Lithium Disilicate Dental Emax Inlay China Dental Lab CE Marked

Emax Inlay: An Overview of Lithium Disilicate Glass-Ceramic Restorations

Within the dental prosthetics sector, the Emax inlay — a product of the IPS e.max® lineup — has emerged as a leading restorative choice for posterior teeth that demand minimally invasive, cosmetically pleasing, and long-lasting treatment. As one of the most commonly employed lithium disilicate glass-ceramics in modern dentistry, it holds a distinctive place between directly placed composite fillings and full-coverage crowns.

Emax serves as the commonly known commercial name for IPS e.max®, a lithium disilicate glass-ceramic created and produced by Ivoclar Vivadent, a company based in Schaan, Liechtenstein. Introduced to the market in 2005, the material has amassed more than a decade and a half of clinical evidence and continues to be a reliable option favoured by dental practitioners and laboratory technicians globally.

An inlay is defined as an indirect restoration that sits entirely within the cusps of a back tooth — in contrast to an onlay, which extends over one or multiple cusps. Emax inlays are crafted either in dental laboratories or directly at the chairside through CAD/CAM milling, and are subsequently adhesively luted into the prepared tooth cavity, delivering a completely metal-free, tooth-coloured restoration that conserves as much healthy tooth tissue as possible.

Emax inlays can be produced through two primary pathways:

• IPS e.max Press — The pressed ceramic technique, where a wax pattern (created conventionally or digitally) is invested and lithium disilicate ingots are heat-pressed into the mold at 915-930°C. The press method is known for delivering highly precise margins and the flexibility to create polychromatic, layered restorations. Long-term clinical studies report a survival rate of 95.3% for IPS e.max Press restorations over periods of up to 16.9 years.
• IPS e.max CAD — The CAD/CAM approach, where restorations are milled from pre-crystallized ("blue-state") lithium disilicate blocks, then crystallized in a furnace (approximately 11-20 minutes depending on the system). The pre-crystallized state facilitates efficient milling with reduced tool wear. IPS e.max CAD is the best-selling glass-ceramic block worldwide.

Long-term clinical evidence strongly supports the use of Emax inlays. In a landmark 10.9-year clinical study by Malament et al. published in the Journal of Prosthetic Dentistry (2021), pressed monolithic Emax lithium disilicate partial-coverage restorations demonstrated a 10-year estimated cumulative survival rate of 95.6%, with inlays specifically achieving a 93.9% survival rate at 9.9 years. The annual failure risk for inlays was estimated at just 0.38% per year, underscoring the material's reliability. Additional data from the broader IPS e.max system shows 97.2% survival of posterior crowns at 10 years, and average survival rates of 95.2% over up to 15 years.

Emax inlays are indicated for conservative posterior restorations where full-coverage crowns are not clinically necessary but direct composite fillings would provide insufficient durability — for example, large Class II restorations or MOD preparations.

Regarding cementation, adhesive bonding is mandatory for inlays and onlays. The recommended protocol involves:

• Etching the internal surface of the restoration with 4-5% hydrofluoric acid for 20-25 seconds
• Applying a pure silane primer to the etched surface
• Using a dual-cure resin cement with adhesive bonding technique on the tooth preparation.

Among ceramic materials, Emax demonstrates the longest documented survival rates — 90% at 10 years — compared to zirconia (88% at 5 years), though the choice of material ultimately depends on occlusal forces, aesthetic requirements, and tooth location.

The Emax inlay represents a mature, scientifically validated restorative solution that combines lifelike aesthetics with high mechanical strength and proven long-term clinical performance. Its versatility in fabrication methods, precision of fit, and conservative preparation philosophy have made it one of the most popular choices in the modern dental prosthetics industry for patients seeking metal-free, tooth-colored posterior restorations.