Here’s a dentist ad from the January 7 1925 edition of the Toronto Daily Star:
Those teeth look kind of gross, actually.
Dr. Boyle appears in Toronto city directories up to 1927. I don’t know what happened to him after that. One clue is that the 1925 directory lists his home address as well as his work address, but the 1927 directory does not – this suggests that he moved out of town. The 1928 directory doesn’t provide a listing for his widow, which supports this hypothesis, I think.