The treatment of Cracked Tooth Syndrome is fairly complex and you may not remember all the details mentioned to you at the time of your visit. To help you remember we are providing you with this web page. Please read every word of it so you are fully informed, and prepared for all eventualities.
In the past, we have had problems when some patients have not been prepared for some eventualities, which can be time consuming and expensive. Therefore, in the interests of the best possible relations with our patients, avoiding problems before they happen, and the principle of being "fully informed", we have prepared the following question and answer page for your consideration.
Why do teeth get cracks?
Cracked tooth syndrome is a very common problem, usually affecting teeth that are heavily filled. The decay and subsequent filling causes a weakening of the remaining tooth structure. Like all materials, teeth are subject to stress fatigue. After many bites on the tooth (stress cycles), a hairline fracture can develop, usually at the bottom corner of the cavity. If you are under a lot of psychological stress, you may grind your teeth (usually at night).
Does grinding my teeth make it worse?
Yes... almost every person who is self employed, at management level, or Type A personality will at some time in their life, grind their teeth. It is a very common habit. Unknown to you, grinding at night causes a massive increase (200-300%) in the stress and strain on your premolars and molars, especially if you have worn down the canines and lost the protective effect they can give in sideways grinding jaw 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 unlucky tooth anatomy (genetic) or worn down fillings, where to "valleys" on top of splitting forces on the tips of the tooth during chewing, leading to cracking. Even unfilled teeth can get cracks.
Why Does it hurt to bite on?
As the tooth flexes microscopically, the nerve is stimulated via tiny tubes ('tubules') which are situated in the dentine (the inner core of the tooth, below the enamel). The tubules run down to the nerve and the fluid moves in them - which you feel as a sharp pain.
Why does it sometimes hurt to hot and cold?
The nerve is aggravated by the crack and by the bacteria being pumped into it via the tubules. It becomes inflamed because of the toxins in the bacteria. A classic symptom of nerve inflammation is hot and cold sensitivity
If I do nothing what eventually happens?
The crack continues to slowly propagate (spread) like a crack in glass. Sometimes the crack goes off to the side and the fragment of tooth breaks off. The crack can also go deep into the root and at times right into the nerve. Teeth can often go for months in a stable, yet inflamed condition. Sometimes they seem to get better, only to suddenly get worse. It is hard to predict the course of the untreated tooth, but usually it is a slow downhill slide as the crack deepens. It is not a good idea to leave it, because a small crack can be treated effectively, but a bigger one can lead to root canal treatment or extraction if you are unlucky. The nerve can be attacked by the bacteria, leading to extreme sensitivity to hot and/or cold and a persistent ache in the tooth as it dies, usually of moderate to severe intensity. The infection in the nerve can then spread into the bone underneath, causing an abscess. This pain is usually severe, not effectively controlled by pain killers.
What is the best way to treat C.T.S?
Unless the crack is immobilized and splinted together 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 fairly unpredictable and ineffective. The only real solution is to bind the whole tooth together with a 'cap' or 'crown' (same thing), so that any chewing force moves the tooth as a whole, rather than splitting it apart.
What colour will this tooth be?
Most people prefer a natural appearance, therefore a porcelain fused to metal crown is made in most cases. You can have gold if you prefer, or if you want something really natural looking, choose one of the new all porcelain crowns (metal free). Because most cracked teeth have large black amalgam fillings, a net improvement in appearance results, which is some small compensation for the time and expense involved.
Are there any other advantages to a full crown?
The crown is bonded over the entire tooth - this seals all micro-cracks and the variety of sources of bacterial leakage coming from the joints in the patchwork of fillings typically in these teeth. The nerve is now given its best chance at recovery because it has been hermetically sealed and the crack has been immobilized - but not necessarily a complete immobilization.
Can you guarantee that the nerve will recover?
No! Despite the best treatment about 10% of cracked teeth have nerves that go on to die. The tooth can still move slightly within the bone and this slight movement can flex the crack from underneath despite the crown on top. Sometimes the existing bacterial damage is so substantial, and the damage to the nerve is so severe that the nerve goes on to die regardless of what we do. Early treatment is therefore recommended to minimize the size of the crack and bacterial invasion.
What will happen if the nerve does not 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 (RCT) or Endodontic Therapy. A small hole is made in the top of the crown (it can not be removed without the risk of breaking the tooth or crown) and access obtained to the nerve for cleaning. Later on, the hole is filled in with a permanent, white plastic filling or porcelain inlay sealed to the tooth and the crown. It is a pity to have a hole in the crown, because it may weaken the crown slightly, but it is a quick and uncomplicated solution to the problem, with few long term problems. The white filling will match the crown reasonable well, but don't expect it to be absolutely invisible against the top of the crown. For most people, it's not a problem. If the hole really worries you, a new crown can be made if you don't mind the additional expense. There is another option, and that is to cement the crown with a temporary cement, so that in the event of the nerve dying, the crown can be removed, and recemented later when the RCT is completed. This saves having a hole drilled in it, but comes with it's own set of problems - and you must decide if you are prepared to accept these. First, if the crown is put on with temporary cement, it will come off one day. Depending on the type of cement and the retentive ability of the crown this could be three months to five years. Usually, 99% of the time, the crown will come off and you will notice it and retrieve it, so that all ends well. However, you may bite on it, break it or swallow it accidentally - so you need consider these possibilities before you make your decision, because you may be up for the cost of repair or a new crown.
After the crown falls out you can elect to have it recemented again with temporary cement or have it cemented permanently. If enough time has passed to decide with a fair degree of certainty that the nerve has survived, you may want to go permanent. Discuss this with your dentist, because the time needed to reach a reasonable safety zone varies from 3 months to three years..... clinical judgment and many complex individual case factors need to be taken into account, and even despite the best efforts, some nerves go on to die after permanent cementing (sometimes years later). Your should also note that the cost of making your crown includes cementing it once only. If you elect to cement it with temporary cement, extra expense will be involved.
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 know as the periodontal ligament. There is no treatment other than extraction for these rare cases. If you end up losing the tooth there are several options for replacement - an implant into the bone which supports the new tooth; a conventional bridge (caps on the teeth on either side of the gap, 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 - but not universally applicable) or a partial denture. The advantages and disadvantages of each of these are discussed in other Patient Education Literature.
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