Generally, it only takes 15-30 minutes for one treatment. And after 7-15 times of practicing, you will notice the remarkable results! Specifically, each individual’s result may vary depends on the different circumstances. Some people takes only 5-10 times of treatment in order to get a obvious result as their teeth could absorb the element quickly. On the other hand, others which have weak absorbing ability of their teeth may require at least 2 boxes of gel to get a obvious results.