A thermal shock test for porcelain-metal systems

Area of Science:

• Materials Science
• Biomaterials Engineering
• Dental Ceramics

Background:

• Porcelain-metal restorations are susceptible to cracking (crazing) under thermal stress.
• Understanding factors influencing crazing resistance is crucial for material selection and restoration longevity.

Purpose of the Study:

• To investigate the influence of alloy, porcelain type, and their interaction on the temperature differential causing porcelain crazing.
• To rank the crazing resistance of different porcelains under thermal shock conditions.

Main Methods:

• Controlled thermal shock testing was employed.
• The temperature differential (delta T) required to induce crazing was measured for various alloy-porcelain combinations.

Main Results:

• Alloy, porcelain, and their interaction significantly affect the temperature differential for crazing.
• Porcelain type was identified as the most critical factor determining delta T values.
• Crazing resistance under thermal shock decreased in the order: V < [C, N, W] > B, with C > W.

Conclusions:

• The thermal shock test effectively differentiates the crazing resistance of porcelain-metal systems.
• Material selection, particularly porcelain type, is paramount for enhancing the thermal shock resistance of dental restorations.