Effects of Primers Containing Thiouracil and Phosphate Monomers on Bonding of Resin to Ag-Pd-Au Alloy

The purpose of the present study was to evaluate the effects of four experilnental prinlers on bond strength between a self-curing luting agent and silver-palladiuln-gold alloy. The experinlental primers were in lnixed solutions of a thiouracil primer (Metaltite) and a phosphate primer (Epricord, PM, PE, or PP), which were designated as Metaltite/Epricord,Metaltite/PM, Metaltite/PE, and Metaltite/PP respectively. Three prilners (Metal Primer II, V-Primer, and Alloy Primer) were also prepared as controls. Allunina-blasted metal alloys \u27were bonded with acrylic rods. After 5,000 thermocycles, the maximu111 shear bond strength was obtained with Metaltite/PE (27.8±2.4 MPa) and Metaltite/Epricord (27.6± 5.9 MPa), followed by Metaltite/PP, Alloy Prilner, Metaltite, Metaltite/PM, Metal Primer II, V-Primer, and Epricord. PE, PM, and PP showed the lowest bond strength. Results of this study revealed that the cOlnbined use of a thiouracil Inonomer and a phosphate lnonomer ilnproved adhesive bonding. In this light, clinicians should pay attention to the types of functional monomers dissolved in a primer when fabricating resin-bonded prostheses

The effect of magnesium oxide supplementation to aluminum oxide slip on the jointing of aluminum oxide bars

The purpose of this study was to investigate the effect of modifying aluminum oxide slips with magnesium oxide (MgO) tocreate a jointing material for In-CeramR Alumina. Jointed In-CeramR Alumina bars with In-CeramR Alumina slips containing0－1.0 mass％ MgO were examined by a three-point bending test. Joint-free bars were also tested as controls.Fracture surfaces were evaluated by scanning electron microscopy. In addition, linear shrinkage and fracture toughnesswere assessed.　　The 0.3 mass％ MgO group showed the highest flexural strength among the jointed groups, and there were no statisticaldifferences between the joint-free control groups. The fracture surface of 0.3 mass％ MgO group showed increasedsintering densification with reduced micropore size. No linear shrinkage was observed with the addition of MgO to thealumina slip. Added MgO was also effective in boosting fracture toughness. The present findings indicate that the MgOsupplementedbinding material is useful for clinical applications

Enhanced initial cell responses to chemically modified anodized titanium.

BACKGROUND: Previously, we reported that anodized porous titanium implants have photocatalytic hydrophilicity. However, this effect was not always sufficient for the significant improvement of bone apposition. PURPOSE: The purpose of this study was to improve the photocatalytic properties of porous titanium implants by the fluoride modification of the anodized titanium dioxide (TiO(2)), and to investigate the initial cell response to it. MATERIALS AND METHODS: The ideal concentration of ammonium hydrogen fluoride (NH(4)F-HF(2)) used in this study was determined by a static water contact angle assay. The ideal concentration of NH(4)F-HF(2) was 0.175%, and experimental disks were treated with this concentration. A pluripotent mesenchymal cell line, C2C12, was cultured on the disks in order to investigate cell attachment, morphology, and proliferation. RESULTS: Cell attachment after 30 minutes of culturing was significantly higher for the ultraviolet-irradiated, fluoride-modified anodized TiO(2) (p < .05), and the simultaneous scanning electron microscope observation showed a rather flattened and extended cell morphology. The proliferation rate after 24 hours was also significantly higher for the fluoride-modified anodized TiO(2). CONCLUSION: Fluoride chemical modification enhances the hydrophilic property of the anodized TiO(2) and improves the initial cell response to it

Enhanced osseointegration by the chemotactic activity of plasma fibronectin for cellular fibronectin positive cells.

Plasma fibronectin (pFN) is known to regulate cell growth, differentiation or survival of osteoblasts in vitro. It is also speculated to be important for the early phase of osseointegration, however, its actual in vivo behavior is unknown. The objective of this study is to clarify the role of pFN during osseointegration. We developed a titanium ion-plated acrylic implant (Ti-acryl) for thin sectioning without removal of the implant. Either Ti-acryl or pFN-coated Ti-acryl (FN-Ti-acryl) was implanted in the mouse femur. Samples were taken on days 1-7 and on day 14 after the operation, and were decalcified and paraffin embedded. The bone healing process and immunofluorescence localization of pFN and cellular fibronectin (cFN), a marker for fibroblastic cells were examined. Simultaneously, the effect of pFN on chemotaxis, proliferation and differentiation of bone marrow stromal cells (BMSCs) was analyzed in vitro. The in vivo results showed that faster direct bone formation was seen for the FN-Ti-acryl group compared to the Ti-acryl group. The in vitro results showed that pFN significantly promoted BMSCs chemotaxis, however, had no effect on proliferation or differentiation. The results indicate that pFN regulated chemotaxis of osteogenic cells and coating the implant with pFN enhanced earlier osseointegration

Influence of ceramic thickness on mechanical properties and polymer structure of dual-cured resin luting agents.

OBJECTIVE: To investigate the influence of ceramic thickness on the mechanical properties and polymer structure (degree conversion and cross-linking density) of three dual-cured resin luting agents. METHODS: Three dual-cured resin luting agents [Linkmax HV (GC), Nexus 2 (Kerr), and Variolink IIHV (Ivoclar-Vivadent)] were polymerized with or without 800mW/cm(2) irradiation through 0-3-mm-thick GN-I (GC) machinable ceramic. Bar-shape specimens were subjected to three-point bending to determine flexural strength (FS) and elastic modulus (EM) after dry storage at 37 degrees C for 24h. Knoop hardness was measured on the irradiated surface of disk-shaped specimens before (KHN1) and after (KHN2) storage of 100% ethanol solution at 37 degrees C for 24h. KHN1 and KHN2 were estimated as indirect indicators of degree of conversion (DC) and cross-linking density, respectively. Data were analyzed by one-way ANOVA and Student-Newman-Keuls test for each luting agent, and four mechanical properties were subjected to regression analysis. RESULTS: For three resin luting agents with dual-cured mode, FS, EM, KHN1, and KHN2 decreased with the increase of ceramic thickness. FS except for Nexus 2 and EM for three resin luting agents had a positive linear relationship with both KHN1 and KHN2. SIGNIFICANCE: The variables tested behaved differently. When the ceramic thickness increased, the chemical cured components of dual-cured resin luting agents did not produce significant compensation for all variables. Mechanical properties and polymer structure of dual-cured resin luting agents was dependent on the intensity of light irradiation

Bond strength between luting materials and a fiber-reinforced resin composite for indirect restorations.

The purpose of the present study was to evaluate the bond strength between a fiber-reinforced composite (FRC) and six luting agents (Panavia F 2.0, Linkmax MC, Chemiace II, Multibond, Super-Bond C&B, and Fuji I). A prosthodontic resin composite material (RC-control) and a luting agent containing no functional monomer (MT) were used as controls. Shear bond strengths between alumina-blasted FRC and the luting agents were determined after 20,000 thermocycles. The FRC showed superior bond strength when compared with the RC-control. Highest bond strengths were achieved when FRC was bonded with Panavia F 2.0, Linkmax MC, Multibond, Super-Bond C&B, and MT, whereas Chemiace II trailed in the list of resin-based luting agents evaluated. Insufficient bonding was obtained with Fuji I. Results of the present study revealed that when fabricating restorations, the clinician should select an appropriate combination of resin composite material and luting agent so as to ensure the longevity of restorations