Evaluation and comparison of shear bond strength of new and rebonded orthodontic brackets having various mesh base designs: An in vitro study

Introduction - To evaluate and compare the shear bond strength of orthodontic brackets with different mesh base design viz. single mesh base,double mesh base , Microlock base & Dynalock base and to assess shear bond strength after rebonding using sand blasting & acid bath method.The surface characteristics of new and rebonded bracket bases were compared using scanning electron microscopy (SEM). Sample comprised of 40 extracted human mandibular premolars. Sample was divided in to four groups and brackets with different mesh base designs were bonded. (n=10 for each mesh base design). SEM was used to compare the surface characteristics of the new & rebonded bracket bases for all the four groups Multiple comparison Scheffe test wasused to compare the shear bond strength of new brackets in all 4 groups revealed that mean shear bond strength for single mesh base(Gr I) , double mesh base (Gr II)& Microlock base (Gr III)were not statistically significant with P-value (P>0.05),whereas Dynalock(Gr IV) showed significant difference ( P< 0.05).Shear bond strength ranking from highest to lowest was highest in single mesh base, double mesh base, microlock base & lowest with Dynalock base brackets Sand blasting showed more shear bond strength than