Space maintainers are used when children have lost their primary teeth prematurely, sometimes this occurs naturally with a tooth that fell out or never came in. If a tooth that is not restorable is extracted and the permanent tooth will not come in soon this appliance must be used to hold the space. The space from the missing tooth can creates shifting of the adjacent teeth, or even prevent the permanent teeth from erupting normally. Space maintainers are custom dental appliances made of  metal and act as place holders. They are made in a dental laboratory and  cemented on adjacent healthy teeth to hold the space and allow for natural tooth eruption.