DENTAL CROWNS..................
What
are dental crowns?
Crowns are a type
of dental restoration which, when cemented into place, fully
cup over the portion of a tooth which lies at and above
the gum line. In comparison, fillings are dental restorations
that are used to fill in or cover over just a portion of
a tooth. Since dental crowns encase the entire visible aspect
of a tooth, a dental crown in effect becomes the tooth's
new outer surface.
Crowns can be made
out of porcelain (or some other ceramic material), gold
(or metal alloys), or a combination of both. Dental crowns
are often referred to as "dental caps" or "tooth
caps".
............................................................................................
Crown
Failures - An Anatomy
Loose Poor Fitting Crowns
Dental crowns can become loose or poor fitting for a variety
of reasons. Bite and occlusal issues are commoncauses...
as well as generalized trauma to the affected tooth.
Three of the more common groups of
factors that are attributed to loose fitting crowns are
addressed here:
First Possiblity
- The crown is old and has decay under it. The tooth structure
is soft and decayed and there no longer is enough retention
or insufficient tooth structure to hold the crown in place.
A new crown needs to be made (old
crowns typically cannot be re-used). The decay needs to
be removed and the tooth may need to be built up. A restorative
or reconstructive build up is made of bonding material designed
to attach to the remaining tooth structure which will give
the crown more surface area for retention.
Second Possibility - The
crown is new and there is not enough tooth structure to
hold it in place. The dentist should know if there is enough
tooth structure to hold a crown and it would be rare for
a dentist tocharge for a crown that he or she just made.
Third Possibility -
Moisture or other foreign material is contaminating the
cementing procedure and thecement cannot harden properly.
......................................................................
DENTAL CROWN FACTS
Crowns in Dentistry
Dental Crowns - Things to
Know about Dentistry
Many people wonder about how long a crown should last and
if the life of a crown depends mostly on oral hygiene and
other factors. Another popular question is whether a cavity
can develop under a crown.
First... there is no general rule
about how long a crown should last.
The factors involved with longevity
are the specific materials used, the type of crown, the
quality of the laboratory engaged in the manufacture, the
competence of the dentist and the level of cooperation the
patient was able to provide during the procedures.
Gold crowns will outlive porcelain
crowns 3 to 1. Different studies indicate crown tend to
endure for 4-10 years depending again on the materials.
Certainly excellent oral hygiene can improve the life expectancy,
however everything man makes fails. Car tires, shoes, stereos
and yes dental repairs wear out.
Dental restorations are subjected
to 24/7 of being bathed in saliva, being pushed and shoved
on and generally surrounded by bacteria just waiting for
their turn at further destruction.
Crowns should probably be replaced
when its functional value has been discovered to be imminently
short. But just because a crown is old, does not necessarily
indicate that it needs to be replaced.
COSMETIC DENTISTRY - PORCELAIN CROWNS
