Abstract: Glass-alumina bi-layer composite was widely used as dental materials, the reliability and
mechanical properties are very important for its practical application. In this work, residual stresses in
dental glass-alumina composite and failure mechanism were investigated through finite element analysis
and 3-point and ball-on-ring bending tests, respectively. The mechanical behavior of the dental material
was studied using the bending tests and indentation method. Small bi-layer disk specimens were prepared
for the axis-symmetrical tests using a set of small device in a universal tester. The results indicate that the
difference in thermal expansion coefficients between two layers lead to residual stresses in both layers,
and the stresses distribution depends on the thickness ratio and temperature difference. Furthermore, a
proof testing method was proposed to estimate the workability and reliability of the dental ceramics.
Abstract: This study investigated the effect of multiple firing on the wear behavior of dental all-ceramic
veneering ceramic (Cercon). Samples were fabricated according to the manufacturer's requirement for
different firing times. The wear test was operated under simulated oral environment. The results showed
that multiple firing could influence wear behavior of all-ceramic Veneer. Significant difference was
observed in wear scar width among different samples. All the groups except 7time-firing one showed
good wear resistance with low wear rate, smooth surface and relatively constant frictional coefficient.
With the increasing firing times the wear scar width became larger. The wear resistance of dental ceramic
after seven times firing was significantly lower. SEM/DFM results showed the wear facets of veneering
ceramic demonstrate grooves characteristic of abrasive wear. The significant change was that severe wear
dominated by brittle fracture could be seen in the 7time-firing group. Multiple firing can decrease the
wear resistance of dental all-ceramic Veneer, and the wear pattern has the tendency to severe wear. The
possible explanation is that the microstructure and properties of all-ceramic Veneering changed during
Abstract: The purpose of this study was to investigate the flexural strength and the mode of failure of
dental colored ZrO2 ceramics with or without porcelain coating. Colorants (Fe2O3,CeO2, etc.) were mixed
with 3Y-TZP powder to prepare colored dental zirconia. Specimens were made in monolithic or bilayered
forms which were coated with veneering porcelain. Experimental results showed that there were not
significantly differences of bending strengths between white and colored materials or between bilayered
specimen, while the strength of monolithic specimen were significantly higher than their bilayered
counterpart. In all bilayered specimens, the bulk fracture initiated at the tensile surface of the core
material and was consistently accompanied with porcelain crush and delamination at the interface.
Colorants for 3Y-TZP had minor effects on its mechanical properties.
Abstract: Partially sintered zirconia ceramics (PSZCs) for dental uses were prepared from zirconia nanopowder
via isostatic pressing and partially sintering. The open porosities, pore diameters, grain sizes and
mechanical properties of the ceramics with different densities were studied. The results show that the
pores formed in the PSZCs are all open pores, with a diameter distribution of 60nm~130nm and a grain
size distribution of 120~170nm. The machinability becomes worse when the density of PSZC is higher
than 75% of the theoretical density, so a ceramic named PSZC-70% with density of 70%TD was selected
as the target material. Its bending strength is 168 MPa and fracture toughness is 1.8 MPa·m1/2. A dental
restoration framework can be obtained via machining the PSZC-70% on a dental CAD/CAM system.
Abstract: This paper explored the color and mechanical properties of CeO2 and Er2O3 shaded zirconia
ceramics for dental application. Twelve kinds of colored dental ZrO2 powders were prepared.
Experimental results showed that the hue of the materials shift from yellow-green to yellow-red with the
increasing concentration of the CeO2 and Er2O3, while reducing of the brightness( L* ) value was little.
Three-point bending strength decreased form 1209MPa to 845MPa after coloring, which was lower than
the uncolored materials (1301MPa). The fracture toughness decrease slightly. SEM observation revealed
more porous microstructure in specimen containing both two additives. Cerium oxide and erbium oxide
are candidates of color additives for shading dental zirconia ceramics.
Abstract: This study was conducted to evaluate shear bond strength between self-made alumina glass
composites (AGC), zirconia glass composites (ZGC) and Vita alpha opaque-dentine porcelain, and also
evaluate the effects of different surface treating methods on the bond strength. The AGC and ZGC
specimens were treated differently and then bonded with Vita alpha opaque-dentine porcelain. The bond
strength was measured by shear test and the surface treating methods included no-treatment, sandblasting
and etching. The results showed that the values of bond strength for AGC groups were 30.1, 41.1 and 41.9
MPa respectively, and the bond strength of both sandblasting group and etching group were significantly
higher than that of the untreated group; the bond strength of ZGC groups were 60.2, 63.6 and 35.5MPa
respectively, and the value of sandblasting group was significantly higher while etching group was lower
than that of untreated group. These results indicated that Vita alpha opaque-dentine porcelain can be well
sintered to self-made AGC and ZGC. Sandblasting can greatly improve the bond strength for both AGC
and ZGC, while the etching treating method had different effect on their bond strengths.
Abstract: This study sought to compare the biocompatibility of four dental ceramics so as to provide
indications useful for the further development of dental materials. Osteoblasts were obtained by culturing
the cranial explant of SD rat and cultured in vitro when they were seeded onto four different materials:
hydroxyapatite, bioactive glass ceramics, tricalciumphosphate-hydroxyapatite and nano-hydroxyapatite
(nHA). The phase contrast microscope and scanning electron microscope were used to evaluate the cell
morphology and attachment. The content of alkaline phosphatase was calculated by molecular biological
methods. MTT method was performed to find the alteration of proliferation. Then by use of wash way
method, the adhesion ability was tested. The results showed that all of the four bioceramics had good
cytocompatibility. There were significant differences among them on the levels of cell growth, differation
and adhesion in vitro. The biocompatibility of nHA is the best and of conventional HA is the worst.
Abstract: HA/ß-TCP is one kind of important bone tissue engineering scaffold materials. In order to
improve the biological performance of materials, HA/ß-TCP ceramics were modified by the cold plasma
technique in this paper. The biological performances of treated materials were evaluated by the results of
bone-like apatite formation in SBF, the coculture of the C2C12 cell line and HA/ß-TCP, cell proliferation
experiments, observations of the electron microscopy and fluorescence staining and the animal
intramuscular implantation experiments. The results showed that after immersion, compared with
untreated HA/ß-TCP, treated materials were more conducive to form bone-like apatite; modified
HA/ß-TCP could promote the cell proliferation more; the cells grew in the course of nature on the treated
scaffold and modified HA/ß-TCP had better bone-forming performance in vivo. It was concluded that
modified HA/ß-TCP had better biological performance; the cold plasma technique could improve the
biological performance of dental biphasic calcium phosphate ceramics.
Abstract: The aim of this investigation is to study the effect of SnO coatings on the bond strength
between titanium and porcelain. The coatings were produced by sol-gel method and heat-treatment at
300°C. Once the coatings have been formed on the titanium substrates, self-made porcelain was fused.
The specimens with pre-oxidation before porcelain fused were set as control group. It was shown SnO gel
formed completely at 300°C and was composed by SnO and SnO2 in the form of a uniform film. The bond
strength between titanium and porcelain of the specimens with SnO coatings was greater than those in
control group statistically, which might prove that the coatings reduced the oxidation of titanium surface
in the porcelain fusing progress. EDS result showed almost all fractures between titanium and porcelain
occurred at the oxide layer. Si and Sn might attend the reaction at interface. It was concluded that the SnO
coatings produced in this study can improved the titanium-porcelain bond strength.
Abstract: Ceramic oxidation coating of approximately 60 m thick was prepared on a Ly12 alloy
substrate by micro-plasma oxidation in an alkali-silicate electrolytic solution. Coating thickness was
measured during coating formation. The influence of current density, electrolyte temperature and
inter-electrode distance on coating kinetics was investigated. Microstructure and phase compositions
were analyzed. The micro-hardness of the coating was also measured. The tribological performance of the
coatings was evaluated using a dry sand abrasion test. In addition, the results are compared to detonationsprayed