Effect of Suface Preparations of Stainless Steel Crown on Composite-resin Shear Bond Strength

Objectives:

Stainless steel Crown (SSC) is the most durable restoration for extensively decayed primary teeth but its metallic appearance is displeasing. The purpose of this study was an in-vitro evaluation of shear bond strength of a composite-resin veneer, using different surface treatments of Stainless steel and bonding agents, for possible future development of  producing esthetic SSC.

Methods:   

The samples (n=90) consisted of SSCs (U6,L6 unitek, 3M) monted in molds with flat surfaces projecting above and divided (n=3/gp). In group 1 they were sandblasted ( Dento-prep 402, 5min), in group 2 a hand-made acidic gel (50% H3PO4, 25% HCL, 25%Methanol, 5min) was applied, rinsed and inserted in ultrasonic (18%HCL, 10min) and in group 3 fissure dimond bur (F2M) created roughness (20 times left to right action).Then each group subdivided (n=3sgp) based on bonding agents applied: Singel-bond(3M-ESPE), PanaviaF-2.0(Kurary), All-bond2(Bisco).Then a composite-resin(Heliomolar-A2, Ivoclar) in transparent cylinders (3-3mm) cured to prepared surfaces, incubated (100% humidity 37’, 24h),its shear bond strength measured (Zwick,0.5mm/min) and statistically analyzed (  ANOVA, p<0.05).

Results:

There was no correlation between surface treatment and bonding agent variables, So they were studied separately (p>0.05). The mean(SD) shear bond strengths of composite-resin in MPa for groups 1-3 were: 10.76(2.57), 10.19(2.57), 10.97(2.57) and in subgroups 1-3 : 10.74(2.57), 10.76(2.57), 10.40(2.57), which showed, there was no significant difference between shear bond strength of composite-resin when three surface treatments were used and also when  bonding agents applied (p>0.05).

Conclusion:   

In this study, the composite-resin mean shear bond strengths were statistically similar when three kinds of surface treatments and bonding agents applied. So because of the simple use of Single Bond ( single bottle, one-step) and also availability and cost-effectiveness of bur treatment , this seems to be a choice for chair-side veneering of composite-resin to SSC , but further research is needed.