Is the pen safe for enamel? June 17, 2021 13:34 Updated Yes, the Colgate Optic White Overnight Teeth Whitening Pen has an enamel safe formula. Related articles Does the pen cause sensitivity? How long does the Colgate Optic White Overnight Teeth Whitening Pen last? The packaging says the product is flammable, can you travel with it on an airplane? Comments 0 comments Article is closed for comments.