This study measures retentive force as function of the diameter, the cross-head speed, and the number of detachments of dental magnetic attachments in a clinical environment, and analyzes the validity of the international standard method for testing them. In this study, tests 1, 2, and 3 were used to measure the retentive force as a function of the contact area of the magnetic attachment, and tests 2 and 4 as a function of the cross-head speed. Test 2 and 5 compared function of the retentive force as a function of repeated detachments Results showed that the retentive force increases as the sample surface increases, and decreases as the cross head speed increases. Additionally, after 1500 detachment cycles, the retentive force increased. Finally, the international standard test method was validated, because an objective method for testing magnetic attachments in clinical environment could not be found.