Dental CrownsPorcelain (aka Ceramic) is an inorganic, non-metallic ceramic material with glass-like properties, created with the use of heat.  Dental porcelains are manufactured in a powder form and are made in many colors and shades corresponding to the primary colors of basic tooth structure.  They are then mixed with water and placed in an oven for “firing” — hence their ceramic nature.  Porcelains are built up in layers to mimic the natural translucency, contours, and coloring of tooth enamel.

Porcelain is the most commonly used material for dental crowns because they look and feel like natural teeth.  Dental porcelain can be sculpted, meaning crowns are not limited to simply replacing an original tooth — they can be designed to create an even better esthetic appearance.  Besides being able to change the tooth shape, crowns are also excellent for changing tooth color.  When there is deep staining, a crown will usually be the restoration of choice, and at the same time will strengthen the tooth.

It takes a talented ceramic artist to sculpt dental porcelain into amazing tooth imitations that mimic tooth enamel.  Because of porcelain’s glass-like whiteness and translucence that allows light to penetrate and/or scatter, the restorations look very life-like and natural.

Much like your original teeth, porcelain crowns only require routine brushing with non-abrasive toothpaste and regular flossing, so maintaining them is really quite simple.

ALL-PORCELAIN CROWNS:

All-porcelain crowns tend to be a little less durable than other types, not having the flexibility of natural teeth, but even so they are highly resistant to wear and can last a lifetime if properly maintained.  For back teeth that receive greater biting force, other types of crowns may be a better alternative.  However chronic tooth-grinders and jaw-clenchers can be fitted with a nighttime mouth guard to protect the porcelain from unnecessary and excessive pressure and wear.  All-porcelain dental crowns are an excellent choice for front teeth because they provide better natural color match than any other crown type.  Also, they may be more suitable for people with metal allergies.

On the down side, in order to guard against fractures due to thinness, all-porcelain crowns must be thicker all around than a gold restoration.  The extra thickness provides overall strength and durability, but to accommodate the greater thickness, more healthy tooth structure may need to be removed to accommodate the smaller interior of the crown.

There are several types of all-porcelain/ceramic crowns:

  • Feldspathic porcelain – Traditional type, most often used, considered the most beautiful.  A conventional powder-slurry ceramic, entire thickness is 100% ceramic and best natural color of all the crowns.
  • Empress crown – Imitates natural teeth’s translucency, a leucite-based material that scatters light naturally and has a lifelike appearance.  By firing glass ceramic over a crystalline core which is compressed under pressure, it has increased resistance without using a metal base
  • Procera crown – Has milled ceramic inside and traditional porcelain on outside. A newer type of crown, created by the dentist during surgery, used because of its extraordinary strength.
  • Lava crown – Has a translucent zirconia core and with a layer of feldspathic porcelain baked onto the outside of it.
  • Zirconia crown – Looks natural and does not reveal a thin black border at the gum line like some other crowns.  It is made of Zirconia dioxide, an advanced type of dental ceramic, i.e. a polycrystalline ceramic core (the same material that forms the basic structure of fake diamonds).
  • Emax crowns – A proprietary form of ceramic crowns, made of monolithic lithium disilicate ceramic, which have been praised for strength, durability, and natural appearance.

PORCELAIN-FUSED TO METAL (PFM) CROWNS:

These crowns are very strong and provide a stronger bond than regular porcelain because it is bonded to a metal structure.  It’s also extremely durable and can be color matched to your adjacent teeth.  On the down side, because porcelain is harder than dental enamel, there may be more wearing to the opposing teeth with this crown type compared with all-metal or composit/resin crowns.  Second only to all-ceramic crowns, PFMs look the most like natural teeth.

There are three basic categories of dental alloys that can be used.  Each type has its own specific advantages and disadvantages, including: color, cost, insurance coverage, and general physical properties.  They are:

  • High noble (Precious metal: gold, palladium and/or platinum) – has a composition that is over 60% noble metal, of which more than 40% must be gold. *
  • Semiprecious – has at least 25% noble metal content.
  • Nonprecious – composed of various combinations of Cobalt or Nickel, Chromium, Molybdenum, Tungsten, Niobium, Tantalum, Silicon, less than 1% Manganese, Iron, Carbon, trace elements.

* High noble alloys constitute the “gold standard” of dental metals, against which all others are compared.

In recent years, a new type of porcelain covered restoration has been developed. It’s called the pressed-to-metal (PTM) or pressed-over-metal (POM) crown.  They look like a PFM, but the method of fabrication offers a stronger, possibly more esthetic, type of ceramic.

But what if a patient wants or needs the strength, durability and predictability that an all-metal crown can offer, but in the front, for instance, the way a metal tooth looks would simply be too objectionable.  As a solution for this dilemma, it’s possible for metal crowns to be surfaced with porcelain just on the side that shows. Dentists refer to this type of option as a “veneer” or “window.”  That way a white look can be given to otherwise all-metal crowns.

Captek™ Crowns:

A brand of PFMs is the Captek™ crown:  This is an alternative to a conventional cast metal PFM restoration.  It is composed of ceramic fused to a Captek 22 karat gold understructure.  Some of the advantages are:

  • Aesthetics – no dark metal margins, no dark oxides produced in casting
  • Strength – 33 percent more density and strength, outperforms conventionally cast metals in fracture resistance tests
  • Highly accurate internal fit and marginal integrity
  • Less tooth reduction required
  • Bio-compatibility
  • Less bacterial accumulation resulting in healthier periodontal tissue
  • Resistance to corrosion and oxidation
  • No toxic or allergic reaction with nearby soft tissue
  • Long lasting

CAD-CAM (Computer Aided Design – Computer Aided Manufacturing) technology:

This is an innovation in dentistry, offering extraordinary accuracy of fit and contour of crown restorations, that was developed in the mid-1980s, with technological advances since then.  It uses a computerized system that has a special wand to scan a tooth that has been shaped for placement of a new crown.  The information is then fed from a computer to a milling machine that sculpts an exact-fitting and strengthened “ceramic core” of the crown. Porcelain is then baked on the outside of this core to mimic tooth form and color, and to impart its natural brilliance and translucence.  The crown is then permanently cemented to the remaining portion of the natural tooth.

If you are interested in porcelain crowns, fill out the “Find a Dentist” form on this page.  One of our patient advocates will reply to your needs.