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Root Canal
Treatment
Introduction
Endodontics is the branch of dentistry that
deals with diseases of the tooth's pulp,
which is located in the center of the tooth
and in canals (called root canals) within
each tooth root. Pulp, consisting of
connective tissue, nerves and blood vessels,
nourishes the tooth when it first erupts
(emerges through the gum). Once the tooth
matures, the pulp can be removed safely from
the pulp chamber and root canals and the
tooth can be maintained. This is because the
tooth also is nourished by a blood supply
that surrounds the tooth. Removing the pulp
is called endodontic treatment, but it is
often referred to as root canal treatment or
root canal therapy. Many people refer to
this as "having a root canal." Root canal
treatments are quite common. They save an
estimated 24 million teeth each year in the
United States.
Do I Need Root Canal Treatment?
Root canal treatment is needed for two main
reasons: infection or irreversible damage to
the pulp. An untreated cavity is a common
cause of pulp infection. The decay erodes
the enamel and dentin of the tooth until it
opens into the root canal system, allowing
bacteria to infect the pulp. Infections
inside teeth don't respond to antibiotic
treatment. The inflammation caused by the
infection restricts the tooth's blood
supply, so antibiotics in the bloodstream
can't reach the infection very well. The
reduced blood supply also limits the pulp's
ability to heal itself.
The pulp also can become damaged from
trauma, a fracture or extensive restorative
work, such as several fillings placed over a
period of time. Sometimes, a common dental
procedure can cause the pulp to become
inflamed. For example, preparing a tooth for
a crown sometimes leads to the need for root
canal treatment.
In many cases, when the pulp is inflamed,
but not infected, it will heal and return to
normal. Your dentist may want to monitor the
tooth to see if this happens before doing
root canal treatment. Sometimes, though, the
pulp remains inflamed, which can cause pain
and may lead to infection.
Once the pulp becomes infected, the
infection can affect the bone around the
tooth, causing an abscess to form. The goal
of root canal treatment is to save the tooth
by removing the infected or damaged pulp,
treating any infection, and filling the
empty canals with an inert material. If root
canal treatment is not done, the tooth may
have to be extracted.
It is better to keep your natural teeth if
at all possible. If a tooth is missing,
neighboring teeth can drift out of line and
can be overstressed. Keeping your natural
teeth also helps you to avoid more expensive
and extensive treatments, such as implants
or bridges. If an infected or injured tooth
that needs root canal treatment is ignored,
not only can you lose the tooth, but also
the infection can spread to other parts of
your body.
Having endodontic treatment on a tooth does
not mean that you'll need to have it pulled
out in a few years. The reason for doing
root canal treatment is often a large
cavity. The tooth often is weakened, but if
the tooth is covered with a crown after the
root canal or, in some cases, restored with
tooth-colored composite filling material,
the tooth can last the rest of your life.
Signs and Symptoms
If you have an infection of the pulp, you
may not feel any pain at first. But if left
untreated, the infection will cause pain and
swelling. In some cases, an abscess will
form. Eventually, the tooth may need to be
extracted. Some indications that a tooth may
need a root canal are:
▪ A tooth that hurts significantly when you
bite down on it, touch it or
push on it
▪ Sensitivity to heat
▪ Sensitivity to cold that lasts longer than
a couple of seconds
▪ Swelling near the affected tooth
▪ A discolored tooth, with or without pain
▪ A broken tooth
To determine whether your tooth needs root
canal treatment, your dentist will place hot
or cold substances against the tooth, feel
surrounding tissues and gently tap on the
tooth. He or she also will take X-rays.
If the condition of the pulp isn't clear
from these tests, your dentist may use an
electric pulp tester. This hand-held device
sends a small electric current through the
tooth and helps your dentist evaluate
whether the pulp is alive. This test does
not cause pain or a shock, but a tingling
sensation that stops immediately when the
tester is removed from the tooth.
Caution:
An electric pulp tester should not be used
if you have a cardiac pacemaker or any other
electronic life-support device.
Length of Treatment
Root canal treatment can be done in one
or more visits, depending on the situation.
An infected tooth will need several
appointments to make sure that the infection
is eliminated. Some teeth may be more
difficult to treat because of the position
of the tooth, because they have many and
curved root canals that are difficult to
locate, or for other reasons. An
uncomplicated root canal treatment often can
be completed in one visit. Once the root
canal treatment is finished, you will need
to see your general dentist to have the
tooth restored with a crown or filling.
Measuring and Cleaning the Root Canals
Measuring
First, your dentist or endodontist will numb
the area around the tooth. You also may
receive sedation, such as nitrous oxide, or
your dentist may offer other
anxiety-reducing techniques if you feel you
need them. He or she will make a hole in the
top or back of your tooth to geet to the
pulp chamber. He or she will remove some of
the diseased pulp. Then the root canals have
to be measured.
Your dentist needs to know how long the
canals are so he or she can make sure all
the diseased tissue is removed and the
entire canal is cleaned. Also, the material
used to fill the canal after it is cleaned
needs to fill the entire canal.
Dentists use X-rays to determine the length
of the canals or use an electric device
called an apex locator. In the first
procedure, your dentist will place a file
into the canal he or she is measuring then
take an X-ray to determine how close the
file is to the end of the canal. An apex
locator makes a calculation based on the
resistance to a small electric current. This
gives an accurate measurement of a root
canal. Often, the two methods are combined.
Cleaning
After the canals have been measured, your
dentist or endodontist will use the
specially designed instruments to clean out
the diseased pulp. After the pulp has been
removed, the canal is cleaned with an
antiseptic solution, which helps to treat
the source of the infection.
For root canal treatment to be effective,
all the canals within the tooth must be
cleaned. Generally, the top front teeth have
one canal, the bottom front teeth one or two
canals, the premolars one or two, and the
molars three or four canals. However, the
location and shape of these canals can vary
significantly. Some endodontists are now
using a microscope to see inside the tooth
to make sure all the canals have been
located and all the pulp has been removed.
Once the canals have been thoroughly cleaned
and the endodontist or dentist has made sure
that the infection has been removed, the
roots are filled. A temporary filling is
then placed to cover the new root filling.
The crown of the tooth should then be
restored with a permanent filling or crown
within a relatively short time.
In most cases, the tooth will need a crown,
especially with molars that are under stress
from chewing. A crown will help to restore
the tooth's strength and protect it from
cracking. A crown should be placed as soon
as possible, ideally within a month of the
root canal. It's important to get the tooth
permanently restored to prevent damage to
the tooth later. The temporary filling you
receive is not meant to last.
The pulp that was removed during root canal
treatment is the part that responds to
temperature. The tissues and nerves
surrounding your tooth remain, however, so
your tooth will still respond to pressure
and touch.
After Root Canal Treatment
Your tooth may be sore for two to three
days after the procedure, and your dentist
will tell you to avoid chewing on the
affected side. The worse the infection and
inflammation was prior to root canal
treatment, the sorer the tooth will be after
treatment. You can take over-the-counter
pain relievers to ease the discomfort.
Possible Complications
As with most invasive medical or dental
procedures, complications can occur. Here
are some possibilities.
Sometimes when a root canal is opened for
treatment, the oxygen in the air will
trigger some bacteria to start growing,
causing inflammation and pain.
Bacteria may get pushed out through the tips
of the roots. Blood vessels enter the tooth
through a small hole (the apex of the root)
at the bottom of the root. Sometimes during
a root canal procedure, bacteria are pushed
out through this small hole into surrounding
tissue. If this happens, the surrounding
tissue will become inflamed and possibly
infected. This can be treated with
painkillers, and sometimes antibiotics, but
the site could be painful until it clears
up.
A root canal treatment can puncture the side
of the tooth. This can happen if the canal
is curved or if the canal cannot be located.
The instruments are flexible so that they
bend as the canal curves, but sometimes the
instrument makes a small hole in the side of
the tooth. If saliva can get into the hole,
the tooth will have to be treated further or
extracted. If the hole is far enough under
the gum line that saliva can't reach it, it
may heal.
A root canal may be missed or an entire
canal may not be fully cleaned out. Locating
canals within the tooth can be difficult. If
a canal or an offshoot of a canal isn't
located and cleaned out, the tooth can
remain infected and the root canal procedure
will have to be repeated. This also can
happen if a canal isn't measured correctly
and pieces of infected or inflamed pulp are
left near the bottom. Occasionally, root
canals have branches that are not accessible
to traditional treatment.
A file may break. The tip of a file may
break off inside the tooth. Usually, it's
possible to leave the piece in the tooth and
finish the root canal. But if the cleaning
of the canal has not been finished, the file
piece may have to be removed. Sometimes this
can be done from the top of the tooth.
However, in some cases, the file can only be
removed through a surgical procedure called
an apicoectomy. A small incision is made in
the gum to access the root of the tooth, and
the portion of the root containing the file
piece is removed.
Pain, or the Lack of It
In most cases, you will not experience
any pain during the root canal procedure.
Your dentist will completely numb your tooth
and the surrounding area. If this doesn't
seem to be working, alert your dentist right
away. Some people fear the anesthetic
injections more than the procedure itself,
but numbing gels and modern injection
systems have made injections virtually
painless. Let your dentist know immediately
and he or she can modify the technique to
avoid repeating the pain.
In addition to anesthetic, you may receive
sedation, such as nitrous oxide treatment.
You can take over-the-counter pain relievers
to ease the discomfort.
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