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Why do Teeth Crack?
Will My Grinding Habit Make It Worse?
Why Does It Hurt So Much To Bite On It?
Why Is It Sensitive to Hot and Cold?
What Will Happen If I Just Do Nothing?
What’s The Usual Treatment For A Cracked Tooth?
Is It Possible That The Nerve Is Already Dead?
Is It Safe to Leave A Tooth With a Dead Nerve?
If The Nerve Is Dead, Do I Still Need a Crown?
Doesn’t The Nerve Always Recover?
What Will Happen If The Nerve Doesn't Recover?
How Successful Is Root Canal Therapy?
Why do Teeth Crack?
Cracked tooth
syndrome is a very common problem usually affecting teeth that have large
fillings.
Like all
materials, teeth are subject to the forces of stress fatigue. Hairline
fractures can and
do develop;
they generally occur at the bottom corner of the restoration.
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’ve worn down your canines and lost
the protective 'lift-off' effect they afford 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.
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 tubules situated in the dentin
(the inner layer of the tooth between the pulp and
enamel). These tubules run down to the nerve;
as the tooth flexes , the crack opens and closes,
causing fluid to flow in and out of the tubules
and apply pressure on nerve. This is perceived as pain.
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 sensitivity to hot and
cold.
What Will Happen If I Just Do Nothing?
The crack will slowly enlarge. 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
not a good idea to 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, resulting in an
abscess.
What’s The Usual Treatment For A Cracked Tooth?
Unless the crack is immobilized, the tooth is
very likely to deteriorate. 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 around the roots of 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
(dead teeth are far more brittle.) Regardless
of how a nerve dies, crack or no crack, it is
standard practice to put a crown on a tooth
that has had root canal treatment because of its
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 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 recemmented after
root canal therapy has been performed. This saves having to drill an additional acces hole through
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 the type of cement and the
retentive nature of the crown this could be anywhere from three months to five years. If the
temporary crown falls off, you can elect to have it recemmented
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?
Root canal treatment is about 95% successful. However, 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.
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