Selecting the right material for dental restorations is often overlooked, which can result in less-than-ideal outcomes. Here’s a breakdown of the key differences between zirconia and lithium disilicate.
Zirconia:
- Composition: 95% zirconium oxide (ZrO2), stabilized with 5% yttrium.
- Translucency: Zirconia has advanced significantly over the past decade and is now available in various translucency levels.
- UTML (Ultra Translucent Multilayer): Best suited for veneers and single crowns in anterior teeth, as well as bridges up to 3 units in the anterior region. It offers very high translucency but has the lowest strength among zirconias, with a flexural strength of 500-600 MPa.
- STML (Super Translucent Multilayer): Suitable for single crowns up to molars and bridges up to 3 units in both the anterior and posterior regions. It offers high translucency and medium strength, with a flexural strength of 700-800 MPa.
- HTML (Highly Translucent Multilayer): This option combines translucency with the highest strength, reaching up to 1200 MPa, making it suitable for crowns and bridges of any length.
- Durability: Extremely durable, making it ideal for areas with heavy chewing forces.
- Wear: Zirconia is harder than natural enamel, which can lead to significant wear on opposing teeth.
- Advantages: Excellent mechanical properties, making it ideal for long-span bridges.
- Appearance: Improved aesthetics, but it lacks natural fluorescence.
Lithium Disilicate:
- Composition: Made from lithium disilicate crystals embedded in a glass matrix.
- Translucency: Available in a range of translucency levels, from low to high, including opaque options. It’s generally more translucent than zirconia, though it also lacks natural fluorescence.
- Strength: Offers good overall strength, with a flexural strength of 400 MPa.
- Durability: Suitable for crowns, veneers, inlays, onlays, and bridges up to 3 units in anterior and posterior areas with low biting forces.
- Advantages: Its high translucency makes it perfect for anterior restorations.
- Appearance: Closely mimics the color and transparency of natural teeth, making it highly aesthetic.
