better late than never i suppose:
ok, i guess as the resident dentist i should chime in on the subject.(unless there is another dentist on this board
then i'm just another opinionated member)
the staining of your teeth can trully vary on the various factors in your life. 1.) have your teeth ALWAYS been yellow? or have you noticed that they have recently started turning yellow?
2.)what do you drink? while you do not drink coffee you might want to consider that tea is a far more staining compound that coffee.(or wine?)
3.) any other factors: smoking?
if you've had teeth which have been just recently becoming yellow it indicatees that the stain is superficial(located within the enamel itself) if so, then your discoloration is caused by something habitual and can be mediated by a good cleaning, some whitening strips, or if you can, there are various bleaching kits availabe thru your dentist(the products we can offer to you are stronger than any over the counter stuff you can get, but they are more costly).
now if your teeth have always been yellow or discolored, that might be due to some intrinstic staining(either from developement, or from medication you took as a child). that type of staining is a bit more premanent and "tough" to get rid of(as it is deposited throughout the dentin and enamel layer). in that situation, a bleaching treatment provided by a dentist will be your main avenue to change color(mind you, some discoloration is so drastic/permanent, possible veneers,etc might be a solution).
now, is bleaching bad for your teeth? essentinally you are placing a slighly acidic material upon the enamel in order to "bleach" the enamel prisims and cause the color to venture to the white spectrum. most patients report sensitivity to color/air in the first few treatments of bleaching. that is an unforunate side-effect. also, keep in mind, any tooth colored fillings will NOT change color, they will in-fact stay the same and perhaps even need to be replaced. so, in turn, the fact is: vanity does come at a price. but as with everything, with moderation you could achieve some good results(and remember, it's not NATURAL to have refrigerator-white teeth)
if you don't want to spend the money on the kits, treatment, thats ok. but please do not to the following: don't bleach w/ diluted bleach(yes, i've had a patient do that before), it will not only ruin your teeth, but its DANGEROUS!
if you have any questions, feel free to ask, i'll do the best i can, but remember, nothing will beat actually going to your family dentist and having him look and exam you himself!!! that said, keeping a 6 month cleaning schedule isn't a bad either either
