They are called Mee's lines.

Page 62 of "Amalgam illness"

"All heavy metals cause Mees' lines on the nails. these usually
begin a few months after significant exposeure starts and may be useful in identifying the source of exposure - dental amalgams or some unregcognised source - if you remember when they started."

I did Google "Mees lines" and the pictures look like the ridges on my nails, so i assume i have them.
<img src="/ubbthreads/images/graemlins/aok.gif" alt="" />

"All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third it is accepted as being self-evident."

Sunshine