Whitening is conservative, but not always the answer
I am a big fan of whitening. It is conservative and very effective as long as your teeth have enough enamel. The yellow part showing through is most likely the dentin and whitening is intended to work on the enamel portion.
For patients who have lost enamel to the degree that you are describing, then a restorative option becomes the best choice. That includes veneers, if there is enough enamel to achieve good bonding, but may mean full coverage all ceramic crowns for the best long term solution.
Remember that you are not only looking to improve the way you look, but you need to restore your function today and for your future.
Teeth that are eroded cant be whitened
Teeth that have been eroded away by acid attack, either by reflux or acidic foods/ drink cannot be whitened with results. The dentin is exposed or very thin enamel has dentin show through. Veneers are the only way to improve the look of this condition
Your best option is either veneers or crowns
With how much your enamel is eroded, whitening may not be the best option for you. You could damage the pulp, and/or your teeth can become extremely sensitive after the procedure. Also, the whitening procedure may not work for you. With how much your enamel is gone, porcelain veneers or crowns will give you a whiter, and longer lasting, smile.
Crowns may be needed for heavily eroded teeth
If your teeth are so eroded that the dentin shows through the translucent enamel on the front part of your teeth, you may have already lost all of the enamel on the back of your teeth. Whatever is left ( the dentin) will wear down much more quckly and will not bleach to a satisfactory shade
You should consider all porcelain crowns to restore the contour and color of your teeth, and protect them from further breakdown.
Full crowns may be a better option
If the strength of your teeth is compromised by erosion then full porcelain crowns may be the best option. Your teeth will get cosmetic improvement AND structural re-enforcement.
Unfortunately, veneers or full porcelain crowns are the best option
The thin enamel may get whitened, however the dentin never will. Additionally, you may traumatize the pulp (nerve) which sits under the dentin, with teeth whiteners.
Thank you for your question.
There may be no other choice
Unfortunately, not everything works for everybody. By doing a "Deep Bleaching" process, you may be able to get the enamel AND dentin to lighten. However, whitening of teeth is unpredictable. Some people lighten very well and others not as much.
Generally speaking, if you want whiter teeth, bleaching may satisfy you. If you have a specific level of white you are seeking, bleaching may be a frustrating process for you. Only porcelain crowns or veneers give you the control of the exact level of white you desire. If your enamel is very thin, you may get an added benefit of stronger teeth by placing porcelain on them, so the restorative work has a functional component and not just a cosmetic desire.