How unsafe is it to bleach your teeth using household teeth by dabbing a cotton bud in watered down bleach and wiping it on front teeth only?

NOT SAFE!! Household bleach is not the same as the bleach dentists use. Household bleach is poisonous and should not be ingested or even inhaled. Only use products meant to whiten your teeth that you get from your dentist or in the mouth care aisle of your pharmacy.
Ineffective. The bleach they use for bleaching teeth is different from household bleach. If you put regular bleach in your mouth, you risk inhaling chlorine, which is irritating to the lungs, .