ผลของการเตรียมพื้นผิวและเรซินซีเมนต์ต่อความแข็งแรงยึดเฉือนกับ โลหะผสมนิกเกิลโครเมียม

Abstract

Objective: To investigate the effect of different surface treatments and thermocycling on the shear bond strength (SBS) between nickel-chromium alloy and resin cements. Methods: 305 nickel-chromium alloy rods diameter 6 millimeters height 2 millimeters were prepared and embedded in metal ring. Embedded specimens were randomly divided into 5 groups (n=60): (1) no surface treatment (Control); (2) sandblasting with aluminium oxide (Sandblast); (3) apply Cesead N Opaque Primer (MDP); (4) sandblasting with aluminium oxide and apply CeseadTM N Opaque primer (Sandblast + MDP); (5) treated with CoJetTM system (Cojet). Surface treated specimens were devided into 3 subgroups (n=20) according to types of resin cement. Then, the composite rod was bonded with NX3 NexusTM or RelyXTM Ultimate or Super-Bond C&B resin cement to the treated alloy surface. Bonded specimens in each resin cement group were devided into 2 subgroups (n=10) according to storage condition. After water storage at 37 °C for 24 h, and 5,000 cycles of thermocycling the specimens were subjected to SBS test with Instron® 5566 universal testing machine at a cross-head speed of 0.5 mm/min. All bond strength data were recorded and calculated in megapascal. Data were analyzed using three-way ANOVA and Dunnett T3 multiple comparison test at the significant level of 0.05. The 5 remaining specimens were surface treated according to 5 groups and observed by scanning electron microscope. Results: The mean SBS of Cojet group was significantly higher than that of other surface treatment groups (p<0.05). The mean SBS of Super-Bond C&B was significantly higher than that of other resin cements (p<0.05). After 5,000 cycles of thermocycling, the mean SBS of all groups was significantly decreased (p<0.05). Conclusion: CoJetTM was the most effective surface treatment in the term of increasing shear bond strength between nickel-chromium alloy and resin cement. Super-Bond C&B showed significantly higher bond strength compared to other cements. Shear bond strength decreased after thermocycling.