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Julian Chen
Julian Chen, Dentist
Category: Dental
Satisfied Customers: 568
Experience:  Practicing General Dentist since 2002
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I have a broken crown with a root canal on one of my large

Customer Question

I have a broken crown with a root canal on one of my large back teeth that I believe is causing a puss pocket on my upper gum line where my cheek meets I have dealt with this for months in fear of having the tooth pulled because I don't know what else could be done to the tooth. I have two crowns on my first two front teeth that are not root canals and the gums are swollen around them now. I'm wondering if this is spreading or if I take amoxicillin will it help?
Submitted: 8 years ago.
Category: Dental
Expert:  Julian Chen replied 8 years ago.

I'm sorry to hear about your dental situation.

It sounds to me that the root canal is leaking and obviously failed. The puss pocket on the upper gum line is suggestive of a deeper abscess that has developed into what we call a fistula (where the pus now drains).

It is possible that the tooth is unrestorable and needs to be extracted. But it is also possible that enough solid/healthy tooth structure remains so that once the root canal is re-treated, perhaps a post placed and some build-up, a new crown can be fitted and last many years.

But by delaying treatment, you may be jeopardizing the restorability of this tooth. So I strongly urge you to find out ASAP by going to see your dentist. If there is a chance at saving the tooth, and you're willing to invest the time and money into doing so, then you don't want to blow the opportunity by letting it go on the way it is.

The infection itself won't spread to the other teeth in terms of causing nerve damage to the adjacent teeth. However, if allowed to persist, what will typically result is you'll end up with excessive bone loss around the current infected tooth, as well as to the bone supporting the adjacent teeth. I guess you can call it collateral damage. And when enough bone is loss, then the teeth loosen up, deep gum pockets may form, and you've essentially created a localized gum disease problem. It is very possible to lose more than just that 1 tooth when given the opportunity.

Taking antibiotics will help suppress the infection for a little bit, for a little while. But until the source of the infection is removed (whether via re-treatment of the root canal, or by extraction) the problem will keep coming back and you'll lose more and more bone because of it. But for the time being, you would benefit by taking some antibiotics. Call up your dentist and get a prescription filled and followed the dosage instruction.

Amoxicillin is the antibiotic of choice for most dental infections, however, do not take it if you are allergic to penicillin. You can start with a loading dose of 1000mg, and then take 500mg after each meal, basically 3x/day for 5-7 days.

Granted the infected tooth is in a somewhat cosmetic region (visible if completely missing), there are ways to restore the gap if we are forced to extract the tooth. You can explore the options of an implant restoration (pricey but most ideal in terms of restoring a single tooth). There's also the choice of going with a bridge (fixed partial denture/FPD), where the adjacent teeth are crowned (or re-crowned) and a floating pontic is attached to span the gap. Or there are removable options such as a temporary partial, or a permanent RPD (removable partial denture). However, RPD is not the best way to go in terms of restoring a single missing tooth.

So don't delay, make an appointment with your dentist and find out what needs to be done. That way, you'll know your options and can then decide, instead of having the tooth decide for because you've lost so much bone that even an implant cannot be placed.

I hope the tooth is salvageable and the prognosis is good. I wish you the best.


Jul***** *****, DDS
Julian Chen and other Dental Specialists are ready to help you
Customer: replied 8 years ago.
I forgot to add that the tooth behind it had a failed root canal with a crown as well and had to be extracted so it would probably be tough to put a bridge there. I did not have the same symptoms as I do now but I figured the ending result would be the same. Bummer. If you can believe this my former dentist told me that I was having all of the problems I was from eating grapenuts cereal. Well, I didn't eat it dry! Anyway, I aprreciate your help.
Expert:  Julian Chen replied 8 years ago.
Hi again,

If you still have another tooth further back on the same side, then a bridge (fixed partial denture) is still possible. What you need to know is that the longer the span of the bridge, the weaker it is. Usually a 4-unit bridge, which replaces 2 missing teeth in between, is about as long as we really should go. The reason is that even though the bridge is made with a rigid metal framework with porcelain backed on top to make it cosmetic, when you bite down in the middle (where there is no root support), the framework can still bend ever so slightly. When this occurs, it puts pressure on the ends of the bridge, where the supporting 2 teeth are and can sometimes cause the cement to slowly break loose. Over time, a small gap may form and saliva and leakage occurs. The longer a bridge, the greater the flexure.

Now, as to address the issue of grapenuts cereal. Although I wouldn't go as far as blaming the cereal as the sole cause of any breakdown, it is comprised of many small, crunchy, hard pieces. For patient who have a lot of medium-to-large sized fillings, and or patients with multiple root canal treated teeth, it is important to be mindful of biting into hard foods.

With regards ***** ***** with large fillings, the way I explain to my patient is that imagine a the tooth is a porcelain bowl, and the filling itself would be if we had poured concrete into this bowl. So for the most part, this now bowl of concrete is rather strong! However, if you clench down on very hard objects, the forces are transferred through the concrete and transferred onto the porcelain bowl itself. Eventually, due to constant wear & tear, stress fracture can and will occur within the bowl, even if the concrete still appear to be strong and intact. It is also possible where if you bite down on the wrong angle, instead of the hard object hitting the concrete, you now hit the edge of the bowl, where the porcelain is. Biting down with the same hard pressure, the porcelain is much more fragile than the concrete, and a piece of the bowl cracks and breaks off.

So in the mouth, a renegade grapenut piece might catch the cusp surrounding a medium filling, the cusp being the porcelain bowl, is now more fragile and breaks off.

With regards ***** ***** that have been root canal treated, they are almost always restored with a crown especially if they're a molar or premolar tooth. We tell the patients that doing so is part of the "standard of care" because the crown will protect the root canal treated tooth. While this is very true, I feel that some of my colleagues may unintentionally neglect to explain to their patients that even though the tooth has been crowned/capped, we still need to worry about the underlying tooth structure.

What root canal treatment does is essentially kill off the tooth; the nerve and blood supply, which carried the nutrients as well as moisturize the tooth are both removed completely and sealed off. The only reason the dead tooth stays in the mouth is due to the healthy bone and gum tissue surrounding it. So over time, the root/tooth itself starts to dry out from within, and the root actually becomes more and more brittle, easier to crack, split, and shatter over time.

And even though we have a nice, beautiful solid crown covering the root, if enough pressure is applied downwards, again, we can induce stress fractures and actually split the walls of the root. When this occurs, saliva and "crevicular fluid" can carry some oral bacteria down into the cracks, leak into the root canal, and subsequently cause a new infection leading to the failed root canal.

Although you've already lost at least 1 previous tooth, and the prognosis of this current tooth is unknown, I wanted to inform you of the dangers of eating crunchy, hard foods. Nut lovers who enjoy eating almonds, or those who may love eating Cornuts, and for you, who enjoy eating Grapenuts cereal, will need to be more mindful of where you bite down. If you have additional teeth in your mouth that have large fillings, or root-canal-treated teeth, you'll want to avoid biting down on hard objects with those teeth.

I am certainly not telling you stop eating your favorite cereal. I just hope with the information provided, we can help prevent additional, unnecessary breakdown of those teeth.

I hope my explanation of why teeth with large fillings and root canal treatments are weaker made some sense and increased your awareness slightly.

I wish you the very best,

Jul***** *****, DDS