Yellow teeth

Hi, I'm under depression because of my stained teeth. I have been in a relationship for two years. Recently we got broke up. I guess whether it is due to my outward appearance. I used a brush and floss every day but there is of no use. On a get-together, I laughed loudly and friends started calling me nicknames which hurt me a lot. I want to overcome this so I'm thinking of undergoing teeth whitening procedure from a dental care clinic in Kingston. I have scheduled an appointment with the dentist in Kingston ( www.dawsondental.ca/our-locations/kingston-dentist/ ). Next month is my bestie's wedding before that wedding I need to regain my smile. Do teeth whiteners damage existing dental restorations? Will it last for a long time? Kindly share your wisdom.