How strong is lithium disilicate?

For restorative dentists selecting a ceramic material, the 360-400 MPa flexural strength range matters most in context: posterior single-unit crowns handle average occlusal loads of 400-800 N depending on the patient. Lithium disilicate sits at the upper edge of what all-ceramic materials can reliably sustain in those positions. A well-milled, properly bonded lithium disilicate crown in a first-molar position performs predictably, provided the prep design maintains at least 1.5 mm of axial wall reduction.

The material's strength comes from interlocking lithium disilicate crystals that make up roughly 70 percent of the glass-ceramic matrix by volume. That microstructure is what separates it from leucite-reinforced glass ceramics, which top out around 160 MPa. The trade-off is translucency: higher crystal density reduces light transmission, which is why some technicians layer a thin feldspathic cap on the facial surface for anterior cases where optical depth matters more than bulk strength.

For prosthodontists managing full-arch rehabilitation cases, lithium disilicate is typically reserved for anterior segments where esthetics outweigh load demands. Posterior implant-supported units or molar-to-molar spans shift the conversation toward monolithic zirconia, which reaches 900-1200 MPa in high-translucency grades. Knowing where each material fits lets the lab and the clinician plan the case together before any prep begins.