INTRODUCTION: Matching dental ceramic translucency is the optimal esthetic goal in restorative dentistry. Several types of ceramics evolved over the years in an attempt to optimize physical mechanical and optical properties of the previous types. OBJECTIVES: The aim of this study is to compare and analyze light transmission, light reflection and light absorption of high translucency zirconia reinforced lithium silicate ceramic, low translucency zirconia reinforced lithium silicate ceramic, high translucency lithium disilicate glass-ceramic and low translucency lithium disilicate glass-ceramic. MATERIALS AND METHODS: Serial cutting of the E.max cad and Vita suprinity blocks was done using isomet 4000 micro-saw microtome. Ten ceramic specimens were obtained for each material, 5 of which were 1.5 mm thick and the other 5 were 1 mm thick to be veneered by 0.5 mm of the corresponding veneering material according to manufacturer's instruction. Spectrophotometric analysis was carried out for the forty ceramic specimens. RESULTS: Light transmission for the four groups of zirconia reinforced lithium silicate was significantly higher than their corresponding groups of lithium disilicate (p<0.005). Light reflection and light absorption for the four groups of zirconia reinforced lithium silicate was significantly lower than their corresponding groups of lithium disilicate (p<0.005). Veneering increased light transmission and light reflection however it decreased light absorption for both materials significantly. CONCLUSIONS: Translucency of zirconia reinforced lithium silicate is better than lithium disilicate. Veneering improved optical properties for both zirconia reinforced lithium silicate and lithium disilicate.
Objectives: Dental implants are currently become a routine treatment decision in dentistry. Synthetic PEEK polymer is a prevalent component of dental implantology field. The current study aimed to assess influence of Nd:YAG laser nano-topographical surface engineering combined with ultraviolet light or platelet rich fibrin on the bioactivity and osseointegration of PEEK implants in laboratory and animal testing model. Materials and Methods: CAD CAM discs of PEEK were used to fabricate PEEK discs(8mmx3mm)N=36 and implant cylinders(3mmx6mm) N=72.Specimens were exposed to Nd:YAG laser at wavelength 1064 nm, Surface roughness topography/Ra parameter was recorded in nanometer using atomic force microscopy. Laser modified specimens were divided into three groups;Nd:YAG laser engineered surfaces(control),Nd:YAG laser/UV engineered surfaces and Nd:YAG laser/PRF engineered surfaces(N=12 discs–N=24 implants).In vitro bioactivity test was performed and precipitated apatite minerals were assessed with XRD and SEM.In vivo histomorphometric analysis was performed in rabbits with BIC% calculation. Results: Ra mean value of PEEK laser engineered surfaces was 125.179nm. For the studied groups,XRD patterns revealed distinctive peaks of different apatite minerals that were demonstrated by SEM as dispersed surface aggregations. There was a significant increase in the BIC% from control group 56.43(0.97)to laser/UV surfaces 77.30(0.78)to laser/PRF 84.80(1.29)(<0.0001). Conclusions: Successful engineered nano-topographical biomimetic PEEK implant could be achieved by Nd:YAG laser technique associated with improving bioactivity. The combination with UV or PRF could be simple and economic methods to gain more significant improvement of PEEK implant surface bioactivity with superior osteointegration.
INTRODUCTION:Veneers are considered the least invasive most reliable solution for treatment of discolored anterior teeth. Edelweiss system is a polymerized, prefabricated, laser-machined, radiopaque, highly-filled nano-hybrid composite enamel shells with a highly glossy inorganic surface. They have a facial anatomical pattern in the shape of a thin composite shell bonded to labial surface of anterior teeth with composite resin, which allows for easy direct veneering of single and multiple anterior teeth. OBJECTIVES Spectrophotometric analysis of discolored anterior teeth restored with Edelweiss veneer system bonded with different shades of composite resin. MATERIALS AND METHODS: Twenty Edelweiss veneers bonded with different shades of composite resin (A2, opaque white and translucent shades) to dies of different shades. Specimens were divided into four groups, each group consists of five specimens, according to the shade of the bonding composite resin used and the shade of the dies. Spectrophotometer was used to evaluate the effect of using different shades of the bonding composite on the final shade of the restoration. Also, to assess the light reflection, transmission and absorption of the Edelweiss Veneer System. RESULTS: The L*a*b* coordinates values of the Edelweiss Veneer Systems were affected by the shade of bonding composite (P<0.05). The use of an opaque bonding composite resulted in an increase of the color coordinates a*, b*, L*, producing the greatest effect on color change, light transmission and light reflection (P<0.05). Light absorption values of the specimens were not affected by the shade of the bonding composite. CONCLUSIONS: On using Edelweiss veneer system, the greatest color shifts and change in light transmission and light reflection were obtained when using opaque shade composite for bonding of the veneers to the substrates. While light absorption was of a non-significant value among the groups.
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