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.

Introduction: Zirconia ceramics have been widely used as a framework material for all-ceramic restorations. The high crystalline content of zirconia renders the material quite opaque, requiring frameworks to be laminated with a veneering material for optimum color and translucency. Aim: The present study evaluated the core-veneer shear bond strength of zirconia-based restorations veneered by four different veneering techniques. Methods: Twenty rectangular shaped zirconia blocks (19×15×2mm) were cut from presintered yttria-stabilized zirconia CAD/CAM blocks with a low speed precision cutting saw using water irrigated diamond disk. Sectioned zirconia blocks were cleaned, dried, sintered then assigned to four groups in accordance with the veneering technique (n=5). Finished zirconia blocks were veneered by either fused lithium disilicate discs, bonded lithium disilicate discs, conventionally layered ceramic discs, or composite discs. Shear bond strength test was performed using a computerized universal testing machine. Results: Zirconia blocks veneered with fused lithium disilicate discs revealed the highest mean shear bond strength, while the lowest mean value was reported with the zirconia blocks veneered with composite discs. Statistical analysis revealed that differences among all groups showed statistical significance. Conclusion:Veneering technique and material significantly affected shear bond strength of zirconia-based restorations.

Aim: to evaluate the shear bond strength of an adhesive system (Single bond universal adhesive+ RelyX Ultimate cement) and Panavia F2.0 to two types of zirconia (conventional ZI zirconia and translucent TZI zirconia) after thermocycling. Materials & Methods: 10 square shaped large samples from Incoris ZI blocks, and 10 from Incoris TZI blocks were prepared with larger dimensions (12x12x2mm). Another 10 square shaped small samples from each type of zirconia blocks were with small dimensions (6x6x2mm). The surfaces of the large and small samples were air abraded with 110 µm AL2O3 particles, then each small sample was bonded to the large sample using two types of cements (RelyX Ultimate cement in combination with Single bond universal adhesive and Panavia F2.0 cement) under 3Kg load and light cured. After bonding, all specimens were thermocycled for 5000 cycles. The cement/ zirconia interface for each subgroup was detected under scanning electron microscope and the shear bond strength was tested using a computerized universal testing machine. Results: No significant difference between shear bond strength of all subgroups tested. Conclusion: The shear bond strength of RelyX Ultimate+ Single bond universal adhesive to two types of zirconia was comparable to Panavia F2.0 , and the shear bond strength of translucent zirconia bonded with two types of cements was comparable to conventional zirconia.

Aim of the study: the purpose of this In-vitro study was to evaluate the effect of surface treatments on the color change and shear bond strength of lithium disilicate glass ceramic veneers. Materials & Methods: Twenty square samples with dimensions (8x8x2) and another twenty samples with smaller dimensions (4x4x2) were cut from five IPS e-max CAD blocks of shade A3. The discs were divided into two groups: 1) Half of the small and large blocks were subjected to hydrofluoric acid (HF); 2) the other half was subjected to Co2 laser irradiation. The conditioned samples were subdivided according to the bonding agent: A) Silane application for 60 seconds; B) Single bond universal light cured for 10 seconds. Each small sample was cemented on the top of a large sample using RelyX veneer cement with translucent shade. The color change was measured using spectrophotometer. The shear bond strength was tested using a universal testing machine. Results: HF resulted in higher bond shear bond strength and ΔE than Co2 laser. Single bond universal resulted in higher shear bond strength values than silane. Conclusion: HF followed by either single bond universal or silane could be the best surface treatment for e-max CAD ceramic. However, Co2 laser could be a promising alternative surface treatment.