One of the many uses of CBCT is to help us determine the depth of a crack - seen on the occlusal surface of a tooth, but uncertain as to how deep it goes down the root. Obviously the deeper the crack goes below the CEJ, the poorer the long term prognosis.
This patient was mostly asymptomatic until he recently bit into something and has had pain ever since.
2 Cracks seen on the MMR - with staining
In this case, the crack would never be completed removed or covered up by the crown making the long term prognosis poor. CBCT allows us to make this evaluation without having to remove the amalgam filling and chase the crack - saving the patient (and us) time and money.