Aim: to evaluate the shear bond strength of zirconia bonded with two self etch adhesive resin cements PANAVIA F 2.0 and BISTITE ΠDC using two surface treatment techniques: sand blasting and silica coating using Cojet system. Materials and Methods: Twenty rectangular samples with dimensions (14.5×13×3.6mm) and twenty samples with dimensions (7.2×6×3.6mm) were cut from three zirconia ceramic blocks. Sandblasting was done using air blasting machine with 110 µm AL 2 O 3 particles and Silica coating surface treatment was done using Cojet system with 30 µm SiO 2 particles. Half of the small sandblasted zirconia samples were cemented to half the sand blasted large samples using PANAVIA F 2.0 adhesive resin cement and the rest were cemented using BISTITE ΠDC adhesive resin cement. Also, half of the small silica coated zirconia samples were cemented to half the silica coated large samples using both cements. Thermocycling were done for 5000 thermal cycles. The shear bond strength was tested using a computerized universal testing machine. Results: Zirconia specimens cemented with PANAVIA F 2.0 showed higher shear bond strength than specimens cemented with BISTITE ΠDC and the zirconia surfaces treated with silica coating and sand blasting surface treatments. Conclusion: PANAVIA F 2.0 resin cement and silica coating surface treatment could be the best cement and surface treatment for zirconia and sand blasting could be a promising alternative surface treatment.

Introduction:Clinical success of ceramic repair system is dependent on integrity of bond between metal, ceramic and resin composite. Aim: Evaluate shear bond strength (SBS) of composite repair material to ceramo-metalic and zirconium restorations using new adhesive system after thermocycling. Materials and methods: 28 square specimens of metal, zirconia, veneering porcelain for metal (VMK95) and veneering porcelain for zirconia (VM9) were prepared (1 x 1 x 0.5 cm) and divided into 4 groups: 1)metal (M) group , 2)zirconia (Z) group , 3)veneering porcelain for metal (VPM) group, 4)veneering porcelain for zirconia(VPZ) group). Then M and Z groups were sandblasted while VPM and VPZ groups were subjected to HF acid. Single bond universal adhesive were applied to exposed surface of all groups then repair composite material was built up incrementally over center of exposed surface using cylindrical teflon mold (3 x 5 mm), stored for 7 days in distilled water followed by 1000 thermocycles then SBS was tested. Results: Highest SBS value between composite repair material and M group followed by Z group and composite repair material then VPM group and composite repair material then VPZ group and composite repair material. Conclusions: Sandblasting and application of single bond universal adhesive containing MDP can be recommended for repair metal and zirconium surfaces with composite material. HF acid etching and application of single bond universal adhesive containing MDP can be recommended for repair VPM and VPZ with composite repair material.

Aim: This study aimed to measure the effect of color stability of tested adhesive resin cements on the final color of cemented ceramic veneers, as well as the effect of different thicknesses of ceramic veneers on their final colors. Materials and Methods: A total of twenty-four disc-shaped resin cement specimens were prepared {12 disks/type of cement; the light-cured NX3 (LC) and the dual-cured NX3 (DC)}. The samples were immersed in water and coffee solutions for 7, 14 days. Forty-eight rectangular-shaped laminate veneers samples were cut from IPS e.max CAD ceramic blocks (24 samples of 0.4mm thickness and 24 samples of 0.6mm thickness; where 12 samples of each thickness were cemented by light cured resin cement (NX3), and the other 12 samples were cemented by dual cured resin cement (NX3); 6 out of 12 samples were either immersed in coffee solution or immersed in water. The samples were cemented on a Delrin background material. All the samples were examined by a spectrophotometer (VITA Easy shade) before and after immersion in the solutions. Results: The ΔE values of dual-cured resin cement disks were higher than those of light cured types. Also, differences were found in ΔE of the final shade of ceramic veneer when cemented by light cured and dual cured resin cements. Furthermore, there were differences in ΔE of the final shade when using different ceramic laminate veneers thicknesses. Conclusions: The ΔE of the final shade of ceramic veneer was affected by the type of the resin cement used as well as the thickness of ceramic laminate veneer.

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Introduction: Fiber posts and cores are usually used for the restoration of endodontically treated teeth with extensive coronal destruction. The most common cause of failure of fiber posts is debonding at the adhesive resin-dentin interface due to bond deficiency. Aim of the study: The purpose of this In-vitro study was to evaluate the effect of different dentin surface treatments including self-etch adhesive system, Er,Cr:YSGG laser irradiation and self-etch adhesive system after Er,Cr:YSGG laser irradiation on the push out bond strength of fiber posts to radicular dentin. Materials and Methods:The coronal portions of fifteen maxillary central incisors were cut till CEJ, the roots were endodontically treated and posts spaces were prepared. The roots were divided according to the dentin surface treatment method used into three groups (n= 5): group A: Optibond XTR self-etching adhesive system. Group B: Er,Cr:YSGG laser irradiation with output power of 2W, a repetition rate of 20Hz and water / air flow (80/60%). Group C: Er,Cr:YSGG laser irradiation with output power of 2W, a repetition rate of 20Hz and water / air flow (80/60%) followed by self-etching adhesive system (Optibond XTR). Dentoclic glass fiber posts were cemented, then each root was sectioned horizontally into three sections. Push out test was performed using a universal testing machine at a crosshead speed of 0.5 mm/min until failure. Results: There was a significant difference in the mean push out bond strength among different groups (p<0.001). The highest push out bond strength value was found in group A followed by group C, while the lowest bond strength value was found in group B. Conclusion: Optibond XTR self-etch adhesive system seemed to be an effective approach for fiber posts cementation.