A baby teeth usually stays in the mouth till the permanent teeth underneath pushes it out and takes its place. A tooth might be knocked out accidently or removed because of dental disease. If a baby teeth is lost too early, the teeth besides may tilt or drift in the space. Teeth in the other jaw may move up or down to fill the gap. When adjacent teeth move into the empty space, they create a lack of space for the permanent teeth. A space maintainer may be required to prevent space loss and dental problems.