Introduccion y Objetivo: Los fabricantes de materiales ortodonticos han tratado de modificar las caracteristicas de la base de los brackets para mejorar las fuerzas de union de la interfase Resina/ bracket. El proposito del estudio fue comparar las fuerzas adhesivas de cizalla de brackets metalicos sin microarenar, Mini 2000, y microarenados con particulas de oxido de titanio, Mini Twin, de la casa comercial ORMCO®. Materiales y Metodos: 60 premolares humanos extraidos por motivos ortodonticos fueron conservados en solucion salina al 0.9% a 4oC durante 5 meses; previo a la cementacion de los brackets, los premolares se asignaron aleatoriamente, 30 en el grupo control, no microarenado, y 30 en el experimental, microarenado. Una vez realizado el termociclaje con 80 ciclos durante 2 minutos cada uno, a 5oC y otro a 55oC, los dientes se sujetaron en un aparato de diseno propio y fueron llevados a la maquina de ensayos Instrom 5582 para someterlos a las fuerzas de cizalla. Se tomaron microfotografias con el microscopio electronico antes y despues de la falla a la cementacion. Resultados: No se encontraron diferencias estadisticamente significativas en cuanto al tiempo de recoleccion de los premolares, Valor p= 0.876 para la prueba de Mann- Whitney, indicando que los grupos desde el inicio son comparables. Se encontraron diferencias estadisticamente significativas en la resistencia a las fuerzas de cizalla, Valor p= 0.005 para la prueba de Mann Whitney, en donde los brackets no microarenados resistieron una fuerza mucho mayor antes de la decementacion del bracket, con una Me= 188.4 N ± 79.0. Conclusion: El proceso de microarenado de la base de los brackets con el objeto de aumentar las fuerzas de adhesion es un procedimiento innecesario que consume tiempo y dinero a las casas fabricantes. Abstract Introduction and Objetives: Manufacturers of orthodontic materials have tried to modify the characteristics of bracket bases in order to improve strength of the resin-bracket interface. The purpose of this study was to compare shear adhesive strength of Mini 2000 non-sandblasted metal brackets and Mini Twin brackets sandblasted with titanium oxide manufactured by ORMCO®. Materials and Methods: Sixty premolars which were extracted for orthodontic purposes and preserved in 9% saline solution at 4°C during five months were used as sample. Teeth were randomly assigned into two groups, 30 in a control group on which non-sandblasted brackets were cemented and 30 in the experimental group on which sandblasted ones were cemented. After a thermocycle of 80 cycles was done during 2 minutes for each group at 5°C and at 55°C, teeth were attached to a device designed for the study and were subjected to an Instrom 5582 Machine in order to determine resistance to shear forces. Microphotographs were taken with an electron microscope before and after bracket decementation Results: No significant statistical differences were found between both groups in terms of the recollection time of premolars (Mann-Whitney test p value 0.876) indicating that the groups were comparable from the beginning. Non-sandblasted brackets presented a statistically significantly higher resistance to decementation when subjected to shear forces than sandblasted ones (Mann-Whitney test p value 0.005) with Me =188.4 N ± 79.0. Conclusion: Sandblasting of bracket bases with the objective of increasing adhesive forces seems to be an unnecessary procedure that is time consuming and increases costs for the manufacturer