Cracked Tooth Syndrome
Below I’ve included responses to some of the more common questions patients have about cracked teeth:
Why do Teeth Crack?
Cracked tooth syndrome is a very common problem., usually affecting teeth that have large fillings. The decay and subsequent filling weaken the remaining tooth structure. Like all materials, teeth are subject to the forces of stress fatigue. Hairline fractures can develop, usually at the bottom corner of the cavity.
Will My Grinding Habit Make It Worse?
Yes. Almost everyone, at some point in their life, grinds their teeth. Grinding can increase the stress and strain on a tooth by 200 to 300%, especially if you worn down your canines and lost the protective ‘lift-off’ effect they can give in sideways grinding movements. You may benefit from either a nightguard or a permanent addition to your canines to protect the back teeth from cracking. You may also have susceptible tooth anatomy or worn down fillings, where the valleys on top of the teeth are deep. When these factors combine with sideways splitting forces generated in chewing fractures often result. Even unfilled teeth, if subject to enough force, can crack.
Why Does It Hurt So Much To Bite On It?
As the tooth flexes (even in microscopic amounts), its nerve is stimulated. There are tiny, fluid-filled tubes (tubules) situated in the dentin (the inner layer of the tooth between the pulp and enamel). These tubules run down to the nerve and as the tooth flexes , the crack opens and closes, causing fluid to flow in and out of these tubules and put pressure on the sensitive nerve.
Why Is It Sensitive to Hot and Cold?
The nerve is aggravated by the crack and by bacteria being pumped into the pulp via the tubules. The pulp becomes inflamed because of the toxins in the bacteria. A classic symptom of nerve inflammation is the extensive sensitivity to hot and cold.
What Will Happen If I Just Do Nothing?
The crack continues to slowly propagate lake a crack in the glass. Sometimes the crack goes off to the side and the fragment of tooth breaks off. The crack can also go deep into the roots and at times right into the nerve. Teeth can often go for months in a stable, yet inflamed condition. Sometimes they may seem to get better, only to suddenly get worse. It’s difficult to predict course of the untreated tooth, but usually if follows a slow downhill course as the crack deepens. It’s not a good idea to the leave the fracture; small cracks can be treated effectively, but if they’re left to enlarge they can lead to root canal treatment or extraction. The nerve can be attacked by bacteria, leading to extreme sensitivity to hot and cold temperatures. A persistent ache or throbbing is often also noted. The infection in the nerve can spread to the bone causing an abscess.
What’s The Usual Treatment For A Cracked Tooth?
Unless the crack is immobilized, the tooth is very likely to deteriorate. Although various methods have been employed in an attempt to stick the crack together, chewing forces are extremely powerful, and these patch-up solutions are often unpredictable and ineffective. The only real solution is to bind the whole tooth together with a crown. With full coverage, chewing forces will move the tooth as a whole rather than gradually splitting it apart.
Is It Possible That The Nerve Is Already Dead?
Yes. Cracks in teeth can develop very slowly, allowing a gradual ingress of bacteria into the nerve. As a result, the nerve can die in a manner that is less noticeable than usual. Nerves can become mildly sensitive to hot and cold without any noticeable symptoms or pain. Many patients have teeth which, unknown to them, have dead nerves. Sometimes there are even dormant abscesses on these teeth.
Is It Safe to Leave A Tooth With a Dead Nerve?
Sometimes you can get away with it for a while, but unfortunately these teeth are like ticking time bombs. The low grade infection that is usually in them can suddenly flare up and cause pain, swelling and pus. This usually happens when your immune system is down. It is best to treat it as soon as possible to minimize the amount of bone destruction that occurs at the end of the root, where the infection comes out of the tooth and into the jaw.
If The Nerve Is Dead, Do I Still Need a Crown?
Yes. You need a crown to stop the existing crack from spreading down the root. This is called a ‘vertical root fracture’. Unfortunately, this results in an untreatable occurrence and the tooth needs to be extracted. Crowns are needed on dead teeth even more so than teeth with living nerves since dead teeth are far more brittle. Regardless of how a nerve dies, crack or no crack, it is standard practice to put a crown a tooth that has had root canal treatment because of this increased brittleness.
Doesn’t The Nerve Always Recover?
No. Despite ideal treatment about 10% of cracked teeth have nerves that go on to die. The tooth can still move slightly within the bone; this slight movement can additionally flex and crack the tooth from below despite the crown protecting it from the top. Sometimes the existing bacterial damage is so great that the nerve goes on to die regardless of the treatment performed. Early treatment is therefore recommended to minimize the size of the crack and the extent of bacterial invasion.
What Will Happen If The Nerve Doesn’t Recover?
The nerve will die and an abscess will probably develop. Therefore, the dead nerve remnants should be removed and the inside of the tooth cleaned and sealed. This process is called root canal therapy or endodontic therapy. A small hole is made in the top of the crown and access obtained to the nerve for cleaning. Later the hole is filled with a permanent white plastic filling or a porcelain inlay sealed to the tooth. The other option is to cement the crown temporarily, so that in the event the nerve dies, the crown can be removed and recommenced permanently after root canal therapy has been performed. This saves having a hole drilled into your new crown. However, this comes with its own set of problems. Firstly, if the crown is put on with temporary cement, it will eventually come off. Depending on th type of cement and the retentive nature of the crown this could be anywhere from three months to five years. Usually, the crown will come off and you will notice it and retrieve it, so that all ends well. However, you may bite on it and break the opposing tooth, or swallow it accidentally; you need to consider these possibilities before you make your decision. If the temporary crown falls off, you can elect to have it recommenced again with a temporary cement or have it cemented permanently. If enough time has passed to decide with fair certainty that the nerve has survived, you may want to have it permanently cemented. Make sure you discuss this beforehand with your dentist; the time needed to reach a reasonable safety zone varies from 3 months to 3 years. Clinical judgment and many complex individual case factors need to be taken into account. Even so, some nerves still go on to die years later.
How Successful Is Root Canal Therapy?
The actual root treatment is about 95% successful. However, where there is a crack in the tooth which is not completely immobilized a further 10% of those root treated teeth will get continuing pain when the tooth is bitten on or sometimes pushed from the side. This is due to the crack movement irritating the tissues around the tooth. There is no treatment other than extraction for these rare cases. If you end up losing a tooth there are several options for replacement – a bridge (caps are placed on the two teeth on either side of the gap and fused to a false tooth resting just above the gum); a Maryland bridge (like the conventional bridge but with special metal wings instead of crowns); an implant into the bone which supports a new tooth; or a partial denture.
The advice provided here is intended to aid you in understanding some of the treatment options available. It is important to note that before beginning any course of treatment you should see your dentist.
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