In dentistry charts, the letter "M" symbolizes this major tooth type
[DOC] [TLE] A new website to aid the interpretation of ante-mortem dental records [PAR] Dec 2, 2014 ... decoding international ante-mortem dental charts for INTERPOL's ... A letter was 
sent to the national dental associations of the 188 ... dental chart represents a 
particular .... the type of dental notation (FDI, Universal System, etc).