Bond Strength Between Ti-6Al-7Nb and Resin Using Phosphate Monomer

Objectives: Ti-6Al-7Nb has gained popularity as the alloy for making removable partial denture framework due to its bio-inert and acceptable mechanical properties.  The objective of this study was to evaluate the different concentrations effect of 10-methacryloyloxydecyl dihydrogen phosphate (MDP, donated by Kuraray Medical, Japan) as the primer to promote bonding between autopolymerized acrylic resin and alloys.  Methods: Three concentrations, 10^-2, 10^-3, 10^-4 mol of MDP in acetone solvent were prepared.  Total 96 disks (12 mm in diameter and 2mm in thickness), half was cast with Co-Cr (Wiron, Bego, Germany) and the other half with Ti-6Al-7Nb (Tough Alloy, GC, Japan) according to manufacturers' recommendation and embedded in a tube using autopolymerized resin.  The surfaces were then polished to #1200 SiC paper with copious water in digital polishing machine (Imptech, DPS 3200, SA).  A double-face tape with a 4-mm diameter hole was put on the alloy surface to regulate adhesive area. Five µl of MDP primer was primed on the circular area and an autopolymerized resin (Unifast, GC, Japan) was applied into the 4-mm diameter plastic tube.  Without MDP was used as control.  Shear bond strength of twelve specimens of each group was tested using universal test machine at a cross head speed of 0.5 mm/min.  Data were analyzed using 2-way ANOVA and Tukey comparison at p<0.05.  Results: The shear bond strengths (SD) in MPa are summarized in table.  Application of MDP significantly increased the shear bond strength of both alloys.  However, other combinations of autopolymerized resins should be evaluated to achieve better bonding.  Conclusion: MDP improved bonding between alloys and autopolymerized resin.

The same superscripts denotes significant indifferences at p<0.05.