This person shares his name with another : Chief William Finley Semple, Sr. (Choctaw Nation)
This William Semple was a dentist in Ohio, as was apparently the grandfather of the other William Semple: http://familytreemaker.genealogy.com/users/p/r/i/Lynn-M-Price-KY/WE...
Could they be uncle and nephew? The link of the two last names Finley and Semple with Ohio dentistry must surely be somewhat rare?
Arild Tørum