When a baby tooth is significantly destroyed from dental caries, then a simple filling could not restore it and protect it from the mastication forces. For that reason, like in the permanent dentition, we need to place a crown on top of it to protect it. The crown is placed on top of the tooth after the dentist drills it. With a crown we avoid getting caries again or having the tooth fractured. They do not interfere with the permanent tooth AT ALL and the fall with the tooth when it is the right time for exfoliation.
The crowns from primary teeth are pre-made and they come in two materials:
Stainless steel crowns: They are very high tolerance crowns. They are very easy to fit on the tooth so the time we need to place them is limited. They are also low cost crowns. They are recommended for teeth that the decay has destroyed most part of the tooth because they have great retention even with minimum tooth structure. They have very poor aesthetics though
Zirconian Crowns (Porcelain Crowns): Happy Tooth Dental Clinic provides the option of placement of prefabricated porcelain crowns in the primary teeth. They have great aesthetics (like a natural tooth) but they also have disadvantages. They need adequate tooth structure in order to have good retention so they cannot be placed on deeply carious teeth. The placement is a very long and thorough procedure so we should have the cooperation of the patient (on chair or under sedation). Because they are prefabricated porcelain crowns they are prone to fracture. In cooperative children though, the aesthetic result is excellent!
This picture shows prefabricated Zirconia crowns on back teeth: