Dental Implants and Metal Allergy

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Dental implant The medical literature suggests that cutaneous reaction to orthopedic metal implants in the knee or hip can occur in the form of skin reactions such as eczema or allergy that is manifest as urticarial, bullous, or vasculitic skin eruptions. There may also be delayed-type hypersensitivity reactions that cause medical problems such as in-stent restenosis, prosthesis loosening, inflammation, pain or allergic contact dermatitis. Dental implants may be subject to the same problem of allergy.

In an article published in Dermatitis, authors J Basko-Piluska, J Thyssen, and P Schalock (Dermatitis, 2011; 22(2):65-79), review  cutaneous and systemic hypersensitivity reactions to metallic implants. They report that such cutaneous reactions have also been associated with dental implants. In a subsection with the heading ‘Allergic Contact Dermatitis from Dental Implants and Prostheses’ they list a number of dental products that have been reported to cause contact dermatological diseases or lichenoid-type disease including dental implants.

However in this section, only one case study with an N of 1 is used to support their speculation regarding dental implants (Pegatto and colleagues, J Eur Acad Dermatol Venereol, 2008;22:124-126). This particular citation describes a 48-year-old female who develops generalized eczematous type lesions on her skin after the placement of titanium dental implants and later a dental prosthesis containing chromium-cobalt alloy. The authors note that subsequent patch testing revealed a number of different metals that could cause allergy including dental amalgam, nickel sulfate, and palladium chloride.

In the medical literature there are few prospective longitudinal studies assessing the association between metal sensitivity and cutaneous allergic reactions. Regardless, what these studies suggest is that approximately five percent of patients receiving orthopedic implants develop cutaneous reactions upon re-exposure to the same metal (Y Niki, et al. Screening for symptomatic metal sensitivity: a prospective study of 92 pateints undergoing total knee arthroplasty.  Biomaterials, 2006;26:1019-1026). In contrast, a prior study of 18 patients assessed over six years did not reveal any complications even though they had confirmed allergy to at least one of the metals in the devices that were place (Carlsson and Moller, 1989). A review of the Pubmed database indicates that to date there are no published prospective longitudinal studies addressing the question of titanium dental implants and allergy.

However there are a number of published case studies. In a recent review titled ‘Is titanium sensitivity associated with allergic reactions in patients with dental implants? A systematic Review’ author F Javed, and colleagues from the College of Dentistry at King Saud University, Riyadh, Saudi Arabia and the School of Dental Medicine at the University of Connecticut and Eastman Institute for Oral Health at the University of Rochester, NY, USA, report the results of seven ‘qualified’ studies that address the question of allergy and dental implants. Of these seven, six are clinical reports and one is experimental in nature.

As noted, these articles were basically case reports in which Titanium (Ti) implants, inserted into the mandible appeared to cause dermal inflammation and gingival hyperplasia. In one case there was swelling in the submental and labial sulcus and hyperemia of the gingival soft tissue. Unfortunately, only two studies used patch testing to confirm a diagnosis of allergy to titanium metal. Even with memory lymphocyte immunostimulation assay and lymphocyte transformation testing the authors concluded that “the significance of Ti as a cause of allergic reactions in patients with dental implants remains unproven’.

An article published in the Journal of Prosthetic Dentistry, 2008 (J Prosthet Dent. 2008; 100(5):344-347) provides an additional case report involving a patient who developed facial eczema in association with the placement of two titanium implants to support a mandibular overdenture. As reported by H Egusa, T Shimazu, and H Yatani of the Osaka University Graduate School of Dentistry, Osaka, Japan, removal of the implants resulted in a complete remission of the dermal lesions.

In a recent study involving 35 subjects out of 1500 implant patients examined between 2002 and 2004, authors A Sicilia et al, in Clinical Oral Implants Research, 2008 (August;19(8):823-835) report that 16 developed ‘allergic symptoms’ after implant placement or unexplained implant failures.  Nineteen had a history of other allergies and/or were ‘heavily’ exposed to titanium during surgery or had explained implant failures. In these patients cutaneous and epicutaneous tests were used to assess for allergy. Thirty-five randomly selected patients served as controls.

What was found was that only 0.6% of patients showed positive reactions to the titanium allergy tests. But those with ‘allergic symptoms’ post placement or unexplained implant failure had a significantly higher risk of positive allergic reaction that the others. This data suggests the possibility that implant failure can be associated with allergy to titanium or other metals used in prosthetic manufacture.

This potential is further supported by a case study published by  LA du Preez, KW Bűtow, and TJ Swart in SADJ (2007;(1)22:24-25).  Six titanium implants were place in the anterior mandible in a 49 year old female patient. All were composed of the same grade of titanium and were of three different  types. Post placement the patient developed a ‘severe reaction’ that involved both periodontal and bone complications. Subsequent pathology revealed an inflammatory response with fibrosis and giant cell reactivity within the tissue. Once the implants were removed the tissue changes were reversed and there was satisfactory healing.

The dental literature is essentially devoid of research assessing implant failure as a result of allergy to titanium or the other newer materials used in fabricating these prosthetic devices. This is in contrast to the orthopedic literature which provides many citations related to hip, knee, and other implant failures thought related to allergy to metal. Nonetheless, even in the face of case studies or case series, the degree to which ‘metal sensitivity’ or allergy contributes to hip and knee implant failure remains very controversial.

The dental literature related to allergy and implant failure doesn’t even rise to the level of a ‘controversy’. There is just too little data to make meaningful conclusions. However, as has been recommended in the orthopedic literature, in patients that develop a cutaneous or mucosal problems months to years after receiving a titanium metal implant there should be patch testing to rule out allergy. And it would seem worthwhile to include in the history prior to surgery, questions about possible allergy to metal and if these are positive, appropriate patch testing or optimized lymphocyte transformation testing (MELISA) should be considered; even if these tests are often ambiguous.

Submitted by Dr Jeff Burgess