ABSTRACT
The aim of this study was to evaluate the shear bond strength of three luting cements and to identify the effect of thermocycling.Zirconia discs were made similar to the inner surface of a preformed pediatric zirconia crown (NuSmile® ZR crown: ZRCr). The similarity between the zirconia discs and the inner surface of a ZRCr was confirmed by scanning electron microscope. Three luting cements were Ketac™ Cem Permanent Glass Ionomer Luting Cement (KGI), RelyX™ Luting Plus Cement (RLP), RelyX™ Unicem Self-Adhesive Universal Resin Cement (RUR). Three luting cements were bonded according to the manufacturer's instructions for 60 zirconia discs and 60 dentin of primary teeth. Total of 120 specimens were divided into two subgroups: One was not aged, and the other was tested with 5500 thermocycling. Shear bond strength was measured using a universal testing machine, and the fracture patterns were observed with SEM.On the zirconia discs and the dentin of primary teeth, shear bond strength of RUR was higher than that of KGI and RLP, and there were statistically significant differences by cement type. The shear bond strength differences for RUR were not statistically significant depending on thermocycling.