Affiliations: Cariology and Operative Dentistry, Department of Restorative Science, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan | The Global Center of Excellence (GCOE) Program, International Research Center for Molecular Science in Tooth and Bone Diseases, Tokyo Medical and Dental University, Tokyo, Japan | Faculty of Dentistry, School for Dental Technology, Tokyo Medical and Dental University, Tokyo, Japan | Fixed Prosthodontics, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
Note: [] Address for correspondence: Toru Nikaido, Cariology and Operative Dentistry, Department of Restorative Science, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. Tel.: +81 3 5803 5483; Fax: +81 3 5803 0195; E-mail: nikaido.ope@tmd.ac.jp.
Abstract: Resin bonding to zirconia ceramic cannot be established by standard methods that are utilized for conventional silica-based dental ceramics. This study was aimed to examine the tensile bond strength of resin cement to zirconia ceramic using a new laboratory technique. Sixty-four zirconia ceramic specimens were air-abraded using Al2O3 particles and divided into two groups; the control group with no pretreatment (Control), and the group pretreated using the internal coating technique (INT), in which the surface of the zirconia specimens were thinly coated by fusing silica-based ceramic and air-abraded in the same manner. The specimens in each group were further divided into two subgroups according to the silane coupling agents applied; a mixture of dentin primer/silane coupling agent (Clearfil SE Bond Primer/Porcelain Bond Activator) or a newly developed single-component silane coupling agent (Clearfil Ceramic Primer). After bonding with dual-cured resin cement (Panavia F 2.0), they were stored in water for 24 h and half of them were additionally subjected to thermal cycling. The tensile bond strengths were tested using a universal testing machine. ANOVAs revealed significant influence of ceramic surface pretreatment (p<0.001), silane coupling agent (p<0.001) and thermal cycling (p<0.001); the INT coating technique significantly increased the bond strengths of resin cement to zirconia ceramic, whereas thermal cycling significantly decreased the bond strengths. The use of a single-component silane coupling agent demonstrated significantly higher bond strengths than that of a mixture of dentin primer/silane coupling agent. The internal coating of zirconia dental restorations with silica-based ceramic followed by silanization may be indicated in order to achieve better bonding for the clinical success.
