Determine the resistance to shear force of the brackets adhered to the tooth surface previously treated with different acid etching techniques. Materials and methods: A quasi-experimental-comparative study was carried out. 30 bovine lower incisors were selected, without damage to the enamel and without defects or fractures resulting from the extraction on the labial surface. The sample was divided into six groups, each made up of five teeth. Liquid 37% orthophosphoric acid was applied to three groups for 30, 20 and 10 seconds respectively, and 37% orthophosphoric acid gel was applied to the other three groups for 30, 20 and 10 seconds respectively. Afterwards, the brackets were cemented and subjected to a shear resistance test on an Instron 5586 instrument of American origin. Results: were analyzed with the Anova and T-Student tests, finding that no statistically significant differences were observed between the coefficients of variation between the six groups (39%; 39.9%; 61.3%; 31.6%; 26 ,3; 66%). Conclusions: There is no statistically significant difference between the groups treated with different acid etching techniques and the control group.