I have heard that enamel can thicken/grow back but what can I do to thicken it so that the dentin does not show through?

Thank you for your question. In that area of your mouth, your enamel thinning will not grow back.To prevent it getting worse, avoid brushing after acidic meals and use a low abrasiveness toothpaste. Composite bonding is likely to be the least invasive method of protecting your teeth. Good luck and kind regardsThomas Dey, BDS, MSc

For the problem you are dealing with, enamel will not grow back. It can sometimes grown back in areas of tooth decay, in small amounts. Your only other options are bonding or veneers.