In the breakfast scene where Annie is wrestling with Helen it shows a candle cover knocked down from a table against the wall. Seconds later, when Annie somersaults out of Helen's grip- it shows it back upright in it's original position. As Annie pulls Helen back to get her spoon, the cover in on the floor again.
During the infamous breakfast scene, while struggling to get Helen back to the table to eat with a spoon, a (presumably) glass candle cover is knocked down from a table against the wall. The sound of plastic hitting the floor is distinctly heard and the cover does not break. It appears again later in the welcome home dinner for Helen. Plastic was not used during the time the film takes place.