Americans now spend an estimated $1.5 billion a year on over the counter teeth whitening products. But dentists say too much whitening can cause problems; the most common -- sensitive teeth and gums.
"Sensitive to cold, sensitive to hot and sensitive to the bleaching agent itself," Professor of Dentistry Dr. Genarro Cataldo said.
"For some people, the products are too strong," cosmetic dentist Dr. Martin Zase said.
"It can make the gums very irritated and they can turn red and they can turn puffy," Cataldo said.
Another warning sign, your teeth become translucent, or worse.
"In some people when you are over-bleaching it gets very blue and it's not very attractive," Cataldo said.
Dentists say the damage is rarely permanent, but can take up to a year to clear up.
Experts recommend waiting six months between treatments to avoid over bleaching.
One other piece of advice: the dentists recommended sticking with name brands, since teeth whitening products are not regulated by the FDA and may vary in strength and formula.
Written and produced by Tim Didion