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The purpose of this study was to evaluate the application of fiberglass reinforcement method in thermoplastic mouthguard materials to improve flexural properties and adhesive strength. Commonly used two types of commercial mouth guard materials (ethylenevinyl acetate copolymer-based and polyolefin-based) were reinforced with glass fiber clothes by two-step hot press. Flexural strength and adhesive strength with each base material were examine via three-point bending test and delamination test, respectively. Ethylene-vinyl acetate copolymer-based fiberglass-reinforced material has significantly greater adhesive strength with base material and improvement of flexural properties compared with polyolefin-based material. These results suggest that flexural properties of both conventional commercial mouthguard materials were improved when the glass-fiber-reinforced method was applied to reinforce mouthguard materials, and more, ethylene-vinyl acetate copolymer was more desirable for the base material. [ABSTRACT FROM AUTHOR]

This study investigates the flexural properties, Knoop hardness number (KHN), and wear behavior of computer-aided design and computer-aided manufacturing (CAD/CAM) resin blocks and compares these values with those of conventional resin composites for direct restoration (RCDs). Four CAD/CAM resin blocks and two RCDs are compared. Ten specimens per material are used to obtain the flexural properties according to ISO 6872 specifications, and five specimens per material are used for KHN measurement. For sliding impact wear testing, twelve specimens are prepared. Confocal laser scanning microscopy (LSM) is used to determine maximum facet depth and volume loss. Polished material surfaces and worn surfaces after wear testing are observed using scanning electron microscopy and LSM. While measured flexural properties and KHN are found to be material-dependent, CAD/CAM resin blocks exhibit higher wear resistance than RCDs. CAD/CAM resin blocks polymerized at high-pressure and high-temperature are found to exhibit wear behaviors far superior to those of RCDs. [ABSTRACT FROM AUTHOR]

We investigated the influence of different curing modes on the mechanical properties and wear behavior of dual-cure provisional resin-based composites (DCPRs). Three DCPRs and a self-curing bis-acryl provisional resin-based composite were used. Flexural strength (σF), elastic modulus (E), resilience (R), and fracture toughness (KIC) were measured. The specimens were fabricated with and without light irradiation, stored in distilled water at 37°C for 24 h, and subjected to 5,000 or 10,000 thermal cycles. For sliding impact wear testing, 12 specimens were prepared with and without light irradiation. The maximum facet depth and volume loss were determined using a noncontact profilometer. Some of the mechanical properties and wear behavior of DCPRs are affected by light irradiation. This study indicated that proper light irradiation is important in polymerization process of the DCPRs to enhance the wear resistance and some mechanical properties. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of titanium tetrafluoride (TiF4) solution on the bond strength of glass fiber post to resin cement. The specimens were divided into eight groups according to the method of surface treatment performed. Flexural properties and microtensile bond strength (µTBS) were determined. Data were analyzed using two-way ANOVA and Tukey's post hoc tests. The highest µTBS achieved with the TiF4 (4 wt/v%-4 min) group compared with the other groups (p<0.05). This finding could be attributed to the effectiveness of TiF4 (4 wt/v%-4 min) on removing the surface layer of the resin matrix of fiber posts that provides more uncovered surface areas of posts which improved the micromechanical retention of the resin cement. Surface treatments did not affect the flexural properties of fiber posts (p>0.05). Surface treatment of fiber post with TiF4 (4 wt/v%-4 min) solution exhibited higher bond strength to resin cement compared with other surface treatments. [ABSTRACT FROM AUTHOR]

This study aimed to investigate amount of γ-methacryloxypropyltrimethoxysilane (MPS) silanized on experimental nanosilica particles (NPs), amount of NP and amount of MPS silanized NP on flexural strength (FS), flexural modulus (FM), and fracture toughness (FT) of NP reinforced polymethyl methacrylate (PMMA). The chemisorbed amount of MPS was determined using elemental analysis. Six groups (n=8) were prepared with chemisorbed amount and mixed with PMMA-monomer to make 0.25, 0.5, 1, 5, 10 and 15% (w/w) of NP reinforced PMMA. PMMA without NP served as control. Seven groups (n=8) were prepared with 1% of NP silanized with 0, 0.061, 0.123, 0.246, 0.493, 0.987, and 1.974 gMPS/gsilica and mixed with PMMA-monomer to make NP reinforced PMMA. FS, FM, and FT were determined using 3-point bending test. One-way ANOVA and multiple comparisons showed that 0.246 gMPS/gsilica of 1% amount of silanized NP group was significantly highest in FS, FM, and FT compared to the others (p<0.05). [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the flexural properties and surface topography of fiber posts surface-treated with various etching protocols. Seventy each of three types of fiber posts: RelyX Fiber Post, Tenax Fiber Trans, and D.T. Light-Post Illusion X-Ro, were randomly divided into 7 groups: no surface treatment, surface treated with hydrofluoric acid (HF) 4.5% for 60 s, HF 4.5% for 120 s, HF 9.6% for 15 s, HF 9.6% for 60 s, HF 9.6% for 120 s, and treated with H2O2 24% for 10 min. The specimens were then subjected to a three-point bending test. Surface topographies of the posts were observed using a SEM. The results indicate that fiber post surface pretreatments had no adverse effects on the flexural properties. However, the fiber posts treated with high HF concentrations or long etching times seemed to have more surface irregularities. [ABSTRACT FROM AUTHOR]

The use of non-metal clasp denture (NMCD) materials may seriously affect the remaining tissues because of the low rigidity of NMCD materials such as polyamides. The purpose of this study was to develop a high-rigidity glass fiber-reinforced thermoplastic (GFRTP) composed of E-glass fiber and polyamide-6 for NMCDs using an injection molding. The reinforcing effects of fiber on the flexural properties of GFRTPs were investigated using glass fiber content ranging from 0 to 50 mass%. Three-point bending tests indicated that the flexural strength and elastic modulus of a GFRTP with a fiber content of 50 mass% were 5.4 and 4.7 times higher than those of unreinforced polyamide-6, respectively. The result showed that the physical characteristics of GFRTPs were greatly improved by increasing the fiber content, and the beneficial effects of fiber reinforcement were evident. The findings suggest that the injectionmolded GFRTPs are adaptable to NMCDs because of their excellent mechanical properties. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the depth of cure, flexural properties and volumetric shrinkage of low and high viscosity bulk-fill giomers and resin composites. Depth of cure and flexural properties were determined according to ISO 4049, and volumetric shrinkage was measured using a dilatometer. The depths of cure of giomers were significantly lower than those of resin composites, regardless of photo polymerization times. No difference in flexural strength and modulus was found among either high or low viscosity bulk fill materials. Volumetric shrinkage of low and high viscosity bulk-fill resin composites was significantly less than low and high viscosity giomers. Depth of cure of both low and high viscosity bulk-fill materials is time dependent. Flexural strength and modulus of high viscosity or low viscosity bulk-fill giomer or resin composite materials are not different for their respective category. Resin composites exhibited less polymerization shrinkage than giomers. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the effects of partial carbon or glass fiber reinforcement on the flexural properties of All-on-Four provisional fixed denture base resin. The carbon or glass fibers were woven (3% by weight) together in three strands and twisted and tightened between the two abutments in a figure-of-"8" pattern. Four types of specimens were fabricated for the three-point loading test. The interface between the denture base resin and fibers was examined using scanning electron microscopy (SEM). Reinforcement with carbon or glass fibers between two abutments significantly increased the flexural strength and flexural modulus. SEM revealed relatively continuous contact between the fibers and acrylic resin. The addition of carbon or glass fibers between two abutments placed on All-on-Four provisional fixed denture base resin may be clinically effective in preventing All-on-Four denture fracture and can provide several advantages for clinical use. [ABSTRACT FROM AUTHOR]

This study evaluated the polymerization shrinkage, flexural and compressive properties of low-shrinkage resin composites. For the study, four methacrylate-based and one silorane-based resin composites were light cured using three different light-curing units (LCUs) and their polymerization shrinkage, flexural (strength (FS) and modulus (FM)) and compressive (strength (CS) and modulus (CM)) properties were evaluated. Data were statistically analyzed using ANOVA and a post-hoc Tukey test. The polymerization shrinkage ranged approximately 7.6-14.2 μm for 2-mm thick specimens depending on the resin product and LCU. Filtek LS showed the least shrinkage while the rest shrank approximately 13.2-14.2 μm. However, Filtek LS showed the greatest shrinkage difference for the used LCUs. FS and CS of the tested specimens ranged 96.2-152.1 MPa and 239.2-288.4 MPa, respectively, depending on the resin product and LCU. The highest and lowest FS and FM were recorded for the methacrylate-based resin composites. Among the specimens, Filtek LS showed the lowest CS and CM. [ABSTRACT FROM AUTHOR]

This study evaluated the different amounts of 3-methacryloxypropyltrimethoxysilane (MPS) coated alumina filler particles on flexural strength and wear resistance of alumina reinforced poly methyl methacrylate (PMMA) denture base. Ten mass% of alumina filler silanized with 0, 0.1, 0.2, or 0.4 mass% of MPS was blended with PMMA. PMMA without alumina particles served as control. Specimens were prepared for flexural strength and wear resistance tests (n-10). Flexural strength was determined using a 3-point bending test and volume loss was measured by in-vitro 2-body wear-testing. The results were analyzed by One-way ANOVA and Tamhane's test (α=0.05). Flexural strength ranged from 95.1-117.8 MPa, while volume loss ranged from 0,038-0.160 mm3. Statistical analysis indicated the 0.1 mass% MPS silanized group had significantly higher flexural strength and lower volume loss than the control group. Adding alumina filler silanized with 0.1 mass% MPS resulted in an improvement of the flexural strength and wear resistance of PMMA. [ABSTRACT FROM AUTHOR]

The aim of this study was to estimate the flexural properties of three kinds of experimental fiber-reinforced composite (FRC) posts and to evaluate their potential use as posts. Experimental FRC posts were fabricated with glass, aramid, and UHMWP fibers. Commercial FRC posts were used for comparison. A three-point bending test was performed at a crosshead speed of 1 mm/min. Experimental glass fiber posts showed significantly higher flexural strengths and moduli than aramid and UHMWP posts. Experimental UHMWP posts demonstrated superior toughness to the commercial posts. The glass fiber posts displayed stiff, strong and brittle features, while the UHMWP posts were flexible, weak and ductile. The flexural properties of the aramid posts fell between those of the glass and UHMWP posts. In conclusion, the glass fiber posts proved excellent in flexural strengths and moduli. However, the superior toughness of UHMWP fibers suggests the possibility of their use as posts in combination with glass fibers. [ABSTRACT FROM AUTHOR]

Light-curing polyethyl methacrylate (PEMA)-urethanc dimethacrylate (UDMA) resins and polymethyl methacrylate (PMMA)-UDMA resins were prepared by two processes. For first step, PEMA or PMMA powders were fully dissolved in ethyl methacrylate (EMA) or methyl methacrylate (MMA) and then the PEMA-EMA/PMMA-MMA mixtures were mixed with UDMA. The flexural properties of cured PEMA-UDMA and PMMA-UDMA polymers were measured using two PEMA (Mw: 300,000-400,000 and 650,000-1,000,000) and three PMMA (Mw: 30,000-60,000, 350,000 and 650,000-1,000,000) powders with different molecular weight, four mixing ratios of PMMA-MMA, and three mixing ratios of PMMA-MMA mixture and UDMA oligomer. Polymers with PMMA(Mw: 350,000)- MMA=25/50, and with PMMA(Mw: 350,000)-MMAIUDMA=1/2 and =1/1, showed no-fracture in a flexural test at 1 mm/min and flexural strength and flexural modulus showed no significant difference compared with those of commercially available heat- and self-curing acrylic resins (p>0.01). Within limitation of this investigation, methyl methacrylate-UD1VIA blend polymer of this composition is available for denture base resin. [ABSTRACT FROM AUTHOR]

This study investigated the effect of the diameter of glass fibers on the flexural properties of fiber-reinforced composites. Bar-shaped test specimens of highly filled fiber-reinforced composites (FRCs) and FRC of 30 vol% fiber content were made from a light-cured dimethacrylate monomer liquid (mixture of urethane dimethacrylate and triethylene glycol dimethacrylate) with silanized E-glass fibers (7, 10, 13, 16, 20, 25, 30, and 45 μm in diameter). Flexural strength and elastic modulus were measured. The flexural strength of the highly filled FRCs increased with increasing fiber diameter. In particular, the strengths of highly filled FRCs with 20-, 25-, 30-, and 45-μm-diameter fibers was significantly higher than the others (p<0.05). The flexural strength of FRC of 30 vol% fiber content increased with increasing fiber diameter, except for the FRC with 45-μm-diameter fibers; FRCs with 20-, 25-, and 30-μm-diameter fibers were significantly stronger than the others (p<0.05). Therefore, it was revealed that the diameter of glass fibers significantly affected the flexural properties of fiber-reinforced composites. [ABSTRACT FROM AUTHOR]

The present study investigated the feasibility of a high short-rod fiber content in denture base resins using polymethylmethacrylate (PMMA) powder with a small particle diameter. The effects of fiber contents on mechanical properties of composite resins were studied. A commercial denture base PMMA powder (AC; average particle size, 150 μm) and an industrial PMMA powder (MB; average particle size, 4 μm) were selected. Short-rod glass fibers were mixed with the two powders at a mass ratio of 0-50%. Flexural strengths and moduli of the mixtures were evaluated by a three-point bending test. The flexural strength of AC composites did not change regardless of fiber content, while that of MB composites increased significantly at fiber contents exceeding 40%. The flexural moduli of AC and MB composites at fiber contents exceeding 20% were significantly greater than those of AC and MB resins without short-rod glass fibers, respectively. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the deformation and flexural properties of acrylic and urethane polymers rein forced with glass fiber sheet. Four types of specimen -- self-curing resin plate (R), light curing oligomer plate containing a reinforcement (GO), and self curing resin plate containing a reinforcement on one (GR) or both (GRG) sides -- were prepared with three thicknesses: 15, 24, and 30 mm. Gaps between polymerized test specimen and a standard rectal plate were measured at the corner (C), middle of the long sides (LS), and middle of the short sides (SS) The gaps for R were 0-2.0 µm. GO and GR markedly deformed at Points C, LS, and SS, and the degree of deformation increased as GO became thinner. Flexural strength was significantly increased by the reinforcement (p<005) The flexural moduli of 3.0-mm thick R, GO, and GR were significantly smaller than that of 15-mm thick specimens. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the application of fiberglass reinforcement method in thermoplastic mouthguard materials to improve flexural properties and adhesive strength. Commonly used two types of commercial mouth guard materials (ethylene-vinyl acetate copolymer-based and polyolefin-based) were reinforced with glass fiber clothes by two-step hot press. Flexural strength and adhesive strength with each base material were examine via three-point bending test and delamination test, respectively. Ethylene-vinyl acetate copolymer-based fiberglass-reinforced material has significantly greater adhesive strength with base material and improvement of flexural properties compared with polyolefin-based material. These results suggest that flexural properties of both conventional commercial mouthguard materials were improved when the glass-fiber-reinforced method was applied to reinforce mouthguard materials, and more, ethylene-vinyl acetate copolymer was more desirable for the base material.

This study investigates the flexural properties, Knoop hardness number (KHN), and wear behavior of computer-aided design and computer-aided manufacturing (CAD/CAM) resin blocks and compares these values with those of conventional resin composites for direct restoration (RCDs). Four CAD/CAM resin blocks and two RCDs are compared. Ten specimens per material are used to obtain the flexural properties according to ISO 6872 specifications, and five specimens per material are used for KHN measurement. For sliding impact wear testing, twelve specimens are prepared. Confocal laser scanning microscopy (LSM) is used to determine maximum facet depth and volume loss. Polished material surfaces and worn surfaces after wear testing are observed using scanning electron microscopy and LSM. While measured flexural properties and KHN are found to be material-dependent, CAD/CAM resin blocks exhibit higher wear resistance than RCDs. CAD/CAM resin blocks polymerized at high-pressure and high-temperature are found to exhibit wear behaviors far superior to those of RCDs.

The use of non-metal clasp denture (NMCD) materials may seriously affect the remaining tissues because of the low rigidity of NMCD materials such as polyamides. The purpose of this study was to develop a high-rigidity glass fiber-reinforced thermoplastic (GFRTP) composed of E-glass fiber and polyamide-6 for NMCDs using an injection molding. The reinforcing effects of fiber on the flexural properties of GFRTPs were investigated using glass fiber content ranging from 0 to 50 mass%. Three-point bending tests indicated that the flexural strength and elastic modulus of a GFRTP with a fiber content of 50 mass% were 5.4 and 4.7 times higher than those of unreinforced polyamide-6, respectively. The result showed that the physical characteristics of GFRTPs were greatly improved by increasing the fiber content, and the beneficial effects of fiber reinforcement were evident. The findings suggest that the injection-molded GFRTPs are adaptable to NMCDs because of their excellent mechanical properties.