When a primary (baby) tooth is prematurely lost due to trauma or abscess, an appliance may need to be used to hold the space for the permanent successor. All twenty primary teeth are replaced with a permanent tooth.
If a primary incisor (front tooth) is lost before two years of age, an appliance with a false baby tooth may be used to hold the space and assist with proper speech development. These appliances can replace one or all four of the upper baby incisors. After age two, the appliance is primarily for esthetic purposes, although the space could still close if an appliance is not used. The upper permanent incisors usually erupt around six years of age, but some children are early with their tooth eruption and others are delayed. In addition to the esthetic considerations, one must consider the age-appropriateness of the child’s appearance. The early loss of a primary incisor in a four year old may not be as much of a concern esthetically as in a three year old. The ability for the child to cooperate for an impression (mold) of the teeth will ultimately determine if the appliance can be made for the child.
If a baby molar is lost due to abscess, an x-ray will determine when the permanent successor should erupt. The eruption status of the six year molars may also be an important consideration to determine the need for or design of the space maintainer along with the location of the tooth in the dental arch.
There are a number of different designs for space maintainers. The appropriate appliance will be chosen according to the eruption status of the permanent successor, the eruption status of the six year molars and the position in the jaw of the lost tooth.
The permanent tooth that replaces the lost tooth may erupt earlier than usual if the primary tooth is extracted due to an abscess. On the other hand, the permanent successor may be delayed, especially with early loss of an upper primary incisor.
Space maintainer appliances are cemented in place. They rarely may come loose and need to be re-cemented. The appliance can also break, requiring an additional lab fee to repair the appliance.
Once an appliance is cemented in place, it is the responsibility of the parent to monitor the eruption status of the permanent tooth. The space maintainer can interfere with or deflect the eruption path of an erupting tooth. As soon as the permanent tooth is ready to break through the gum or has just appeared, the space maintainer should be removed.