Diametral Tensile Strength Values Research Articles

The effect of oxygen-inhibited layer and its inhibition technique on diametral tensile strength values of various nanofilled composite resin types

Abstract Aim: To investigate the impact of different inhibitory techniques on the thickness of oxygen-inhibited layer (OIL) and diametral tensile strength (DTS) value in various types of nanofilled composite resins. Materials and Methods: Thirty-six nanofilled composite resins specimens, consisting of packable, flowable, high-viscosity bulk-fill (HVBF), low-viscosity bulk-fill (LVBF), shaped as half disk (diameter: 6 mm and height 3 mm) and randomly allocated to three groups (n = 3): with Mylar strip, glycerin application, and without OIL inhibitors. OIL thickness was observed with an optical microscope. Furthermore, 60 specimens of composite resins were incrementally created in disk-shaped molds (diameter: 6 mm, height: 1.5 mm × 2 mm). DTS measurements were carried out using a universal testing machine. Data were statistically analyzed using a two-way analysis of variance (ANOVA) test and Pearson’s correlation test (P < 0.05). Results: OIL inhibitor techniques (Mylar strip and glycerin) significantly affected OIL formation across various types of nanofilled composite resins (P < 0.05). Changes were also observed in how these techniques influenced DTS values. Correlation analysis indicated a positive relationship between OIL thickness and DTS value. Conclusions: Application of Mylar strip and glycerin reduced OIL thickness and DTS values in packable, flowable, HVBF, LVBF nanofilled composite resins. Glycerin proved to be more effective than Mylar strips in reducing OIL thickness, which is reflected in the DTS values of nanofilled composite resins. Greater OIL layer thickness on the outermost layer of the nanofilled composite resin correlated with a higher DTS value.

Comparative Evaluation of Compressive and Diametral Tensile Strength in Die Stone Reinforced With Different Types of Nanoparticles: An In Vitro Study.

To investigate the effect of different types of nanoparticles on the compressive strength (CS) and diametral tensile strength (DTS) of type IV dental stones. A total of 100 specimens were made from the mould for all five groups. Four commercially available nanoparticles (aluminium oxide (Al2O3), silicon dioxide (SiO2), zinc oxide (ZnO), and zirconium oxide (ZrO2)) were used in this study in a concentration of 10%. CS and DTS tests were performed in a universal test machine. The data were statistically analysed using ANOVA and Student's t-test. The interaction between nanoparticles and the type of dental stone was found to be statistically significant (p < 0.05). CS and DTS values decreased by adding all four nanoparticles. The lowest CS and DTS were observed in 10% ZnO nanoparticles when added to type IV dental stone. It was concluded that the addition of nanoparticles (Al2O3, SiO2, ZnO, and ZrO2) to die stonesignificantly decreased the CS and DTS for all groups. Among all groups, the incorporation of 10% ZrO2 nanoparticles (group E) to die stone showed significantly less decrease in CSandDTS compared to Al2O3, SiO2, and ZnO. Incorporation of ZnO nanoparticles, on the other hand, showed a significantly more amount of decrease in theCSandDTScompared to Al2O3, SiO2, and ZrO2.

Can Modification with Urethane Derivatives or the Addition of an Anti-Hydrolysis Agent Influence the Hydrolytic Stability of Resin Dental Composite?

Due to the questionable durability of dental restorations, there is a need to increase the lifetime of composite restoration. The present study used diethylene glycol monomethacrylate/4,4'-methylenebis(cyclohexyl isocyanate) (DEGMMA/CHMDI), diethylene glycol monomethacrylate/isophorone diisocyanate (DEGMMA/IPDI) monomers, and bis(2,6-diisopropylphenyl)carbodiimide (CHINOX SA-1) as modifiers of a polymer matrix (40 wt% urethane dimethacrylate (UDMA), 40 wt% bisphenol A ethoxylateddimethacrylate (bis-EMA), and 20 wt% triethyleneglycol dimethacrylate (TEGDMA)). Flexural strength (FS), diametral tensile strength (DTS), hardness (HV), sorption, and solubility were determined. To assess hydrolytic stability, the materials were tested before and after two aging methods (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). The aging protocol resulted in no noticeable change (median values were the same as or higher than the control value) or a decrease in the DTS value from 4 to 28%, and a decrease in the FS value by 2 to 14%. The hardness values after aging were more than 60% lower than those of the controls. The used additives did not improve the initial (control) properties of the composite material. The addition of CHINOX SA-1 improved the hydrolytic stability of composites based on UDMA/bis-EMA/TEGDMA monomers, which could potentially extend the service life of the modified material. Extended studies are needed to confirm the possible use of CHINOX SA-1 as an antihydrolysis agent in dental composites.

An investigation of wear, mechanical, and water sorption/solubility behaviors of a commercial restorative composite containing nano-additives

Resin-based composites used in dentistry often possess undesirable characteristics. This study investigated the effect of two different nano-additive materials, namely aluminum oxide (Al2O3) and titanium dioxide (TiO2), on the mechanical, wear, and water sorption/solubility behavior of a commercial restorative composite used in dental treatments (Nexcomp Flow A2). The results showed that dental materials containing the introduced nano-fillers have a higher wear resistance than their neat counterparts. Correspondingly, the average diametral tensile strength values were improved from a value of 14.6 MPa to values of 26.6 MPa and 50.8 MPa when reinforced with TiO2 and Al2O3, respectively. It has been found that there is a significant relationship between the improvements in wear resistance and tensile strength due to the addition of nano-additives. Further, the water sorption/solubility of the pure composite was lower by 60% after introducing 1% wt. Al2O3 and by more than 80% when 1%wt. TiO2 was the reinforcement additive. Scanning electron microscope images of the tested samples on worn and unworn surfaces showed that the nano-additives helped carry the load subjected to the surface. After introducing nano-additives into the matrix, surface degradation, which may occur due to water uptake, was suppressed.

Effect of sintering temperature on physical, mechanical, and electrical properties of nano silica particles synthesized from Indonesia local sand for piezoelectric application

ABSTRACT This study aims to determine the effect of the sintering temperature of nanosilica on physical, mechanical, dielectric, and output voltage properties. The nanosilica particles used in this experiment were produced using the alkaline fusion method from natural sand. The green bodies were uniaxially formed with a pressure of 75 MPa and then were pressureless sintered at various temperatures of 1330, 1360, 1390, 1420, and 1450°C for 2 hours in an air atmosphere. The results of sintering showed that the highest bulk density and the relative density of 2.49 ± 0.03 g/cm3 and 94.03 ± 0.01% respectively were achieved at a sintering temperature of 1390°C. The XRD patterns of the sintered silica indicated phases of quartz, tridymite, and cristobalite, with the strongest peak corresponding to the cristobalite phase. The highest compressive strength and diametral tensile strength values of 17.23 ± 0.27 MPa and 6.06 ± 0.71 MPa respectively were obtained on specimens sintered at 1390°C. However, the highest values of the dielectric constant of 544.28, dielectric loss of 195.94, and output voltage of 1.58 mV were obtained at a sintering temperature of 1330°C. Various sintering temperatures do not significantly influence the characteristic of dielectric and output voltage of the sintered specimens.

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.

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.

&lt;strong&gt;Effect of 3-methacryloxypropyltrimethoxysilane on diametral tensile strength of rice husk silica-based dental composite &lt;/strong&gt;

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.

THE EFFECT OF MAULI BANANA STEM (Musa acuminata) AND BASIL LEAF (Ocimum basilicum L.) EXTRACT ON THE VALUE OF DIAMETRAL TENSILE STRENGTH OF BIOACTIVE COMPOSITE RESIN

Background: Chemical contents in mouthwash could cause several side effects in the oral cavity, hence natural ingredients were used such as Mauli banana stem and basil leaf extract. Mouthwash exposure in the oral cavity affects composite resin, one of it is a bioactive composite resin which has advantages over conventional ones. The contact of mouthwash with bioactive composite resin affects strength properties. Purpose: To analyse the effect of Mauli banana stem and basil extract on the diametral tensile strength value of the bioactive composite resin. Method: Thirty specimens (diameter 6mm x thickness 3mm; n=5/ group) were made using Activa™ Bioactive Restorative (Pulpdent) and immersed in the following group of 25%, 50%, 75% and 100% Mauli banana stem and basil leaf extract as a treatment groups, chlorhexidine gluconate 0,2 % (CHX) and aquadest as a control groups for 24 hours in the incubator at 37oC. Diametral tensile strength value was measured by Universal Testing Machine (Tokyo Testing Machine MFG CO.LTD) with 0,5 mm/minute crosshead speed and 250 kgF load cell. Result: One Way Anova and Post Hoc Bonferroni show there is a significant difference between treatment groups of 25% extract (41,33±6,20 MPa) and treatment groups of 100 % extract (55,06±6,42 MPa). Meanwhile, there is no significant difference for other groups. Conclusion: There is a significant effect of Mauli banana stem and basil leaf extract on the diametral tensile strength value of bioactive composite resin.

The Influence of Low-Molecular-Weight Monomers (TEGDMA, HDDMA, HEMA) on the Properties of Selected Matrices and Composites Based on Bis-GMA and UDMA.

Bisphenol A-glycidyl methacrylate (bis-GMA) and urethane dimethacrylate (UDMA) are usually combined with low-viscosity monomers to obtain more desirable viscosity, handling characteristics and general properties. The present study determined the flexural strength (FS), flexural modulus (FM), diametral tensile strength (DTS), and hardness (HV) of five matrices and composites based on these resins. The polymerization shrinkage stress (PSS) was also studied for the composites. The polymer matrices were formed using bis-GMA and UDMA. TEGDMA, HEMA and HDDMA acted as co-monomers. The composites had 45 wt.% of filler content. The highest FS and FM were obtained from the UDMA/bis-GMA/TEGDMA/HEMA matrix and the composite (matrix + filler). The best DTS values were obtained from the UDMA/bis-GMA/HEMA matrix and the composite. One of the lowest values of FS, FM, and DTS was obtained from the UDMA/bis-GMA/HDDMA matrix and the composite. All the composites demonstrated similar hardness values. The lowest polymerization shrinkage stress was observed for the UDMA/bis-GMA/TEGDMA/HEMA composite, and the highest PSS was observed for the UDMA/bis-GMA/TEGDMA/HDDMA composite. The addition of HEMA had a positive effect on the properties of the tested materials, which may be related to the improved mobility of the bis-GMA and UDMA monomers.

Ag-substituted octacalcium phosphate blocks that exhibit high osteoconductivity and high antibacterial activity toward various pathogens

In this study, Ag-substituted octacalcium phosphate (OCP) blocks exhibiting contact antibacterial ability were fabricated from precursor dicalcium dihydrate anhydrate blocks via immersion in both Ag+- and Na+-containing ammonium phosphate weak basic buffer solutions. The diametral tensile strength (DTS) value of the Ag-substituted blocks was ~2.5 MPa, which is sufficient for them to be used as a bone substitute material. Although the Ag contents of the Ag-substituted OCP blocks (0.17 ± 0.01 at%) were much lower than those of Ag-substituted OCP powders (1.72 ± 0.18 at%) prepared using Ag solutions with the same Ag concentration (20 mmol/L), the Ag-substituted OCP blocks exhibited excellent contact antibacterial activities toward various pathogens. In vivo implanting in bone defects evaluations indicated that the biocompatibility of the Ag-substituted OCP blocks was excellent and similar to that of the OCP blocks without Ag.

A Comparative Study of the Mechanical Properties of Selected Dental Composites with a Dual-Curing System with Light-Curing Composites

Dual-curing composites have a wide spectrum of use in practice (rebuilding, reconstruction, and luting). The characterization of this type of material and comparative study of selected mechanical properties with light-cured materials were carried out for this paper. In this study, we used six materials with a dual-cure system—Bulk EZ, Fill-Up!, StarFill 2B, Rebilda DC, MultiCore Flow, Activa Bioactive-Restorative—and three light-cured materials—Filtek Bulk Fill Posterior, Charisma Classic, and G-aenial Universal Flo. The materials were conditioned for 24 h in water at 37 °C before testing. Selected material properties were determined: three-point bending flexural strength, diametral tensile strength, hardness, microhardness, and shrinkage stress. The highest three-point bending flexural strength (TPB) was 137.0 MPa (G-aenial Universal Flo), while the lowest amounted to 86.5 MPa (Activa Bioactive). The diametral tensile strength (DTS) values were in a range from 39.2 MPa (Rebilda DC) to 54.1 MPa (Charisma Classic). The lowest hardness (HV) value of 26 was obtained by the Activa Bioactive material, while the highest values were recorded for Filtek Bulk Fill Posterior and Charisma Classic-53. The shrinkage stress of the tested materials ranged from 6.3 MPa (Charisma Classic) to 13.2 MPa (G-aenial Universal Flo). Dual-curing composites were found to have similar properties to light-cured composites.

Effect of the incorporation of hydroxyapatite on the diametral tensile strength of conventional and hybrid glass ionomer cements.

The objective was to evaluate the effect of the incorporation of calcium hydroxyapatite particles (HAp) in the diametral tensile strength of a conventional type II glass ionomer (GC Gold Label 2) and a resin-modified glass ionomer cement (GC Gold Label 2 LC R). Two experimental HAp (E1HAp or E2HAp) were synthesized and characterized using X-ray diffraction and Confocal Raman spectroscopy. Both HAp were added into the powder of a conventional or resin-modified glass ionomer cement at 5 or 10 wt.%. A commercial HAp (CHAp) was used as reference material. For each glass ionomer cement, a group without the incorporation of HAp was used as a control. A universal testing machine was used for the mechanical test. The results were analyzed through a two-way ANOVA test followed by a complementary Tukey test. For all analyzes, the level of significance was set at α = 0.05. The average particle size for E1Hap was 15µm, E2HAp was 35μm and for CHAp was 1µm. For conventional GIC, the addition of 10% E1HAp and 5% CHAp significantly increased the diametral tensile strength values (p ≤ 0.005). On the other hand, for the resin-modified GIC, except for the 5% E2HAp group, all experimental groups significantly reduced the values of diametral tensile strength (p ≤ 0.007). The addition of HAp improved the mechanical properties only for the conventional glass ionomer cement.

Comparative evaluation of mechanical properties of three resin composite materials with different filler particle sizes

Aim: The aim of this study was to evaluate and compare the mechanical properties of three resin composites core materials with different filler particle sizes. Materials and methods: nanofilled (Filtek Z350 XT , 3M, ESPE USA), microhybrid (Te Econom, Ivoclar, Vivadent, India) and nanohybrid (Nexcomp, Meta biomed, korea) resin composites were used during this study. Mechanical properties regarding the compressive strength, diametral tensile strength and surface hardness were tested and results were collected and evaluated. Data were statistically analyzed using one-way Analysis of Variance and Tukey HSD test. Results: The nanofilled type revealed the highest significant compressive and diametral tensile strength values while the nanohybrid type showed the least significant hardness values among the results of the two types of composite resin for the three tests. Conclusions: after evaluation it was shown that the tested nanofilled resin composite type is more appropriate for use as core material compared to the other tested types.

PROPERTIES OF COMPOSITE RESIN ALKASIT AND ZIRCONIA-REINFORCED GLASS-IONOMER CEMENT IN DIFFERENT STORAGE

Background: The temperature and salivary pH in a person's mouth are highly dynamic (e.g., before, during, and after eating) and so restorations in a cavity must be resilient to these variable conditions. Temperature and immersion conditions affect the mechanical properties of a restoration. This study aimed to determine the effect of environmental conditions on diametral tensile strength (DTS) and surface microhardness of a resin composite with alkaline fillers or zirconia–reinforced glass ionomer cement (Zr-reinforced GIC). Method: Thirty specimens of a resin composite with alkaline fillers (Cention-N, Ivoclar-Vivadent, Lichtenstein) and 30 specimens with zirconia-reinforced GIC (Zirconomer, Shofu, Japan) were stored at different conditions (23°C and 37°C; with and without immersion in water) for 24 hours. DTS was tested with a Universal Testing Machine (AGS-X series, Shimadzu, Japan) and surface microhardness was tested with a Vickers Microhardness tester (HMV-G Series Micro Vickers Microhardness Tester, Shimadzu, Japan). Data were analyzed statistically using a one-way ANOVA test (and Shapiro-Wilk test. Result: The values of microhardness and DTS increased significantly both for the composite resin alkasite and zirconia-reinforced GIC with increasing temperature in the groups without immersion. However, there was a significant decrease in microhardness and DTS after immersion in distilled water at 37°C for both the composite resin alkasite and zirconia-reinforced GIC. Conclusion: It can be concluded that storage conditions affect the microhardness and DTS of resin composite Alkasite and Zirconia-reinforced GIC

Effects of aging on shear bond strength to dentin and mechanical properties of restorative glass ionomer cements

ObjectivesTo evaluate the shear bond strength to dentin (SBS), flexural strength (FS), and diametral tensile strength (DTS) of four restorative glass ionomer cements after aging in artificial saliva. Materials and methodsFor SBS testing, sound molars were ground to flat occlusal dentin and fixed with acrylic resin. Teeth were randomly divided into four groups along with the following materials: Ketac Nano, Ketac Molar, Fuji II LC and Equia. Glass ionomer cylinders were bonded to each dentin surface. For testing the mechanical properties, FS bars (25 mm × 2 mm x 2 mm) and DTS discs (4 mm × 2 mm) were fabricated. All specimens were stored in artificial saliva (37 °C) and tested after 24 h and 6 months. Data was analyzed with two-way ANOVA and post-hoc Tukey's tests (α = 5%). ResultsThe SBS results were statistically similar among the four glass ionomer cements (p > 0.05). No significant differences in SBS after 24-h and 6-month storage were found, except for in the Ketac Nano group, where a significant decrease in SBS was found after aging (p < 0.05). All materials had a significant increase in FS after aging. The DTS values did not change significantly after aging, with the exception of the Fuji II LC group. Overall, the Fuji II LC group showed significantly higher DTS and FS compared to the other materials. ConclusionsAging for 6 months did not affect the SBS of restorative glass ionomer cements, except in the case of Ketac Nano. All glass ionomer cements showed increased FS over time. The DTS remained unchanged – except for the Fuji II LC, which experienced increased DTS.

Post-gel and Total Shrinkage Stress of Conventional and Bulk-fill Resin Composites in Endodontically-treated Molars.

The clinician should consider the polymerization shrinkage stress when selecting a composite resin for posterior restorations. The use of post-gel shrinkage values should guide the selection of a composite resin for posterior teeth. Objectives: The objective of this study was to evaluate the effect of the method used for calculation of polymerization shrinkage, total or post-gel, on the shrinkage stress of conventional and bulk-fill composite resins for restoring endodontically treated teeth using finite element analysis.Methods and Materials: Four composite resins were tested for post-gel shrinkage (P-Shr) by the strain-gauge test and total shrinkage (TShr) using an optical method (n=10). Two conventional composite resins, Filtek Z350 XT (3M-ESPE; Z350) and TPH3 Spectrum (Dents-ply; TPH3) and two bulk-fill composite resins. Filtek Bulk-Fill Posterior (3M-ESPE; POST) SureFil SDR flow (Dentsply; SDR) were tested. Elastic modulus (E), diametral tensile strength (DTS), and compressive strength (CS) were also determined (n=10). The residual shrinkage stress was evaluated by finite element analysis with four restorative techniques: incremental with Z350 and TPH3; SDR/TPH3 (two bulk increments of 4 mm and two occlusal increments); and two bulk increments of 5 mm for POST. Data for P-Shr, T-Shr, E, DTS, and CS were analyzed by analysis of variance and Tukey's test (α=0.05), and residual shrinkage was analyzed quantitatively and qualitatively by the modified von Mises criteria.Results: SDR had the lowest CS values, POST and TPH3 had similar and intermediate values, and Z350 had the highest CS. TPH3 and Z350 had similar DTS values and values higher than SDR. Z350 and POST had higher P-Shr, and SDR had lower T-Shr. T-Shr resulted in higher shrinkage stress than P-Shr values. SDR/TPH3 resulted in higher shrinkage stress when using T-Shr and lower values when using the P-Shr value.Conclusion: T-Shr resulted in higher stress in the enamel and in root dentin close to the pulp chamber than P-Shr values. The selection of the T-Shr or P-Shr changed the ranking of the shrinkage stress of the tested composite resin.

Preparation, micro-structure and mechanical properties of porous carbonate apatite using chicken bone as raw material

Introduction: The increasing in bone loss due to trauma disease or accident leads to the demand for bone substitute materials. Autograft is the gold standard for bone graft; however, it has limited supplies and additional surgery for harvesting. Therefore, the artificial bone graft is necessary for bone defect treatment. One of the potential candidates for bone repair and regeneration is porous Carbonate Apatite (CO3Ap) due to its excellent biodegradability and biocompatibility. Understanding the importance of recycling of waste materials and by-products from the food industry such as poultry bone could be used as the alternative source for starting material. Thus, recycling and adding value for the food waste could be done with the development of artificial bone graft.&#x0D; Method: In this study, porous CO3Ap was prepared using bio apatite powder derived from chicken bone via the sacrificial template technique. Templates such as chopped cotton fibers were used to make porous CO3Ap with interconnecting pores. X-ray diffraction (XRD) and Scanning electron microscope (SEM) were used to characterize phase composition and structure. Carbonate content was evaluated using elemental analysis CHN (carbon hydrogen and nitrogen) analyzer.&#x0D; Results: The results indicated that a pure CO3Ap block consisting of elongating pores could be obtained. Mechanical strength was evaluated in terms of Diametral Tensile Strength (DTS). Porous CO3Ap had a mean DTS value of 198.5 +/- 12.9 kPa and an average porosity of approximately 70%.&#x0D; Conclusion: As a conclusion, CO3Ap containing 5.25 ± 0.03 % wt of carbonate with low crystallinity and the inter-connecting porous structure is advantageous on bone regeneration as being a useful material for application to repair the bone defect.&#x0D;

Setting time, mechanical and adhesive properties of magnesium oxide nanoparticles modified glass-ionomer cement

Nanoparticle modifications of glass-ionomer cement are interesting research subjects. This study investigated the effect of MgO nanoparticles on the setting time, compressive and diametral tensile strength, and adhesive properties of glass-ionomer cement. A conventional GIC was modified by the incorporation of MgO nanoparticles at 1%, 2.5%, 5%, and 10% (w/w) ratios with an unmodified GIC used as the control group. The data were analysed using a one-way analysis of variance (ANOVA) and Tukey's HSD test (p < 0.05). Although the GICs with 1% and 2.5% MgO nanoparticles were still within the ISO standard range specified for the GIC setting time, increasing the MgO nanoparticle concentration significantly increased the setting time of the tested cement (p < 0.05). GICs with 1% MgO nanoparticles had the highest compressive and diametral tensile strength values. Increasing the nanoparticle content from 5% and more significantly decreased the cement strength (p < 0.05). The shear bond strength (SBS) of enamel and dentine showed statistically significant differences among the tested groups (p < 0.05). However, the addition of MgO nanoparticles up to 5% (w/w) did not have an unfavourable effect on the cement adhesiveness. Although cohesive and mixed type failure modes were more common than adhesive failure modes, no statistically significant associations were found between the failure mode and type of GIC (p > 0.05).Within the limitations of this study, the current findings suggest that modifying GICs by incorporating MgO nanoparticles up to 2.5% (w/w) could be a promising restorative material for clinical dental applications.

The Influence of Aging in Solvents on Dental Cements Hardness and Diametral Tensile Strength.

Prosthetic materials must exhibit adequate resistance to the oral environment. The aim of this paper was to study the resistance of selected cements used for cementing restorations (Breeze—composite, Adhesor Carbofine—zinc-polycarboxylate and IHDENT–Giz type II—glass-ionomer) against ethanol, soda and green tea solutions. The highest values of hardness and DTS (diametral tensile strength) were obtained by composite cement (HV = 15–31, DTS = 34–45 MPa). Ethanol solution had the greatest impact on the hardness value of composite cement, and soda solution on zinc-polycarboxylate cement. No significant differences were noted in the DTS values of composite cements after immersion in solvents; however, the DTS value of zinc-polycarboxylate cement increased after prolonged immersion time in ethanol and the DTS of glass-ionomer cement (IHDENT Giz type II) clearly decreased after submersion in soda solutions. Variation in pH across the range of 6 (tea) to 9 (soda solution) had a low impact on the properties of dental cements. Extended exposure to solvents appears to worsen the properties of cements.