The objective of this study was to assess the bonding performance of a new universal self-adhesive cement RelyX Unicem (RXU) to dentin and enamel compared to four currently used luting systems, using a shear bond strength test with and without thermocycling. Median bond strengths were determined after 24 h storage, and after thermocycling (6,000 cycles, 5-55 degrees C) for RXU and compared to Syntac/Variolink II (SynC/V) as a standard for luting conventional ceramics, ED-Primer II/Panavia F2.0 (EDII/PF2), Prime and Bond NT/Dyract Cem Plus (PBNT/DyCP), and a glass ionomer cement, Ketac Cem (KetC), as a standard for luting high-strength ceramic and metal-based restorations. Data (n=10 per group) were statistically analyzed using the Mann-Whitney-Wilcoxon test at the 0.05 level of significance. The bond strength (MPa) of RXU to dentin (10.8) was not statistically different from those of SynC/V (15.1), EDII/PF2 (10.5) or PBNT/DyCP (10.1), and statistically higher than KetC (4.1). The bond strength of RXU to enamel (14.5) was significantly lower than those of SynC/V (32.8), EDII/PF2 (23.6), and PBNT/DyCP (17.8), but higher than KetC (6.1). After thermocycling, the bond strength of RXU to enamel significantly decreased, but was still significantly higher than that of KetC. RelyX Unicem may be considered an alternative to Ketac Cem for high-strength ceramic or metal-based restorations, and may be used for luting conventional ceramic crowns with little or no enamel left.

The aim of this in vitro study was to examine the curing efficiency of three different polymerization methods through ceramic restorations by determination of the depth of cure and the universal hardness of a composite resin luting material. Therefore, 36 ceramic specimens [Empress 2 (Ivoclar), color 300, diameter 4 mm, height 2 mm] were prepared and inserted in steel molds (diameter 4 mm, height 6 mm) using a composite resin luting material [Variolink II (Vivadent)] with and without catalyst. The polymerization through six specimens of each group was done conventionally (40 s), by softstart polymerization (40 s), or by plasma arc curing (10 s). Depth of cure under the ceramic specimens was assessed according to ISO 4049. Additionally, universal hardness was determined at 0.5 and 1.0 mm from the ceramic using a universal testing machine (Zwick 14040). Curing without a catalyst, using conventional and softstart polymerization, resulted in greater hardness in both layers, compared to plasma arc curing. The use of a catalyst always produced a greater hardness and depth of cure with all polymerization methods. Depth of cure was always greater using conventional polymerization and softstart polymerization, compared to plasma arc curing. The curing efficiency of plasma arc curing through ceramic was lower compared to conventional and softstart-polymerization.

SUMMARYThis study compared the ability of a variety of light sources and exposure modes to polymerize a dual-cured resin composite through ceramic discs of different thicknesses by depth of cure and Vickers microhardness (VHN). Ceramic specimens ( The results showed that increasing ceramic disc thickness had a negative effect on the curing depth and hardness of all light curing units, with hardness decreasing dramatically under the 2-mm thick discs using LuxOmax, e-Light (12 sec- Clinical RelevanceThe ability of modern light curing units to photocure luting resin through ceramic restorations is dependent on the type of light source, ceramic thickness and use of a self-curing catalyst.

The production of metal‐based hybrid laminates, such as aluminum combined with thermoplastics like polyamide 6, requires a precise and purposeful design of the interface between the two components. The utilization of twin polymerization has been successfully examined and an improved adhesion behavior is shown. By utilizing the monomers 2,2′‐spirobi[4H‐1,3,2‐benzodioxasiline] and 2‐(3‐amino‐n‐propyl)‐2‐methyl‐4H‐1,3,2‐benzodioxasiline in a molar ratio of 15:85, medial tensile shear strength values of 12.9 ± 3.9 MPa are achieved in tests according to DIN EN 1465. Electron microscopic and atomic force microscopic investigations give further structural details of the hybrid material. Additionally, the results of nanoindentation and microscratch tests clearly demonstrate that the choice of an adhesion promoter depends on its chemical as well as its mechanical characteristics.

Sandwich structures consist of one light core layer and two top layers, which form the load-bearing structure. These layers have to be stiff and strong and have to protect the structure against indentations. The main task of the core layer is to keep the top layers in place and to generate a high shear stiffness. In order to obtain the required space between the top layers, the core layer has to have a high specific volume. Different sandwich materials with aluminium or steel top layers and cores of aluminium combs, corrugated aluminium sheets or aluminium foams are already known. In order to obtain better properties in terms of strength fibre-reinforced plastics (FRP) are utilised as top layers; this is the focus of numerous of the current research studies. The sole use of these materials leads to negative effects regarding the damage and impact behaviour. New top layers with high strength and high stiffness characteristics as well as good damage tolerances are to be expected by utilising metal layers in combination with endless fibre-reinforced plastics, so called hybrid laminates. These hybrid laminates combine the positive properties of metals (e.g. ductility) and fibre-reinforced plastics (e.g. tensile strength). The focus of this investigation lies on the production and characterisation of sandwich structures with aluminium foam core layers and hybrid laminate top layers. The foam cores consist of closed pore aluminium foams produced by utilising ingot and powder metallurgical techniques. The top layers consist of glass fibre-reinforced thermoplastics and aluminium layers. The production of the sandwich materials is realised by means of thermal pressing.