Titanium Allergy Caused by Dental Implants: A Systematic Literature Review and Case Report

Abstract

(1) Background: Hypersensitivity reactions to metals may arise in predisposed patients chronically exposed to metallic materials, including dental implants made of titanium alloys. The purpose of this article was to systematically review titanium allergy manifestations in patients treated with dental implants and report a clinical case; (2) Methods: A systematic electronic search was performed for articles published in the English language until July 2021. The following eligibility criteria were adopted: (1) Population: individuals undergoing titanium and/or titanium alloy implant-supported rehabilitations; (2) Exposure: peri-implant soft tissue reactions attributable to implant insertion; (3) Outcome: evidence of titanium allergy, diagnostic methods, and forms of resolution; (3) Results: The included studies, in summary, presented evidence that titanium should not be considered an inert material, being able to trigger allergic reactions, and may be responsible for implant failure. A 55-year-old male patient received 3 implants in the posterior region of the left mandible and presented an epulis-like lesion developed from the peri-implant mucosa. The immunohistochemical analysis of the biopsy specimen confirmed the initial diagnosis of allergic reaction to titanium; (4) Conclusions: Although the evidence is weak, and titanium allergy has a low incidence, hypersensitivity reactions should not be underestimated. A rapid and conclusive diagnosis is mandatory to prevent further complications.

Keywords: allergy; dental implants; hypersensitivity; peri-implant disease; titanium alloy.

Figure 1

Flow diagram according to the PRISMA guidelines summarizing the systematic screening process.

Figure 2

Clinical situation at baseline. (a) Intraoral view of the peri-implant lesion after 7 days of healing; (b) Intraoral view of the peri-implant soft tissues after biopsy of the lesion.

Figure 3

Histological analysis of the lesion. (a) Histological image showing inflammatory process, magnification: 10×, staining: hematoxylin and eosin; (b) Histological image showing polymorphonuclear cells (black arrows), magnification 100×, staining: hematoxylin and eosin.

Figure 4

Immunohistochemical panel of (a) TNFα, (b) IL1, (c) IL6, (d) IL17, (e) IL23, (f) IFNγ, (g) CD45 proteins, and (h) negative control, showing intense areas of allergic response labelling. Magnification 100×, staining: Harris’s hematoxylin.

Figure 5

Clinical situation during the healing phase. (a) Intraoral view of the peri-implant soft tissues and the plastic healing caps connected to the distal implants after 10 days; (b) Intraoral view at the 5-year follow-up recall.