Crowns
At Amirad Family Dentistry, we make it our aim to educate our patients as much as possible. So that we can come up with a treatment plan that best suits your personal and financial situation. At Amirad Family Dentistry we offer one appointment crowns!
Rejuvenate the health of your teeth
A crown or ‘cap’ is used to completely cover a damaged tooth and maybe used for esthetic or functional reasons. Besides strengthening a severely broken down tooth. It can also be used to improve appearances, Shape and even alignment of teeth.
Crowns are quite often used to strengthen root canal treated teeth as these teeth are more brittle and likely to fracture.
Crowns may also be used in case of large irritable fillings. Aging teeth or improper bite due to excessive grinding of teeth and also use in dental implant for replacing missing teeth.
you might have a crown over a molar that rarely shows, except when you yawn widely, or you might have crowns on your front teeth that were specifically designed to match your other teeth.
Several factors are important to consider when choosing a crown, including:
• Cost
• Strength
• Durability
A natural appearance that doesn’t detract from your smile may also be a priority for you- A dentist can discuss the various options and help you to figure out what best meets your needs.
Indications
• Replace existing crowns which have failed
• Restore the form, function and appearance of badly broken down, worn or fractured teeth, where other simpler forms of restorations are unsuitable or have been found to fail clinically.
• Improve the aesthetics of unsightly teeth which cannot be managed by simpler cosmetic and restorative procedures.
• Maintain the structural stability and reduce the risk of fractures of extensively restored teeth including those which have been endodontically treated.
Traditionally, it has been proposed that teeth which have undergone root canal treatment are more likely to fracture and therefore require cuspal protection by providing occlusal coverage with an indirect restoration like crowns. This led to routine prescribing of crowns for root-treated teeth.
Types of dental crowns
The choice (s) of crown restoration can be described by:
The dimensions and percentage coverage of the natural crown:
• 3/4 and 7/8 crowns
• Full crowns
Material to be used:
• Full metal crown
• Full ceramic crowns
• Metal-ceramic crowns
• Composite resin
• A combination of materials
These restorations are a hybrid between an Onlay and a full crown. They are named based on the estimated wall coverage of the walls of the tooth. They are normally fabricated in gold. These crowns are not commonly prescribed in practice because they are technically difficult and poor patient acceptability due to the metal showing through in their smile.
As the name suggests, these crowns are entirely cast in a metal alloy.
The American Dental Association categories alloys in three groups:
• high noble
• noble
• base metal alloy
Noble and high noble are generally based on alloys of gold.
ADVANTAGES
• They are strong and highly resistant
• They are long-lasting
• Less proportion of your natural tooth needs to be removed
• They wear down quite slowly, just like the natural enamel
• They are ideal for posterior restorations
DISADVANTAGES
• poor aesthetics: They obviously don’t look like a natural tooth
• Gold alloy crowns can affect some people and produce some side effects such as allergic reactions or swelling
Cast base-metal alloys are rarely used to make full metal crowns. They are stronger and harder and thinner (0/3 mm) and cause excessive wear on real opposing teeth.
Dental ceramics or porcelains are used for crowns manufacture primarily for their aesthetic properties compared to all metal restorations. These materials are generally quite brittle and prone to fracture. The simplest classification of dental ceramics based on the material from which they are made i.e. silica, alumina or zirconia.
ADVANTAGES
• Porcelain crowns provide the best and more natural look
• The best option for front tooth restorations
• They are biocompatible, that means no metal is used, so they are Toxic-free.
DISADVANTAGES
• They are not as strong as metal crowns. Porcelain crowns can last long but they have to be well taken care of
• They may be more costly than other types of crowns, such as metal crowns.
a- silica
Silica- based ceramics are highly aesthetic due to their high glass content and excellent optical properties due to the addition of filler particles which enhance opalescence, fluorescence which can mimic the colour of natural enamel and dentine. These ceramic, however, suffer from poor mechanical strength, and therefore often used for veneering stronger substructures.
Examples include: alumina silicate glass, feldspathic, synthetic porcelain, and leucite reinforced ceramics.
Mechanical properties can improved by the addition of filler particles, lithium disilicate, and are therefore termed glass ceramics.
Glass ceramic can be used alone to make all-ceramic restorations or can act as a substructures subsequent veneering with weaker feldspathic porcelain.
b- Alumina
Alumina was introduced as a dental substructure (core) in 1989 when the material was slip cast, sintered, and infiltrated with glass. More recently, glass- infiltrated alumina cores are
produced by electrophoretic deposition.
Glass-infiltrated alumina has significantly higher porcelain bond strength over CAD/CAM produced zirconia and alumina cores without glass.
Alumina cores without glass are produced by milling pre-sintered blocks of the material utilizing a CAD/CAM dentistry technique.
All alumina cores are layered with feldspathic porcelain to make true-to-life color and shape.
Alumina cores have better translucency than zirconia but worse than lithium disilicate.
C- Zirconia
Zirconia is the hardest known ceramic in industry and the strongest material used in dentistry, it has to be fabricated using a CAD/CAM process but not the conventional manual dental technology.
The zirconia core structure can be layered with tooth tissue-like feldspathic porcelain to create the final color and shape of the tooth.
Because bond strength of layered porcelain fused to zirconia is not strong, chipping of the conventional veneering ceramic frequently occurs, crowns and bridges are now a day increasingly made with monolithic zirconia crowns produced from a color and structure graded zirconia block, and coated with a thin layer of glaze stains.
d- CEREC
The CAD/CAM method of fabricating all-ceramic restorations is by electronically capturing and storing a photographic image of the prepared tooth and, using computer technology, crafting a 3D restoration design that conforms to all the necessary specifications of the proposed Inlay, Onlay or single-unit Crown; there is no impression.
After selecting the proper features, the dentist directs the computer to send the information to a local milling machine. This machine use specially bar to mill the restoration from a solid ingot of a ceramic of pre-determined shade to match the patient’s tooth. After about 20 minutes, the restoration is complete and the dentist can sections it and cement the restoration immediately.
Porcelain fused to metal (PFM) crowns is another widely used type of dental crowns.
They provide both strength (due to their metal structure) and aesthetics (due to the porcelain coat that covers the cap).
ADVANTAGES
• They provide great aesthetics and durability
• They are less costly than all porcelain crowns
DISADVANTAGES
• The metal in these crowns may cause a grey line over the gum line.
This may not give the 100% aesthetic look that all porcelain crowns provide.
• For people who clench their teeth, this type of crown, May wear down more easily against the opposing teeth.
Composite resin dental crowns are less expensive than other crown types. However, they wear down over time and more prone to fractures than PFM crowns.
There are a few questions you may ask!
So what should I consider when getting a dental crown?
How long do dental crowns last?
What is possible complications of having a crown?
What steps are involved in preparing a tooth for a crown?
Does a crowned tooth require special care?
How much do crowns cost?