While looking through the 1911 CD, I found this bizarre advert appearing at roughly 40-page intervals. The classified entry (included below the main advert) spells the doctor's name as Schiffman rather than Shiffman. I think that the 107 N Spring address puts him in the Schumacher Block near First and Spring, although I haven't found any pictures.
LAPL
The same directory also lists a W W Schiffman Dental Co at 427 S Main - I wonder if they were related. I did find a picture of this one within an image previously posted by
Flyingwedge. By 1917, this Dr Schiffman was a close neighbor of the Rosslyn Hotel.
Detail of picture in
USC Digital Library