1-Fixed space maintainer
Generally, a fixed space maintainer is a semi-permanent tooth fixture that keeps enough space open for the adult tooth to grow. After the permanent tooth has grown in, your dentist can remove the space maintainer.
Depending on the case, a pediatric dentist can use one of the four types of fixed space maintainers to care for your child’s teeth.
These different types are:

Crown and Loop
These dental devices have mainly two pieces, a crown(placed over one tooth) and a stainless steel wire loop.
Usually, dentists use this type for maintaining space in cases of premature loss of a single tooth.
The loop presses against the tooth on the other side of the gap(space) and keeps enough room for the new tooth. Once the new tooth correctly grows in its place, the dentist will remove the crown and the loop.

Distal Shoe
Distal shoe space maintainers have two main parts: the crown and the extension(vertical bar).
After a baby molar falls out prematurely, your dentist will insert the maintainer into the gum line to guide the unerupted adult molar as it grows.
Dentists use this type of space maintainer only for permanent first molars that have not grown in yet. Unlike other space maintainers, the drawback is that it requires extra care and attention from your child’s dentist.
If your child’s case calls for a distal shoe maintainer, it will be necessary for you to schedule regular check-ups with your dentist to observe the progress and ensure a good result for the treatment.

Lingual
Lingual space maintainers use wire and crowns to maintain spacing across several teeth gaps.
Usually, dentists use this type of maintainer in pediatric dentistry cases with congenital disabilities that lead to teeth loss in children.

Unilateral
This type of space maintainer is similar to the crown and loop space maintainers. Still, unlike in crown and loop space maintainers, the dentist wraps the unilateral maintainers’ wire part around the teeth on one side of the gap(fixed to one side of the mouth).

2- Removable

Removable space maintainers are dental devices usually made of acrylic material. They are very similar to the ones used in orthodontic treatments. Your dentist can fit them with a fake tooth and customize them for your child’s needs.
Removable maintainers are usually less effective at maintaining space compared to fixed ones. Still, removable space maintainers can be the ideal option for your child if his tooth is almost ready to grow in its place.
Removable maintainers also help your child keep good oral hygiene habits(brushing and flossing).
You can always ask your dentist about the best option in your child’s case.

Space maintainers help your teeth grow in their spaces naturally without becoming crooked(which usually happens when a baby tooth falls out prematurely).

Make sure you consult a pediatric dentist if your child loses a tooth prematurely, and they will tell you what’s best for your child’s case.