Why Do Crowns Fall Off?

Like all dental work, “caps” can’t always last forever. Problems can occur with either the crown itself or with the underlying tooth.

Common reasons for failure include:

  • Trauma – As mentioned above, a sudden impact can unseat a cap. This may be from an external force, such as a sport injury, or biting down on a very hard or chewy food. The damage can be enough to loosen the crown, chip a piece of it off, make it fall out altogether or damage the foundation (tooth or root fracture).
  • Heavy grinding – If you are a habitual grinder or clencher of your teeth, then the forces involved, can debond a cap (or any other similar prosthesis – like a bridge or veneer).
  • Decay – The margin where the underlying tooth meets the edge of the crown can be a site of dental decay. When a gap forms at this area (e.g. with an ill-fitting crown). Decay can spread quite quickly under a crown (or bridge), weakening the underlying foundation and leading to the cap falling out.

If a crown comes off without any “provocation”, this can sometimes be due to the cement leaching out gradually over a period of years – and a simple recementingprocedure can mean further years of service. But when it is because of decay getting in underneath and weakening the tooth, or a piece or all of the tooth has fractured, this will complicate things.
If a crown repeatedly comes off then it suggests that unfortunately the fit is no longer adequate or the foundation is too weak – and further treatment may be required.