A post
and core is a prosthetic
device that is recommended when there is inadequate tooth structure remaining
to support a traditional restoration or an artificial crown.
Post and core procedure is painless and does not even require local
anesthesia as the tooth has long been dead after the root canal treatment. A
post and core can only be made for a tooth that has had root canal treatment.
Some posts are ready made, whereas others are made in the
laboratory especially to fit the tooth.
Why
are post and cores needed ?
A great deal of dental crown stability depends on the amount
of tooth structure that extends into its interior. If very little tooth
structure occupies this space, the crown will be easily dislodged, especially
by forces directed at its side.
Basically, the core is rebuilding the tooth so it is
closer to its original dimensions. Hence, the crown's stability will greatly
increase, and therefore its long-term chances for success are maximized.
Is
a post always needed ?
A dental post is generally recognized as just an aid
in helping to anchor a dental
core to a tooth.
As a rule of thumb, if more than half of a tooth's
original crown portion has been lost, a post is needed to assist in anchoring
the core to the tooth. If more than half still remains, a core by itself (which
basically means a direct build up with composite materials) will probably
suffice.
Factors to
be considered in making the decision to use a post
Many have
stated that the main reason for placing a post is to strengthen the connection
between the coronal build-up material and remaining tooth structure to the root
portion of the tooth. In my opinion, that is only partially true. Additionally,
the following potentially negative or positive factors should be considered in
the decision to use a post. All of these factors should be observed before
making the decision:
• Quantity of remaining tooth structure
• Quality of remaining tooth structure
• Remaining adjacent teeth
• Occlusion
• Planned restoration to be placed on the tooth
When
is a post and core not indicated ?
There are certain conditions that make the use of a post and
core device inadvisable :
·
Intense pain, gingival bleeding, suppuration, advance
infections, tooth abscesses etc. These situations will be evaluated on a
case-by-case basis and the post and core should be placed with the greatest
caution.
·
Tooth shows advance mobility. Mobility is an indicator
of bone loss around the tooth and it should be evaluated on a dental X-ray as
well.
·
When the tooth crown is severely damaged (especially
when the tooth is fractured bellow the gumline) and the remaining part of the
tooth is not strong enough to support the post.
Structure
A post and core consists of two parts :
·
The
post
The post is a small
rod, usually metal/carbon fiber, which is inserted into the root space of the
tooth and protrudes from the root a couple of millimetres. The post is then
used to hold the core, or a filling in place.
Because the post is inserted into the root canal, a
post and core can only be made for a tooth that has had root canal treatment.
·
The
core
The core replaces
missing tooth structure in preparation for making a new dental crown. Normally,
a dental core can be directly built up from composite materials without a post
to hold it in place.
However, a dental post can be used to help to anchor
the core to the tooth. In this case, the core is generally made off metal
alloys and the device is called post
and core.
The core is then utilized to hold a dental crown in
place. The crown can be a single unit crown or a retainer crown for a dental
bridge.
Success
rates
The
procedure is successful in over 90% of cases.
Potential
risks
·
Tooth fracture
·
Root fracture
·
Root canal failure (it is difficult to repeat root canal
treatment once the post is in place)
·
Post coming out
·
Post protruding through the side of the root (this is a
particular risk if the root is curved)
After Dental Post And Core
Post procedure care
Patients should avoid eating on the crown, following a post
and core procedure. Certain foods, such as hard or chewy sweets, should be
avoided as the crown could become loose.
Possible discomfort
Some minor discomfort to be expected after this procedure,
but this can be easily controlled with normal painkillers.
