The need to bond orthodontic brackets onto various alloys has increased because of the increasing demand for adult orthodontic treatment. This study tried to evaluate the shear bond strength between gold alloy and metal bracket using light emitting diode (LED) light curing after metal primer and silicoating surface conditioning.
Half of the type III gold alloy plates were treated with sandblasting with aluminum oxide and metal primer containing 4-META, the other half were treated with silica and silane. Metal brackets were bonded with Transbond XT light curing adhesive on these plates and shear bond strength were evaluated 1 hour, 6 hours, and 24 hours later. The differences of shear bond strength between groups were evaluated with two-way ANOVA.
The results showed higher bond strength in the silicoating group and a tendency of bond strength increase over time.
When using LED curing lights for metal bracket bonding to alloy surfaces, long curing time and silicoating can produce a reliable bonding strength.
Alloy plates were embedded in cold curing acrylic and placed in acrylic rings. Each plate was oriented so that its surface would be parallel to the force during the shear bond test.
Alloy surface-conditioning methods and test timing of each group
Mean and standard deviation in shear bond strength of each group
MPa, Megapascal. The same letters are not statistically significant at α = 0.05 by Scheffe's multiple comparison.
Frequency and percentage distribution of the ARI scores of the 6 groups
*ARI scores: 0, No adhesive left on the specimen; 1, less than half of the adhesive left on the specimen; 2, more than half of the adhesive left on the specimen; 3, all adhesive left on the specimen.