What is lithium disilicate?

Lithium disilicate runs around 400 MPa flexural strength with high translucency; monolithic zirconia hits 1,200+ MPa but transmits less light. The practical split: lithium disilicate for anterior crowns, veneers, and short-span bridges where esthetics dominate. Zirconia for posterior crowns and full-arch bridges where load capacity dominates. Many anterior cases use lithium disilicate over a zirconia substructure to capture both properties. At Dani Dental we discuss the material choice case-by-case during case planning rather than defaulting either direction.

Yes. Lithium disilicate is indicated for single posterior crowns at minimum 1.5 mm occlusal thickness on functional cusps. The 400 MPa flexural strength handles posterior occlusal load reliably for single units. Where it falls short is posterior bridges spanning molar abutments, where the connector dimensions and span flex put zirconia ahead. For a posterior single-unit case where the patient wants better esthetics than monolithic zirconia delivers, lithium disilicate is the standard recommendation.

Published clinical studies (Pieger et al., 2014, in The Journal of Prosthetic Dentistry) report survival rates of 96-97% at five years and around 94% at ten years for single crowns. Veneer survival runs similar. The dominant failure modes are debonding (not material fracture) and secondary caries at the margin. Bonded with resin cement after proper etching and silane treatment, lithium disilicate restorations routinely outlast the 10-year benchmark in well-maintained patients.