NEW : Claudia Rivera teacher Vance Miller pleads not guilty . The L.A. school board fires him . In unrelated case , the board fires a high school teacher after sexual misconduct claims . In all , 3 Los Angeles teachers face sexual misconduct accusations since October 2010 .
NEW : Miramonte Elementary School teacher Martin Bernard Springer pleads not guilty . The Los Angeles school board fires him . In unrelated case , the board fires a high school teacher after sexual misconduct claims . In all , 3 L.A. teachers face sexual misconduct accusations since last week .