Whitening teeth. Does this sound right?

My dentist gave me some whitening formula toothpaste to use (professional bleaching) with a mold he made of my top teeth and told me to use it every night for two weeks. I did this and when I went back he told me that they did not look any whiter and wondered if I was doing it correctly so we went over the instructions again. I was doing it right. He said to just keep using it then every night until they are white! I'm worried...I thought you can wear the teeth down and turn them gray if you keep bleaching them all the time! I've done this for two weeks, all night long for a month now and he says keep going cuz they still look yellow. My gums are so raw and sore from doing this and my teeth don't change to white. : ( Do I just keep bleaching indefinitely?? How long is to long? Is this safe?
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Some teeth are very hard to whiten, like those with Tetracycline stain. Sometimes you must whiten for an extended period of time and sometimes it just wont get your teeth the shade you want. I don't expect any ill effects on the teeth form the whitening because you are not whitening them too much (too white), which is where you get into problems. The gums issue is from the gel sitting on the tissue. After placing the trays, push and spread the gel evenly over the teeth thru the trays. Wipe off the excess that comes in contact with your gum tissue. Some people grind or clench their teeth at night and this causes the gel to squeeze out of the trays. This could be causing the decrease in effectiveness and the irritation of the gum tissue. I would recommend that you try to wear the trays for several hours during the day, so that you can make sure the gel isn't getting onto the tissue. If it does, then you can wipe it off before it really has time to irritate the tissue. If you continue to try and whiten and still see no results and are getting frustrated then talk to your dentist again. It may not be worth it for you personally. If you are happy with your teeth then that is all that is important!
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