7. Shear Bond Strengths of Dental Cements for Luting to Zirconia Ceramics

「Introduction」The bonding characteristics of zirconia ceramics to dental luting materials are not well known yet. In this study, we measured the shear bond strengths of resin modified glass ionomer cement(RMGI)and resin based luting cement(RBL)cements to zirconia ceramics to evaluate the bonding characteristics and the effect of primers on RBL cements. Materials and Methods We used three kinds of RMGI cement(G-Cem, Ionotite, Resiglass)and RBL cement(Panavia, SuperBond C＆B, Rely-X ARC). Primers used were a silane coupling agent(Espesil), a functional monomer(Epricord), those mixed type(Creafil Ceramic Primer), and a primer for zirconia ceramics(AZ primer). Plate specimens of zirconia ceramics(Noritake Dental, Japan)were sintered at 1350℃ for 2h, the specimens were embedded in an acrylic tube. A titanium cylindrical specimen with a sand-blasted surface was bonded to the zirconia surface with each cement. Shear bond tests were performed using a universal testing machine at 1mm/min. We observed SEM images of the fractured surfaces. Results and Discussion RMGI cements seemed to have much better to the bonding characteristics for zirconia than RBL cements. However, it is thought that RMGI cements are inferior to RBL cements in terms of the durability. On the other hand, there is some possibility to enhance the bonding characteristics of the RBL cement by surface treatment and primer treatment to the zirconia surface. These results suggest that the present primers could not produce bonding strength. Therefore, further investigation of surface treatments will be needed to enhance the bonding characteristics for zirconia surfaces.