To Evaluate the Shear Bond Strength of Bondable Molar Tubes by Two Enamel Conditioning Techniques

ABSTRACT

Shear Bond Strength (SBS) is considered to be the main factor in the evolution of bonding. The bracket bond strength should withstand the forces during the orthodontic tooth movement. The commonly used technique by Orthodontists is to attach the brackets to the enamel surface is the acid-etch bonding technique along with 37 % phosphoric acid as etchant. With time, a new technique emerged in orthodontics which is used before bonding for the primary preparation of teeth as well as for the purpose of increasing bond strength known as Sandblasting. This study was done to compare the shear bond strength of acid etching and air abrasion technique used in orthodontic practice. MethodsA total of 100 extracted human first molar teeth were selected and segregated into 4 groups of 25 teeth. Group I bonding without enamel preparation, Group II using acid etching with 37 % phosphoric acid, Group III - sandblasting with 50 μ aluminium oxide, Group IV - sandblasting with 100 μ aluminium oxide. These 100 samples were then subjected to the measurement of the shear bond strength with an Instron machine and was measured in Newtons. ResultsGroup 1 showed a mean shear bond strength of 7.21 ± 0.29; for group II it was 7.77 ± 0.53; for group III it was 8.3 ± 0.3 and for group IV it was 10.04 ± 0.45. Groups 2 and 3 and groups 2 and 4 showed statistically significant difference. Shear bond strengths of both the groups 3 and 4 showed highly statistically significant difference. Conclusions100 µ aluminium oxide group showed the highest Shear Bond Strength. On inter group comparison, sandblasting with aluminium oxide was found to have better shear bond strength compared to conventional acid etching techniques.