A root canal treatment is carried out on teeth that have become infected at their very core, usually because of decay, failing older fillings, or even a tooth fracture. Nobody likes to undergo a root canal, but this dental procedure can make the difference between losing your tooth and keeping it.
There are not too many complications or side effects that can happen after getting root canal treatment for your tooth. One of the most common complaints, though, that patients have after getting root canal treatment is of a cracked tooth.
Why do root canal treated teeth fracture more easily than normal teeth?
The most common reason for needing root canal treatment is tooth decay [1]. A lot of the tooth has already been destroyed by the time the patient actually gets a root canal done. This destruction in itself compromises the structural integrity of the tooth [2].
Furthermore, the very process of performing root canal treatment involves drilling inside the tooth and removing all the diseased structures, so that the infection that has invaded the tooth can be completely eradicated. What is left after the completion of the root canal treatment is akin to a shell of the tooth, which can logically fracture very easily under pressure [3].
This is why almost all root canal treated teeth are advised to be covered with crowns for their protection.
Can a cap be avoided after root canal treatment?
There are a few exceptions to the rule of requiring a cap when it comes to placing a crown on root canal treated teeth. The front teeth — which are not under excessive biting pressure — and those teeth that have a healthy amount of tooth structure left after the treatment can be left without a crown [4].
The front teeth of the jaw also have a single root, so only a small hole in the tooth needs to be made to gain access to the root. A simple filling to fill in the access hole created by the drilling is sufficient in such cases.
In some cases, if the root canal treated tooth does not have an opposing tooth then it can be left without a crown as well.
How quickly must a crown be placed on a root canal treated tooth?
It is nearly impossible to predict when a tooth will crack after root canal treatment and therefore it is recommended that a crown be placed on a root canal treated tooth as soon as the tooth is symptom-free [5]. In general, dentists like to wait a week after the completion of root canal treatment to place a crown just to make sure that there is no post-operative pain or discomfort to the patient.
The reason that a tooth cracks after root canal treatment is because it is unable to bear the normal chewing forces in the mouth [6]. A back tooth whose primary function is to chew could fracture at any time and render the entire root canal process useless.
It may be difficult to predict when a root canal treated tooth is going to fracture, but the possibility of it happening is almost certain.
Can a root canal treated tooth fracture even after having a crown on it?
Yes. Even a tooth that received a crown following root canal treatment most certainly can crack, and often does [7]. The chances of a fracture reduce immensely when the tooth is protected by a crown, but just having a crown does not make the tooth invulnerable. There are a number of other factors at play [8]. If the tooth in question is supporting a bridge, then its chances of fracturing increase. If the patient has a habit of grinding their teeth, then the chances of tooth fracture increase exponentially [9].
Also, if there are many other missing teeth in the patient's mouth, this increases the load on the remaining teeth, meaning the root-canal treated tooth will be exposed to greater chewing forces more often. In these cases, the risk of a tooth fracture increases as well.
How to prevent a root canal treated tooth from fracturing?
There are several things that can be done to prevent root canal treated teeth from fracturing [10]. The first, as has been mentioned many times before, is to get a crown to protect the teeth. The second step patients can take to protect their teeth after a root canal treatment is to replace other missing teeth in the mouth too, if there are any.
Equal force distribution between all the teeth of the jaw is vital to the longevity of the teeth. A lot of times, patients are missing teeth on one side and can only eat from the side where the root canal treated tooth is located.
Third, whether there is one single root canal treated tooth in the mouth or many, patients should be careful about trying to chew hard foods which require a lot of effort. Either break the hard object (like nuts) into smaller pieces before you eat them, or avoid such hard foods altogether.
The fourth and final thing which should be done is also the most basic advice given to all dental patients. Keep good oral hygiene. A root canal treated tooth can become decayed again whether it is under a crown or not. The patient may not have pain because the previous root canal treatment killed the nerves that perceive discomfort, but the tooth will continue to get weaker until it finally fractures.
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