Reliability of reduced-thickness and thinly veneered lithium disilicate crowns

Area of Science:

• Materials Science
• Biomaterials Engineering
• Dental Ceramics

Background:

• Dental restorations require durable materials to withstand occlusal forces.
• Lithium disilicate and zirconia are advanced ceramic materials used in CAD/CAM restorations.
• Assessing the reliability of reduced-thickness ceramic crowns is crucial for clinical longevity.

Purpose of the Study:

• To evaluate and compare the reliability of reduced-thickness monolithic lithium disilicate crowns against veneered zirconia and metal-ceramic systems.
• To test the hypothesis that monolithic lithium disilicate crowns offer high reliability.

Main Methods:

• CAD/CAM fabrication of 1.0-mm and 2.0-mm monolithic lithium disilicate crowns and 2.0-mm crowns with a 0.5-mm buccal thin veneer (BTV).
• Step-stress fatigue testing (sliding contact) of crowns on standardized dies until failure or suspension.
• Weibull analysis of failure loads to compare reliability between material groups (MON, BTV, Y-TZP, MCR).

Main Results:

• No significant difference in Weibull characteristic failure loads between monolithic (MON) and buccal thin veneer (BTV) lithium disilicate crowns.
• MON and BTV crowns exhibited significantly higher failure loads than Y-TZP (zirconia).
• Reliability of MON and BTV crowns was comparable to metal-ceramic (MCR) systems.

Conclusions:

• Reduced-thickness monolithic lithium disilicate crowns exhibit high reliability.
• These crowns are a viable alternative to metal-ceramic restorations.
• Monolithic lithium disilicate demonstrates superior performance compared to veneered zirconia in this fatigue model.