Side effects of Dental Implants

Dear Doctor,
I am interested in getting a dental implant to replace a missing tooth. However, I have metal allergies so I'm not sure if this is possible. What should I do?

Dear Bart,
Allergies to metals (elements) and metallics (alloys – compounds of two or more metals) can cover a lot of ground and really can open the proverbial can of worms. So let's give you a short overview for the sake of clarity. Allergy is a response of the body's immune (resistance) system that recognizes substances, whether living or non-living. Four types of allergic reactions are known which includes initiation of a specific (antibody) response to the offending entity. When the normally protective immune system, which defends us from bacteria, viruses, pollens and more causes an exaggerated response that is not protective, it is known as allergy. Allergic responses can be as minimal as a mild rash to, in rare cases, death from a multi-system shutdown known as anaphylaxis (“ana” – without; “phylaxis” – protection). You can become allergic to virtually anything, and at any time, including metals.

It has been reported previously that more than 5% of the population experiences allergic reactions to metallics. More recently, it has been reported that 17% of women and 3% of men are allergic to nickel and that 1% to 3% of the people are allergic to cobalt and chromium. Among dermatitis patients, (“dermat” – skin; “itis” – inflammation), the prevalence of metal allergy is even higher. Environmental exposures to metallics include jewelry, buttons, clothing fasteners, dental restorations, mobile phones, and more. Consumer exposure is responsible for most cases of metal allergy, even more than occupational exposure. Traditionally, nickel, cobalt, and chromium have been the most important contact allergens. However, recently, gold and palladium (primarily alloys that contain more than one metal) have drawn more attention, as the prevalence of contact allergy to these alloys is recognized. In the United States, studies show that the prevalence of nickel allergy is increasing. Furthermore, metal allergy has been associated with some device failures following placement of stents into coronary (heart) blood vessels, hip and knee prostheses, as well as other implants. These numbers are relatively small when compared with numbers of applications, however more research is needed in this area.

The above illustration shows the assembly necessary to restore an implant with a crown. The assembly consists of an abutment with a screw that fits into the implant and a permanent crown, which is then cemented onto the abutment.

The American Dental Association (ADA) reports that, for many years, the only available choices for dental fillings were metals and alloys. Traditionally, these were gold alloy or “amalgam, ” a mix of approximately 43% to 54% mercury with other metals, including silver, copper and tin. Because of the development of other “tooth colored” materials today, amalgam is used most commonly in the back teeth. It is one of the oldest filling materials, used and improved upon for more than 150 years, and is the most thoroughly researched and tested filling material. In rare cases, a localized allergic reaction such as inflammation or rash may occur with its use.

That gets us to the topic of dental implants. Dental implants are generally made of commercially pure titanium or titanium alloy. One aspect of titanium and alloy is that they are osteophilic (“osteo” – bone; “philic” – loving) and therefore very biocompatible. Because of this, dental implants have had a truly amazing track record of success. A recent study in Clinical Oral Implants Research reported that in dentistry, allergic reactions to titanium implants and the associated intraoral prostheses have not been studied in great detail. However, placing metallic dental implants and associated restorations can potentially provoke allergic reactions. The study, involving 1, 500 patients, reported that titanium allergy could be detected in dental implant patients, even though its estimated prevalence is low (0.6%). A significantly higher risk of positive allergic reaction was found in patients who had lost implants for no other known reason other than that they had a higher incidence of allergy, in which case testing could be recommended. However, this issue is confounded by the use of many different metallics and other materials as a part of the overall implant construction.

As for replacing your missing tooth, a dental implant is an excellent long-term option, given today's advanced knowledge about dental and oral health. The ADA states that, whenever something foreign is put into your body, there is a chance of side effects. Thus all biomaterials (implants) and other dental materials used in the mouth may cause localized allergic reactions in a very small number of individuals. This is why your dentist needs to know about your allergies. It may be an important part of determining what the right material is for you. We hope that you receive the tooth you want and deserve without any fear of metal allergies.

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