MATERIALS IN FOCUS: Titanium

Titanium: more complex than it looks

Titanium has been used in dental and orthopaedic implants for decades and is valued for its strength, corrosion resistance and biocompatibility. But “titanium” does not always mean one single material.
What is actually in a titanium implant?

Implants may be made from commercially pure titanium or from titanium alloys. One of the most widely used is Ti-6Al-4V, which contains approximately 6% aluminium and 4% vanadium. Other biomedical titanium alloys may include elements such as niobium, zirconium, tantalum, molybdenum or iron, depending on the properties required.

Even commercially pure titanium may contain trace amounts of other metals, including aluminium, manganese, iron, beryllium and nickel. This matters when investigating suspected metal hypersensitivity, because a reaction associated with a titanium implant may not necessarily be caused by titanium alone.


What does the research show?

A 2023 literature review examined reported cases of dental implant failure where allergy was considered a possible cause. Twelve studies were included, and several used patch testing, LTT/MELISA or both as part of the assessment.

Reported symptoms included eczema, swelling, gingival changes, cheilitis and mucosal pain. In some cases, symptoms appeared weeks or months after implant placement.

Ten papers reported improvement after titanium implants were removed. Some cases also described good outcomes after replacement with zirconia implants.


Why is diagnosis not straightforward?

The authors stress that there is still no single definitive test for titanium allergy. Patch testing and blood-based LTT/MELISA can contribute to the assessment, but both have limitations when titanium is being investigated.

The key point is that suspected titanium hypersensitivity needs to be considered in context: the patient’s symptoms, clinical history, implant composition and other possible causes of implant-related problems all matter.

Read the original study: Are Allergy-Induced Implant Failures Actually Hypersensitivity Reactions to Titanium? A Literature Review