A common thing that we see in practice is cracking of teeth, but how it looks or feels can vary quite a lot.
They happen for a few reasons: pressure from tooth grinding, large fillings that weaken the tooth, chewing or biting hard foods, blows to the mouth, abrupt temperature changes or in ageing teeth.
Roughly speaking, cracks happen either over a long time due to long term chewing stresses through the teeth, or can happen quickly when chewing hard food or in an accident.
In long term cracks that happen over a long time, the first signs dentists often see are craze lines, which are super small cracks in the outer covering of the teeth (enamel). They cause no symptoms and your dentist might say something like "There are signs of tooth grinding pressures on your teeth,". I often liken these cracks to those on the underside of a china plate, where you can see the cracks in the glaze but the plate still functions properly as a plate. Often this type of cracking doesn't get treatment, but if you have a lot of this type of cracking wearing a preventative splint would be a good idea, or replacing missing teeth.
When these cracks start to progress into the softer body of the tooth (dentine) patients sometimes start to notice more symptoms like sensitivity or even a pain when biting down. Often the first sign is a broken tooth corner. This is really common when a big filling in a tooth has undermined the strength of that tooth to withstand biting stress. It can also happen with age as the front teeth get more worn and the back teeth start to contact together more when the teeth slide side to side.
The picture below shows exactly this sort of case, where the corner of the tooth has broken off. At first appearance you might think the brown decay is the cause, but during cleaning out of the tooth you can see a crack on the floor of the hole is really evident, as well as one under the remaining tooth cusps. One of the cracks here has progressed until it has separated the corner of the tooth off.
Cracks above the gum line are generally saveable and the dentist will talk about covering the cusps of the teeth. The cusps are the pointed corners of a molar tooth. Because a lot of cracks progress due to the biting pressures going side to side forcing cracks open, overing the top of the tooth with a hat called an overlay or even a crown is the gold standard to stop the forces travelling along the crack during function. Ie to stop it progressing further. Sometimes we might use white filling material over the cusps as the first port of call to do the same job, but in time this will not be as strong. This patient had no symptoms from this tooth of pain before this happened, but at her check up I had seen the crack and told her about it. This can be a common situation where the dentist can see the problem but the patient can't feel it so doesn't think they need treatment.
In the picture below you can see where we ended up with this tooth. It will need a little more polishing and refining, and the gum will heal over the next week or so from the clamp I used. I placed a white filling here in the first steps for treatment of this tooth because the crack was a little deeper here, more on why thats important next. Interestingly, you can see from these pictures that this has happened to both of the teeth ahead of the molar tooth. When we look at how this patients teeth meet together, the front teeth are worn down and there are lots of big fillings in weakened back teeth. This combination often leads to multiple breakages and the front teeth should really be addressed to prevent the problems with the back teeth progressing. This patient is likely to need all three of these teeth to be given proper "cusp coverage" with laboratory made overlays or crowns.
When the cracks are a little deeper the problem faced is a little more complicated. Usually a dentist will take an X-ray picture of a tooth like this, do some gum tests and test the health of the nerve in the tooth. When the dentist takes that X-ray they aren't looking for the crack, unfortunately cracks are rarely seen on X-ray, they are looking for signs of infection underneath the tooth that will tell them whether the tooth is salvageable. Even when all of these tests who the the gum and nerve health are favourable, like in the above case, there is still a chance that the tooth health will deteriorate and the tooth will need more treatment. Why? Well because cleaning under the gum line is not possible for patients, under the gum there is no hard enamel layer and the crack line is big enough when visible that the oral bacteria can get inside it. The body of the tooth is made out of a material called dentine which is more porous with lots of little tubes running through it all the way back to the middle of the tooth where there is a chamber for the nerve and blood supply that gives your tooth feeling. If bacteria can get into that space, the nerve and bloody supply to the tooth will die. This might happen with a big toothache, or will no symptoms at all until an abscess forms.
Cracked teeth where the crack extends under the gum line can need crown lengthening surgery, where the gum is lifted and bone removed so that the end of the crack is raised above the gum line. They can need root canal treatment. Or they can need extraction. Often this is down to the patients wishes and their attitude to risk. Basically the deeper the crack goes, the less likely treatments will be successful, but the more treatment is needed to give the tooth a chance. So its the conundrum of whether to invest in the tooth or not when the outcome is unpredictable.
Some cracks can split the root of the tooth and present with an abscess and become so deep that they actually split the tooth in half and often these teeth cannot be saved.
Signs that you may have a cracked tooth include pain when chewing or biting on a tooth, especially if the pain comes as you release the bite, sensitivity to hot and cold, pain that comes and goes or swelling of the gum around a tooth. All of these need to be investigated as that crack will continue to get bigger.
Your dentist may suggest a filling, overlay, crown, root canal treatment, extraction, tooth replacement (if some of your teeth are missing), building the front teeth up to relieve back teeth pressures, splints or sports guards. They might suggest one tooth treatment or your whole mouth. Cracks are one of the most difficult treatments for general dentists because of the unpredictable nature of the outcome, so I always try to make this as clear as possible right from the beginning. Some of my patients say, okay Rachael, I'm happy to monitor this in time and manage the issues as they arise, while others want to prevent the problem and take treatment earlier to avoid tooth loss.
Things that you can do to avoid this happening include, regular dental and hygienist visits to keep your teeth strong and healthy, avoid sugary foods and drinks that might lead to big fillings in your teeth, avoid chewing on hard foods or ice, wear sports guards in contact sports or wear a splint if you know you grind your teeth together, a condition called bruxism.
If you think you may have a cracked tooth or want to discuss tooth cracking further please contact me for further info.
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