3 weeks post op. Do crowns settle in and appear to shorten?

Porcelain crowns or teeth can crack due to excessive forces of your bite (occlusion) . That can be due to para functional habits such as grinding, clenching, crown being too high, chewing on hard food, trauma and many other factors..... I am sorry to hear that your tooth was cracked and needed...

Well during late months in pregnancy you may get an xray to r/o any infection. it is possible following a crown placement the pulp gets too stressed and eventually will need a root canal. you need to see a dentist to figure it out

Hi:I definitely advise you to contact your dentist right away and share your concern.Best,Dr. Maddahi