If a tooth falls out due to injury or decay, a space maintainer may be needed to hold the place of the tooth. If a space maintainer is not put in the vacant space the surrounding teeth can crowd and take over that space. This makes the permanent tooth come in crooked or crowded which can cause difficulties in chewing and talking. A space maintainer can be a band or crown attached to another tooth. When the permanent tooth starts to grow in, the dentist can remove the space maintainer.