Development of dual-curing type experimental composite resin cement for orthodontic bonding -effect of additional amount of accelerators on the mechanical properties-.

In this study, a dual-curing type composite resin cement that included a photo-initiator and two accelerators was designed. In particular, special emphasis was made on addressing questions on the effects from different amounts of additional accelerators on the flexural strength of the designed experimental composite resin cement, as well as on the tensile bond strength of the bracket bonded onto the enamel surface by the experimental composite resin cement. When 0.

NMR study on the adhesion efficacy of experimental phosphonic acid monomers.

Three experimental self-etching primers - consisting of N-methacryloyl-omega-aminoalkyl phosphonic acid (NMomegaP) with different methylene chain lengths and N-methacryloyl glycine (NMGly) - were formulated. The influence of methylene chain length in NMomegaP derivatives on the chemical nature of calcium salts was examined following their application to tooth components. Bond strengths of experimental self-etching primers created with these monomers to enamel and dentin were also investigated.

Trabecular bone response to titanium implants with a thin carbonate-containing apatite coating applied using the molecular precursor method.

Purpose: The influence of thin carbonate-containing apatite (CA) coating on the trabecular bone response to titanium implants was investigated.

Materials And Methods: Thin CA coatings were deposited by a new method known as the molecular precursor method. Using a precursor solution composed of an EDTA-calcium complex, a CA film was deposited on the titanium surfaces.

[Effectiveness of methacrylamide monomer for dentin bonding].

Purpose: In this study, we investigated the conditioning efficacy of a self-etching primer consisting of methacrylamide, N-methacryloyl-omega-amino acid (M omega A) derivatives for enhancing the bond strength of resin to crown and root dentins.

Methods: A series of four M omega A derivatives, with different methylene chain numbers, were synthesized, as follows. 1: N-methacrylole glycine (Gly); 2: N-methacrylole-beta-alanine (beta Ala); 3: N-methacrylole-4-aminobutyric acid (Bu); 4: N-methacrylole-5-aminovaleric acid (Va).

Effect of sintering temperature on flexural properties of alumina fiber-reinforced, alumina-based ceramics prepared by tape casting technique.

Purpose: The purpose of this study was to investigate the effect of sintering temperature on flexural properties of an alumina fiber-reinforced, alumina-based ceramic (alumina-fiber/alumina composite) prepared by a tape casting technique.

Materials And Methods: The alumina-based ceramic used a matrix consisting of 60 wt% Al(2)O(3) powder and 40 wt% SiO(2)-B(2)O(3) glass powder with the following composition in terms of wt%: 33 SiO(2), 32 B(2)O(3), 20 CaO, and 15 MgO. Prepreg sheets of alumina-fiber/alumina composite in which uniaxial aligned alumina fibers were infiltrated with the alumina-based matrix were fabricated continuously using a tape casting technique employing a doctor blade system.

Mode superposition transient dynamic analysis for dental implants with stress-absorbing elements: a finite element analysis.

The purpose of this study was to analyze the dynamic behavior of a dental implant with a stress-absorbing element, using dynamic analysis. Two model types, stress-absorbing model with a resilient stress absorber made of polyoxymethylene and non-stress-absorbing model with rigid titanium, were employed. In both model types, the implant was 4.

Dynamic viscoelastic behavior of dental composites measured by Split Hopkinson pressure bar.

The present study evaluated the dynamic viscoelastic behavior of commercially available dental composites by a Split Hopkinson pressure bar (SHPB) test machine. Five commercially available composite resins--namely, two conventional hybrid composites (Filtek Z100, Z100; Filtek Z250, Z250), a packable composite (Filtek P60, P60), a flowable composite (Filtek Flow, FL), and a nanofill composite (Filtek Supreme, SU)--were evaluated. By means of SHPB technique, the dynamic stress-strain curve, storage modulus, and loss tangent of the five dental composites were calculated.

Non-linear finite element analysis of the failure progression of fiber-reinforced ceramics produced by tape casting technique.

The purpose of this study was to investigate the failure progression process of fiber-reinforced ceramic by finite element (FE) analysis. The three-dimensional FE model for three-point bending simulation was 40 mm long, 4 mm wide, 3 mm thick, and with a span length of 30 mm. Nodal force with load increment of 20 N was applied at the center of the upper surface of the beam.

Characterization of sintered TCP sheets with various contents of binder prepared by tape-casting technique.

Objectives: The purpose of this study was to investigate the effect of binder content on the characterization of sintered tricalcium phosphate (TCP) sheets prepared by the tape-casting technique.

Methods: Poly(acrylic acid)-based binder was added at four contents: 5, 10, 15, or 30 mass%, to a beta-TCP aqueous slurry. The TCP green sheets were fabricated with the prepared TCP slurry by the tape-casting technique, and were sintered at 1200 degrees C for 2h.

Effect of acidic primers on bonding three magnetic steel alloys with tri-n-butylborane initiated methacrylic resin.

The purpose of this study was to evaluate the effect of acidic primers on bonding magnetic steel alloys. Three alloys (XM27, 447J1, and AUM20) were primed with one of the following materials: Acryl Bond, Estenia Opaque Primer, Eye Sight Opaque Primer, M. L.

Effect of base monomer's refractive index on curing depth and polymerization conversion of photo-cured resin composites.

In this study, we examined the effect of the transmitted amount of visible light through a resin composite on the curing depth and polymerization conversion. Transmitted amount of visible light was strongly dependent on the magnitude of refractive index difference that existed between the resin and silica filler. More specifically, the differences arose from the type of base monomer used.

Characterization and bioactivity of tape-cast and sintered TCP sheets.

The purpose of this study was to investigate the influence of sintering temperature on in vivo and in vitro bioactivities of sintered tricalcium phosphate (TCP) sheets prepared by the tape casting technique. Green sheets of beta-TCP prepared by tape casting were sintered for 2 h in a furnace at atmospheric pressure, at five different sintering temperatures: 900, 1000, 1100, 1150, and 1200 degrees C. Measurement of X-ray diffraction and Fourier transform infrared spectrometry showed the presence of alpha-tricalcium phosphate phase in the TCP sheet sintered at 1200 degrees C, in addition to beta-TCP phase.

Influence of implant/abutment joint designs on abutment screw loosening in a dental implant system.

The objective of this study was to investigate the influence of implant/abutment joint designs on abutment screw loosening in a dental implant system, using nonlinear dynamic analysis of the finite element method (FEM). This finite element simulation study used two dental implant systems: the Ankylos implant system (Degusa Dental, Hanau, German) with a taper joint (taper joint-type model), and the Bränemark implant system (Nobel Biocare, Gothenburg, Sweden) with an external hex joint (external hex joint-type model). The nonlinear dynamic analysis was performed using three-dimensional finite element analysis.

Development of self-etching primer adhesive in all-in-one bonding system.

The self-etching primer adhesives examined in the present study were aqueous mixtures of 5 wt% MDP, 35 wt% HEMA, 3 wt% 2-hydroxyl-3-(3,4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl-1-propanaminium chloride (QTX), 0.5 wt% ethyl-p-(N,N-dimethylamino)benzoate (EDM), and 30 wt% water-soluble dimethacrylate (i.e.

Influence of cortical bone quality on stress distribution in bone around dental implant.

Using finite element method (FEM), this study sought to investigate how the thickness and Young's modulus of cortical bone influenced stress distribution in bone surrounding a dental implant. The finite element implant-bone model consisted of a titanium abutment, a titanium fixture, a gold alloy retaining screw, cancellous bone, and cortical bone. The results showed that von Mises equivalent stress was at its maximum in the cortical bone surrounding dental implant.

Efficacy of water-soluble photoinitiator on the adhesion of composite resin to bovine teeth in all-in-one bonding system.

The self-etching primer adhesives examined in the present study were aqueous mixtures of 30 wt% 2-methacryloyloxyethyl phenyl hydrogen phosphate, 35 wt% 2-hydroxyethyl methacrylate, and photoinitiator. For the photoinitiator, camphorquinone (CQ) or 2-hydroxyl-3-(3,4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl-1-propanaminium chloride (QTX) was used--where QTX is a unique water-soluble photoinitiator. The self-etching primer adhesive was applied directly to polished bovine dentin or enamel.

Tape-casting technique can prepare beta-TCP sheets with uniform thickness and flexibility.

The objective of this study is to propose a new fabrication technology for bone substitutes. In this study, a tape-casting method was used to prepare flexible beta-tricalcium phosphate (beta-TCP) sheets. A beta-TCP slurry containing a binder and plasticizer was used in a doctor blade system.

The effect of hydrophilic adhesive monomers on the stability of type I collagen.

The adsorption effects of adhesive monomers on the structural stability of type I collagen were studied at an acid pH condition for two monomers: 2-hydroxyethyl methacrylate (HEMA), a neutral monomer and N-methacryloyl glycine (NMGly), an acidic monomer. Differential scanning calorimetry (DSC) measurements were done to assess the denaturation temperature (Td), which is a measure of the structural stability of the proteins, including the bovine tendon collagen (BTC). While HEMA lowered the Td of the BTC linearly with HEMA concentrations, NMGly exhibited a two-step decrease of the Td.

Efficacy of varying the NMEP concentrations in the NMGly-NMEP self-etching primer on the resin-tooth bonding.

It is well understood that the application of a self-etching primer enhances the bonding at the resin-teeth interface. In this study, we designed a self-etching primer consisting of N-methacryloyl glycine (NMGly) and N-methacryloyl-2-aminoethyl phosphonic acid (NMEP). The demineralization effects on the hydroxyapatite or dentin by the carboxylic acid in the NMGly and by the phosphonic acid in the NMEP and their effects on the bond strength of the resin to the tooth were examined.

Development of Al2O3 fiber-reinforced Al2O3-based ceramics.

The purpose of this study was to use a tape casting technique to develop an Al2O3 fiber-reinforced Al2O3-based ceramic material (Al2O3-fiber/Al2O3 composite) into a new type of dental ceramic. The Al2O3-based ceramic used a matrix consisting of 60 wt% Al2O3 powder and 40 wt% SiO2-B2O3 powder. The prepreg sheets of Al2O3-fiber/Al2O3 composite (in which uniaxially aligned Al2O3 fibers were infiltrated with the Al2O3-based matrix) were fabricated continuously using tape casting technique with a doctor blade system.

Tensile bond strength of 4-META/MMA-TBB resin to ground bovine enamel using a self-etching primer.

The purpose of this study was to examine the effectiveness of self-etching primer in adhering 4-META/MMA-TBB resin to bovine enamel. In this study, we designed an original self-etching primer which contained an aqueous mixture of 4-MET, 35 wt% HEMA, and ferric chloride. The polished bovine enamel surface was treated with self-etching primer for 30 seconds.

Bonding durability between orthodontic brackets and human enamel treated with megabond self-etching primer using 4-META/MMA-TBB resin cement.

The purpose of this study was to determine the bonding durability when a Megabond self-etching primer is used with 4-META/MMA-TBB resin to bond metal orthodontic brackets to human premolar enamel. Three conditions of enamel were prepared: Megabond self-etching primer without saliva contamination, Megabond self-etching primer with saliva contamination, and repeat Megabond self-etching priming after saliva contamination. Shear bond strengths were measured after immersion in water at 37 degrees C for 24 hours, or after 2000 or 5000 cycles of thermal cycling between 5 degrees C and 55 degrees C.

Analysis of photopolymerization behavior of UDMA/TEGDMA resin mixture and its composite by differential scanning calorimetry.

The aim of this study was to investigate the extent of polymerization (Ep) in terms of polymerization rate of UDMA/TEGDMA resin mixtures and its composite resin, by using a differential scanning calorimeter (DSC) technique employing a photopolymerization apparatus. The resin mixtures used in this study consisted of urethane dimethacrylate (UDMA) as a base monomer and triethyleneglycol dimethacrylate (TEGDMA) as a low viscosity monomer. The concentration of TEGDMA in the mixed monomer was varied to 0, 20, 40, 60, 80, and 100 mol %.

Effect of filler content on bending properties of dental composites: numerical simulation with the use of the finite-element method.

The purpose of this work is to investigate the influence of filler content on the bending properties of dental composites by use of the finite-element method (FEM). The proposed numerical model was constructed from isotropic shell elements representing silica filler, and isotropic beam elements representing the remaining matrix resin. The proposed model was applied to failure analysis under three-point bending conditions.

The pKa effects of the carboxylic acid in N-methacryloyl-omega-amino acid on the demineralization and bond strengths to the teeth.

It is understood that the application of a self-etching primer to the tooth enhances the bonding of the resin to the tooth. In this study, we designed a self-etching primer consisting of a series of three N-methacryloyl-omega-amino acids (NMomegaA) with different methylene chain lengths. The demineralization aspect of the teeth components by the carboxylic acid in the NMomegaA and its effects on the bond strength of the resin to the tooth were examined.