Hello! thanks for write!. Bonding is indicate for patients that do not drink coffee or food with colorant because it will always be discoloured by the time. In spite of composite is cheaper than any other porcelain veneer, people should be a good candidate for it. I personally recommended you a teeth whitening and them replace the actual bonding with a porcelain veneer. You have to work with an especialist in esthetic dentistry to get really good results including the color. Asl you can go for dental tourism in another country where you can found cheaper prices.
Great Question--with discolored teeth--you have 2 options--either bleach or cover the tooth--in this case it sounds like the composite and or tooth behind it is darkening --porcelain is a great option and composite in the hands of an accomplished cosmetic dentist can be a great option as well--the right materials in the hands of a dentist trained in cosmetic composite bonding can look great for many years. Good luck
This discoloration can only be corrected by placing an all porcelain crown on the tooth. Good luck.