A baby tooth acts as a guide for the permanent tooth that replaces it. If a primary tooth is lost too early, the permanent tooth loses its guide and can drift or erupt incorrectly into the mouth. Neighbouring teeth also can move or tilt into the space, so the permanent tooth can’t come in. The result is crooked or crowded teeth.
To prevent that, your dentist can insert a space maintainer to hold the spot left by the lost tooth until the permanent tooth comes in. The space maintainer might be a band or a temporary crown attached to one side of the vacant space. Later, as the permanent tooth emerges, your dentist removes the device.