Sometimes a primary tooth is lost before the permanent tooth beneath it is ready to erupt. The most common causes for this are cavities and injuries. If your child loses a tooth prematurely we may recommend a space maintainer. A space maintainer is an appliance that holds open the space left by the lost tooth.The space maintainer helps prevent the nearby teeth from shifting into the vacant space. If this happens, when the permanent tooth is ready to erupt may not have enough room or may erupt in a wrong position.Once the spacer is in place, the eruption of the permanent tooth is monitored and when the time is right, the spacer is removed.