BACKGROUNDThe lithium disilicate-based ceramic is a newly developed all-ceramic material, which is lithium disilicate-based and could be used for fabricating almost all kinds of restorations. The extent of light attenuation by ceramic material was material-dependent. Ceramic materials with different crystal composition or crystalline content would exhibit distinct light-absorbing characteristics. The aim of this study was to analyze the influence of ceramic thickness and light-curing time on the polymerization of a dual-curing resin luting material with a lithium disilicate-based ceramic.

METHODSA lithium disilicate-based ceramic was used in this study. The light attenuation caused by ceramic with different thickness was determined using a spectral radiometer. The commercial dual-cured resin cement was light-cured directly or through ceramic discs with different thickness (1, 2 and 3 mm, respectively) for different times (10, 20, 30, 40, 50 and 60 seconds, respectively). The polymerization efficiency of resin cement was expressed in terms as Vickers hardness (VHN) measured after 24 hours storage. Two-way analysis of variance (ANOVA) and Tukey's HSD tests were used to determine differences.

RESULTSIntensity of polymerizing light transmitted through ceramic discs was reduced from 584 mW/cm(2) to about 216 mW/cm(2)2, 80 mW/cm(2) and 52 mW/cm(2) at thicknesses of 1 mm, 2 mm and 3 mm, respectively. Resin cement specimens self-cured alone showed significantly lower hardness values. When resin cement was light-cured through ceramic discs with a thickness of 1 mm, 2 mm and 3 mm, no further increasing in hardness values was observed when light-curing time was more than 30 seconds, 40 seconds and 60 seconds, respectively.

CONCLUSIONSWithin the limitation of the present study, ceramic thickness and light-curing time had remarkable influence on the polymerization of dual-cured resin cement. When resin cement is light-cured beneath a lithium disilicate ceramic with different thickness, prolonging light-curing time accordingly may still be necessary to insure complete polymerization.

Ceramics ; chemistry ; Dental Porcelain ; chemistry ; Light ; Resin Cements ; chemistry

Studies on bioactive glass and glass-ceramic are important research high-lights in the field of biomedical materials. Due to their bioactivity, these materials can form a tight chemical bond with the living bone, when implanted. As a preeminent kind of these materials, A-W(Apatite/Wollastonite) bioactive glass ceramic has not only the excellent bioactivity and biocompatibility, but also the eminent mechanical properties, so it has been largely applied and developed in clinical practice. The development, preparation, properties, applications and the mechanism of its bond with bone are introduced in this paper. We will also put forward the prospect of the research and development of A-W bioactive glass ceramic.
Apatites ; chemistry ; Bone Substitutes ; chemistry ; Calcium Compounds ; chemistry ; Ceramics ; chemistry ; Mechanics ; Research ; Silicates ; chemistry ; Surface Properties

HAP-Glass-alpha-Al2O3 gradient coating on alumina ceramics substrate was prepared by multi-layer slurry-dipping and sintering process, effects of the composition of the coating on the microstructure and adhesion strength of the gradient coating were studied. R2O-Al2O3-B2O3-SiO2 system glass with low softening temperature and thermal expansion was used in the gradient coating. The composition of the coating was varied from interface to surface layer, i.e. the HAP concentration increased and glass concentration decreased gradually from the under layer to the surface layer. A suitable amount superfine alpha-Al2O3 was added in the gradient coating to reinforce the bonding strength between the coating and substrate. The results show that the use of R2O-Al2O3-B2O3-SiO2 system glass is propitious to sintering the coating at low temperature and to combination between the coating and substrate. The addition of superfine alpha-Al2O3 can reinforce the bonding strength between the coating and substrate, the highest bonding strength is about 48.2 MPa.
Adhesiveness ; Aluminum Oxide ; chemistry ; Ceramics ; chemistry ; Coated Materials, Biocompatible ; chemistry ; Durapatite ; chemistry ; Glass ; chemistry

OBJECTIVETo analyze the effect of different silane coupling agents on the resin bond durability of glass-infiltrated alumina ceramic. Methods A glass-infiltrated alumina ceramic was silanized or not by three silane coupling agents. The treated ceramic surfaces were bonded with two resin cements. Their micro-bond strength were measured after 0, 30,000 thermal cycles.

RESULTSBefore thermal cycling, resin cement A had lowest bond strength to ceramic, and ceramic treated by silane coupling agent A with two cements had lower bond strength than those treated by silane coupling agent B and C. After thermal cycling, cement A had no bond strength with no treated ceramic, only ceramic treated by silane coupling agent A with two cements had more than 5 MPa bond strength.

CONCLUSIONThe glass-infiltrated alumina cermaic treated by the silane coupling agent activated by 10-methacryloyloxydecyl-dihydrogen phosphate could obtain better bond durability with different type of resin cements.

Aluminum Oxide ; chemistry ; Ceramics ; chemistry ; Dental Bonding ; Glass ; chemistry ; Resin Cements ; chemistry

BACKGROUNDThe low-temperature resistance aging performance of Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) is the key effective factor that influences the long-term success rate of prosthesis. The objective of this study was to test and compare the aging performances for resisting low temperature of Lava Frame, Cercon Smart, and Upcera Yttria-stabilized zirconia core materials, via analyzing the micro and the crystal phases of the materials, and measure the three-point bending strength and the fracture toughness.

METHODSThe three zirconia green bodies were prepared as 60 test samples for three-point bending strength and as 60 test samples for fracture toughness. The test samples for three-point bending strength and fracture toughness were assigned to five groups and were treated respectively for 0, 5, 10, 15, and 20 hours to observe the micro and the crystal phases of the test samples. Then the three-point bending strength and fracture toughness were tested by X-ray diffraction (XRD).

RESULTSThe m phase content of Lava Frame was raised from 7.70% to 13.01%; the m phase content of Cercon Smart was raised from 4.95% to 8.53%; and Lava Frame is raised from 10.84% to 35.18%. The three-point bending strengths of the three zirconia core materials were higher than 1100 MPa and the fracture toughness was higher than 3 MPa·m(1/2). The three-point bending strength and the fracture toughness of Upcra zirconia decreased the most, followed by Lava Frame, and then by Cercon Smart.

CONCLUSIONThe aging resistance sequences of the three zirconia core materials are, from strong to weak, Cercon Smart, Lava Frame, and Upcera.

Ceramics ; chemistry ; Dental Porcelain ; chemistry ; Microscopy, Electron, Scanning ; Temperature ; X-Ray Diffraction ; Yttrium ; chemistry ; Zirconium ; chemistry

To optimize the pretreatment of Huanglian Jiedu decoction before ceramic membranes and verify the effect of different pretreatments in multiple model system existed in Chinese herb aqueous extract. The solution environment of Huanglian Jiedu decoction was adjusted by different pretreatments. The flux of microfiltration, transmittance of the ingredients and removal rate of common polymers were as indicators to study the effect of different solution environment It was found that flocculation had higher stable permeate flux, followed by vacuuming filtration and adjusting pH to 9. The removal rate of common polymers was comparatively high. The removal rate of protein was slightly lower than the simulated solution. The transmittance of index components were higher when adjust pH and flocculation. Membrane blocking resistance was the major factor in membrane fouling. Based on the above indicators, the effect of flocculation was comparatively significant, followed by adjusting pH to 9.
Ceramics ; chemistry ; Drugs, Chinese Herbal ; chemistry ; Flocculation ; Membranes, Artificial ; Polymers ; chemistry ; Solutions ; chemistry ; Ultrafiltration ; methods

OBJECTIVEThis study aims to investigate the color stability of ceromer with different thicknesses and different types of resin adhesive materials after accelerated aging and provide references for clinical application and selections.

METHODSNine groups of experimental samples were used, and each group contained five samples. We made joint samples with ceromer having three different thicknesses (1.00, 0.75, 0.50 mm) combined with three different resin adhesive materials (RelyX Veneer, RelyX Unicem, Filtek Z350 Flow), respectively. All samples were placed into Xenon Lamp Aging Instrument to implement accelerated aging. Spectrophotometer was used to measure the lightness (L*), red green color value (a*), and blue yellow color value (b*) of all samples before and after accelerated aging. The change of lightness (ΔL), red green color value (Δa), blue yellow color value (Δb), and color variation (ΔE) were also calculated. We investigated the influence of ceromer veneer thicknesses and resin adhesive material types on color variation by two-factor analysis of variance.

RESULTSThe thickness and type factors showed significant influence on ΔE values, and exhibited interactions (P < 0.05). The ΔE values of all experimental groups were lower than 3.3. After the accelerated aging process, all L*, a*, and b* values of the experimental groups decreased and the ΔL values were lower than 2.0.

CONCLUSIONCeromer veneer thickness and resin adhesive material types could affect the color stability of ceromer veneer and resin adhesive materials. The changes in lightness and color in ceromer veneer and resin adhesive materials are considered clinically acceptable after accelerated aging.

Ceramics ; Color ; Composite Resins ; Dental Cements ; chemistry ; Light ; Resin Cements

OBJECTIVEThe purpose of this study was to determine the thermal, mechanical properties and density of the composite infiltrated with GI-II tinted infiltration glass.

METHODSThe bar-shaped aluminum oxide and glass/alumina composite specimens with the size of 20 mm x 5 mm x 5 mm were prepared, with two free-end surfaces perpendicular to the long axis of the specimens and parallel to each other. The thermal expansion curves were obtained on a TMA2940 thermal analyzer with heating rate of 5 degrees C/min and temperature range of 25 degrees C to 1000 degrees C. The bar-shaped specimens with the size of 25 mm x 5 mm x 2 mm were fabricated and employed to test the density using Archmede's method. The flexural strength, elastic modulus were measured by means of 3-point bending test with the same specimens. The fractured specimens were indented with Vicker's diamond pyramid under load of 49 N for 15 seconds to determine the hardness and indentation fracture toughness.

RESULTSThe thermal expansion coefficient of the glass/alumina composite was 7.620 x 10(-6) degrees C-1 (25-500 degrees C), which was higher than that of Vitadur alpha veneering porcelain. The 3-poit flexural strength, elastic modulus, Vicker's hardness, indentation fracture toughness and density were 389.6 MPa, 92 GPa, 9.409 GPa, 3.2425 MNm-3/2 and 3.662 g/cm3 respectively.

CONCLUSIONThe thermal expansion of the GI-II glass/alumina composite is compatible with that of Vitadur alpha veneering porcelain, and the material could meet the strength demands for clinical use.

Aluminum Oxide ; chemistry ; Ceramics ; Dental Materials ; Dental Porcelain ; chemistry ; Glass ; chemistry ; Tensile Strength ; Transition Temperature

This investigation was amied at the infiltrative capability of the machinable-infiltrated-ceramic(MIC) glass and the color of the composite after the MIC glass infiltrated through the aluminous matrix with different packing densities. By heating the components to 1100 degrees C for 2 hours, the MIC glass was made to infiltrate through the aluminous matrix with different packing densities. We measured the infiltrative depth and the color parameter and observed the rupture surface of the composite by means of SEM. There was a linear relation between the square of infiltrative depth and the packing density of aluminous matrix. The minimal depth was 3.092 mm. No relationship was noted between the composite's color coefficient and the packing density of aluminous matrix. In the rupture process of the composite, crack deflexion, crystal evulsion, and rupture through crystal could be observed. This experiment proved that the infiltrative characters of MIC glass meet the clinical requirement, the composite's color is steady and the mechanical intensity is stable.
Aluminum Oxide ; chemistry ; Ceramics ; chemistry ; Color ; Dental Porcelain ; chemistry ; Hardness ; Materials Testing ; Osmosis

Some techniques of compounding bioactive ceramics and polymer biomaterials with mechanical and biological properties and the clinical applications of the composites produced are presented.
Biocompatible Materials ; chemistry ; Biomechanical Phenomena ; Ceramics ; chemistry ; Humans ; Polymers ; chemistry ; Surface Properties