Study: IPS e.max lithium disilicate material the most durable ceramic tested to date

The researchers used the mouth-motion-simulator test to compare the durability of IPS e.max CAD lithium disilicate full-coverage crowns to veneered zirconia crowns.

By replicating actual forces exerted in the human mouth, this test provided a more realistic assessment of how ceramic materials hold up to the forces of chewing.

In particular, unlike previous laboratory tests that only assess a material’s physical properties to meet minimal standards, the mechanical mouth simulator stressed the restorations using clinically relevant directed loads over thousands of cycles (similar to how people chew) until failure occurred.

Failure was considered to be chip-off fractures of the veneering ceramic in the case of the zirconia crowns or fracture/chip through the lithium disilicate crowns.

The research found that none of the IPS e.max CAD lithium disilicate crowns failed below 1,000 N and 1 million cycles.

In comparison, the veneered zirconia crowns tested demonstrated limited reliability, with approximately 50 percent of the crowns tested failing from veneer chip-off fractures by 100 K cycles at 200 N, which is similar to previous research findings. Also, 90 percent of the veneered zirconia crowns tested failed by 100 K cycles at 350 N.

Overall, in comparison to the veneered zirconia systems that were tested, the IPS e.max CAD lithium disilicate full-coverage crowns can be expected to demonstrate excellent clinical performance relative to chipping or fracture based on the findings of the NYU College of Dentistry mouth motion simulator testing.

The failures reported in this study mimic those reported in clinical studies, suggesting that IPS e.max lithium disilicate is the most robust all-ceramic system tested to date.

(Edited by Fred Michmershuizen, DTA)