Especially once one has seen a few imitation pearls in person and knows what to look for, there is no need for a tooth test! One can gently rub one pearl gently against another to check for grittiness, my preferred method. Some faux pearls are gritty from d i r t, not something I want in my mouth.
Agreed, there are many examples of vintage genuine akoya and Mikis that are strung or mounted on sterling silver and employ the bead tips finish.
Many of the older faux pearls like these can be cleaned and restrung, restoring much of their former attractiveness and honoring their sentiment value. I so wish I still had my Mother's long strand of imitation pearls; she wore them for many, many years.