Why Are Dental Implants Categorized into Grade 4 Pure Titanium and Grade 5 Titanium Alloy, And What Are the Differences Between Them?
Titanium Materials for Dental Implants Have Different Grades
Many people considering dental implants are concerned about how to choose the right implant, especially when encountering terms like "pure titanium," "titanium alloy," "Grade 4 pure titanium," or "Grade 5 titanium alloy," which can be confusing. Given that we've previously discussed pure titanium, today we'll delve into pure titanium versus titanium alloy, specifically exploring the differences between Grade 4 pure titanium and Grade 5 titanium alloy for dental implants.
Different Materials and Properties of Dental Implants
Before discussing the differences between Grade 4 and Grade 5 titanium for implants, let's first understand the material properties of implants.
1. Compositional and Structural Differences
| Feature | Grade 4 Pure Titanium | Grade 5 Titanium Alloy, Ti-6Al-4V |
|---|---|---|
| Component | Over 99.5% pure titanium (containing trace amounts of oxygen and iron) | Titanium (90%) + Aluminum (6%) + vanadium (4%) |
| Crystal Structure | α phase (closely packed hexagonal structure) | α+β duplex (higher intensity) |
Key points:
• Grade 4 pure titanium is a single alpha phase, offering excellent biocompatibility but lower strength.
• Grade 5 titanium alloys form an α+β duplex phase through the addition of aluminum and vanadium, significantly improving mechanical properties.
2. Comparison of Mechanical Performance
| Capability | Grade 4 Pure Titanium | Grade 5 Titanium Alloy |
|---|---|---|
| Tensile Strength, MPa | 550-700 | 900-1200 |
| Yield Strength, MPa | 480-550 | 800-1100 |
| Modulus of Elasticity, GPa | 104-110 | 110-125 |
| Ductility, Elongation at Break | 15-20% | 8-15% |
3. Biocompatibility and Safety
Grade 4 Pure Titanium:
- • The titanium dioxide passivation film formed on the surface of pure titanium is more stable, resulting in virtually no biological rejection and a very low risk of allergy.
- • International standards (ISO 5832-2) explicitly recommend it for medical implants.
Grade 5 Titanium Alloy:
- • Aluminum and vanadium may trigger sensitivity reactions in a very small number of patients (point of contention: some literature reports potential toxicity of vanadium ions, but modern processes have reduced this risk through surface treatment).