Angie,
Hi - I used to be a full time lab technician (doing mostly crowns) and worked in a dental office in Colorado - so I've seen a lot of teeth whitening.
The most effective whitening method you can use at home is custom trays with a whitening reagent such as carbamide peroxide with Calcium.
You can order custom teeth whitening trays and gel from a number of online retailers (which is a lot cheaper than going to the dentist).
The only problem with whitening tetracycline stains is that it takes much longer and requires more whitening gel (about 3x as much).
As I mentioned above, one of the most effective whiteners I've seen for tetracycline patients are those that include a calcium base such as is found in Calcium White or in some of Discus Dental's products.
Just give it time and be persistent for at least 4 weeks (with two whitening sessions per day) and you will see measurable results.
Good luck!
