Your teeth are porous. Although you can't see it with your eyes, your teeth actually have tons of microscopic holes in them. Those holes are pores and are what lead to discoloration and staining from food and beverages. During a teeth whitening session these pores open a bit to lift, lighten and brighten your smile. After your session you pores need time to remineralize and become smaller again so they don't immediately stain. Following aftercare is important for the first 24-48 hours.
*Care instructions must be followed for the first 24-48 hours*