Australian Dental Council (ADC) Practice Test

The major cause of jacket crown breakage is often attributed to the thickness of the porcelain used in its fabrication. When porcelain is thinner than 1mm, it lacks the necessary structural integrity to withstand normal functional forces in the oral cavity. This reduced thickness can lead to an increased risk of fractures under stress, particularly during biting and chewing.

Porcelain is inherently more brittle compared to metals, making it susceptible to failure if it does not have sufficient thickness. A minimum thickness of 1mm is generally recommended to provide adequate strength and durability for the restoration. Thinner porcelain layers can also be less able to distribute forces evenly, which can further increase the likelihood of cracking and breaking.

Understanding this aspect of dental materials is crucial for clinicians to design and create more resilient dental restorations. Ensuring that porcelain used in jacket crowns meets the appropriate thickness standards is an essential practice to enhance their longevity and functionality.