Dental Crowns

Why a crown?
A crown can be done for any number of reasons:

  • Broken tooth
  • Root canal treated tooth (to protect it from breaking)
  • Large old filling (that can no longer support the tooth)
  • Reshape tooth (for appearance and/or improved bite)

A filling really only repairs a small hole. To rebuild, reshape, or protect a
substantial part of your tooth, a filling just won’t do the job, and a crown
is preferred. A crown is also called a cap.

Sometimes, a filling is not sufficient for long-term strength, yet there is quite a bit of healthy tooth. In this instance a partial crown or inlay is appropriate.

tooth1

Making a Crown

The tooth is reshaped or “prepared”, often including rebuilding part of the tooth with a crown build-up. The amount of enamel removed is exactly the thickness of the crown (about 0.5-2 mm, depending on materials used: less with all metal, more with porcelain). A mould is made of this tooth (the mould usually includes adjacent teeth and the teeth that this one bites against). From this mould the laboratory constructs your crown (the porcelain colour is matched to your tooth). While the crown is being constructed you have a temporary crown on your tooth. It takes about 10 working days before your crown is back from the laboratory. At the second appointment, the crown is bonded on your tooth (you may need to have anaesthesia and/or nitrous oxide if your tooth is sensitive).

What is a crown made of?

A crown can be made from different materials: all porcelain, gold alloy (white or yellow), porcelain and gold alloy, other metal combinations (I only use noble or high noble metals). Different situations often suggest different materials to be used depending on durability, aesthetics, and physical limitations – this is determined in concert with your wishes. When a porcelain crown is made, I match the shade(s) of your adjacent teeth for the new crown, so that it is indistinguishable.

Classification of Metals:

The noble metal classification system has been adopted as a more precise method of reporting various alloys in dentistry commonly used in crowns, bridges and dentures. These alloys contain varying percentages of gold palladium and/or platinum.

High Noble contains more than 60% of gold, palladium, and/or platinum (with at least 40% gold)

Noble contains more than 25% gold, palladium and/or platinum

Predominantly Base contains less than 25% gold, palladium and/or platinum

Care of your temporary crown

The temporary crown is usually made of plastic (it can also be metal), and is not intended for long-term wear – usually for 2-6 weeks (longer in certain situations). It is to protect the tooth from sensitivity (temperature, touch), protect the gums, and to hold the bite (keep the adjacent and opposing tooth from shifting). A temporary crown is like a temporary tire, it is sufficient for short-term, careful use.

Brush, floss, Waterpik, clean, etc. as usual, except, when you floss pull the floss through instead of up/down, so as not to dislodge the temporary crown. Avoid sticky things that could pull off your temporary crown.

Care of your tooth and gum

The gum is often a little irritated next to the crown. A salt water rinse is very helpful – a teaspoon of salt in a warm glass of water, rinsed gently a couple times a day, until your gum feels better. Advil, aspirin, or Tylenol before the anaesthesia wears off is always helpful.

What if the temporary crown comes off?

If it is only a day or two before your visit to try in your new crown, and the tooth is not sensitive, you can leave it out – BUT save it! If the time is greater before your appointment, you can put it back in temporarily with Vaseline, but call to have it re-cemented. Without the temporary crown on, adjacent and opposing teeth can shift, sometimes so much that the permanent crown won’t fit.

What’s next

At your next appointment, the temporary crown is gently removed. If your tooth is sensitive, you may require some anaesthesia (or laughing gas). Your new crown is tried in to check it for: fit, colour, shape and appearance, bite, fit between teeth, seal against your tooth. If everything is correct and it meets your approval, it is cemented with long-term cement. Treat the crown as if it is your own tooth, especially for cleaning. It is not uncommon to experience a little sensitivity to cold after getting a new crown, but this should diminish quickly (over a couple weeks).

There is a process available for making a permanent crown in one-visit. At this time we feel that this type of crown (Cerec 3) does not yet meet the accuracy (occlusion, contacts, anatomy) and aesthetics (translucency, natural colour) that our laboratory can create. If and when it does, we look forward to offering this service.

What is a dental crown?

As we get older, many of us discover that our teeth that are no longer as structurally sound as they were in our youth. Your regular dentist will usually be able to recognize problem areas which may lead to tooth damage and a need for dental crowns.

Grinding your teeth, an improper bite, age, fillings and tooth decay are all contributing factors in the erosion, cracking or breakage of your teeth. If the entire surface of the tooth is damaged, but the root system has remained intact, your dentist will usually suggest that a dental crown be put in place.

Dental crowns are also capable of replacing missing teeth entirely. The dental crown is secured to the teeth on either side using a bridge section which connects the two dental crowns. Alternatively, single tooth dental implants can be placed. This eliminates the need for supporting the dental crowns so no bridge is required.

So, we may recommend the placement of a dental crown for a wide range of problems but, in general, the majority of these reasons usually fall within one of the following basic categories:

The restoration of a tooth to its original shape

The strengthening of a weak tooth

To improve the aesthetic appearance of a tooth

Metal-Free Crowns ( Procera, CERCON, IPS, LAVA, ZIRCON)

Porcelain Crowns and Biologic Compatibility (Dental Allergies)

All Porcelain crowns as Procera crowns are the most biologically compatible crowns available today. Some of the latest research ranks all porcelain dental crowns as 99% biologically compatible, which means they have fewer allergy problems. Because very few patients have allergies to gold or to porcelain, many dental offices offer inexpensive dental crowns that have non-precious metals inside them that contribute to allergic reactions.

Procera – All Ceramic Crowns

Procera – All Ceramic Crowns

We offer new machined / hand-laid porcelain technology that is now available for front teeth is now the first metal-free crown technique that is truly strong enough to be universally recommend for the replacement of crowns or large silver fillings for your back teeth.

This new system, called “Procera”, gives you the strength of the traditional gold / porcelain crown (which is how over 95% of all crowns are currently made), while providing the beauty and translucency of porcelain. As with front tooth crowns, the metallic, greyish metal underpinning found in most of today’s crowns is replaced by an aero-space porcelain foundation. You’ve probably seen that unsightly “grey line at the gum” on existing crowns (for yourself or other people) that can be caused by the current mainstream metallic-based technique.

We now have the solution – PROCERA AllCeram. PROCERA AllCeram is a coping made of extremely densesintered aluminium oxide. The coping is produced in an industrial process known as PROCERA method, which ensures optimal fit, great strength, non-porosity and has the ability to transmit light without being transparent.

The secret behind Procera All Ceram is its unique combination of strength and beauty. Over the last few years, new technology has made dental porcelain more practical. Until now, porcelain coated ceramic copings has been neither strong enough nor durable enough for widespread use. Procera All Ceram is translucent giving the tooth a natural appearance. At the same time Procera All Ceram is excellent for concealing underlying surfaces, such as amalgam and root fillings. This ceram is also customized but still industrially produced, ensuring predictable results. You should try quickly in your mouth with minimal adjustments.

Due to the strength in the core material, PROCERA AllCeram can be recommended for prosthetic reconstructions anywhere in the mouth. More and more patients are asking for constructions made of material not containing metal or other alloys. PROCERA AllCeram is made of bio-compatible material (comparable to Titanium) which minimizes the risk of allergic reactions.

The translucent coping offers remarkable aesthetic characteristics. When combined with PROCERA AllCeram Porcelain these characteristics are put to their very best advantage. In order to recreate the beauty of natural teeth, the porcelain has been formulated to make the most of the coping’s inherent potential.

The Procera Abutment is created by CADD design using the Procera technique. The scanner is used to create a custom milled implant abutment that is designed by the dentist and the laboratory for a specific patient’s needs. The data is then transferred by modem to the production plant in Sweden and the custom Procera Abutment is machined.

Procera® – Zirconia

Strength no longer has to be compromised to achieve extreme aesthetics. Zirconia is like a much awaited CHANGE over traditional P.F.M in the present dental world.

Zirconia combines the aesthetics of our patients demand with the strength and affordable prices they desire.

Laboratory tests have shown the fracture toughness and flexural strength of zirconia is significantly higher than that of alumina or any other all ceramic. Excellent strength and versatility can be achieved.

Procera Zirconia, made of Yttria Stabilized Zirconium (YZ) has substantial advantages compared to other dental materials: mechanical resistance, biocompatibility and a fracture toughness two times greater than Alumina.

Conventional precious metal ceramics restorations are at 800 MPa or less. Metal ceramics cannot compete with the aesthetics of Procera Zirconia. It is capable of being placed anywhere in the mouth and can accommodate 3-4 unit bridges

Procera Zirconia restorations can be inserted using conventional cementing techniques. Bonding is not required.

Benefits of Procera Zirconia

Uncompromised beauty

Upto 3 to 16 Units Bridge

Any number of pontics

Available in all shades

Outstanding compatibility

Procera® – Alumina

Procera® (Alumina) is composed of a densely sintered high-purity aluminium oxide coping that is manufactured using CAD/CAM technology. The core has the ability to transmit light without being transparent. The secret behind Procera® is its unique combination of strength and beauty.
Extremely low fracture rates have been reported and the restorations serve for many years.
More and more patients are asking for restorations made of material not containing metal or other alloys. Procera® is made of a bio-compatible material (comparable to Titanium) which minimized the risk of allergic reactions.

Conventional cementation like PFM’s

ZIRCON crowns

These are full ceramic crowns and bridges without metal reinforcement. Zircon (synthetic diamond) has exceptional rigidity. This enables us to carry out great restorations with improved mechanical forecast. Zircon is very high melting point ensures perfect stability during the heat treatment of the various ceramic layers. By utilizing Zircon, the crown or bridge will adjust perfectly. Not utilizing metal reinforcement (which the dental technician must usually mask by an opaque ceramic layer) makes it possible to produce crowns with low thickness, thus saving healthy tissue during preparation of teeth. Finally,

due to this technique, the aesthetic results are excellent because the light is no longer interrupted by subjacent metal, therefore it can cross the crown and restore the natural appearance to the tooth.

3MT ESPET LavaT Crowns and Bridges

A LAVA Crown is one of the strongest all ceramic crowns available in the world. LAVA crowns are reported to have three times more tensile strength than any other style of all ceramic crowns.

LAVA is an inert and biocompatible ceramic, and is the name trademarked by the 3M ESPE Company, for yttrium zirconia. Yttrium zirconia is strong enough to be used as a heat shield on the Space Shuttle. The sub-coping and internal aspect of a LAVA crown is made with this material, which is manufactured by 3M ESPE. The disadvantage of LAVA is that it is monochromatic (it only comes in one colour), and it is not very aesthetic, by itself. LAVA resembles mother-of-pearl, visually, in it’s natural state.

To make the external part of your dental crown perfectly aesthetic and functional, a layer of quality dental porcelain is fused to the external aspect of your LAVA crown. This adds some translucency, vibrancy, proper shade and colour, and gives your new tooth a comfortable texture.

The 3MT ESPET LavaT Crowns and Bridges system is an innovative CAD/CAM technology using a zirconium oxide base. The aesthetics of Lava restorations represent the optimum in all-ceramic systems. Preparations require removal of less tooth structure, and cementation can be accomplished using proven, conventional techniques. Colourable frameworks that are thin and translucent ensure a natural and vital appearance. Lava crowns and bridges provide some of the most durable and aesthetic all-ceramic restorations available today. The Zirkonia frameworks are biocompatible and exhibit the highest strength available in all-ceramic restorations.

LAVA is also an excellent dental material for dental implant abutments.

LavaT crowns and bridges offer the highest strength restorations to the dental industry.

Applications:

All-ceramic crowns.

All-ceramic bridges

Benefits:

Excellent aesthetics and translucency

Outstanding marginal fit.

Superior strength of zirconia with high fracture resistance