Resorption is the process of breaking down or dissolving tissues and the term is often used to describe the dissolving of hard tissues. Resorption is not an autoimmune disease or cancer. There are many types of resorption and it can be a very complicated subject.
Some types of resorption are normal. For example, in bone there are specialized cells (called osteoclasts) that are constantly dissolving bone, so that other cells (called osteoblasts) will have space to make new bone. This balance of breakdown and new growth is what allows bones to grow, heal, adapt to stresses, and atrophy. Orthodontists actually manipulate these processes in order to move teeth through the jawbones over time. Some types of tooth resorption are normal too, such as when the roots of a baby tooth resorb prior to falling out. Unlike bone however, tooth structure does not grow back once it is has resorbed.
Although there is a lot that is not known about Resorption, it is important to understand that almost all resorption occurs from these specialized cells doing their normal job, but in an abnormal location.
RESORPTION VS. DECAY
Similarities - Root resorption is similar to decay in that it results in a destruction of the hard substance of a tooth. That are also similar in that the location, the extent, and accessibility are generally the factors in determining whether or not the tooth can be saved.
Differences - Decay is caused by bacteria that dissolve the tooth, whereas resorption is facilitated by your own body’s cells. Decay usually occurs on the visible surfaces of the tooth, where as resorption occurs in the roots which are submerged deeper into the surrounding gums and bone.
TYPES OF RESORPTION
Resorption is generally divided in to 2 main categories - internal and external. As the names imply, internal resorption occurs from within the tooth, where as external occurs on the outer surfaces of the tooth. A Cone Beam CT scan is an invaluable tool for determining the type, location, and extent of the resorption. It has greatly improved the accuracy is assessing resorption and whether or not a tooth should be saved. Assessing resorption was previously much more difficult, uncertain, and may have even required exploratory surgery.
Internal - occurs generally from diseased pulp cells and arrests after the pulp loses its vitality and becomes necrotic. Typically endodontic treatment is all that is needed in a tooth with internal resorption.
External - is a more complicated category of resorption with many subtypes, but odds are if you have referred to a specialist to evaluate resorption, it it because of “external or cervical resorption”. The formal name for this resorption type is Extra-Canal-Invasive-Resorption (ECIR) and. Most dentists are reporting seeing an increase in the number of ECIR cases. One problem with ECIR is that it is very difficult to detect in its early stages. This is because there are typically no symptoms until the later stages, and because it can be very difficult to see on x-rays.
The tooth has natural protective layers that protect it against these normally occurring resorptive cells that exist in the surrounding bone. Certain factors, like trauma, can compromise these protective layers, allowing these cells to gain entry into the substance of the tooth and begin to break it down. Sometimes however, it occurs for no apparent reason at all. Other factors, like inflammation or active infection, can amplify the speed and the amount of destruction. As a general rule, the earlier resorption is detected, the better chance a dentist will have in helping you to stop it. Most often ECIR occurs on a single solitary tooth however there are infrequent cases where patients have ECIR on multiple teeth.