Diametral Tensile Strength Research Articles

Effect of TiO2 as sintering additive on microstructural, physical, and mechanical properties of CeO2 doped zirconia toughened alumina ceramic composite

Ceramic composites based on Zirconia Toughened Alumina (ZTA) are a good option to meet the requirements of outstanding mechanical properties in modern manufacturing and medical science. In this study, the influences of TiO2 on microstructural, physical, and mechanical properties of ZTA-CeO2 composites are examined by keeping CeO2 fixed at 5 wt% and varying TiO2 from 0 to 4 wt%. Each combination was pressed at a pressure of 300 MPa for 2 min in a hydraulic press. The pressed samples were sintered at 1450 °C for 4 h at atmospheric pressure. The prepared ceramic composites were characterized for their microstructure analysis, phase analysis, density, porosity, Vickers hardness, fracture toughness, and diametral tensile strength (DTS). TiO2 was found to have a substantial impact on the solidification of the composites by lowering the sintering temperature. SEM images showed that the lowest grain size of alumina was attained at 1.5 wt% TiO2, which resulted in the lowest porosity as well as the highest density, hardness, and fracture toughness of the composites. The XRD analysis revealed a secondary phase, Al2TiO5, after the 1.5 wt% TiO2 addition. This phase increased the size of the alumina grains and made the composites more porous and less dense, which resulted in lower hardness and fracture toughness than the maximum. Therefore, the composite (ZTA-CeO2) with 1.5 wt% TiO2 was found to have the optimum results with density (4.16 g/cm3), percentage of porosity (8%), Vickers hardness (1485 HV), fracture toughness (7.54 MPa√m), and DTS (126.4 MPa).

Physico-chemical, mechanical and antibacterial properties of the boron modified biphasic larnite/bredigite cements for potential use in dentistry

In recent years, there has been a growing interest in developing more reactive calcium silicate cements (CSCs) with superior bioactivity, self-setting properties and mechanical strength, allowing them to be used for various dental applications. In this study, we have produced a biphasic larnite/bredigite calcium magnesium silicate cement (CaMgSi) by the low-temperature sol-gel method and calcination of xerogels at 700 °C. The effect of boron (B) incorporation (0.25 and 0.5 mol) on the structural and physico-chemical properties of CaMgSi and boron-modified CaMgSi/0.25B and CaMgSi/0.5B cements was evaluated using various characterization techniques, such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning and transmission electron microscopy (SEM/TEM) and solid-state NMR spectroscopy (ssNMR). The results showed that with the increasing boron content, the cements hydration, self-setting and mechanical properties were improved. Hence, the final setting time of CaMgSi/0.5B cement decreased from 30 (undoped cement) to 19 min, while the compressive (CST) and diametral tensile strengths (DTS) increased almost twice to the highest values of 85 ± 9 MPa and 8.8 ± 1 MPa, respectively. The in-vitro bioactivity and degradation of cements were examined in simulated body fluid (SBF) solution during 8 weeks of soaking. Interestingly, the prevalence of calcite and aragonite crystals of various morphologies was observed on all cement surfaces, whereas a plate-like particles of precipitated calcium phosphate layer were found only in the boron-modified CaMgSi/0.25B and CaMgSi/0.5B cements. In addition, a very good antibacterial activity of the cement suspensions was revealed against all the tested bacteria, i.e. Staphylococcus aureus, Escherichia coli and Enterococcus faecalis, showing a promising result for potential use in dentistry.

An in-vitro comparative evaluation of mechanical properties of Cention N, FujiCEM 2 with a conventional glass ionomer cement

To evaluate and compare the diametral tensile strength and shear bond strength of Cention N, FujiCEM 2 with a conventional glass ionomer cement. A total of thirty samples were used for the evaluation and comparison of diametral tensile strength. Ten samples of each of the restorative material were prepared with the help of metallic moulds and stored in distilled for 24hrs, following which they were tested on the Universal Testing Machine at crosshead speed of 5.5 mm/min. A total of thirty-three premolars were used to evaluate the shear bond strength with eleven premolars in each group. The premolars were then grinded perpendicular to the long axis of the tooth, restored with the respective cements following the manufacturer’s instructions and stored in distilled water at room temperature for 7-10 days, later they were subjected to thermocycling. After 24 hours, the specimens were tested in the Universal Testing Machine at a crosshead speed of 0.5 mm/min. The obtained data was statistically analyzed. There was statistical difference in diametral tensile strength values of Cention N when compared to FujiCEM 2 and Fuji IX (p value= 0.00). The shear bond strength of Cention N was significantly higher than that of FujiCEM 2 and Fuji IX (p=0.005 and p=0.008 respectively). The results of our study concluded that Cention N performed better in terms of mechanical properties than FujiCEM 2 and Fuji IX.

Can TPO as Photoinitiator Replace "Golden Mean" Camphorquinone and Tertiary Amines in Dental Composites? Testing Experimental Composites Containing Different Concentration of Diphenyl(2,4,6-trimethylbenzoyl)phosphine Oxide.

The aim of this research was to compare the biomechanical properties of experimental composites containing a classic photoinitiating system (camphorquinone and 2-(dimethylami-no)ethyl methacrylate) or diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) as a photoinitiator. The produced light-cured composites consisted of an organic matrix-Bis-GMA (60 wt.%), TEGDMA (40 wt.%) and silanized silica filler (45 wt.%). Composites contained 0.27; 0.5; 0.75 or 1 wt.% TPO. Vickers hardness, microhardness (in the nanoindentation test), diametral tensile strength, resistance to three-point bending and the CIE L* a* b* colorimetric analysis was performed with each composite produced. The highest average Vickers hardness values were obtained for the composite containing 1 wt.% TPO (43.18 ± 1.7HV). The diametral tensile strength remains on regardless of the type and amount of photoinitiator statistically the same level, except for the composite containing 0.5 wt.% TPO for which DTS = 22.70 ± 4.7 MPa and is the lowest recorded value. The highest average diametral tensile strength was obtained for the composite containing 0.75 wt.% TPO (29.73 ± 4.8 MPa). The highest modulus of elasticity characterized the composite containing 0.75 wt.% TPO (5383.33 ± 1067.1 MPa). Composite containing 0.75 wt.% TPO has optimal results in terms of Vickers hardness, diametral tensile strength, flexural strength and modulus of elasticity. Moreover, these results are better than the parameters characterizing the composite containing the CQ/DMAEMA system. In terms of an aesthetic composite containing 0.75 wt.%. TPO is less yellow in color than the composite containing CQ/DMAEMA. This conclusion was objectively confirmed by test CIE L* a* b*.

An In Vitro Study Comparing the Diametral Tensile Strength of Composite Core Build-Up Material With Three Different Prefabricated Post Systems.

Statement of problemDental restorations are subjected to tensile stresses from oblique or transverse loading of their complex geometric forms, making tensile strength a fundamental mechanical property. Since composite core build-up materials are brittle, the integrity of the post and core depends on their tensile strength and resistance to fracture when utilized with various prefabricated post systems. Therefore, it is essential to determine the tensile strength of the prefabricated metallic and nonmetallic posts used to reinforce the composite resin core.PurposeThis study compared the diametral tensile strength (DTS) of three prefabricated post systems with composite core build-up material.Material and methodologyTen composite resin cores from four different groups were formed. The control group was the composite resin core without a post (group 1). Group 2 was composed of composites with metal posts, group 3 was composed of composites with glass fiber posts, and group 4 was composed of composites with carbon fiber posts. All the samples were kept in a humid place for seven days to mimic the conditions in the mouth. DTS was determined by recording the tensile force required to fracture the core material by performing a diametral compression test for tension after a week. The observations were analyzed using a one-way analysis of variance (ANOVA), followed by a post-hoc test.ResultsThe tensile strength of the resin core material was decreased by 28.1%, 20.8%, and 10.4% by using posts made of stainless steel, carbon fiber, and glass fiber, respectively. Among the three post systems, stainless steel had the lowest mean DTS values, while glass fiber had the highest mean DTS values.ConclusionComposite core glass fiber post systems showed higher tensile strength than other post systems.

Microstructural, dielectric, mechanical, and biological properties of hydroxyapatite (HAp)/BZT-BCT (0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3) bio-composites with improved mechano-electrical properties for bone repair

Hydroxyapatite (HAp; Ca10(PO4)6(OH)2) is a commonly used biomaterial for bone tissue repair applications but it has poor electrical conductivity. Whereas, BZT-BCT (0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3) is a lead-free piezoelectric material which can mimic the stress-generated electric potential of electrically-excitable tissues such as bone. This study investigated the mechanical, electrical and bio properties of xHAp/(1-x)BZT-BCT composites. xHAp/(1-x)BZT-BCT composites (with x = 5, 10, 15 and 20 wt%) were synthesized by high energy ball milling (HEBM) assisted solid-state reaction route. X-ray diffraction, scanning electron microscopy, density measurements and cell-material interaction studies of sintered HAp/BZT-BCT composites were carried out and discussed in detail. Dielectric properties of sintered composites were evaluated and compared with the existing theoretical models. Different mechanical properties like Vicker's hardness, fracture toughness, and diametral tensile strength were measured to assess the usability of synthesized composites for load-bearing orthopaedic applications. These various studies showed that incorporation of BZT-BCT in HAp improved its mechanical and electrical properties and thereby significantly increased the proliferation of human osteogenic MG-63 cells. Among all the composites, better mechanical, electrical and biological properties were obtained in 10HAp/90BZT-BCT composites.

Diametrical tensile strength test of dental bioactive cement

Introduction: Bioactive dental cement material is widely used in root canal treatment in order to provide long lasting result of the root canal treatment. The test ofmechanical properties on this bioactive dental cement material is a diametrical tensile test. The purpose of this study was to examine the diametrical tensile strength (DTS) of bioactive dental cement materials found in Indonesia. Methods: Specimens of bioactive dental cement material are disc-shaped, 6 mm in diameter, 3 mm in height which were divided into 2 groups; Group I is Maarc MTA and Group II is MTA plus white cerkamed, each group contains 4 speci-mens. Mechanical properties test was carried out using Universal Testing Machine (UTM), analyzed with one-way Anova. Re-sults: The DTS mean of Group Iwas 2.48564 N/mm2 and Group II of 7.872175 N/mm2; significantly different (f count: 0.065). Conclusion: MTA white plus cerkamed has higher DTS than Maarc MTA.

Rice Husk as a Pore-Forming Agent: Impact of Particle Size on the Porosity and Diametral Tensile Strength of Porous Alumina Ceramics

This study describes the porosity and particle size effects of rice husk pore former on the diametral tensile strength of porous alumina (Al2O3) ceramics. Porous Al2O3 ceramics with high porosity and sufficient diametral tensile strength were successfully prepared by the pore-forming agent method using rice husk (RH) as the pore former according to the sample formulation Al2O3-xRHy (where ‘x’ denotes the particle size range in µm and ‘y’ denotes the percent weight content (wt%) of RH). The thermogravimetric analysis (TGA) and X-ray diffractometer (XRD) results revealed that silica was retained as rice husk ash in the developed porous Al2O3 after the decomposition of the starting rice husk pore former. Microstructures of the as-prepared porous Al2O3 ceramics having different RH additions exhibited hierarchical pore structures with increased particle size of the pore-forming agent. Porosity increased with larger particle size range of rice husk where the Al2O3-63RH5 demonstrated the least porosity (44.2 vol%), while the highest porosity (70.9 vol%) was demonstrated by the Al2O3-125–250RH20. The diametral tensile strength of the RH-shaped porous alumina ceramics declined from 16.97 to 0.65 MPa with increased particle size of the rice husk.

Evaluating the Mechanical Properties of Restorative Glass Ionomers Cements

The aim of this research was to assess the efficiency of 4 restorative glass ionomer cements (GICs): Fuji IX (GC), ChemFil Rock (DENSPLY), Riva Self-Cure (SDI), and Ketac Nano (3M ESPE). The 4 restorative glass ionomers' diametral tensile and compressive strengths were evaluated at room temperature for 24 hours and then stored in distilled water. The universal testing machine (INSTRON 5566A) was used to record the maximum load necessary to fracture specimens. Surface wear, diametral tensile strength, and compressive strength against dental ceramic were compared using analysis of variance followed by the Bonferroni method at a significance level of 0.05. Ketac Nano and ChemFil Rock were found to have better diametral tensile strength than Riva Self-Cure and Fuji IX. The significant difference between ChemFil Rock and Fuji IX (P ≤ .005) and ChemFil Rock with Riva Self-Cure (P ≤ .005) was shown by post hoc analysis. Ketac Nano had better tensile strength than Riva Self-Cure and Fuji IX. Fuji IX showed the lowest material loss of the GICs as revealed by wear against VITABLOCS Mark II (VITA Zahnfabrik). This study indicated a significant difference in the compressive strengths of ChemFil Rock and Riva Self-Cure. ChemFil Rock had the highest tensile strength. The diameter tensile strength of all 4 materials was statistically insignificant. Finally, Fuji IX had the least amount of material loss. ChemFil Rock was proven to be more effective than Fuji IX.

Evaluation of the Mechanical Properties of Three Resin-Modified Glass-Ionomer Materials.

This study is aimed at evaluating the flexural strength (FS), fracture toughness (FT), and diametral tensile strength (DTS) of three resin-modified glass-ionomer cements (RMGICs): Ketac Nano, Riva Light Cure, and Fuji II LC. One hundred twenty specimens were prepared from the RMGIC materials (n = 10). The cements were mixed and inserted into different mould sizes according to the test performed: FS: rectangular Teflon mould (32 mm × 3.15 mm × 2 mm); FT: notchless triangular prism (NTP) Teflon mould (6 mm × 6 mm × 6 mm × 12 mm); and DTS: ring road stainless steel mould (6 mm × 3 mm). Specimens were light cured for 20 seconds on each surface and stored in distilled water at 37°C ± 2°C for seven days prior to tests. To evaluate the influence of storage in the mechanical properties of the RMGIs, specimens tested for DTS were stored in distilled water at 37°C ± 2°C for 32 days prior to test. Data were analyzed by ANOVA and Tukey's test (α = 0.05). Fuji II LC presented significantly higher values for all tests employed when compared to Ketac Nano and Riva LC RMGIs. There was no significant difference on DTS before and after the 32-day storage for each material. Fuji II LC presented superior mechanical properties when compared to Ketac Nano, and Riva LC storage showed no influence on the mechanical properties of the RMGI materials tested.

Comparative Evaluation of Bulk-Fill Composite Resins: Knoop Microhardness, Diametral Tensile Strength and Degree of Conversion.

PurposeBulk-fill composite resins were developed to reduce time and facilitate the restorative procedure. However, considering their recent introduction on the market and the new formulations, their performance still requires evaluation. This study aimed to evaluate Knoop microhardness (KHN), diametral tensile strength (DTS) and degree of conversion (DC) of three Bulk-Fill composite resins and a conventional one.Materials and MethodsSixty samples (n = 15; 8 mm ø x 4 mm height) were confectioned using a mold. Filtek Bulk-Fill (FBF), Tetric N-Ceram Bulk-Fill (TNC) and SonicFill 2 (SF2) were placed in 4 mm increments, and Filtek Z350 (FZ350) was placed in 2 mm increments. The KHN of top and bottom surfaces were tested using Knoop Hardness tester at 10 gf/10s. The DTS was tested under compressive load at 1.0 mm/min. The DC was measured by Fourier Transform Infrared (FTIR) spectroscopy. Differences in DTS and DC were analyzed by ANOVA and Tukey post hoc test. For KHN, Kruskal–Wallis and Wilcoxon tests were performed at α = 0.05.ResultsTop surfaces of all composite resins had higher KHN than bottom surfaces. At top and bottom surfaces, FZ350 showed higher KHN than TNC and SF2. The highest DTS was obtained by FBF, followed by FZ350 and SF2. The highest DC was obtained by SF2, the lowest one was obtained by FBF.ConclusionFrom Bulk-Fill composite resins, FBF presented the best KHN and DTS results. The SF2 showed the best DC. Further studies are required to ensure whether these differences can negatively influence the behavior of in vivo restorations.

Mechanical Behavior of Epoxy Reinforced by Hybrid Short Palm/Glass Fibers

Natural fibers (NFs) have recently been the center of attention among researchers due to their low cost, availability, ease of manufacture, and potential environmental friendliness as reinforcing agents in composites. The present work deals with the mechanical behavior of palm fiber-reinforced epoxy-based composites with different weight percentage (Wt.%) ratios, ranging from 6% to 31.6%. Glass and hybrid fiber-reinforced epoxy-based composites were also examined. The indirect tensile test, i.e., diametral tensile test (DTT) and the small punch test (SPT), were used in the present work to determine the mechanical properties of the epoxy reinforced with discontinuous random oriented short fibers. Furthermore, short glass fibers were used to compare with palm fiber-reinforced epoxy. In addition, morphology observations of epoxy residue clinging to the natural fibers were carried out using the optical microscope and Scanning Electron Microscopy (SEM). The results showed that the natural fiber has a better adhesion bonding between the palm fiber/epoxy than that of glass fiber/epoxy. Therefore, adding palm fibers improves epoxy’s mechanical properties compared with synthetic glass fibers. The composite with high Wt.% of NF showed the highest diametral tensile strength (DTS), 21.74 MPa, over other composites. The DTS of composites with medium and low Wt.% of NF was lower than that of the high Wt.% by 14% and 30%, respectively.

<strong>Effect of 3-methacryloxypropyltrimethoxysilane on diametral tensile strength of rice husk silica-based dental composite </strong>

ABSTRACTIntroduction: Rice husk silica has been studied as a filler in dental composite, however, the mechanical properties of the resulting composites are below the commercial due to the poor surface modification between silica and resin matrix. 3-methacryloxyprpyltrimethoxysilane (MPTS) is one of the coupling agents that are effective to modify the silica surface. The purpose of this study to analyze the effect of MPTS on the diametral tensile strength (DTS) of the self-made composite using rice husk silica. Methods: The research type of this study was an experimental research laboratory. The samples (26 samples) were divided into two groups, namely the test group (using MPTS-modified silica) and the control group (using non-modified silica). The samples were cylindrical in shape with a diameter of 6.0 ± 0.1 mm and a height of 3.0 ± 0.1 mm according to ANSI/ADAS No. 27, 1993 and ISO 4049, 1988. The Fourier Transform Infrared (FTIR), HORIBA, was used to characterize the MPTS grafting on the silica surface. The DTS value is measured by Universal Testing Machine (UTM), Lloyd LRX Plus. Results: FTIR presents the additional peak of carboxyl and methacryloyl group at 1716, 1555, and 1410 cm-1 wavenumber, respectively in MPTS-modified silica. The DTS value of the test group was 43.40 ± 4.43 MPa and the control group was 25.80 ± 2.63 MPa. The test group was significantly higher than the control group (p-value = 0.001). Conclusion: The MPTS is effective to enhance the DTS value of rice husk silica-based composite.Keywords: Rice husk silica; dental composite; diametral tensile strength; 3-methacryloxypropyltrimethoxysilane.

An Evaluation of the Hydrolytic Stability of Selected Experimental Dental Matrices and Composites.

Materials with potential use as dental restoration should be evaluated in an aggressive environment. Such accelerated aging is widely used in other industries and allows the assessment of service life. In the presented study, three neat resins (UDMA/Bis-GMA/TEGDMA 70/10/20 wt.%, UDMA/Bis-GMA/TEGDMA 40/40/20 wt.% and UDMA/Bis-EMA/TEGDMA 40/40/20 wt.%) and three composites based on these matrices were tested before and after aging protocols (I-7500 cycles, 5 °C and 55 °C, water and 7 days, 60 °C, 0.1 M NaOH; II-5 days, 55 °C, water and 7 days, 60 °C, 0.1 M NaOH). Flexural strength (FS), diametral tensile strength (DTS) and hardness (HV) were determined. Applied aging protocols resulted in a decrease in the value of the FS, DTS and HV. Larger changes were noticed for the neat resins. Materials in which the content of bis-GMA was lower or substituted by bis-EMA showed better resistance to degradation. The choice of mixtures with monomers characterized by lower sorption values may favorably affect hydrolytic stability. It was shown that for composites there was a drastic decrease in hardness, which suggests a more superficial effect of the used protocols. However, degradation of the surface layer can result in a growing problem over time given that the mastication processes are an inherent element in the oral environment.

The effect of filling technique on the cuspal strain, polymerization shrinkage stress, enamel crack formation and depth of cure of restored molars

ObjectiveEvaluate the effect of different restorative filling techniques on the residual shrinkage stress (ShrS), cuspal strain (CS), depth of cure (DC), and enamel crack formation (Ec) in molars with MOD restorations. MethodsPost-gel shrinkage, elastic modulus, compressive and diametral tensile strength of the Filtek One Bulk Fill composite were calculated. Sixty molars with MOD preparations were restored using four filling techniques: Bulk; Horizontal; Oblique; Natural enamel and dentin substitution (NEDS) technique. CS was measured using a strain gauge (n = 10). The DC (n = 5) was measured using Knoop hardness. Shrinkage stress/strain was analyzed using 3D finite element analysis. The Ec analysis was carried out by transillumination. Two-way ANOVA with repeated measures and Tukey’s HSD test (α = 0.05) was performed for the CS data. Two-Way ANOVA and Tukey’s HSD test was performed for the DC data (α = 0.05). ResultsCS was higher at the lingual cusp for the horizontal and NEDS technique. No statistical difference was found between the buccal and lingual CS values for the Bulk (p = 0.367) or Oblique techniques (p = 0.192). CS values were lower for the Bulk. More enamel cracks were found for the Bulk. DC was lower at 4 mm regardless the filling technique. The Horizontal showed the highest ShrS values. The Bulk generated the lower ShrS values. SignificanceA Bulk technique caused the lowest shrinkage stress/strain. An Oblique technique yielded the best balance between stress, strain and crack formation. NEDS technique is a good alternative to decrease the number of increments while maintaining the stress levels nearby the Oblique technique.

Assembly of Ultralong Hydroxyapatite Nanowires into Enamel-like Materials

To develop dental restorative materials with enamel-like structures, ultralong hydroxyapatite (HA) nanowires were synthesized by a hydrothermal method, followed by functionalization with 3-methacryloxypropyltrimethoxysilane (KH-570). The mixture of HA nanowires, KH-570, and light initiator was stirred and centrifuged. The precipitate was vacuum filtered to remove excessive KH-570 and then pressured under cold isostatic pressing (10 MPa × 24 h). Finally, the block was polymerized by lighting. Scanning electron microscopy and transmission electron microscopy showed that HA nanowires with aspect ratios >1,000 were assembled into enamel rod–like microstructures and evenly dispersed in the polymerized KH-570 silane matrix to form enamel-like structures. Thermogravimetric analysis demonstrated that the content of HA nanowires reached 72 wt% in the composite. The enamel-like composite showed a similar hardness, frictional property, and acid-etching property to those of enamel and a comparable or even better diametral tensile strength and compressive strength than some commercial composite resins in mechanical tests in vitro. In addition, the enamel-like composite had good cytocompatibility. Such enamel-like composites may have the potential to be used in biomimetic tooth restorations in the future.

COMPARATIVE EVALUATION OF MICROLEAKAGE AND DIAMETRAL TENSILE STRENGTH OF VARIOUS RESTORATIVE MATERIALS - AN IN VITRO STUDY

Aim: To evaluate and compare microleakage and diametral tensile strength of various restorative materials. Materials & Method: For the evaluation of microleakage, Class V cavities were prepared on sixty human premolar teeth and restored according to five study groups (n = 15): Group I (Fuji ix), Group II (Zirconomer Improved), Group III (Glasionomer FX Ultra), Group IV (Positive Control) and Group V (Negative Control). The samples were thermocycled and subjected to dye penetration test. The sections were made and evaluated under stereomicroscope at × 40 magnification. For the Diametral Tensile strength evaluation, fourty five cylindrical specimens were fabricated measuring 5 mm × 6 mm and grouped into three study groups (n = 15): Group I (Fuji ix), Group II (Zirconomer Improved) and Group III (Glasionomer FX Ultra). Diametral Tensile Strength was evaluated using Universal Testing Machine. Statistical analysis used: The data were analyzed using TUKEYS and ANOVA. Results: For microleakage, all intergroup comparisions were significant except between Group A (Fuji IX) and Group C (Glasionomer FX Ultra), with Zirconomer Improved showing maximum followed by Fuji IX and Glasionomer FX Ultra. The Diametral Tensile strength was found to be highly significant (P < 0.01) except between Group B (Zirconomer Improved) and Group C (Glasionomer FX Ultra) with the maximum score for Zirconomer Improved followed by Glasionomer FX Ultra and Fuji IX. Conclusion: Glasionomer FX Ultra is recommended as a restorative material because of its comparable Diametral Tensile Strength to Zirconomer Improved and effective sealing ability.

The First Step in Standardizing an Artificial Aging Protocol for Dental Composites—Evaluation of Basic Protocols

The clinical performance of a dental restoration is strongly influenced by the complex and dynamically-changing oral environment; however, no standard procedure exists to evaluate this lifetime. This research provides an in-depth analysis of the effect of different aging procedures on the flexural strength (FS), diametral tensile strength (DTS) and hardness (HV) of selected dental materials (Resin F, Flow-Art and Arkon). Material structure was evaluated by scanning electron microscopy. It was found that each aging protocol had some influence on the tested properties, with continual erosion and degradation being observed. Greater mechanical degradation was observed for Resin F (neat resin) after the applied aging protocols, suggesting that a resin matrix is more susceptible for degradation. The most aggressive aging protocol was Protocol 5: 0.1 M NaOH, seven days, 60 °C. Further studies on the effect of artificial aging on dental materials should include a study of the thermal and chemical factors. A standardized aging procedure is crucial for improving the resistance of dental resin composite to oral conditions and their clinical performance.

Comparative Evaluation of Effect of Microwave Disinfection on Compressive and Diametral Tensile Strength of Various Type IV Dental Stones–An In Vitro Study

Comparative Evaluation of Effect of Microwave Disinfection on Compressive and Diametral Tensile Strength of Various Type IV Dental Stones–An In Vitro Study

POLYSACCHARIDE-BASED MATRIX DOPED WITH PLANT EXTRACT FOR MEDICAL AND COSMETIC APPLICATIONS

Herein, we present a new biomaterial based on xanthan, chitosan and lignin, which served as a matrix for the incorporation of flavonoids extracted from Agropyron repens L. rhizomes. The simultaneous presence of lignin and xanthan esterified with acrylic acid leads to better retention of the active principles in the polymer matrix, which is reflected in their slow release into the environment. A more compact structure resulting from the incorporation of lignin into the chitosan/xanthan matrix contributed to a three times higher value of diametral tensile strength. The release kinetics of flavonoids through the matrix components was described by the Korsmeyer-Peppas model, indicating Fickian diffusion. The presence of bioactive principles extracted from Agropyron repens L. (couch grass) imparts an antioxidant capacity to biomaterials, on average 30% higher compared to that of the base matrix. Considering the mucoadhesiveness, bioadhesiveness, release kinetics and antioxidant capacity of all the formulations developed in this study, it can be concluded that they have potential for health and cosmetic applications.