides abutment types (solid and Ti-base abutments), two ceramic systems (IPS e.max CAD and Zirconia inCoris ZI) and two occlusal thicknesses (0.5 and 1.5 mm) were also investigated in this study. In total, eight groups (n = 8) with 64 maxillary second premolar crowns were fabricated. All the crowns were cemented with resin cement, and the screw accesses in Ti-base groups were sealed with composite resin. After mechanical cycling, the specimens were submitted to fracture load test with the maximum force recorded in Newtons (N). Three-way analysis of variance (ANOVA) and Tukey post hoc test were used for statistical analyses (α = .05). Results: Both the abutment type (P = .0001) and the ceramic system (P = .0001) significantly affected the results. Screw-access channels reduced the fracture load of crowns by half compared to those cemented on solid abutments. The 1.5-mm and 0.5-mm zirconia crowns placed on solid abutments had similar highest fracture loads, while the e.max CAD groups positioned on Ti-base abutments showed significantly lower values compared with other groups. Conclusion: The screw access reduces the resistance of crowns supported by Ti-base abutments compared to crowns cemented on solid abutments. The inCoris ZI showed a higher fracture load than the IPS e.max CAD regardless of the abutment type and thickness. [ABSTRACT FROM AUTHOR]

Resin‐based three‐dimensional (3D) printing finds extensive application in the field of dentistry. Although studies of cytotoxicity, mechanical and physical properties have been conducted for newly released 3D printing resins such as Crowntec (Saremco), Temporary Crown Resin (Formlabs) and Crown & Bridge (Nextdent), the resistance of these materials to esterases in saliva has not been demonstrated at the molecular level. Therefore, in this study, the binding affinities and stability of these new 3D printing resins to the catalytic sites of esterases were investigated using molecular docking and molecular mechanics with Poisson–Bolzmann and surface area solvation (MM/PBSA) methods after active pocket screening. Toxicity predictions of the materials were also performed using ProTox‐II and Toxtree servers. The materials were analyzed for mutagenicity, cytotoxicity, and carcinogenicity, and LD50 values were predicted from their molecular structures. The results indicated that out of the three novel 3D printing materials, Nexdent exhibited reduced binding affinity to esterases, indicating enhanced resistance to enzymatic degradation and possessing a superior toxicity profile. [ABSTRACT FROM AUTHOR]

Hydrometallurgical gold recovery processes play a pivotal role in the gold mining industry, contributing to more than 90% of global gold production. Among the array of techniques available, the Merrill–Crowe process, adsorption, ion exchange, and solvent extraction are central in extracting gold from leach solutions. While the Merrill–Crowe process and gold complex adsorption onto activated carbon represent historical cornerstones, their inherent limitations have prompted the emergence of more recent innovations in ion exchange and solvent extraction, offering enhanced selectivity, control, and sustainability. The evolution of modern organic chemistry has significantly influenced the progress of ion exchange technology, mainly through the introduction of advanced polymer matrix synthetic resins. At the same time, novel solvents tailored to gold complex interactions have revitalized ion exchange and solvent extraction. Introducing ionic liquids and deep eutectic solvents has also added a new dimension to efforts to improve gold extraction metallurgy. This paper reviews these cutting-edge developments and their potential to revolutionize the hydrometallurgical gold recovery process, addressing the pressing need for improved efficiency and environmental responsibility. [ABSTRACT FROM AUTHOR]

Egyptian Faience, a revolutionary innovation in ancient ceramics, was used for crafting various objects, including amulets, vessels, ornaments, and funerary figurines, like shabtis. Despite extensive research, many aspects of ancient shabti production technology, chemistry and mineralogy remain relatively understudied from the 21st to the 22nd Dynasty, belonging to a recovered 19th-century private collection. The fragments' origin is tentatively identified in the middle Nile valley in the Luxor area. Our study focused on a modest yet compositionally interesting small collection of shabti fragments to provide information on the glaze's components and shabti's core. We found that the core is a quartz and K-feldspars silt blended with an organic component made of plastic resins and vegetable fibres soaked with natron. The studied shabti figurines, after being modelled, dried, and covered with coloured glaze, were subjected to a firing process. Sodium metasilicate and sulphate compounds formed upon contact of the glaze with the silica matrix, forming a shell that holds together the fragile inner matrix. The pigments dissolved in the sodic glaze glass, produced by quartz, K-feldspars, and natron frit, are mainly manganese (Mn) and copper (Cu) compounds. The ratio Cu2O/CaO > 5 produces a blue colour; if <5, the glaze is green. In some cases, Mg and As may have been added to produce a darker brown and an intense blue, respectively. Reaction minerals provided information on the high-temperature firing process that rapidly vitrified the glaze. These data index minerals for the firing temperature of a sodic glaze, reaching up to a maximum of 1050 °C. [ABSTRACT FROM AUTHOR]

INTRODUCTION Smoking is a common risk factor for multiple diseases, including diabetes mellitus, cardiovascular diseases, pulmonary diseases, and different cancers. It is an established cause of multiple oral health conditions, in addition to adversely impairing the appearance of oral tissues. Smoking has also been identified to impact dental restorations' functional and esthetic aspects. This narrative review is focused on the significance of the esthetic consequences of smoking on resin-based dental restoration. It provides an understanding of the challenges dental professionals and patients face. METHODS A literature search was conducted to identify studies on the impact of smoking exposure on the esthetic appearance of composite restorations. The inclusion criteria were met by five studies selected for analysis. RESULTS The studies revealed that conventional cigarettes cause more noticeable color changes than electronic cigarettes. Additionally, the choice of composite material significantly influences the color stability of dental restorations. Exposure to both smoking and staining agents could worsen the color alterations in dental restorations. Smokers may benefit from dental ceramics, which offer better aesthetics. Quantitative insights into these effects can be gained by incorporating delta E (AE) values and fluorescence intensity in esthetic evaluations. CONCLUSIONS The studies provide valuable insights into the multiple factors that can impact the aesthetics of dental restorations. Dental professionals should take into account the smoking type, composite material, and patient habits when planning treatments. Utilizing AE values and fluorescence intensity in esthetic evaluations can provide a more comprehensive understanding. Future research should focus on longitudinal studies, alternative materials, and individual patient profiles. [ABSTRACT FROM AUTHOR]

Diatoms are among the most common epibionts and have been recorded on the surfaces of various living substrates, either plants or animals. However, studies on them are still scarce in view of the many substrata available. In this study, epibiotic diatoms living on Callinectes bellicosus were identified for the first time from a subtropical coastal lagoon in Northwest Mexico. We tested the null hypothesis that the diatom flora living on the carapaces of C. bellicosus would not be similar to that recorded for mangrove sediments, its typical habitat. The epibiotic diatoms were brushed off from the carapaces of two specimens, acid-cleaned, mounted in synthetic resin, and identified based on frustule morphology. This way, 106 taxa from 46 genera were recorded, including 25 singletons, and 6 new records for the Mexican northwest region. The best-represented genera were Nitzschia (10 taxa), Mastogloia (9), Diploneis (8), Navicula (7), Amphora (5), Cocconeis (5), Tryblionella (4), and Gyrosigma (4). Species composition included 93% of local taxa, thus refuting the proposed hypothesis and supporting the alternate one. Although the estimated species richness was lower than that in sediments, it deems the green crab carapace a favorable substrate for the growth of benthic diatoms. [ABSTRACT FROM AUTHOR]

A metallic foam specimen was plastically joined with a resin (polymethyl methacrylate, PMMA) sheet by applying friction stir incremental forming (FSIF) process. In FSIF process, a rotating flat-ended (no probe) rod tool was pushed vertically and fed horizontally against the resin sheet which was placed on the foam. The tool operation heated frictionally the resin and deformed incrementally to the resin, while the tool operation did not deform plastically to the cellular matrix of the foam. Due to the plastic flow of the heated resin, the bottom of the resin was interlocked mechanically to the pores near the top surface of the foam. In this study, the relationship between the pore morphology (form and size) and the joining characteristics (joinability, flow thickness of the resin, and joining strength) was investigated using commercial open-cell nickel and closed-cell aluminum foams. According to the experimental investigations, the foam with small size and low depression angle of the surface pore showed better results in relation with the joining strength and the (flow thickness of the resin)/(depth of the surface pore). [ABSTRACT FROM AUTHOR]

Polypropylene is one of the most widely used synthetic resins, which is mainly synthesized with Ziegler-Natta catalysts. In this paper, the functionalized Ziegler-Natta catalyst is applied to prepare high-performance polypropylene. A new way to synthesize functionalized Ziegler-Natta catalysts is to dope with inorganic nanoparticles. The MgCl2 /TiCl4 /BMMF catalysts doped with halloysite nanotubes were prepared and applied to synthesize polypropylene containing less than 200 ppm halloysite nanotubes. It is found that doping nanotubes in Ziegler-Natta catalyst has little impact on the structure, composition and activity of the catalyst, and polypropylene with high isotactic degree and molecular weight was synthesized with the functionalized Ziegler-Natta catalyst. Halloysite nanotubes are found to be dispersed in polypropylene in the form of individual nanotube, forming percolated network in the polymer melt effectively. Moreover, the polypropylene containing halloysite nanotubes exhibited better mechanical and thermal resistance properties as compared with conventional polypropylene, and the thermo-oxidative properties of which do not deteriorate as the introduction of nanotubes. This research provides a facile way to relieve the contradiction between the high activity of catalyst and high content of nanoparticles during the preparation of polyolefin nanocomposites by in-situ polymerization, and a new idea to prepare polyolefin nanocomposites by in-situ polymerization. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) has several potential uses, including in polycarbonate plastics and epoxy resins, which could expose humans to it. Recognized for its hepatotoxicity and ability to accumulate in organs. We prompted this study to explore the hepatoprotective potential of astaxanthin (ASTX), an antioxidant against BPA toxicity. We used 32 male Wistar Albino rats and randomly assigned them as: Control, Sham (olive oil), BPA, and BPA+ASTX. At the end of the experiment, Native Thiol, Total Thiol, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were measured in serum samples. Histopathological scoring was performed to evaluate the changes caused by ASTX in the liver. Caspase 3 and caspase 9 expression in liver tissues was demonstrated immunohistochemically and by PCR. Collagen I (COL1A1) and collagen III (COL3A1) mRNA levels were measured by PCR in the tissue samples. The BPA group showed elevated AST and ALT with decreased Thiol levels. ASTX administration reversed these changes as observed by reduced AST and ALT levels and increased Thiol levels. Histopathology indicated increased liver damage and fibrosis in the BPA group which were alleviated in the BPA+ASTX group. Gene expression analyses revealed upregulated COL1A1 and COL3A1 in BPA, which was downregulated with ASTX. Immunohistochemistry and PCR confirmed BPA-induced caspase 3 and caspase 9 expression, which were attenuated by ASTX. This study underscores ASTX's hepatoprotective efficacy against BPA-induced hepatotoxicity which ultimately attributed to its antioxidant and antiapoptotic properties. Consequently, ASTX emerges as a promising therapeutic agent for preventing and treating BPA-related liver diseases. [ABSTRACT FROM AUTHOR]

A purification method is developed to determine 90Sr in radioactive waste. A separation based on Sr-resin® with a pretreatment using TRU-resin® provides satisfactory Sr recovery yields before the 90Sr measurement by liquid scintillation counting (LSC) regardless the analyzed samples with low or high activity level. The selectivity of the procedure is checked by measuring the 90Y ingrowth after different days of separation without waiting for secular equilibrium. In order to obtain a REACH compliant method without scintillation cocktails, a plastic scintillation resin selective for Sr is implemented on the basis of the developed protocol. The optimized method is applied successfully to representative nuclear waste including samples with high Pu content (effluents, concretes and sludges). [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of different cavity designs and cement types on the fracture resistance of monolithic zirconia inlay-retained fixed dental prostheses (IRFDPs).Materials and Methods: Four study models consisting of a second premolar, a missing first molar, and a second molar were used for the different cavity designs. Four different inlay cavity designs were prepared: DO-MO (disto-occlusal-mesio-occlusal cavity), MOD-MOD (mesio-occlusodistal-mesio-occlusodistal cavity), WDO-WMO (DO-MO with additional wings), and WMOD-WMOD (MOD-MOD with additional wings). A total of 64 epoxy resin models were produced and scanned individually. IRFDPs were then fabricated from monolithic zirconia using CAD/ CAM software. The bonding surface of the IRFDPs was airborne particle abraded (50-μm alumina/2 MPa), then cemented onto the epoxy resin models using two cementation protocols (n = 8 per group): (1) P = cemented with Panavia SA Cement Plus Automix; and (2) Z/C = cemented with MDP-containing primer (Z-Prime Plus) combined with Calibra Universal resin cement. All IRFDPs were fatigued through thermal aging (6,000 cycles/5°C to 55°C) and chewing simulations (600,000 cycles × 50-N load, 2.1 Hz). All IRFDPs were then subjected to a fracture resistance test using a universal testing machine with a crosshead speed of 0.2 mm/minute. Data were statistically analyzed using one- and two-way ANOVA and Bonferroni multiple comparisons test (P = .001).Results: The mean fracture load (N) of the designs were as follows: WMODWMOD = 1,111.1; WDO-WMO = 1,057.4; MOD-MOD = 725.6; DO-MO = 682.7. According to two-way ANOVA, the differences among the cavity designs were statistically significant (P < .05).Conclusion: The cavity design of IRFDPs affected the fracture resistance. However, the fracture resistance of monolithic zirconia IRFDPs with any cavity design was enough to withstand expected posterior chewing forces. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to measure and compare the retention degrees of different attachment systems before and after 1 year of mastication and removal/insertion simulations. Materials and Methods: A 4 x 10--mm implant embedded in self-curing acrylic resin was placed inside a rectangular metal frame installed in a plastic container with artificial saliva at 37ºC. Three different attachment systems were connected to the implants: Dalbo Classic, Locator (with blue, pink, and clear inserts), and Klockner Rotula. A loading test at 100 N and 1.25 Hz frequency was repeated 10 times for each attachment (changing the matrix component or plastic insert) until a total of 300,000 cycles and 1,095 removal/insertion sequences. The retention force was assessed at baseline until the end of the test (1 year) after 3-month intervals of simulation. One-way analysis of variance (ANOVA) and post hoc Tukey test (P < .05) were performed for statistical analyses. Results: Klockner Rotula showed the highest retention values at the beginning (69.6 ± 9.2 N; 7.1 ± 0.9 kg) and the end of the test (51.4 ± 5.4 N; 5.2 ± 0.6 kg), while Dalbo Classic showed the lowest values both at the beginning (13.1 ± 1.7 N; 1.3 ± 0.2 kg) and the end of the test (6.7 ± 1.6 N; 0.7 ± 0.2 kg). Locator with clear insert exhibited the lowest retention loss ratio (20.4%), while Locator with blue insert showed the highest (50.8%). At the end of the test, all attachment systems showed a significant decrease in retention force in comparison with the initial retention (P < .001). Conclusion: Locator attachments with clear and pink inserts and the Klockner Rotula attachment system showed retention forces > 20 N (2 kg) after 1 year of mastication and prosthesis insertion/removal simulation. All attachment systems showed a progressive loss of retention, which was higher for Locator attachments with blue and pink inserts and Dalbo Classic. The Klockner Rotula attachment system showed the highest retention values both at the beginning and the end of the test. [ABSTRACT FROM AUTHOR]

The replacement of synthetic and petroleum-based ingredients with greener alternatives of natural origin is an imperative issue in rubber technology for the tire industry. In this study, a glycerin-esterified maleated rosin resin, derived from natural resources, is examined as a potential tackifier in styrene–butadiene rubber (SBR) formulations. A comparison is made with two synthetic resins commonly used as tackifiers in tire manufacturing: a petroleum-derived aromatic resin and a phenolic resin. Specifically, this research investigates how these resins affect the structure, dynamics, and curing characteristics of SBR compounds, which are strictly related to the mechanical and technological properties of the final products. Moving die rheometer and equilibrium swelling experiments are employed to analyze vulcanization kinetics and crosslink density, which are differently influenced by the different resins. Information on the polymer–resin compatibility is gained by differential scanning calorimetry and dynamo-mechanical analysis, while solid-state NMR methods offer insights into the structure and dynamics of both cured and uncured SBR compounds at the molecular level. Overall, our analysis shows that the resin of vegetal origin has a comparable impact on the SBR compound to that observed for the synthetic resins and could be further tested for industrial applications. [ABSTRACT FROM AUTHOR]

Over time, Goldner's trichrome staining has been essential in paraffin soft tissue research. However, its classic application involves prior decalcification, generating disadvantages in the integrity of the samples and the interpretation of results. This study seeks to overcome the limitations associated with decalcification when applying Goldner's trichrome stain with plastic resins. It focuses on detailed visualization of non-decalcified bone and dental samples in animal models. Samples of jaw and tooth from a dog (Canis familiaris) were used, as well as tibia from a rabbit (Oryctolagus cuniculus) with a titanium dental implant and bone graft substitute. Adjustments were made to the original protocol, including a surface treatment prior to staining. Plastination and inclusion in specific plastic resins were part of the process. The microplastinated and stained samples showed optimal quality for optical microscopy. Those from dogs allowed detailed observation of the tooth-periodontal tissue relationship, while those from rabbits revealed a clear differentiation between mineralized and osteoid bone tissue. The staining made it easy to examine the precise interface between soft tissues, bone graft, and implant. The successful adaptation of Goldner's trichrome stain to specimens in plastic resins represents a significant advance in histological investigation of hard tissues. This methodology stands out as an effective tool to evaluate implants and biomaterials in animal models, providing detailed visualization without compromising the integrity of the samples. The combination of histochemistry and plastic resins offers a valuable alternative for microanatomical studies, opening new possibilities in hard tissue research and evaluation of bone structures. [ABSTRACT FROM AUTHOR]

This study investigates the potential of fatty acid methyl esters (FAME) as environmentally sustainable alternatives to traditional solvents for the removal of low-polarity materials commonly found in cultural heritage artefacts. Recognizing the environmental and health concerns associated with conventional solvents, this research focuses on FAME to remove low/non-polarity or non-polar substances used in cultural heritage preservation. Laboratory samples coated with low molecular synthetic resins (LMW) such as Regalrez 1094 and microcrystalline wax were treated with FAME applied in gel to prevent solvent–substrate interactions. Photographic documentation under UV-vis light, optical microscope observations, and spectrocolorimetric analysis were used for assessing surface "cleanness", while FTIR-ATR spectroscopy was used to detect possible residue from treatment. Moreover, SEM analysis was used for a better understanding of the results. The best results were obtained using FAME base on methyl stearate according to Hansen-RED. [ABSTRACT FROM AUTHOR]

Background: The preparation of the middle mesial (MM) canal of mandibular molars represents a challenge because it is often curved, narrow, and close to the root concave. The purpose of this study was to evaluate the ex vivo shaping ability of 3 nickel-titanium (NiTi) rotary systems in the MM canal using 3D printed resin tooth replicas. Methods: A permanent mandibular first molar with a MM canal was acquired from a pool of extracted teeth and reproduced by a 3D printer. The resin tooth replicas (n = 18) were equally assigned to 3 groups for the evaluation of the shaping abilities of 3 NiTi rotary systems (OneShape [OS], Twisted Files [TF], and ProTaper Gold [PTG]) according to the manufacturer's recommendations. The tooth replicas were scanned by micro-computed tomography (micro-CT) twice before and after instrumentation of the mesiobuccal (MB), mesiolingual (ML), and MM root canals. After 3D reconstruction, the canal straightening, change of root canal volume and surface area, the mesial and distal canal wall thickness and canal transportation at the levels of 1, 2, and 3 mm below furcation were assessed. One-way variance analysis and Turkey's post hoc test were used for comparisons of the means among different groups, and paired-t test was used to compare the mesial and distal sides of the mesial roots. Results: As compared with OS and TF, the use of PTG in preparation of MM canals resulted in significantly more straightening of canal curvature (p < 0.05), greater post-instrumentation canal volume and surface area, and thinner mesial and distal remaining canal wall thickness at 1, 2 and 3 mm below furcation (all p < 0.05). Regarding the root canal transportation in the mesiodistal direction, there was no significant difference among the 3 instruments (all p > 0.05) after the preparation of the MB and ML canals. However, in the MM canal, more pronounced transportation was detected in the PTG group at 2 mm below furcation, and in the TF group at 3 mm below furcation as compared with the other 2 systems (both p < 0.05). Conclusions: 3D printed tooth replicas have the advantages of consistency and can be an ideal model to evaluate the shaping ability of different instruments in the MM canal. OS and TF files performed similarly and both are appropriate for shaping the MM canal, while PTG may cause excessive and uneven resin removal, especially near the furcation, and may lead to root fragility and procedural errors. [ABSTRACT FROM AUTHOR]

Purpose: Oral hygiene, maintained through plaque control, helps prevent periodontal disease and dental caries. This study was conducted to examine the accuracy of plaque detection with an intraoral scanner (IOS) compared to images captured with an optical camera. Materials and Methods: To examine the effect of color tone, artificial tooth resin samples were stained red, blue, and green, after which images were acquired with a digital single-lens reflex (DSLR) camera and an IOS device. Stained surface ratios were then determined and compared. Additionally, the deviation rate of the IOS relative to the DSLR camera was computed for each color. In the clinical study, following plaque staining with red disclosing solution, the staining was captured by the DSLR and IOS devices, and the stained area on each image was measured. Results: The stained surface ratios did not differ significantly between DSLR and IOS images for any color group. Additionally, the deviation rate did not vary significantly across colors. In the clinical test, the stained plaque appeared slightly lighter in color, and the delineation of the stained areas less distinct, on the IOS compared to the DSLR images. However, the stained surface ratio was significantly higher in the IOS than in the DSLR group. Conclusion: When employing IOS with dental plaque staining, the impact of color was minimal, suggesting that the traditional red stain remains suitable for plaque detection. IOS images appeared relatively blurred and enlarged relative to the true state of the teeth, due to inferior sharpness compared to camera images. [ABSTRACT FROM AUTHOR]

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-1Dmp1 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. [ABSTRACT FROM AUTHOR]

Background: Studies investigating thermocycling effect on surface topography and fracture toughness of resins used in digitally manufactured denture bases are few. The study aimed to assess the impact of thermocycling on surface topography and fracture toughness of materials used for digitally manufactured denture bases. Methods: Water sorption, solubility, hardness, surface roughness, and fracture toughness of both three-dimensional (3D)-printed and computer-aided design, computer-aided manufacturing (CAD-CAM) milled specimens (n = 50) were assessed both prior to and following 2000 thermocycles, simulating 2 years of clinical aging. Surface hardness (n = 10) was measured using a Vickers hardness testing machine, surface roughness (n = 10) was determined by a contact profilometer, and fracture toughness (n = 20) was measured using the 3-point bend test, then studying the fractured surfaces was done via a scanning electron microscope (SEM). Prior to and following thermocycling, water sorption and solubility (n = 10) were assessed. Normally distributed data was tested using two-way repeated ANOVA and two-way ANOVA, while Mann Whitney U test and the Wilcoxon signed ranks test were used to analyze data that was not normally distributed (α < 0.05). Results: Following thermocycling, Vickers hardness and fracture toughness of both groups declined, with a significant reduction in values of the 3D-printed resin (P <.001). The 3D-printed denture base resins had a rougher surface following thermocycling with a significant difference (P <.001). The sorption and solubility of water of both materials were not affected by thermocycling. Conclusions: Before and after thermocycling, milled specimens had lower surface roughness and a greater degree of hardness and fracture toughness than 3D-printed specimens. Thermocycling lowered hardness and fracture toughness, and increased surface roughness in both groups, but had no effect on water sorption and solubility. [ABSTRACT FROM AUTHOR]

This paper introduces an innovative sensor utilizing bubbles coated with thermochromic paint, aiming to facilitate temperature measurements in challenging-to-reach locations without the requirement of an external power source. The research conducted is innovative in terms of both methodology and application. The characterization of the thermochromic properties of paints was, in fact, performed using spectroradiometric measurements by selecting a temperature range useful for applications in various fields including preventive conservation. The study encompasses two main objectives: (1) analyzing the color characteristics of thermochromic paint and plastic resin that forms the bubbles, and (2) assessing a temperature sensor comprising a thermochromic paint-coated bubble subjected to temperature variations. The thermochromic paint exhibits reversible color modifications in response to temperature changes, making it an ideal candidate for applications of this nature. The color characterization phase involves measurements using a spectroradiometer to compare the spectral reflectance factor (SRF%) of the colored plastic resin spread on canvas with that of the inflated bubbles. The sensor characterization entails evaluating color changes of the thermochromic paint on the bubble surface with varying temperatures. Experimental results indicate that the combination of a red (R) bubble and blue (B) thermochromic paint produces quantifiable color variations suitable for the proposed applications, whereas the alternative combination under examination, namely a blue bubble and red thermochromic paint, yields less accurate results. Considering that for both thermochromic paints the color change temperature is 35 °C, it is possible to see how, for B bubble with R thermochromic paint, the chromatic coordinates change value: C* = 3.14 ± 0.14 and h = 289.54 ± 11.58 at room temperature, while C* = 2.96 ± 0.12 and h = 304.20 ± 12.17 at 35 °C. The same is true for R bubble with B thermochromic paint where C* = 25.31 ± 1.01 and h* = 285.05 ± 11.40 at room temperature, while C* = 20.87 ± 0.85 and h = 288.37 ± 11.53 at 35 °C. The study demonstrates the potential of the approach and suggests further investigations into reproducibility and expanded color combinations. The results provide a promising basis for future improvements in temperature monitoring with thermochromic bubble sensors. [ABSTRACT FROM AUTHOR]