There is no proof that metal tooth fillings have any effect on lichen planus.
I would strongly consul you to leave things alone.
I fear you will find,after a lot of pain, time and cost to replace your current fillings, your lichen planus will be unchanged.
I realize that this was not the answer you were hoping to hear but it would be unfair to you and unprofessional of me were I provide you with anything less than truthful and honest information.
Surely, you prefer that I tell the truth rather than what you wish to hear. Because it reflects very poorly on me unless you press one of the top three feedback choices, keep this in mind when rating my answer and please do not punish me for being honest. I understand that this may not be easy to hear, and I empathize.
Even though my answer was not quite what you were hoping for, please understand that my priority was to provide you with the most honest information. With that in consideration, I hope that you found my answer useful. Please click the excellent feedback button so that I can receive credit for my efforts.
Dr. Rick MD FACS