Physical Properties
Mechanical Properties: The sintered powder of lithium disilicate microcrystalline glass has a bending strength of up to 450-650MPa, a Vickers hardness of about 5-6GPa, and a fracture toughness of 2-4MPa・m¹/². Compared to traditional feldspathic ceramic (bending strength of about 100-150MPa), its mechanical properties are significantly improved. During a three-point bending test, lithium disilicate microcrystalline glass can withstand greater loads, demonstrating excellent deformation and fracture resistance.
Melting Point: Theoretical melting point is approximately 986°C, but as microcrystalline glass, the sintering temperature is usually between 700~900°C. Grain size and distribution can be adjusted by controlling the crystallization temperature.
Thermal Properties: Coefficient of thermal expansion ranges from 9.5-10.5×10⁻⁶/℃ (25-300℃), close to human teeth (approximately 11×10⁻⁶/℃), suitable for dental restorations, reducing cracking caused by thermal stress. By adjusting the ratio of alkali metal ions such as Li⁺ and Na⁺, the coefficient of thermal expansion can be precisely controlled to 6-12×10⁻⁶/℃, achieving good thermal matching with materials like metals and ceramics.
Heat Stability: Resists softening at high temperatures, suitable for long-term use at 300~500°C, with short-term resistance exceeding 800°C.
Grain Size: After crystallization, lithium disilicate crystals are needle-like or plate-like, typically measuring 0.5~2μm, uniformly distributed within the glassy matrix, imparting strength and toughness to the material.
2. Chemical Properties
Acid and Alkali Resistance: Resistant to dilute acids (such as citric acid,Acetic AcidIt has good tolerance to neutral solutions, but may experience slight corrosion when soaked in strong alkaline solutions (such as NaOH) for extended periods. Its chemical stability surpasses that of traditional glass.
Water resistance: Meets ISO 7405 dental material water resistance standard, suitable for oral moist environment.
Biocompatibility (Non-toxicity): Passed biocompatibility tests (such as cytotoxicity, sensitization tests), suitable for dental restorations (like all-ceramic crowns), and has good affinity with human tissues.
3. Mechanical Properties
Bending Strength (Strength and Hardness): Up to 300~500MPa (common glass is about 50~100MPa), even exceeding 600MPa after optimization through crystallization process, approaching the strength of metal alloys.
Compressive Strength: Approx. 1200~1500 MPa, Hardness (Vickers): 300~400 HV, excellent wear resistance, suitable for long-term chewing pressure.
Fracture Toughness (KIC): Approximately 3~5 MPa·m¹/², higher than standard glass
