A crown buildup is essentially a large filling that is used to replace enough missing tooth structure to retain a crown (or cap). Most teeth that require a crown (or cap) are broken down due to a large cavity or fractured cusp. Depending on the amount of missing tooth structure, there are times that there is not enough tooth remaining above the gums to allow a crown to grab hold of. Even though a crown is glued on, there must still be enough tooth structure present to provide a friction fit since the glue is not strong enough to bear the brunt of one’s bite.
Teeth that have undergone root canal treatment usually need crown buildups. This is because by the time the inner surface is removed to provide access to the root canal space and the outer surface is removed to provide space for the porcelain, there is not much tooth structure left to retain a crown.
Broken tooth with a buildup
There are different materials available for crown buildups: composite (tooth-colored filling material), amalgam, and glass ionomer. I prefer the glass ionomer because it leaches fluoride into the surrounding tooth structure. This makes the tooth more resistant to decay. This is an important feature since decay sneaking up under a crown can be its achilles heel. A crown that is placed on a properly constructed crown buildup should give a person decades of service.
The gum line (cervical area) is a common location for fillings to be needed. They can be needed due to decay, toothbrush abrasion, erosion, or abfraction. Cavities along the gum line are totally preventable with good oral hygiene on a daily basis. Toothbrush abrasion is another preventable reason for needing cervical fillings. Chemical erosion can dissolve tooth structure. It is most common on any exposed dentin since dentin is significantly softer than enamel and the gum line is where most of the exposed dentin will be. Chemical erosion can come from acidic foods or reflux of stomach acids. Abfraction is thought to be caused by tooth flexure from biting and chewing forces. It is postulated that tiny particles of tooth structure fracture off at the cervical area eventually getting deep enough that it would need to be repaired. There are two types of materials used to restore cervical defects – composite and glass ionomer. Glass ionomer is most helpful in individuals with a high cavity rate. The glass ionomer will leach fluoride into the surrounding tooth structure making those areas more decay resistant. Unfortunately, glass ionomers are not very wear resistant and need to be replaced frequently. The other material that is used for gum line fillings is composite, the one that is normally used for tooth-colored fillings. Since the composite doesn’t leach fluoride, it tends to get small cavities around its edges and must be replaced frequently. The best thing to do is prevention by gentle tooth brushing along the gum line on a daily basis.