A Comparative Evaluation of Bond Strength among Three Commonly used Straight Wire Brackets in Clinical Practice

The bonded brackets should have enough bond strength to withstand masticatory forces, and forces applied during orthodontic treatment and should enable easy debonding, clean up procedure at the end of the treatment without causing iatrogenic damage such as cracks and loss of enamel. Bond strength is reported as the initial mechanical load (stress) to fracture divided by the simple geometrically defined cross-sectional area of the bond. Depending upon the mode and direction of the loading force different types of bond strengths are evident. Thus, the aim of this study is to evaluate shear and tensile bond strength of Metal-Chrome Cobalt TP Nu-edge L N bracket system with Primekote base and to compare it with that of 3M Gemini Metal-Stainless Steel bracket with woven mesh base and Ormco Metal-Stainless Steel bracket with Optimesh base. Shear and Tensile bond strength of three commercially available pre-adjusted edge-wise premolar brackets with different base designs were used for the study on 54 premolar teeth. Hounsfield Tensometer Universal Testing Machine was used to determine the shear and tensile bond strengths. Shear strength and tensile strength were calculated. Statistical analysis: Students' t-test and one-way ANOVA was performed. Ormco Optimesh brackets had the highest shear bond strength value of 20.08 MPa, followed by 3M Gemini bracket with a value of 16.22 MPa. The lowest bond strength value was noticed for TP Primekote brackets with 13.87 MPa. The tensile bond strength values of 3M Gemini brackets, Ormco Optimesh brackets and TP Primekote brackets were 7.42 MPa, 6.57 MPa and 7.31 MPa, respectively. The differences noted among the three brackets were not statistically significant. There was a significant difference in shear bond strength of the three brackets compared. There was no significant difference in the tensile bond strength between the three brackets compared. Ormco Optimesh bracket and 3M Gemini bracket is a good choice for Orthodontic bonding in clinical practice.