A tooth that is badly damaged, decayed or discolored can often be restored with a crown or cap, so that it looks indistinguishable from a natural tooth and usually it gives many years of trouble-free service.
It is however possible occasionally for a crown to come unstuck (“debond”), especially if it is knocked or if you happen to bite into something hard or very sticky. The crown can come loose in the mouth or be embedded in food as you’re eating.
This can be a shock if you have had the crown for a long time as you will probably have forgotten that you even had a “false” tooth at all. You are suddenly faced with a difficult and embarrassing situation if it involves a tooth at the front of the mouth, since it will be obvious to everyone!
Note that this article relates to ‘permanent’ crowns (and to bridges as they are similar in nature). Temporary crowns (‘temps’),as their name would suggest, are much more prone to falling out. However, much of the advice contained here will remain true though. If a temporary crown fell out on you, in short – keep the area clean and get into your dentist as soon as you can. Read the advice below if you are going to use a temporary cement to stick it back in place.
Why Do Crowns Fall Out?
Like all dental work, “caps” can’t always last forever. Problems can occur with either the crown itself or with the underlying tooth.
Note that some crowns, for example those placed on posts, are more prone to falling out than others. The retention depends to a large extent on the quality and amount of tooth structure that is underneath.
So, some 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 sports injury, or biting down on a very hard or chewy food. The damage can be enough 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. This is particularly true if you do not look after your teeth (e.g. you have a high sugar diet) and/or 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 recementing procedure with your dentist 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.
What To Do?
However you should try not to panic, but should carefully take the crown out of your mouth to avoid the risk of swallowing it or breathing it into the windpipe. A cap which is swallowed will work its way through the digestive system without causing harm, but is usually regarded as lost and not retrievable…
Ideally you should see your dentist straight away to get the crown properly fixed back into place, but this is not always possible depending on the circumstances. Your dentist may have a busy schedule and not be able to fit you in straight away or you may not be able to easily get to him. Usually, however, you can get an appointment within a day or two and in the meantime you could clean and sterilize the cap with some Milton solution and then dry it and put it safely into a small container.
The tooth from which the crown came needs to be kept clean by carefully brushing with a soft toothbrush. The tooth may still be alive (vital) and thus could be sensitive to hot or cold drinks and food, so these need to be avoided. If the tooth is non-vital it will not hurt at all, but it’s important to try to prevent any food debris from lodging into any opening there may be into the root – if it’s a crown with a post attached.
If the tooth is right at the front of your mouth you may feel it necessary to try to fix it back temporarily and there are temporary cements you can buy at the chemist or drugstore. Be aware, however, that these are not strong cements and may not hold the crown securely. There might be a risk of it coming loose while you sleep and it being swallowed or inhaled, so it’s best to manage without it if you possibly can. In some cases people have been known to fill the gap with chewing gum to make it appear that a tooth is still present but of course it’s not very satisfactory and won’t stay in place for long.
If you decide to refix a crown with temporary cement you must take great care not to put any pressure on it whilst eating or cleaning your teeth since it is very easily dislodged.
DO NOT be tempted to use something like “SUPER-GLUE” – not only is this dangerous, it likely will also ruin the crown and tooth.
It is a good idea to have a look in the mirror and examine the tooth which held the cap or get someone to look for you in order to see if anything looks broken. Sometimes, especially if you suffered a knock, the tooth can break inside the cap and part of the enamel or dentin itself comes away with the crown. Needless to say, this may complicate the situation for the dentist somewhat and it’s best to report this fact when making an appointment, in order to get the soonest appointment possible.
If it cannot be “re-cemented”?
- If the underlying tooth remains strong enough, but your crown no longer fits, then a new one will need to be made.
- Where it is possible, root treatment and a post are required where the tooth breaks underneath and inside a crown.
- Where the tooth is no longer of adequate strength to hold a new cap, even with root treatment and a post, then extraction and replacement are the only options. Read this page for more advice on replacing a missing tooth.
Most often, however, when a crown falls out it is simply the cement bond which has failed. It is thus a fairly simple matter for a dentist to re-cement it, so that it gives many more years of service.