How do ceramic inlays/onlays most commonly fail?

Ceramic inlays and onlays are commonly used in restorative dentistry due to their aesthetic appeal and functional properties. However, their longevity can be compromised by certain failures. The most prevalent reasons for the failure of these restorations involve fracture and marginal breakdown.

Fracture occurs due to the inherent brittleness of ceramic materials, which can lack the ductility found in metals. When subjected to excessive occlusal forces, whether from grinding or heavy occlusion, these restorations can crack or shatter. The design and fit of the inlay or onlay are critical; if they are not properly contoured or if they occupy a position where they are susceptible to stress concentrations, the likelihood of fracture increases.

Marginal breakdown refers to the degradation of the interface between the tooth structure and the ceramic material. Over time, factors such as wear, thermal cycling, or the effects of saliva and food can compromise this seal. Loss of bonding integrity at the margins can lead to micro-leakage, recurrent caries, and ultimately the failure of the restoration.

While some options mention debonding, which can indeed be a concern, the combination of fracture and marginal breakdown effectively encapsulates the most common modes of failure for ceramic inlays and onlays. This