Effect of surface abrasion and silica coating on tensile bond strength of a resin cement to zirconia ceramics

Lei Zhu, DDS,(a) Toru Nikaido, DDS, PhD,(a) Shuzo Kitayama, DDS, PhD,(a) Masaomi Ikeda, BSc, RDT, PhD,(b) Richard M. Foxton, BDS, PhD, MFDS RCS (Ed), FHEA,(c) and Junji Tagami, DDS, PhD(a),(d)

(a)Cariology and Operative Dentistry, Department of Restorative Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, (b)Faculty of Dentistry, School for Dental Technology, Tokyo Medical and Dental University, (c)Division of Conservative Dentistry, King’s College London Dental Institute at Guy’s, King’s College and St. Thomas’ Hospitals, King’s College London, London, UK , and (d)Global Center of Excellence (GCOE) Program; International Research Center for Molecular Science in Tooth and Bone Diseases at Tokyo Medical and Dental University, Tokyo, Japan

Purpose: To evaluate the effects of different surface treatments on the tensile bond strengths of a resin cement to zirconia ceramics.
Materials and Methods: Zirconia discs (Lava) were fabricated and the surfaces of the specimens were ground with #600-grit SiC paper. Then the specimens were divided into four groups according to the surface treatment: (1) no pretreatment (control); (2) air-abrasion with 110 μm Al2O3; (3) laboratory tribochemical silica coating (Rocatec) with 110 μm Al2O3 and 30 μm silica modified Al2O3; (4) coating the surface (INT coating) with silica-based porcelain (Vintage ZR). Each group was subsequently divided into two subgroups assigned to be silanated using a ceramic primer (RelyX Ceramic Primer) or not. The bonding procedure was then performed using a dual-cure resin cement (RelyX ARC). After 24 h storage in water, the specimens were thermocycled (5-55°C, 5,000 cycles). The bonding performance was evaluated by the tensile bond strength test. Statistical analyses were performed at the level of p=0.05.
Results: The control groups showed the lowest bond strengths. The silanated groups showed significantly higher bond strengths than the non-silanated groups for each surface condition (p>0.05). The highest bond strength (27.2±6.2 MPa) was provided by the INT coating group with silanization. However, no significant difference was obtained between the INT coating and Rocatec groups after silanization (p>0.05).
Conclusion: With silanization, the INT and tribochemical silica coatings were the most effective in improving the bond strengths of the resin cement to zirconia ceramics. (Int Chin J Dent 2009; 9: 23-30.)

Key Words: INT coating, resin cement, silica coating, tensile bond strength, zirconia.