The Effects Of Sandblasting On Shear Bond Strength Of Recycled Orthodontic Metal Brackets With Two Braket Base Design-an In Vitro Study

Objective The purposes of this study was to evaluate the effects of sandblasting on Shear bond strength ( SBS) of recycled orthodontic metail brackets with two braket base design.Methods 120 extracted human promolars were collected which had been extracted for orthodontic purposes and were divided randomly into two groups(60 each):half an hour ( group I ) and 24 hours ( group II ) .For each time group,30 speccimens of 2 types of metal Brackets:Swallow-tailed base brackets(group A) and foil mesh base brackets(group B) were bonded to the teeth.All the specimens were stored in 37°C artificial saliva after bonding .Brackets were debonded half an hour or 24 hours later ,and the shear bond strength and the adhesive remnant index(ARI)was recorded.Ten debonded Brackets of each type from each time group were selected at random,and sandblasted or burned.All the teeth were cleaned,and 1/3 were rebounded with new brackets, 1/3 were rebounded with sandblasted used brackets,and 1/3 were rebounded with burned used brackets. The shear bond strength and the adhesive remnant index(ARI) were measured again, half an hour or 24 hours later.Results 1. The results of the analysis indicated that the mean shear bond strength values for two bracket types increased with time, Furthermore rebonded brackets had higher mean shear bond strength values and that shear bond strength increased over a 24-period.On the other hand,the...