Under normal circumstances, a dead tooth should not spontaneously fall out of your mouth because the condition does not induce mobility. However, if a complication occurs it can potentially make it fall out.
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Dead teeth don't become mobile
A dead tooth (non-vital or necrotic) is a nerve condition and it does not affect the periodontium. In other words, it does not possess the capability of loosening the tooth and making it more mobile.
In conclusion, you don't have to worry about your necrotic tooth falling out of your mouth.
When a tooth dies it is the nerve that stops functioning. It will no longer be able to sense external stimuli such as cold, heat, and pain.
The overall point is that it is a nerve condition and it only affects that and nothing else. The overall structural integrity of the tooth remains unchanged even after it has died. The tooth doesn't start breaking down nor does it start getting looser.
No effect on periodontium
A non-vital tooth only affects the nerve while leaving the periodontium intact. That is an important point to understand because it is the health of the periodontium which affects whether a tooth will become mobile and fall out.
Your teeth are embedded in the jaw bone. The deeper they are embedded into the bone the more stable they will be. Essentially the periodontium consists of all of the surrounding structures and tissues which hold the tooth in place. Without it you will have a mobile tooth.
However the most common reason for teeth to be come loose and potentially fall out is when the periodontium is affected such as with severe gum disease like periodontitis. In this situation the tooth starts losing bone around it and eventually gets loose enough to fall out.
Fortunately, necrotic teeth is a condition which only affects the nerve and not the periodontium.
Complications that may induce tooth mobility
Despite dead teeth having no effect on it's mobility, the condition does not make it immune to other ones which can loosen it. That means it can still fall out of your mouth if it becomes afflicted by other conditions that do affect the periodontium.
Gum disease. Gingivitis may not loosen your tooth but the advanced stage periodontitis certainly can. In the latter, the disease starts to erode your bone and when left untreated you will have teeth that are no longer embedded in bone. They will become very loose and can potentially fall out on their own.
Excessive trauma. If you sustain heavy trauma to your face, you can potentially knock your tooth out of your mouth. An example would be a hockey player getting struck in the face with a hockey stick during a game.
Fracture. Non-vital teeth are typically devoid of nutrients so they are more fragile and prone to fractures. That is especially true if you happen to bite into something hard and crack your tooth.
The two x-rays below show the difference in the health of the periodontium. One is healthy and you can see the teeth are very well embedded into the jaw bone. The other one you can see teeth floating around in the mouth since they barely have bone supporting them.
How long can a dead tooth last in your mouth?
If your tooth has been properly treated with a root canal and a crown, it can last for many years in your mouth. As long as you take care of it properly there is no reason why it would fall out or succumb to other dental conditions.
Taking care of it:
Brush and floss. You should brush and floss it as if it was any other tooth in your mouth.
Minimize sugar. Despite being dead, it doesn't make it immune to tooth decay. If you eat too many sweets it can become decayed.
Regular dental check ups. Your dentist can evaluate its condition at every check up. If something needs to be done it would be prudent to do it.
Conditions which may affect its longevity
If you don't take care of your root canaled tooth, it may not last as long as you would like. Here are a couple of dental conditions which it may fall prey to.
Tooth decay. Yes, it can potentially develop a cavity because bacteria don't care if it is alive or not. Bacteria will attempt to eat through your tooth.
Recurrent infection. After the root canal the tooth is properly disinfected but there is always the possibility of a dental abscess returning via other means. If that happens you will need a root canal retreatment.
Fracture. Teeth that have died will have a non-functioning nerve and blood supply. That means it will no longer receive any nutrients thus making it become brittle over time. If you eat something hard you can potentially crack it.
Treatment for necrotic teeth
The best course of treatment would be to get a root canal and a crown on it.
Root canal. Leaving it untreated can eventually develop periapical pathology which is an abscess. One way to minimize the chances of infection would be to get a root canal.
Crown. These teeth often become discolored afterwards and a dental crown can help mask the color. There is also the additional benefit of it being able to protect your tooth.
We have a lot of patients who ask if they can simply leave the tooth alone without treatment. Sometimes the tooth can last many years without developing an infection but that is a risk you will be taking. For that reason we always recommend to get treatment for it. At the very least you should discuss your options with your dentist and go from there.
While your tooth may not fall out of your mouth just because it is dead, it may still succumb to other dental conditions which can. The reason why it won't loosen is because it is solely a nerve condition and does not affect anything else. However just because it has died it does not make it immune to periodontal disease which can make it loose!
If you're still concerned, you can book a dental consultation with one of our dentists in Long island city... that is if you're in the area.