14th President: Franklin Pierce, 1853

Tar = 14 (Pierce was the 14th president)

Pierce with a drill = Pierce

Film = 853 = 1853 became president

Frankenstein = Franklin

The tar(tar) (14) on the patient's teeth was so thick the dentist couldn't pierce (Pierce) it with his drill; it was a solid film (853).

Connect Pierce to Franklin

The patient whose tartar the dentist couldn't pierce (Pierce) was actually Frankenstein. Frankenstein has a scar, like a line, on his forehead (Frank + line = Franklin).

NOTE: The way Mammoth Memory remembers Frank is to think of Frankenstein.