I had a couple of dental fillings on my upper teeth that just do not match my teeth. I’ve tried bleach, which had no affect of them, Additionally, brushing makes no difference, though I will do it anyway for hygienic reasons. I really like my smile, except for that one issue. My dentist is suggesting Lumineers. While they are expensive, if that is what will make my smile the same color I am willing to pay it.
While Lumineers can be done well, most cosmetic dentists prefer a different brand of porcelain veneers. This is because the Lumineers lab is not always known for their artistic results.
Also, you mentioned you loved your smile with the exception of the difference in color. Therefore, porcelain veneers, no matter which brand, would be a massive overtreatment.
Plus, your dentist struggled to match the fillings. This tells me he does not have much expertise in cosmetic work. You would likely be disappointed in his results.
The solution for discolored dental fillings is to replace the fillings. The truth is the composite bonding used for fillings can be made to match any color if the dentist knows what they are doing and has the materials.
You will save yourself a lot of money and grief just going to a dentist who can match your dental fillings to your natural teeth.
If you want your teeth any whiter than they currently are, just make sure you whiten your teeth before having the dental fillings replaced. As you learned in your efforts to match the current ones to your teeth, teeth whitening does not have any impact on dental work. It will only whiten natural tooth structure.