Can a tooth with a crown still get a cavity?

Yes, a tooth with a crown can still decay. The crown itself does not rot, but if bacteria get in through a tiny gap where the restoration meets the gum, the natural tooth underneath decays - a secondary cavity. A tooth that has had root canal treatment cannot feel pain, so this is easily missed and needs extra care. To prevent it we recommend 1) brushing the crown margin (gum line) thoroughly, 2) using floss and interdental brushes as well, and 3) a check-up every 6 months to inspect the margin. If the crown feels loose or food often gets caught, please come in right away.