Dental Implants Metal Allergy
Dental implants are considered the optimal type of dental restoration for many people and most closely resemble the natural tooth in durability, stability, and appearance. Dental implants replace missing teeth, but they also replace missing tooth roots, using a small cylindrical post that is surgically embedded into the bone. These metal posts are usually made of titanium, a metal that is highly biocompatible and easily integrated into the bones of the jaw for most people. Titanium is a popular choice for implants used in both dentistry and medicine, largely because of its unique and specific ability to permanently bond with natural bone. This specific feature of titanium was first observed in the 1950s, and the material was first used in dental implants in the 1960s. Titanium encourages the growth of healthy bone cells, encouraging healthy bone to grow around the dental implants as the implants heal. This process of the dental implant fusing together with the surrounding bone is called osseointegration. When osseointegration occurs, the bond that is formed between the implant and the bone becomes permanent, and, when cared for properly, dental implants can be expected to last a lifetime, functioning as a permanent part of the mouth. For people who have metal allergies, however, titanium can lead to complications. The good news is that people with metal allergies can often still be good candidates for dental implants, thanks to material and technological innovations in dentistry.
A metal allergy, like any type of allergy, manifests in the immune system overreacting to a foreign substance that has been introduced into the body. Some allergic reactions are relatively minor and merely cause mild discomfort, like a minor rash, until the allergen is removed, while other allergies can be life-threatening. Any material that is introduced to the body can induce an allergic reaction -- including metals. In most cases, when a person is allergic to a metal, they are allergic to a specific kind of metal. Nickel is one of the most highly allergenic metals, and cobalt and chromium are also more commonly allergenic than other metals. Exposure to metal is usually external, as with jewelry, which can lead to a rash on the skin. When the metal is inserted into the body, however, as with a prosthesis, and the person is allergic to that metal, the body will reject it.
Many dental procedures rely on one or more kinds of metal; the most commonly known procedure that often uses metal is the dental filling, which usually uses a dental amalgam made of silver or gold mixed with copper, tin, and small amounts of mercury. Dental amalgam can be used without incident in a vast majority of patients, though there have been some cases of rashes or inflammation being caused by dental amalgam. Another common dental procedure that relies on the use of metal is the dental implant, which primarily uses titanium. Titanium is an indispensably important metal when it comes to medical and dental applications, largely because of its biocompatibility. Titanium has been found to encourage the growth of healthy bone cells, which easily bond with the metal and create a strong connection and a durable base for the pressures exerted on the teeth when speaking, biting, and chewing. Titanium allergies are exceedingly rare, and there are tests available to determine a person’s potential allergies before any implant procedure takes place. When allergy is present, common reactions include bumps or hives inside the mouth, patches of dryness on the gums, swelling or inflammation of the tissues surrounding the implant, and swelling or sores in the soft tissues of the mouth. Before implants are placed, some dentists use a simple skin patch test to determine whether a patient is allergic to titanium, while others use a more comprehensive blood test, called a MELISA test. The MELISA test exposes only the white blood cells to titanium and then measures their immune response to determine whether an allergy is present. The MELISA test is considerably more accurate than skin patch tests, though either can determine whether a titanium allergy is present.
When a titanium allergy does exist, alternatives to titanium can allow allergic patients to safely receive dental implants. The most widely appreciated and used alternative to titanium in dental implants is zirconia. Zirconia is a highly inert, non-metallic ceramic material that presents an extremely minimal risk of allergic reaction. Zirconia is strong and anti-corrosive, and it is a highly hygienic material that resists the accumulation of plaque. Zirconia also provides aesthetic benefits that titanium may not. When titanium implants are used, some grayish metal may be visible through the thin tissue of the gum, creating a darkened appearance at the base of the crown. Because zirconia is a naturally white, ceramic material, it won’t cause any discoloration to show through the gums like titanium might. For this reason, zirconia can be a particularly beneficial material for restorations of the teeth at the front of the mouth or in other situations where aesthetics are particularly important. Zirconia implants were first introduced into dentistry in 1987 and have become more and more widely used since then. Because its use in dental implant procedures is relatively new, however, some dental practitioners may not yet offer zirconia implants, though positive feedback from patients who have received zirconia implants are helping broaden its availability, and, as more and more technological innovations take place, zirconia can be expected to become even more widely available in the coming years.
Although it is highly unlikely, some patients can be allergic to both titanium and zirconia. If this is the case, these patients may be best suited for dental bridges. A dental bridge uses two crowns, one on either end, to support a bridge that contains one or more natural teeth and fills the gap created by missing teeth. Dental bridges don’t use implants as their support and therefore do not require that any metal at all be implanted into the bone. This makes them an entirely non-allergenic option for people who wish to replace one or more natural teeth with a durable and natural-looking dental prosthesis.