If the tooth is loose or shifting, an inlay should not be placed on it. When the tooth clearly requires a crown because simply replacing the cusps won’t provide enough support, a crown is the better option. If the cavity is very small and can be treated effectively with a traditional filling, then a filling is preferable. Additionally, if the gums around the affected tooth are swollen or show signs of infection, the tooth should be thoroughly cleaned and possibly undergo root canal treatment before an inlay can be placed.