Which Glue To Buy For a Temporary Crown Fix?
If your crown keeps coming out, this guide will tell you why this happens and what you can do about it. A crown that keeps coming out for no apparent reason is the one dental problem that annoys and causes most upset to patients. The result is that it leaves a massive gap which is really unsightly especially when the gap is at the front of the mouth for everyone to notice. Even if the gap is at the back of the mouth, food will tend to get trapped where the crown was, causing halitosis. The result is embarrassment and a damn nuisance especially if it is at an inconvenient time when you can’t get to your dentist quickly.
In theory all crowns can come out at any point but we are talking about a crown that repeatedly dislodges within a short period of time. Most patients never get to find out why their crown repeatedly dislodges so you just need
to ask your dentist for the reason and if it can be rectified. The article will look at the reasons why your crown keeps coming off so let’s go through each one in turn.
Decay
Decay under a crown is perhaps the most common reason why your crown came off and why it keeps dislodging. When there is decay inside the remaining tooth, the glue or cement that is used to keep the crown in
place will not adhere to decay. Decay reduces the surface area of the underlying tooth to hold the crown securely in place. Until all the decay is totally removed, the crown will keep on coming out. Often, you won’t even be eating anything particularly hard or sticky and out comes the crown again. So firstly ask your dentist if the underlying tooth is healthy.
If there is decay under the crown, the only remedy to this problem is to clean out the decay inside your tooth and then make a new crown because the old crown will no longer match the shape of what your tooth originally was like. ( In some exceptional cases if there is a small amount of decay and away from the crown margins, then it is still possible to use the old crown.)
One thing to bear in mind is that often early decay or caries cannot be easily picked up on your routine x-rays or by visual probing so during this time, the decay becomes worse. If the decay has become extensive, the only solution is eventually to have the tooth extracted.
Lack of Retention
A crown relies on 2 factors to keep it in place. The most important factor is a shape of the underlying tooth that is used to hold the crown in place. All crowns are “glued on “and the material used is also important. Nowadays, the dental glue or cement is quite consistent compared to years ago when the cement was hand mixed and this could lead to discrepancies in consistency and quality. If you had a crown placed many years ago and it has now come off, it can be that the cement has partly washed away under the crown and deteriorated. The older type of dental cements were based on Zinc phosphate or Zinc Polycarboxylate. The newer modern types of dental luting cements for crowns are based on Glass Ionomer or resin based. Glass Ionomer Cements
have advantages as they bond onto enamel and dentine. They also have good strength and release fluoride which is beneficial in reducing recurrent of secondary caries around the crown margins.
However, the luting cement is not the only factor which holds the crown securely in place. The other factor is the shape of the underlying remaining tooth over which the crown fits. If you recall to when you first had your
crown made, the dentist shaped your tooth first. The shape of the tooth over which your crown goes over is called the “crown preparation” or crown prep. There are certain rules for an ideal crown preparation such as having near parallel walls with a small taper and adequate tooth height. These factors will all provide the retention for your permanent crown and therefore if your crown keeps on coming out, it may be that the crown preparation lacks retention. When the underlying tooth lacks retention, the tooth will need further preparation and a new crown to make it more retentive.
Changes to the bite
You may not think so but even tiny changes or alteration to your bite (sometimes referred to as the occlusion) will dislodge your crown. The answer is to make sure that your crown is not subject to heavy unbalanced forces on its biting surface. The bite or occlusion is probably the most commonly overlooked factor when trying to see why your crown keeps falling out. When a crown is put back in having fallen out, the bite should feel absolutely exactly the same as before it fell out. If your bite feels odd then the chances are that much increased that your crown will fall out again. Even, once your crown has been re cemented and your bite seems comfortable, it is critical that your dentist rechecks the bite to make sure it is balanced because changes in occlusion can occur over a period of time due to reasons such as loss of a tooth/teeth elsewhere, a new filling, or the bite changing as a result of a parafunctional clenching/ teeth grinding habit ( bruxism) or other factors. How does a dentist check your occlusion? Even a highly trained dentist just cannot assess your bite from just looking at your teeth so he uses a thin narrow strip of special paper called articulating paper. Articulating paper is very thin and has a coloured dye coating which transfers marks onto your teeth. The articulating paper is placed between your upper and lower teeth and you are instructed to tap your teeth up and down a couple of times and also to grind from side to side and backwards and forwards. In this way, the dentist can assess how your teeth meet in function i.e in a grinding type of motion which is how your teeth connect together during eating. The dentist then takes the articulating paper out of your mouth and looks where the dye has marked areas on your teeth and looks for premature contacts. Premature contacts are specific points where the occlusion is unbalanced. Where premature contacts exist, it is important to adjust the patient’s bite so that the bite is balanced again. It is the case that crowns that keep falling out often have premature contacts which need to be corrected otherwise the same
problem will reoccur. This is why sometimes the biting surface of a crown needs to be adjusted in order to create an even bite again. If this is not done, then you are increasing the like hood of the crown falling out again. An important point to bear in mind is that as soon as your crown has come off, you should make arrangements to have it re cemented again before there is any chance of opposing or adjacent teeth moving hence changing the occlusion. I have seen changes in occlusion in less than 24 hours of crowns coming off so it’s imperative to have your crown re cemented as soon as it has dislodged and to prevent the bite from altering.
The fit is no longer tight.
When your crown has come off for the very first time, in order for your dentist to put it back onto your tooth again, it is necessary to clean out the old luting cement first. This is performed by drilling out the old cement which is still stuck to the inside of the crown. The problem that can arise here is when the luting cement is drilled off, the crown material itself can also in the process be slightly drilled away as well hence creating a less tight fit compared to the original crown. From this point onwards, your crown will never have the same fit as when it was constructed originally and this will naturally increase the chances of the crown coming off again in the future. If this is the problem, then the only solution is to re-make a new crown from scratch again.
Other Reasons
Fracture of underlying root
A fracture of the underlying root occurs when a tooth has been root filled or the tooth has become dead also known as the tooth becoming non vital.
A root treated tooth or a non-vital tooth is always much weaker than a tooth which has its nerve and blood supply still intact.
Root fractures are especially common in teeth which have a post crown following root canal treatment.
Root fractures involving post crowns are more common in the upper and lower anterior incisors/ canines but do occur in molars as well.
When a dentist sees the tooth where the crown has come out, it will be immediately obvious that a root fracture has occurred.
There is no treatment for root fractures. In the past, however at our practice we have managed to “have a go” at trying to put a crown back in which has sustained a fracture and in few cases have lasted a considerable length
of time but as a general rule, they do not last. If a crowned tooth has a root fracture and it is re cemented back in, the patient obviously has to be very careful not to put any direct pressure but on the whole, once a root has
fractured, that crown will just keep on coming out. Root fractures unfortunately have a poor outlook.
The treatment options here are therefore an extraction and a replacement tooth using either a denture, a bridge or an implant.
Fracture of the post or pin
Many crowns have additional retention such as using a pin or a post in order to stay in properly. This is quite normal especially if there was not a lot of underlying tooth remaining when the crown was done initially.
However, the pin or post can fracture off under heavy loading forces.
When there is a fracture of the post or the pin, there is now nothing for the crown to hold on to and as a result the crown will keep on coming off.
Sometimes, it is possible to take the fractured post or pin out of the root of the tooth, and then insert a new post or pin.
However, in a significant number of cases, the only option unfortunately is to have the tooth taken out. Once the tooth has been taken out, it can be replaced if necessary with a denture, a bridge or a dental implant.
Broken core
When your crown has come off you may have noticed that there is little remaining tooth left. This can be because the core has also come off and is attached inside the crown itself. If you then look at the inside of the
crown you will notice that the core is inside there. You may even notice that part of the tooth itself has fractured off and has attached itself inside the crown. There are various explanations for this. It can be that the original
core has simply come away. It can come away either through decay or simply of the stresses falling onto the tooth over a period of time. Also one sudden large force can cause the core to break off. In these cases, in order to salvage the crown in may be possible to build up a new core and then drill out the old core from the crown and we fix it back on. This also depends on the extent of any caries that might be present and whether there is remaining tooth structure left to hold a core in place. Sometimes the core needs to be reinforced with a dentine pin or prefabricated post.
A common reason why the tooth could fracture off and remain inside the crown is when it becomes non-vital. It may be that the tooth has already been root treated in which case the core has dislodged away from the root.
We know that from studies approximately 20 to 30% of all teeth which are crowned become non vital. A non- vital tooth is more prone to fracture and this is what can happen in this case.
Although in many cases a new crown becomes necessary, there are certain instances where it is possible to salvage the old crown with necessary modifications such as building up a new core after removing caries and
using pins or post for further retention.
Fracture of underlying tooth
When your crown keeps on coming out, you may have noticed that a part of the underlying tooth has also broken off. The underlying tooth may break off partially or extensively.
If it has broken off partially and the dentist feels the tooth can still be saved, it will be necessary to have the tooth built backup and a new crown constructed.
If the break or fracture is extensive, it depends on whether the fracture is above or below the gumline.
If the fracture is above the gum line, the tooth can often still be saved by cleaning out any decay present, and then building the tooth back up with a pin or a post. Once your tooth has been built back up, a new crown can
be constructed.
If the fracture is below the gum line, it then becomes extremely difficult or impossible to salvage the tooth. In a few cases, you may be lucky to have gum surgery and repair the broken tooth but more often than not, you will be advised to have the tooth taken out and have a replacement as necessary such as a denture, Bridge or a dental implant.
What to do in an emergency if your crown keeps coming out
It just happens that a crown always seems to be coming out during the most inconvenient of times. These times always just seem to happen in an evening, on a weekend and during a long bank holiday when dentists are closed. They can also be at times when you are away from home on holiday. Panic sets in as you say to yourself that it’s the last thing you need. Depending on which area you live in, you may be able to access an emergency dentist in your area. The Out of hours NHS service is there by calling 111 but a “crown coming off”
is not classified as a true dental emergency so you won’t be seen. The Out of hours 111 NHS service defines a true dental emergency as one that causes severe pain, swelling or bleeding. So if you did ring the Out of hours 111 NHS service, you will be informed that they are unable to put your crown back on and will advise that you need to contact your regular dentist to have your crown “recemented.”
A crown which has come off is made worse when it is also in the front of your mouth for everyone to notice. If you need to keep your crown in your mouth to save dignity, super glue is not the best of methods. Although superglue is often used by patients as a quick fix, it has two main issues. Superglue is very runny and hard to control. Patients usually end up with superglue on their gums and even onto the adjacent teeth. When it sticks onto the gums, this can cause gum inflammation and a form of gum infection can initiate. If it inadvertently sticks onto adjacent teeth, your dentist will then have to drill the excess glue off. You may then think to yourself that you will only use a small amount of superglue. The problem with this is a space or void is created
underneath the crown. The space or void can become infiltrated with plaque bacteria which can cause gum disease or tooth decay. And finally, once superglue does go onto your tooth under the crown, it has to be drilled
off by the dentist which then in turn affects the original fit of a crown. In my clinical practice, once a patient uses superglue, it creates so many problems and a new crown becomes necessary. As the worst case scenario
you may even need to have a tooth extracted if it becomes irreparably damaged as a result of using superglue to put your crown back on.
Therefore if you are going to use any form of glue do not use super glue but go to any supermarket or a chemist, where you can buy a simple emergency dental kit which will have some temporary glue that you can use for this purpose. Another option is to buy a tube of denture adhesive. Denture adhesive is normally used when you have dentures which are loose and you want to keep them in the mouth with more security. The consistency of denture adhesive is that of being tacky and gloopy. It’s very similar to the consistency of wall paper adhesive. This denture adhesive/fixative can sometimes be sufficient to hold the crown until a more definitive solution is found. Denture adhesive also does not damage your gums or your teeth and is relatively cheap hence can be applied repeatedly. Denture adhesive is however not very strong so sometimes the hold is insufficient and may not last long.
Finally, if your crown keeps on coming off and you haven’t decided on a more permanent option such as a new crown, you should always have some temporary dental adhesive with you at all times as you never know when that crown will come off again without warning. In particular, don’t leave the house without and it’s a good idea to keep some in the car.
Conclusion
So in conclusion, when a crown keeps falling out or is repeatedly becoming loose, there are two aspects to address. Firstly and foremost, you need to have it fixed back in your mouth as soon as possible. Secondly, it’s imperative to find out the reason why it may have dislodged and to address the causes. If the reason is not identified, then the crown is likely to come off again. You should always be prepared to have further treatment such as a new crown altogether. If you do need a new crown, then this is a two visit procedure consisting of impressions of your mouth followed by the fitting appointment.
What glue to buy for a temporary Crown Fix?
If you are not fortunate enough to visit a dentist immediately after your crown has come off, or the crown/inlay/bridge is loose, then we did research on where you can buy dental glue in an emergency in order to put to your crown back on. In particular, we looked at how effective the glue was in terms of its strength; also how easy it was to mix and whether it was good value for money. At the end of the day, if the crown is put back on and the glue does its job, the price is somewhat immaterial.