Literally a 'dens in dente'.
Norton
M R
MR
London Hospital Medical College.
D000328:Adult; D003719:Dens in Dente / Q000601:surgery*; D006801:Humans; D008297:Male; D008437:Maxilla; D008964:Molar, Third / Q000002:abnormalities* / Q000601:surgery; D014081:Tooth Extraction; D014096:Tooth, Supernumerary / Q000601:surgery*