Bacteria, that are normally present in the mouth, convert all foods, especially sugar and starch, into acids. The acids, produced by the bacteria, dissolve the enamel, which is the surface of the tooth, resulting in holes that we call cavities. Cavities are usually painless until they get close to the nerve inside the tooth. Once you start feeling pain from a cavity, in most cases, it is too late for conservative treatment, and a root canal is needed. In some cases the tooth can actually become weak and fracture.
If a cavity is left untreated, the nerve becomes compromised, the bacteria gets into the vascular system of the tooth and creates an infection, called an abscess. This could ultimately result in the loss of the tooth. There are different severities of tooth decay. If the decay is extensive, a simple filling may not be enough so the doctor will suggest a root canal and crown.
Treatment of cavities involves multiple steps that frequently commence with the dentist, numbing the tooth to be filled with a local anesthetic. Next, a drill, air abrasion instrument, or laser will be used to remove the decayed area. After the decayed portion of the tooth has been removed, it will be filled with one of several filling material. Patients have the option of having their teeth filled with gold, porcelain, silver amalgam (which consists of mercury mixed with silver, tin, zinc, and copper), or tooth colored composite resin.
Gold and porcelain are the best restorative materials, but because of the cost, the most commonly used and recommended material is composite resin. Although silver amalgam fillings are less expensive, there are distinct advantages to composite resin. Composite resin can be color matched to existing teeth so it can go virtually undetected, which makes it a great choice for the teeth in the front of the mouth, that are readily seen during talking and smiling.
This type of filling is more aesthetically pleasing than the silver amalgam fillings. Composite fillings actually chemically bond to the tooth structure itself, where amalgam fillings are a mechanically retained restoration, that can expand the tooth, causing it to crack or break. The fact that composite chemically bonds to teeth allows the doctor to remove only the portion that is decayed, where placement of amalgam requires removal of some healthy portions of the tooth. The last argument for composite fillings over amalgam fillings is the age-old controversy about whether amalgam fillings are really safe for us.
One of the major components of amalgam fillings is mercury, and even though the ADA and the FDA have deemed them safe, there are still concerns about low levels of mercury vapors, released by the fillings. In the end, composite fillings allow us to restore our teeth while keeping that natural beautiful look.