• The korean journal of orthodontics
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• v.29 no.5 s.76
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• pp.613-625
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• 1999

The purpose of this study was to compare the bracket shear bond strengths of the crystal growth solutions with those of the $37\%$ phosphric acid etch technique. The 4 crystal growth solutions were made experimentally in the lab, that is, (1) $30\%$ polyacrylic acid solution containing 0.3 M sulfuric acid (ES 1), (2) $30\%$ polyacrylic acid solution containing 0.6M sulfuric acid (ES 2), (3) $30\%$ polyacrylic acid solution containing 0.3 M sulfuric acid and 0.6 M lithium sulfate(ES 3), and (4) $30\%$ polyacrlic acid solution containing 0.3 M sulfuric acid and $5\%$ phosphoric acid(ES4). The $37\%$ phosphoric acid solution used as a control. Bovine lower incisor tooth enamel was treated by the above solutions for 60 sec, washed out for 20 sec with slow water stream, and bonded lower anterior edgewise bracket with the light curing orthodontic composite resin adhesives. The teeth bonded brackets were stored in the distilled water at room temperature for 24 h, and followed to test the bracket shear bond strength. The acid etch technque showed 177.6 kg/$cm^2$ of mean shear bond strength which was the highest among the enamel treatment solutions. ES 1 shown 58.4 kg/$cm^2$ of mean shear bond strength and that of ES 4 showed 66.5 kg/$cm^2$. There was no significant difference between the two(p>0.05). ES2 showed 110.6kg/$cm^2$ of mean shear bond strength which was $62.3\%$ of that of acid etch technique. ES 3 showed 131.1 kg/$cm^2$ of mean shear bond strength which was the highest among experimental crystal growth solutions and which was $74\%$ of that of acid etch technique. The shear bond strengths of the crystal growth solutions were significantly lower that that of acid etch technique(p<0.05). The results sugest that although bracket shear bond strength of $30\%$ polyacrylic acid solution containing 0.3M sulfuric acid and 0.6 M lithium sulfate were showed the highest, it is low for the clinical application of this solution.