A space maintainer is an oral appliance made to “maintain” the space left behind by a missing baby tooth. They are generally made out of metal or acrylic and can either be fixed into the mouth or removable. Fixed space maintainers are cemented into the mouth, while removable space maintainers look similar to orthodontic appliances and may even have an artificial tooth.

Their main function is to prevent the surrounding teeth from shifting into the space left by a baby tooth that was lost too soon. Once the permanent tooth begins to erupt, the space maintainer will be removed since it has served its purpose.