Translucent tiles are among the tiles that have recently been featured. Passing part of the light is an important feature of these tiles. The passage of light from within, create a beautiful effect. In particular, it can be combined with LED, in which its beauty will be multiplied. In this research, the effect of using transparent frit and feldspar on porcelain tile composition was studied to obtain semi-transparent properties. Compositions of 10-%50 frits and feldspars were prepared by powder pressing and fired in a rapid roller furnace at 1150 ℃ and 70 minutes. The phase composition and microstructure were investigated by X-ray diffraction (XRD) and electron microscopy (SEM). A light spectrometric test was used to examine the light transmission and the white index of the samples was determined using a spectrophotometer. The flexural strength, density, and water absorption were also measured. The results showed that 50% frit, along with 20% feldspar, have a semi-transparent property and a better white index than other samples.

Objective: Zirconia cores have limited light transmittance and data are scarce on light transmission through zirconia cores with and without the veneering ceramic.Methods: In this in vitro study, Disc-shaped specimens (11.5 mm in diameter and 0.4 (0.05) mm in thickness) were fabricated of three types of zirconia namely Mamut, Heany and ZirkonZahn (n=5).A disc-shaped specimen (11.5 mm in diameter and 0.65 (0.05) mm in thickness) of veneering ceramic (Cerabien ZR, Kuraray, Noritake, Japan) was also fabricated. The intensity of light transmitted through the zirconia specimens with and without the veneering ceramic was recorded using a light curing unit (LED, SDI Radii Plus, Australia) and its respective radiometer (LED Radiometer, SDI, Australia). Data were analyzed using repeated measures ANOVA and Tukey’s HSD test.Results: A significant difference was noted in light transmission among different types of zirconia before and after veneering. After veneering, light transmission decreased in all specimens and the reduction in light transmission in Zirkonzahn group was significantly greater than that in Heany and Mamut groups (p<0.001).Conclusion: Veneered zirconia systems have limited translucency and ceramic veneering significantly decreases light transmission through zirconia.

Background and objectives: This study assessed the effect of thickness of high-translucent (HT) and super-translucent (ST) monolithic zirconia on its color, translucency, and marginal and internal adaptation. Materials and methods: Monolithic zirconia restorations were fabricated from HT and ST zirconia blanks (n=30) with 0. 5-, 1-and 1. 5-mm thicknesses (n=10). The color and translucency parameter (TP) was measured by a spectrophotometer, and marginal gap (MG), internal gap (IG), and occlusal gap (OG) were measured by the replica technique. Results: Zirconia type had no significant effect on TP (P=0. 362) but the effect of thickness was significant (P<0. 001),1. 5-mm thickness yielded the lowest and 0. 5-mm thickness yielded the highest TP. Zirconia type (P<0. 001) and thickness (P=0. 001) had significant effects on color difference (ΔE),ST yielded significantly higher ΔE, and 0. 5-mm thickness resulted in significantly lower ΔE than 1-mm (P=0. 047) and 1. 5-mm (P<0. 001). The MG of both HT and ST increased with thickness (P<0. 05). The IG of 0. 5 mm-thick restorations was significantly higher than 1 mm (P=0. 005) and 1. 5 mm (P=0. 003). In ST restorations, the difference in IG was not significant among different thicknesses (P>0. 05). OG was the highest in 0. 5 mm thickness. In ST restorations, minimum OG was found in 1 mm thickness. Zirconia type had no significant effect on adaptation (P>0. 05). Conclusion: Zirconia type had no significant effect on TP or adaptation. Increasing the thickness decreased TP. ΔE was lower in lower thicknesses, and ST zirconia yielded higher ΔE. Thickness had a direct correlation with MG and an inverse correlation with IG and OG.

In this article, the effect of type and content additive on sintering behavior and properties of translucent alumina ceramics were investigated. a-Al2O3 nanopowder with various content of additives (MgO, La2O3), was compacted under a pressure of 300MPa and was sintered at temperatures of 1700 and 1875oC. The microstructure of sintered samples were studied by scanning electron microscope (SEM) and Optical microscope .The results indicate that with increasing content of MgO increase formation of Spinel secondary phase within grains that these flaws act as points of scattering and reduce the transparency of the sample. With increase La2O3 alumina grains with almost no pores trapped in, become fine and compact. Alumina codoped with 0.12%wt MgO and 0.2%wt La2O3 sintered at 1750°C for 1 h show maximum transmittance 60%, hardness 1840 VHN and relative density 99.95%.

Objective: The aim of the present study was to compare microtensile bond strengths (mTBS) of glass fiber posts to different parts of intra-radicular dentin using conventional method and one-shot technique under different light intensities.Materials and Methods: Twenty-eight single-rooted teeth were prepared to receive fiber posts: Group 1: Conventional method at light intensity of 600 mW/cm2; Groups 2, 3 and 4: One-shot technique at light intensities of 600, 800 and 1000 mW/cm2 respectively. Dumbbell- shaped slices were obtained from the samples and submitted to micro-tensile testing. The data were analyzed using two-way ANOVA and paired-samples t-test.Results: There were no significant differences in mTBS values of the cervical and middle thirds between the groups (P>0.05). mTBS values in the cervical thirds in groups 2 and 3 were significantly higher than those in the middle thirds (P>0.05). However, there were no such differences in groups 1 and 4 (P>0.05).Conclusion: It is proper to simultaneously cure the resin cement and the adhesive agent (one-shot technique); however, in that case, high light intensities (1000 mW/cm2) are recommended to achieve identical bond strength values in the cervical and middle thirds.

Background and Aim: This study evaluated the effect of hydrothermal aging on optical and mechanical properties of opaque and translucent zirconia. Materials and Methods: For the biaxial flexural strength (BFS) test, 40 sintered opaque and translucent disc-shaped zirconia, and for the assessment of surface roughness and optical properties, 20 specimens were fabricated and artificially aged in an autoclave for 10 h. The CIE L*a*b* color parameters were measured. The translucency parameter (TP), contrast ratio (CR), opalescence (OP), and color difference against a white (Δ EW) and a black (Δ EB) background were all calculated. The surface roughness (Ra and Rz) was analyzed using a profilometer and the BFS test was performed at a crosshead speed of 1 mm/min. Data were analyzed using two-way ANOVA, t-test, and Mann-Whitney test (α =0. 05). Results: The mean Ra (P=0. 023) and Rz (P=0. 011) significantly decreased after aging. Aging had no significant effect on TP (P=0. 384), CR (P=0. 261), or BFS (P=0. 912). The mean TP values of translucent specimens were significantly higher than those of opaque specimens (P=0. 046). For translucent specimens, the mean OP did not significantly change after aging (P=0. 685) but aging significantly increased the OP of opaque specimens (P=0. 007). The mean Δ EW and Δ EB of translucent specimens were higher than those of opaque specimens (P=0. 044 and P=0. 019, respectively). Conclusion: Although aging affected the OP parameter, other optical properties and also BFS of both zirconia types were not affected by hydrothermal aging. However, the surface roughness of both zirconia types significantly decreased as a result of aging.

Background and Aim: The opacity of dental ceramics has important role in final appearance of all ceramic restorations. opacity of super high translucent zirconia is not clearly determined. The aim of this study was evaluating the opacity of two super high translucent zirconia (zolid fx and DD cubeX2 ) and lithium disilicate reinforced glass ceramic(IPS e. max CAD LT). Materials and Methods: In this experimental study, 30 ceramic discs with 1 mm thickness and 10 mm diameter in two groups of super high translucent zirconia ( zolid fx and DD cubex2) and one group of lithium disilicate reinforced glass ceramic (IPS e. max CAD LT) were fabricated(n=10). For determining the contrast ratio (CR), spectrophotometer was used to measure Y parameters of each sample in black and white backgrounds. One-way ANOVA and Tukey Post Hoc statistical tests were used to analyze the data. Level of significancy was 0. 05. Results: The mean of CR in the three groups of IPS e. max CAD LT، zolid fx and DD Cubex2 were 0. 97 ±,0. 002, 0. 96 ±,0. 004 and 0. 96 ±,0. 005 respectively. Significant differences were not found in the CR values of three groups (P = 0. 2). Conclusion: Regarding the limitation of this study, Opacity of three ceramic were similar.