Diametral Tensile Research Articles

Effect of Incorporating Strontium Fluoride and Fluoride on Compressive and Diametral Tensile Strengths of Biodentine

Abstract: Objective: The objective of this study was aimed to evaluate the effect of incorporation strontium fluoride and fluoride on compressive and diametral tensile strengths of biodentine. Materials and Methods: Materials used in this study was divided into three main groups according to materials used Group I: Calcium silicate based material (biodentine) as a control material, Group II: Strontium fluoride modified calcium silicate based material, Group III: Fluoride modified calcium silicate based material. Each main group was subdivided into two subgroups according to test type (compressive and diametral tensile strength). Each subgroups dividing into two categories according to storage time at one week and one month. Results: According to compressive and diametral tensile strength test, biodentine recorded highest compressive and diametral tensile strength followed by strontium fluoride modified biodentine followed by fluoride modified biodentine. For storage time the four weeks compressive and diametral tensile strength is higher than Seven days. Conclusion: Modification of biodentine with strontium fluoride and fluoride don’t have considerable effect on the tested properties of biodentine. Key Words: Biodentine, compressive strength, strontium fluoride, fluoride.

A Novel Dental Polymer with a Flipped External Ester Group Design that Resists Degradation via Polymer Backbone Preservation.

Current dental sealants with methacrylate based chemistry are prone to hydrolytic degradation. A conventional ethylene glycol dimethacrylate (EGDMA) was compared to a novel methacrylate monomer with a flipped external ester group (ethylene glycol ethyl methacrylate - EGEMA) that was designed to resist polymer degradation effects. Fourier transform infrared spectroscopy and water contact angle confirmed a comparable degree of initial conversion and surface wettability for EGDMA and EGEMA. EGDMA disks initially performed better compared to EGEMA as suggested by higher surface hardness and 1.5 times higher diametral tensile strength (DTS). After 15 weeks of hydrolytic and accelerated aging, EGDMA and EGEMA DTS was reduced by 88% and 44% respectively. This accelerated aging model resulted in 3.3 times higher water sorption for EDGMA than EGEMA disks. EGDMA had an increase in grain boundary defects and visible erosion sites with accelerated aging, while for EGEMA the changes were not significant.

Tailored pore structures and mechanical properties of porous alumina ceramics prepared with corn cob pore‐forming agent

AbstractIn this work, the effects of porosity and different particle sizes of pore‐forming agent on the mechanical properties of porous alumina ceramics have been reported. Different grades of porous alumina ceramics were developed using corn cob (CC) of different weight contents (5, 10, 15, and 20 wt%) and particle sizes (<63 µm, 63‐125 µm and 125‐250 µm) as the pore‐forming agent. Experimental results showed that total porosity and pore cavity size of the porous alumina ceramics increased with rising addition of CC pore former. Total porosity increased with increasing particle size of CC with the Al2O3‐<63CC5 sample exhibiting the lowest total porosity of 41.3 vol% while the highest total porosity of 68.1 vol% was exhibited by the Al2O3‐125‐250CC20. The particle size effect of CC on the mechanical properties revealed that diametral tensile strength and hardness of the porous alumina ceramics deteriorated with increasing particle size of CC pore former. The Al2O3‐<63CC5 sample exhibited the highest diametral tensile strength and hardness of 25.1 MPa and 768.2 HV, respectively, while Al2O3‐125‐250CC20 exhibited the lowest values of 1.1 MPa and 35.9 HV. Overall, porous alumina ceramics with the smallest pore sizes under each particle size category exhibited superior mechanical properties in their respective categories.

Evaluation of physical-mechanical properties of self-adhesive versus conventional resin cements

Aim: The purpose of this study was to compare the microhardness, diametral tensile strength, compressive strength and the rheological properties of self-adhesive versus conventional resin cements. Methods: Specimens of a conventional (RelyX ARC) and 3 self-adhesive (RelyX U200, Maxcem Elite, Bifix SE) types of resin cements were prepared. The Knoop test was used to assess the microhardness, using a Microhardness Tester FM 700. For the diametral tensile strength test, a tensile strength was applied at a speed of 0.6 mm/minute. A universal testing machine was used for the analysis of compressive strength and a thermo-controlled oscillating rheometer was used for the Rheology test. One-way ANOVA and Tukey’s test (α=0.05) were used for data analysis. Results: According to microhardness analysis, all the cements were statistically similar (p>0.05), except for Maxcem that presented lower hardness compared with the other cements in relation to the top surface (p<0.05). In the diametral tensile strength test, Relyx U200 and RelyX ARC cements were statistically similar (p>0.05), presented higher value when compared to the Maxcem and Bifix cements (p<0.05). The compressive strength of RelyX ARC and Maxcem Elite cements was statistically higher than RelyX U200 and Bifix cements (p<0.05). Regarding the rheology test, Maxcem Elite and RelyX ARC cements showed a high modulus of elasticity. Conclusions: The self-adhesive cements presented poorer mechanical properties than conventional resin cement. Chemical structure and types of monomers employed interfere directly in the mechanical properties of resin cements.

Mechanical Properties of Glass Ionomer Cements after Incorporation of Marine Derived Porous Cuttlefish Bone Hydroxyapatite.

The purpose of this study was to evaluate the effects of the incorporation of hydroxyapatite (HA) derived from cuttlefish bone on the mechanical properties of glass ionomer cements (GIC). Fuji II LC and Fuji IX GP Extra (GC Corporation, Tokyo, Japan) were used in the study. There were four groups (n = 11–18) for each material: a group without the addition of HA particles and three groups modified by incorporation of 2, 5, and 10 wt% HA. The tests were performed on a universal testing machine (Shimadzu, Duisburg, Germany) and descriptive statistics, two-way analysis of variance (ANOVA) for the comparison of three mechanical properties, and one-way ANOVA for the comparison of different concentrations for each material were performed. Regarding the Fuji IX groups, compressive strength (CS) and flexural strength (FS) were highest in the group without HA particles added. The differences in CS between the Fuji IX group without HA particles and the Fuji IX groups with 2 wt% HA and 10 wt% HA were significant. The Fuji II 5 wt% HA group exhibited higher diametral tensile strength (DTS) and CS than other Fuji II groups, but not significantly. The Fuji II group, modified with 10 wt% HA, exhibited significantly higher FS than the Fuji II group without HA particles (p < 0.05). Porous HA incorporated into the Fuji IX groups had a significant impact on mechanical properties only in the Fuji IX 5 wt% HA group. Fuji II groups modified with 10 wt% HA showed the most favorable results with respect to FS.

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;

Synthesis and characterization of magnesium-lanthanum dual doped bioactive glasses

Dual ion-doped bioactive glass has drawn high attention during recent years because of well-improved therapeutic characteristics and mechanical properties. In this study, 5 different ion-doped (1 wt% Lanthanum with 0, 1, 2.5, 5, and 10 wt% Magnesium) 58S bioactive glasses (BGs) were synthesized. The physicochemical results revealed that Lanthanum (La) and Magnesium (Mg) ion doping has been successfully done. Mechanical characterization results depicted that La-doped and Mg-La double doped samples with Mg less than 2.5 wt% had higher diametral tensile strength compared to BG and other co-doped samples. However, Vickers hardness values were not affected by ion dopings. Apatite formation and bioactivity were also improved in double ion-doped samples, especially in those with the higher magnesium content. Cell culture studies showed that synthesized BGs were not cytotoxic. Especially, groups having 2.5 to 5 wt% Mg showed the highest cell viabilities at day 7. Results indicated that Mg- La dual doped bioactive glasses possess improved properties compared to BG, and thus, have potential for bone regeneration applications.

The effect of repeated preheating on diametral tensile strength of composite resin with different fillers

Background: The development of adhesive systems has made the removal of carious lesion a minimally invasive procedure. Composite resin is the material of choice today, but the filler composition of the resin varies. Packable composite resin has good mechanical properties, but its high viscosity makes it hard to manipulate. Several methods, such as preheating, are used to decrease this viscosity. A syringe of composite resin might be preheated several times, but the effect of repeated preheating is unknown. Objectives: The purpose of this research was to analyze the effect of repeated preheating on the mechanical properties of a composite resin with different fillers. Method: Microhybrid, nanohybrid, and nanofill composite resins were preheated (ten times, twenty times, and control), molded into cylinder molds 6 mm in diameter and 3 mm in height, flattened with a celluloid strip, and polymerized with an light-emitting diode light-curing unit for 40 s. A total of 180 specimens were tested. The specimens were divided into two groups: Group 1 was immediately tested using a universal testing machine. Group 2 was soaked in 37°C artificial saliva for 24 h before testing. Each specimen was tested using the universal testing machine with the pressure side with a 1 mm/s crosshead speed. Result: Nanohybrid composite resin had the most stable diametral tensile strength after repeated preheating, whereas nanofill composite had the weakest strength. The increase and decrease in the diametral tensile strength in each group were not statistically significant. Conclusion: Repeated preheating does not significantly affect the diametral tensile strength of composite resin.

Incorporation of amoxicillin-loaded microspheres in mineral trioxide aggregate cement: an in vitro study.

ObjectivesIn this study, we investigated the potential of amoxicillin-loaded polymeric microspheres to be delivered to tooth root infection sites via a bioactive reparative cement.Materials and MethodsAmoxicillin-loaded microspheres were synthesized by a spray-dray method and incorporated at 2.5% and 5% into a mineral trioxide aggregate cement clinically used to induce a mineralized barrier at the root tip of young permanent teeth with incomplete root development and necrotic pulp. The formulations were modified in liquid:powder ratios and in composition by the microspheres. The optimized formulations were evaluated in vitro for physical and mechanical eligibility. The morphology of microspheres was observed under scanning electron microscopy.ResultsThe optimized cement formulation containing microspheres at 5% exhibited a delayed-release response and maintained its fundamental functional properties. When mixed with amoxicillin-loaded microspheres, the setting times of both test materials significantly increased. The diametral tensile strength of cement containing microspheres at 5% was similar to control. However, phytic acid had no effect on this outcome (p > 0.05). When mixed with modified liquid:powder ratio, the setting time was significantly longer than that original liquid:powder ratio (p < 0.05).ConclusionsLack of optimal concentrations of antibiotics at anatomical sites of the dental tissues is a hallmark of recurrent endodontic infections. Therefore, targeting the controlled release of broad-spectrum antibiotics may improve the therapeutic outcomes of current treatments. Overall, these results indicate that the carry of amoxicillin by microspheres could provide an alternative strategy for the local delivery of antibiotics for the management of tooth infections.

Different Molarities and Dissolution-Precipitation Duration Affect the Formation of Carbonate-Apatite Blocks for Bone Graft Material

Objective: To determine diametral tensile strength and water absorption ability of Carbonate-apatite blocks fabricated from gypsum precursors (CaSO4) through a dissolution-precipitation method, with different solution molarities and immersion times. Material and Methods: Thirty-six CaSO4 gypsum specimens with 6 mm diameter; 3 mm height (Group A for diametral tensile strength) and 36 specimens of 6 mm diameter; 3 mm thickness (Group B for water absorption ability) were used. Each group was divided into 4 group treatments of: 1) dissolution-precipitation in solution of 0.5mol / L Na 2 CO 3 + 0.5mol / L Na 3 PO 4 for 48 hours and 72 hours; 1mol / L Na 2 CO 3 + 1mol / L Na 3 PO 4 for 48 hours and 72 hours. The C-Ap blocks were then tested using ATR-FTIR spectrometer to identify the formation of C-Ap functional groups. Furthermore, Group A specimens were tested for diametral tensile strength using Universal Testing Machine, and Group B specimens were tested for water adsorption ability using an analytical balance by measuring initial and final weight after immersion in saline solution at 37 o C for 24 hours . Results: The formation of carbonate-apatite (C-Ap) in groups with solution molarity of 1 mol/L for 48 hours and 72 hours resulted in a lower diametral tensile strength and water absorption ability than the groups with a 0.5 mol/L solution . Conclusion: Solution with different molarities and dissolution-precipitation duration affect the formation of carbonate-apatite blocks.

Effect of Preheating and Fatiguing on Mechanical Properties of Bulk-fill and Conventional Composite Resin.

Bulk-fill composite resins may have comparable mechanical properties to conventional composite resin. Preheating does not reduce the mechanical properties of composite resins.

The Use of Sucrose Granule as Pore Maker in Preparation of Porous Calcium Sulfate Dihydrate

Calcium sulfate dihydrate (CSD) has been clinically used as bone filler for decades. CSD bone graft is cheap, biocompatible and can be transformed to other osteoconductive ceramics such as hydroxyapatite and carbonate apatite. In addition, porous ceramic bone grafts is desired clinically. Development of porous ceramics bone graft with simple and cost-effective method is preferred. Thus, in this study, porous CSD was developed. Porous CSD can be used both as bone filler or precursor for porous hydroxyapatite and carbonate apatite. Porous CSD was prepared by mixing calcium sulfate hemihydrate (CSH) containing sucrose granules with distilled water. After setting, the sucrose granules were removed by immersion in distilled water. Porous CSD was obtained after sucrose leaching. It was observed that more pore formed in the specimen with 50% sucrose granule compared with that of 25% sucrose granule. The sucrose was completely removed from the porous CSD evident from ATR-FTIR analysis. The diametral tensile strength of the porous CSD tend to decrease with the increase of sucrose granule. Finally, sucrose granule was feasible to be used as pore maker in preparation of porous CSD.

Setting Time, Handling Property and Mechanical Strength Evaluation of SCPC50 and Apatite Cement Mixture in Various Combinations

Apatite cement is ideal self-setting cement for bone substitute material, however its use is limited only to areas that receive minimum load bearing because mechanical strength of apatite cement is low. Silica-calcium phosphate nanocomposite (SCPC50) is material having good mechanical strength and has an important role in bone remodeling (bone metabolism), mineralization, synthesis of cartilage, collagen production, proliferation and differentiation of bone cells. However, the unsetting and granule’s physical shape of SCPC50 limits the application. The purpose of this study is to determine the effect of various mixtures of SCPC50 and apatite cement to manipulative index (setting time and handling property), and mechanical properties. The experimental results show that the setting time of apatite cement mixture with 5% and 10% SCPC50 was 40% higher (p&lt;0.05). The mechanical strength evaluated by Diametral Tensile Strength showed that the addition of both 5% silica and 10% SCPC50 composition to apatite cement mixture increased the mechanical strength of apatite cement mixture (p&lt;0.1). The handling property of cement paste was significantly increased between the apatite cement without SCPC50 and apatite cement with both 5% SCPC50 and 10% SCPC50 (p&lt;0.05). It is concluded that the addition of SCPC50 to apatite cement mixture could improve the mechanical properties and it is expected to improve its bioactivity.

Diametral Tensile Strength and Hardness Evaluation of Prototype Composite Based on Natural Zircon Sand Using Geopolymerization Method with Coupling Agent Variation

The widely use of dental composite triggers a lot of research to synthesize composite made from natural sources. One of the natural sources that could be used as a filler of composite is natural zircon sand from Indonesia. The physical properties of dental composite, such as Diametral Tensile Strength (DTS) and hardness could be affected by the filler of the composite. The aim of this research is to determine the value of diametral tensile strength and hardness of prototype composite with natural zircon sand-based filler by using geopolymerization method with various coupling agents. The procedures began from synthesizing Zirconia-Alumina-Silica filler from natural zircon sand using geopolymerization method with two different coupling agents, 3-mercapto propyltrimethoxysilane (3-MPTS) and 3-aminopropyltriethoxysilane (3-APTS), which then mixed with resin matrix to form composite resin, some of the samples were then subjected to a DTS test using Lloyd Universal Testing Machine (5.6 N initial load) until a crack/fracture was formed while some of them was subjected to a hardness test using Vickers Hardness Tester. The results showed the average DTS of dental composite using MPTS coupling agent was 13.78 MPa, while the average DTS of dental composite using APTS coupling agent was 8.90 MPa, and the average hardness result of dental composite coated by 3-MPTS was higher (20.68 VHN) than composite coated by 3-APTS (18.02 VHN). This difference could be affected by filler particle composition, filler surface area and also coupling agent variation. In conclusion, the tensile strength of the prototype resin composite sample group with the natural zircon sand filler using MPTS coupling agent was higher than the APTS coupling agent group.

Diametral Tensile Strength Evaluation of Carbonate Apatite Cement Reinforced by Genipin Cross-Linked Gelatin

Carbonate apatite is one of the most widely studied bioceramic material for its use as bone cement. On the previous study, it has already stated that CO3Ap cement has good osteoconductivity which makes this cement could be replaced by bone. However, the mechanical strength of CO3Ap cement is still low. This low mechanical strength is estimated due to the high porosity and absence of organic components. The aim of this study is to improve the mechanical strength of the CO3Ap cement reinforced by gelatin as an organic component with genipin as a cross-linking agent (Gelapin). The powder phase of vaterite and DCPA at weight ratio 40:60 were mixed with 0.2 mol/L Na2HPO4, 5% (w/v) gelatin, and 20% (v/v) genipin using 0.5 liquid to powder (L/P) ratio. The liquid phase ratios of Na2HPO4 and Gelapin were 50:50, 70:30, and 90:10. For control group, Gelapin were didn’t mixed in the liquid. Diametral tensile strength was improving and statistically significant (p&lt;0.05) on set cement with 50:50 liquid ratio, the average value was 6.02 ± 0.14 MPa whereas the average value of the control group was only 3.10 ± 0.15 MPa. For this instance, gelatin serves a polymer matrix so the carbonate apatite crystallites could be well distributed within it which then gives more flexibility and resistance for the cement. On the other hand, genipin was also successfully cross-linked the gelatin. This study showed that by reinforcing CO3Ap cement using genipin cross-linked gelatin might be a good candidate for a bone substitute material.

Carbon Nanotube Reinforced Hydroxyapatite Nanocomposites As Bone Implants: Nanostructure, Mechanical Strength And Biocompatibility.

PurposeHydroxyapatite (HA) is a biologically active ceramic which promotes bone growth, but it suffers from relatively weak mechanical properties. Multi-walled carbon nanotubes (MWCNTs) have high tensile strength and a degree of stiffness that can be used to strengthen HA; potentially improving the clinical utility of the bone implant.MethodsHA was precipitated by the wet precipitation method in the presence of pristine (p) or functionalised (f) MWCNTs, and polyvinyl alcohol (PVA) or hexadecyl trimethyl ammonium bromide (HTAB) as the surfactant. The resulting composites were characterised and the diametral tensile strength and compressive strength of the composites were measured. To determine the biocompatibility of the composites, human osteoblast cells (HOB) were proliferated in the presence of the composites for 7 days.ResultsThe study revealed that both the MWCNTs and surfactants play a crucial role in the nucleation and growth of the HA. Composites made with f-MWCNTs were found to have better dispersion and better interaction with the HA particles compared to composites with p-MWCNTs. The mechanical strength was improved in all the composites compared to pure HA composites. The biocompatibility study showed minimal LDH activity in the media confirming that the composites were biocompatible. Similarly, the ALP activity confirmed that the cells grown on the composites containing HTAB were comparable to the control whereas the composites containing PVA surfactant showed significantly reduced ALP activity.ConclusionsThe study shows that the composites made of f-MWCNTs HTAB are stronger than pure HA composites and biocompatible making it a suitable material to study further.

Improving the microstructural and mechanical properties of in-situ zirconia-mullite composites by optimizing the simultaneous effect of mechanical activation and additives

The current study aims to investigate the microstructural properties, diametral tensile strength, Weibull modulus, and surface roughness (Ra) of the zirconia-mullite composites. The simultaneous effect of duration of the mechanical activation (MA) process of starting materials, as well as TiO2 and ZnO additions on the mentioned properties, were studied. X-ray diffraction analysis showed that mullite was the main crystalline phase in 6–24 h mechanically activated-TiO2 containing samples which were subsequently heat treated at 1450 °C. Prolonging the duration of the MA process to 72 h led to the crystallization of the tetragonal zirconia as one of the main crystalline phase in the mentioned samples. As the heat treatment temperature increased to 1550 °C, the dependence of the type of the crystalline phases on the milling time eliminated and mullite became the main crystalline phase in 6–72 h MA processed samples. The transformation of starting materials to mullite and t-zirconia was not progressed effectively in ZnO containing samples which were heat treated at 1450 °C. However, by increasing the temperature of the heat treatment process to 1550 °C, both mullite and zirconia were efficiently crystallized in 6–72 h MA processed ZnO containing ones. Scanning electron microscopy results revealed that prolonging the duration of the milling process of the additive containing mixtures from 6 to 72 h could eliminate the acicular morphology of the mullite phase. 72 h mechanically activated ZnO containing sample which was later heat-treated at 1550 °C had the highest noticeable diametral tensile strength of 270 ± 15 MPa. The Weibull modulus of composite samples increased from 10.07 to 12.37 and 20.95 by the addition of TiO2 and ZnO to the starting mixture, respectively. Finally, it was found that prolonging the milling time increased the Weibull modulus remarkably and decreased the Ra values as a result of the homogeneity development in the composite samples.

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.

Comparative evaluation of the physical properties of a reinforced glass ionomer dental restorative material

Statement of problemWhile glass ionomer cements have many unique properties and advantages, they still lack favorable mechanical properties. EQUIA Forte Fil is a newly developed glass ionomer cement (GIC) with improved mechanical strength. However, research and data on the physical properties of EQUIA Forte Fil are lacking. PurposeThe purpose of this in vitro study was to evaluate and compare the compressive, diametral tensile, and flexural strengths of EQUIA Forte Fil with Fuji IX GP and ChemFil Rock, restorative GICs commonly used in dentistry. Moreover, fluoride-releasing properties and surface hardness of the GICs were also assessed. Material and methodsTen disk-shaped specimens of each GIC (EQUIA Forte Fil, Fuji IX GP, and ChemFil Rock) were fabricated for mechanical and surface hardness tests by using polydimethylsiloxane (PDMS) molds. The specimens were tested after 24 hours and 7 days of immersion in distilled water at 37 °C. By using a mechanical testing machine, the compressive, diametral tensile, and flexural strengths of each GIC were measured. Fluoride-releasing properties were also evaluated (10 specimens per group). A microhardness tester was used to measure the surface hardness. The mean data were analyzed by using 1- and 2-way ANOVA (α=.05). ResultsEQUIA Forte Fil glass ionomer cements exhibited significantly greater (P<.05) flexural strength and surface hardness than Fuji IX GIC specimens. However, no significant difference (P>.05) was observed between the compressive and diametral tensile strength of EQUIA Forte Fil and Fuji IX GIC specimens. ChemFil Rock exhibited higher flexural strength than EQUIA Forte Fil (P>.05) but significantly lower compressive strength and microhardness (P<.05). Tested GICs matured after 1 week of immersion in distilled water, demonstrating a significant improvement in their mechanical properties. All the examined glass ionomers exhibited comparable initial fluoride-releasing properties, whereas EQUIA Forte Fil exhibited significantly higher (P<.05) amounts of fluoride release from the bulk of the material after 4 weeks. ConclusionsEQUIA Forte Fil is a promising restorative material with superior flexural strength and surface hardness compared with its predecessor, Fuji IX GP, or other commercially available glass ionomers.

The Addition of Poly(Vinyl Alcohol) Fibers to Apatitic Calcium Phosphate Cement Can Improve Its Toughness.

Calcium phosphate cements, and in particular hydroxyapatite cements, have been widely investigated for use as bone void fillers due to their chemical similarity to bone and related osteoconductivity. However, they are brittle, which limits their use to non-load-bearing applications. The aim of the current study was to improve the toughness of hydroxyapatite cements through fiber reinforcement. The effect of the addition of hydrophilic, poly(vinyl-alcohol) (PVA) fibers to hydroxyapatite cement was evaluated in terms of mechanical properties, including compressive strength, diametral tensile strength and toughness (work of fracture), as well as setting time, phase composition and cement morphology. The fiber reinforcement enhanced the fracture resistance of the hydroxyapatite cement, but also simultaneously reduced the compressive strength and setting time of the cements. However, cement with 5 wt % of fibers (of the powder component) could be considered a good compromise, with a compressive strength of 46.5 ± 4.6 MPa (compared to 62.3 ± 12.8 MPa of that without fibers), i.e., still much greater than that of human trabecular bone (0.1–14 MPa). A significantly higher diametral tensile strength (9.2 ± 0.4 MPa) was found for this cement compared to that without fibers (7.4 ± 1.5 MPa). The work of fracture increased four times to 9.1 ± 1.5 kJ/m2 in comparison to the pristine apatite. In summary, the hydroxyapatite cements could be reinforced by suitable amounts of PVA fibers, which resulted in enhancing the material’s structural integrity and ductility, and increased the material’s resistance to cracking.