I want to whiten my teeth, but I may have a cavity. Anyway I can still do this b4 getn the cvty taken care of?

I've lost dental care a couple of years ago and haven't been to the dentist since (and know I need to go). I believe I have a cavity on one of my lower rear teeth. I've come to the conclusion that I would use either Rembrandt's 2-hour whitener or Crest Premium Strips. So if I used the strips, would this get affected at all? If so, could I just use on the top teeth? If I use the 2-hour tray, could I do only the top teeth and not inflict pain on my bottom tooth? Would drying my teeth as much as possible and applying a film of vaseline over the tooth prevent this (might as well do the gums as well if I go this far). Thanks. Have a wedding to attend soon.
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The whitening agent really shouldn't hurt the cavity...but to be on the safe side, I would stick with the strips so they won't even touch that back tooth. I have found that the regular Crest White Strips work better than anything (I've even used the jel prescribed by the dentist). Also, the Listerine or Crest whitening rinse is good. Rinse well with it before brushing. Next, floss your teeth so that the rinse gets all the interproximal stain. Then, brush. It is VERY important for you to use a flouride rinse after brushing, especially since you can't see a dentist right now. Use a good flouride toothpaste as well. For the tooth with the cavity....I know this sounds crazy, but when you use flouride rinse, put some rinse on a q-tip or cotton ball and literally soak the tooth with the flouride. This will NOT repair the cavity, but in some cases, it can arrest the spread of decay.
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