Crowns are much more durable than fillings, and usually last until the baby tooth falls out. It is very important to repair and restore primary teeth. Although children begin to lose a few baby teeth by about six, they won't lose their baby molars until age 12 or 13. Why are caps put on teeth? Dentists install crowns to perform several important functions. They protect weak teeth, restore broken teeth, prevent cracked teeth from breaking further, and support teeth that have large fillings. ... Crowns restore the appearance, shape, and alignment of a damaged tooth