3D enhanced toothpastes in the USA can last up to 12 months after whitening. 3D is certified by the American Dental Association for at-home deep tooth whitening, and the safety and effectiveness of whitening are recognized.Please read instructions carefully before using. Slight discomfort is common but in most cases it won't harm your teeth and gum. You can pause for 2~3 days before second use. If your teeth or gum are still in aches and pains, please stop using it.Safety Warning:1. Keep out of reach of young children. Product is not intended for use in children under the age of 12.