Porcelain Veneers

Porcelain veneers are a wafer-thin shell bonded to the front, side and edge of a tooth, designed to change the way it looks. Although porcelain is inherently brittle, when it is firmly bonded to a sturdy substructure like tooth enamel it becomes very strong and durable. They work best on teeth which have few or only small fillings and which require minor modification of shape or colour.

They may be used to improve teeth that are lightly discoloured, worn, chipped or slightly misaligned.

They are used to improve teeth that are:

Lightly discoloured.
Worn.
Chipped.
Slightly misaligned.

Porcelain veneers are usually chosen because of their exceptional aesthetics and because they involve much less tooth reduction compared to crowns. Being glass-like is a great advantage over other types of cosmetic dental bonding because of translucency. When they are bonded onto a tooth’s surface they mimic the light handling characteristics of the enamel beneath. This translucency provides a sense of depth, and thus a very life-like appearance. Being glass-like also means an extremely smooth and impervious surface that will not pick up permanent stains.

How long should veneers last?

There are no hard and fast rules about how long porcelain veneers will last.

While you can certainly expect veneers to last many years, it is unrealistic to expect them to last forever. With good home care and by exercising good judgment, it seems likely that a porcelain veneer could last well in excess of ten years.

Tips for maximizing the lifespan of your porcelain veneers include:

Practice good oral home care.
Avoid exposing porcelain veneers to excessive forces.
Avoid clenching and grinding the teeth.
Minimize influences which stain near the edges of the veneers (coffee, tea, smoking).
Wear a nighttime protective appliance (splint) to minimize the effects of nighttime grinding or clenching.

What is involved in preparing a tooth for a veneer?

Preparation (one, but sometimes two appointments):

Removal of existing filling materials from the tooth or teeth to be veneered.
Replacement of any underlying fillings with composite resin).
Veneer preparation (removal of 0.5–1.5mm of tooth structure from the front and biting edge of the tooth).
Detailed impression.
Impression of the opposing teeth, face bow and bite registration.
Provisional veneer construction.

Issue (usually 2 weeks later):

Removal of the provisional restorations.
Cleaning of the tooth and isolation of the margin.
Bonding of the veneers.

Crowns

What are crowns?

A crown is a cap that fits over and around a tooth to protect it. Some tooth structure must be removed to make room for it but, once it is cemented into position, it usually makes the tooth much stronger and better looking than it was before. Crowns can also be placed on implants.

The pictures above have had some badly broken down teeth restored with ceramic and zirconia crowns.

If a tooth is missing, crowns may be placed on the adjacent teeth or implants (the "abutments"). These are then used to to support a false tooth (the "pontic") or teeth in between. Bridges are thus essentially three or more crowns all fused together to replace a missing toothe or teeth. Bridges restore aesthetics and stability the bite after a tooth is lost.

Materials used:

There are many materials available today and whether one is recommended over another depends on the patient's specific need.

They may include:

Metal ceramic (porcelain fused to high noble, semi-precious or non-precious alloy). Our practice only uses high noble alloys in its crowns.
All ceramic. In some situations these may have better aesthetics than metal ceramic but slightly reduced fracture resistance.
Gold. The beauty of gold is it will not fracture, even in the most severe bruxer. It is the best material from a functional point of view but these days is generally used only at the back of the mouth in patients with a history of breakage of other materials.
Composite resin or acrylic resin. These are only for provisional crowns.

Reasons why teeth are crowned;

Large, worn, fractured or defective fillings. Crowns can work where there is not enough tooth structure to support a normal filling. Once a tooth is 70% filled, it is best restored with a crown to hold what is left together and help prevent future tooth fractures.
Fractured teeth caused by cracks, trauma, large unsupported fillings or habitual or accidental grinding and clenching. A crown can physically bind the cusps together preventing them from flexing under load. Of course it also makes a broken tooth look good again.
Endodontically treated teeth (teeth which have had a root canal therapy). If a tooth is not restored promptly bacteria can contaminate the root canal therapy or cause recurrent decay. Molars and premolars that are endodontically treated are at risk of root fracture. An appropriate crown can give them an excellent long term prognosis.
Missing teeth. Shifting and tipping of adjacent teeth can lead to changes in the jaw muscles, bones and joints, and make chewing and cleaning harder.

Stages involved in constructing crowns:

Preparation (usually one, but often two appointments).
Removal of existing filling materials from the tooth, or teeth, to be crowned.
Core or foundation buildup (composite resin).
Crown preparation (removal of 1-1.5mm of tooth structure from the top and sides of the tooth).
Provisional crown or bridge construction.

Detailed impression: