Titanium Alloy for Dental Crowns in Patients with Metal Allergies
For patients with documented metal allergies or sensitivities, titanium alloys are the preferred material for dental crowns and should be used instead of cobalt-chromium alloys. 1
Why Titanium Alloys Are Superior for Metal-Sensitive Patients
Titanium alloys demonstrate significantly better outcomes in patients with metal hypersensitivity compared to traditional alloys. Patients with documented hypersensitivity to Co-Cr-Mo alloy who received titanium alloy components experienced substantial improvements in jaw function, diet, pain levels, jaw opening, headaches, disability scores, and overall quality of life. 1
Biocompatibility Profile
- Titanium forms a protective TiO₂ oxide layer that provides excellent biocompatibility and reduces allergic reactions. 1
- Approximately 10-15% of the population exhibits allergy to one or more metals commonly used in dental applications, making material selection critical. 1, 2
- Both commercially pure titanium (Cp Ti, 98.8-99.6 wt% Ti) and Ti-6Al-4V alloy have FDA approval for dental applications due to their optimal biocompatibility and mechanical strength. 1
Specific Titanium Alloy Options
Standard FDA-Approved Alloys
- Ti-6Al-4V (89.0-91.0 wt% Ti, 5.5-6.5 wt% Al, 3.5-4.5 wt% V) offers enhanced tensile and fatigue strength through thermo-mechanical processing, making it suitable for load-bearing dental restorations. 1
- Commercially pure titanium provides superior corrosion resistance due to the absence of alloying elements in its protective oxide layer, though it has lower mechanical strength than Ti-6Al-4V. 1
Newer Beta-Titanium Alloys for Highly Sensitive Patients
If the patient has documented sensitivity to aluminum or vanadium, consider newer beta-Ti alloys such as Ti-Zr-Mo-Fe or Ti-Nb-Zr-Ta, which incorporate nontoxic elements (tin, zirconium, tantalum, molybdenum, niobium) instead. 1
- These beta-Ti alloys form more stable protective oxide layers (Nb₂O₅, ZrO₂, or Ta₂O₅) that enhance corrosion resistance and biocompatibility. 1
- However, beta-Ti alloys have lower fatigue strength than Ti-6Al-4V, which may limit their use in high-stress areas. 1
Critical Pre-Treatment Screening Protocol
Before placing any metal restoration, perform pre-implantation screening via skin patch tests or lymphocyte transformation tests for patients with:
- History of intolerance to jewelry, belt buckles, or watches 1, 2
- Prior metal implant complications 1, 2
- Known metal allergies 1, 2
The lymphocyte transformation test measures lymphocyte proliferation in the presence of metal ion stimuli and can identify patients who might benefit from titanium-based restorations even when skin patch tests are negative. 1
Important Caveats
Titanium Can Still Cause Reactions
While rare, trace elements in titanium alloys (Ni, Al, V, Ti itself) may elicit allergic reactions in some patients. 1 This is why pre-implantation screening remains essential even when choosing titanium.
Processing Requirements
Careful selection of processing methods and laboratory skill are necessary to ensure success with titanium crowns. 3 Titanium and titanium alloys can be considered viable options to traditional noble and base metal alloys, but require specialized fabrication techniques. 3, 4
Surface Preparation
For optimal adhesive retention with titanium restorations, sandblast with 50-μm Al₂O₃ particles to create micromechanical retention and increase surface area for bonding. 5
Clinical Performance
Titanium and titanium alloy restorations fabricated with various systems demonstrate marginal gaps and internal fit within clinically acceptable ranges. 4 These restorations have less effect on periodontal tissues and show good long-term clinical performance when fabricated as monolithic restorations (avoiding metal-ceramic combinations which have higher ceramic fracture rates). 4