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A dental crown is a tooth-shaped "cap" that is placed over a tooth – covering the tooth to restore its shape, size and strength, and/or to improve its appearance.The crowns, when cemented into place, fully encase the entire visible portion of a tooth that lies at and above the gum line.
Why is a dental crown needed?
A dental crown may be needed when at least one of the following occurs:
- To protect a weak tooth (for instance, from decay) from breaking or to hold together parts of a cracked tooth
- To restore an already broken tooth or a tooth that has been severely worn down
- To cover and support a tooth with a large filling when there isn't a lot of tooth left
- To hold a dental bridge in place
- To cover misshaped or severely discolored teeth
- To cover a dental implant
What types of crown materials are available?
Permanent crowns can be either all metal, porcelain-fused-to-metal, all resin, or all ceramic.
Porcelain-fused-to-metal dental crowns can be color matched to your adjacent teeth (unlike the metallic crowns). However, more wearing to the opposing teeth occurs with this crown type compared with metal or resin crowns. The crown's porcelain portion can also chip or break off. Next to all-ceramic crowns, porcelain-fused-to-metal crowns look most like normal teeth. However, sometimes the metal underlying the crown's porcelain can show through as a dark line, especially at the gum line and even more so if your gums recede. These crowns can be a good choice for front or back teeth.
Porcelain-fused-to-zirconium-oxid
This innovative system combines the durability of porcelain fused to metal bridges with the aesthetic appearance of metal–free crowns. This system is based on the material zirconium-oxide.
Nowadays we can hear more and more about the probable allergic effects of metals applied in dentistry. Therefore the use of a material having the same good mechanical properties as metals but doesn't affect allergic reactions in human organism became necessary. While zirconium oxide does not have any allergic effects described in scientific publications, this material can be told as "biocompatible". It appertains to his good qualities that it conducts heat very badly, so the patients do not complain about cold or heat sensitiveness. This material is produced with the help of the most modern CAD/CAM computer technologies. Zirconium oxide crowns and bridges are the most aesthetic solutions.
The traditional crowns have a porcelain layer burnt on a metal cap, so its light permeability is weak. The light permeability of porcelain crowns burnt on zirconium oxide look like the own natural teeth. Because there aren't any metal caps, the dark metal frame-edge of the crown will not be visible if the gums may draw back in after years. |
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All-resin dental crowns are less expensive than other crown types. However, they wear down over time and are more prone to fractures than porcelain-fused-to-metal crowns.
All-ceramic or all-porcelain dental crowns provide the best natural color match than any other crown type and may be more suitable for people with metal allergies. However, they are not as strong as porcelain-fused-to-metal crowns and they wear down opposing teeth a little more than metal or resin crowns. All-ceramic crowns are a good choice for front teeth.
Temporary versus permanent. Temporary crowns can be made in your dentist's office whereas permanent crowns are made in a dental laboratory. Temporary crowns are made of acrylic or stainless steel and can be used as a temporary restoration until a permanent crown is constructed by the dental laboratory.
Dental veneers:
Veneers are a way to change the appearance of your teeth. Veneers are thin porcelain made coveringsshells of tooth-coloured material which are bonded to the front of the tooth. Veneers are fabricated by a dental technician in the dental laboratory from the impression provided by the dental office.Veneers are used to cover gaps or teeth that are stained, poorly shaped or crooked.Veneers may last from 3 to 12 years or longer.
A
denture is a removable replacement for missing teeth. A denture
is made of acrylic resin, sometimes in combination with various
metals, and comes in two types; complete denture or partial denture.
Complete dentures replace all the teeth, while a partial denture
fills in the spaces created by missing teeth and prevents other
teeth from changing position.
Complete dentures are either "conventional" or "immediate."
A conventional denture is placed in the mouth about a month after
all the teeth are removed to allow for proper healing, whereas an
immediate denture is placed as soon as the teeth are removed, however
a drawback to the immediate denture is that it may require more
adjustments after the healing has taken place.
People who have lost most or all of their teeth are ideal candidates
for complete dentures. A partial denture is suitable for those who
have some natural teeth remaining.
Advantages of using a denture are that it improves chewing ability,
speech and provides support for facial muscles whilst greatly enhancing
the facial appearance and smile.
Fitting
a denture takes about one month and five appointments. The process
required to have a denture fitted is more complex than people think
and follow the following pattern. An initial diagnosis is made then
an impression and a wax bite are made to determine vertical dimensions
and proper jaw position. After the taking dimensions a "try-in"
is placed to assure proper color, shape and fit. Only after these
steps have been taken is the patient's final denture placed.
New denture wearers need time to get accustomed to their new teeth
because even the best fitting dentures will feel awkward at first.
While most people can begin to speak normally within a few hours,
many people report discomfort with eating for several days to a
few weeks after having dentures fitted. |
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A denture is fragile, so it is important to handle it with care.
Cleaning the denture is also important and requires the removal
and brushing of the denture daily, preferably with a brush designed
specifically for cleaning dentures. You should never use harsh,
abrasive cleansers, including abrasives toothpastes, when cleaning
dentures as they may scratch the surface of the denture. Sterilizing
your denture with boiling water will cause it to become warped and
is not a good idea.
If you wear a partial denture remove it before brushing your natural
teeth and when not in use soak it in a cleanser solution or in water.
While you may be advised to wear your denture almost constantly
during the first two weeks under normal circumstances it is considered
best to remove dentures at night as research has shown that removing
the denture for at least eight hours during either the day or night
allows the gum tissue to rest and allows normal stimulation and
cleansing by the tongue and saliva. This promotes better long-term
health of the gums.
To maintain a proper denture fit over time, it may be necessary
to adjust your denture or possibly remake your denture. Never attempt
to adjust a denture yourself and do not use denture adhesives for
a prolonged period because it can contribute to bone loss.
Dentures are no longer the only way to restore a mouth that has
little or no non-restorable teeth. Strategically placed implants
can also used to support permanently cemented bridges, eliminating
the need for a denture. The cost tends to be greater, but the implants
and bridges more closely resemble the feel of real teeth, although
not everyone is a candidate for implants.
Sometimes dentures or partial dentures may irritate soft tissues
in the mouth. If the irritation continues, a person may develop
mouth sores, which can be found on the upper jaw, lower jaw, under
the tongue, or on the palate. They are usually red and a little
swollen. The main causes of theses denture sores include alcoholism,
allergies, smoking and chewing tobacco.
An overdenture is a type of denture that is secured by precision dental attachments. The attachments are placed in tooth roots or dental implants, which have been placed specifically for the overdenture attachment. Types of overdentures include bar joint dentures and telescopic dentures.
If you lose most or all of your lower teeth, there is nothing to hold a denture down while you chew. An overdenture fastens a denture to the jawbone, much in the way natural teeth are anchored. The adjacent teeth may be altered with locking devices or connecting bars to ensure the denture fits properly. These bar joints support the dentures better than individual implants, though implants are still required to support the bars. Generally, the more implants, the stronger the bar, and bars on the upper arch always require more implants than bars on the lower arch due to the lesser bone density in the upper jaw.
When patients have compromised bone density due to age or oral disease, a telescopic denture, a type of overdenture system is probably the best option.
The procedure consists of a double crown system, “the telescopic," and involves fitting inner metal crowns and outer crowns on the remaining natural teeth to create a natural looking removable overdenture. |
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Though this is a reliable denture system that ensures even bite stress distribution, the procedure is extremely complicated and requires root canal therapy for each remaining natural tooth and the insertion of a metal post to ensure the root is strong enough.
Some of the benefits of overdentures include the prevention of bone loss (dental implants actually strengthen the surrounding bone structure), esthetic appeal, improved speech (when compared with other types of dentures), proper jaw alignment, and improved chewing efficiency.
These overdenture systems can last a lifetime and increase chewing power by up to 300%. |
