How safe are store teeth whiteners to be used at home? how often can i use them?

DDS consult first: They are relatively safe but we can't know about every single one that may be available. Stick with the name brand ones such as crest whitestrips. While safe, they have limitations & your teeth and gums should be healthy prior to their use. They do not whiten fillings & other restorations. Therefore, it is always best to consult with a dentist prior to their use. Professional methods work better.

Be careful: I know crest white strips are safe and effective. I am sure there are others but there are some that will seriously damage your teeth.

They are safe: To use. Each product has its usage instructions which should be followed. They are not as effective as professional systems available through your dentist, but then again they are significantly cheaper.

OTC Whiteners: Generally safe when used EXACTLY as per package directions, although some people describe mild irritation. Should have your teeth cleaned first. Whiteners will not lighten crowns/veneers. If Dentist provided whitening is a 10, OTC strips are about a 2, whitening t'pastes about a 1.