75 - Bond Strength of Multi-Step Adhesive at Intraoral Repair

Abstract

In recent years, dental bonding system have been improved its bond strength not only to tooth structure but also to prostheses such as metals and ceramics at intraoral repair. However, in order to provide reliable adhesion to prostheses, repairing procedure is complicated and different depending on product and type of prosthesis and its bonding durability has not been much reported. We have developed a new two-step self-etching adhesive "G2-BOND Universal" that make simplify repairing procedure even multi-step adhesive. In this study, bonding durability of multi-step adhesive at intraoral repair cases was evaluated. Several prostheses, [initial LiSi Block] (GC, LiSi), [initial LRF BLOCK] (GC, LRF), [Ti alloy] (GC, T-ALLOY) and [Aadva Zirconia disk EI] (GC, Zirconia) were used. The adherend were embedded in acrylic resin (GC, Unifast II). The multi-step adhesives used in this study were G2-BOND Universal (GC, G2B), SE BOND2 (kuraray, SE2) and Optibond FL (Kerr, OFL). The flat adherend surface was prepared by 600-grit SiC paper. Each adhesive was applied to the prepared adherend surface according to the manufacturer's instructions, and composite resin (Clearfil AP-X, kuraray) was applied to create an adhesion test specimen referred to ISO29022. After 24 h storage in 37 degree C, the specimens were subjected to a thermocycling (5-55 C, 30 s). Shear bond strength (SBS) was tested by Universal testing equipment, SHIMADZU Autograph, testing speed at 1 mm/min (n=5). Data were analyzed by Tukey test (p<0.05). As results of OFL, its SBS was low and pre-testing failures (PTF) were observed in all prostheses cases. On the other hand, G2B showed high SBS for all prosthesis cases, since G2B contains thiophosphate ester monomer and phosphate ester monomer for precious metal and zirconia. On comparison with G2B and SE2, there was significant difference of SBS on Zirconica which might indicate difference of functional monomer effectiveness and G2B could make functionalize its phosphate ester monomer. G2-BOND Universal has high bond strength at intraoral repair cases, so stable bond strength may be expected in clinical practice.