Porcelain Veneers

Porcelain Veneers image

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One of the most significant breakthroughs in dentistry has been the development of new adhesion techniques (click “Technical Specifications: Bonding”) and materials (click “Technical Specifications: Empress”) that enable the dentist to successfully adhere dissimilar materials to each other.

The bonding strength between a porcelain veneer and the tooth surface is often so great that a trauma may cause a fracture within the tooth and not at the interface between the porcelain veneer and the tooth surface.

Bonded to tooth structure, certain porcelain veneer materials display similar physical properties as natural enamel. In addition, with the advance of ceramic technology, natural layers and translucencies of vital teeth can be perfectly mimicked.

For further information, go to page “Materials and Methods” in the section “Technical Specifications.”

Porcelain Veneers image 05The correction of unattractive front teeth with porcelain veneers involves two office visits. The first visit entails the preparation of the teeth, taking impressions of the prepared teeth, and the placement of temporary acrylic veneers. The processing time at the dental laboratory is usually two weeks. The final porcelain veneers are permanently bonded at the second office visit.

Some dentists place dental veneers that consist of resin composite. However, the long-term prognosis of porcelain veneers is much better.

Dental porcelains and ceramics are superior to metals with respect to corrosion, galvanism, and biocompatibility. Emergence profiles are less likely to be over-contoured, as is often the result with metal-ceramic restorations in an effort to mask metal sub-structure.

The conclusions of many studies are that porcelain surfaces accumulate much less dental plaque compared to resin composites, gold alloys, and amalgams. In addition, the plaque formed on ceramic surfaces is of healthier composition.

The clinical images below show different views of the same porcelain veneers:

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The design of several porcelain veneers for an entire smile makeover is often based on provisional acrylic restorations (also called temporaries) that are placed in the patient’s mouth to determine the individual morphological characteristics of each tooth and the overall appearance of the veneer group.
This has to go hand in hand with the verification of the envelope of function of the entire group of porcelain veneers. The final result has to be total harmony with speech, lip closure path, smile line, and guidance of the mandible during chewing function.

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A quick word about porcelain veneer technology:

More and more people want whiter teeth. The cosmetic dentist needs to know how to keep porcelain veneers natural despite their bleached shades. This is done with anatomic layering with porcelains of different optical characteristics.

The exact pathway of achieving the optimum result is determined by the original condition of the teeth, such as:

  • tooth position
  • crowding or spacing
  • dental misalignments
  • defects
  • degree of discolorations
  • gum line
  • prior dentistry (unfortunately this often dictates the design of new porcelain restorations)

The optical characteristics of porcelain veneers are:

  • transparency
  • hue
  • chroma
  • shade
  • value

The more existing tooth characteristics need to be mask the thicker the porcelain layer needs to be. In addition, pressable ceramics need a little bit more space than feldspathic porcelains. They require a minimum reduction of 0.8 mm for pressing ingots and additional 0.3 to 0.4 mm for enamel layering techniques, while conventional feldspathic porcelains require only a 0.5 mm reduction at the gingival half and 0.75 mm at the incisal half. Porcelain veneers that are fabricated out of pressable porcelains require an over-the-edge preparation to stabilize the wax-up and the veneers on the stone models throughout the fabrication process.

The tooth preparation for a porcelain veneer is always dictated by what the veneers needs to compensate for. Diagnostic wax-ups and smile designs using long-term provisionals are used for this. Based on the optimum position and dimensions of a prcelain veneers, which is indicated by preparation guides that are fabricated on the diagnostic wax-up of the patient’s models, the cosmetic dentist determines how much tooth structure needs to be removed. Since cosmetic dentistry does not use opaque porcelains that would make a tooth look very artifial, the shade of the underlying tooth structure needs to be considered. A porcelain veneer needs a minimum thickness of 0.2 to 0.3 mm for each shade change. This means that a change by three shades would require a minimum thickness of 0.9 mm in an ideal scenario. In addition, porcelain veneers of 0.3 mm thickness have been shown to crack easily.

In short, the thickness of a porcelain veneers is determined by the amount of desired shade change and the final tooth position, which is dictated by functional and aesthetic parameters.

When patients have extremely dark teeth, it is necessary to prepare the teeth through the enamel into the dentin layer. This is no problem if the cosmetic dentist understands the state of the art of dentin-bonding technology. Unfortunately, this is the point at which many dentists try to simplify or use a cheaper product. This is one of the most important steps of the entire delivery process of porcelain veneers and should not be cut short. The dentin-bonding technology is covered elsewhere on this website.

When teeth are prepared into dentin due to their dark shade, a dentin porcelain is used so that it restores the shape of the original dentin layer and creates a more favorable color. This is also recommended for the matching one tooth to existing natural and lighter neighboring teeth, because the control of dentin color improves the accuracy of the match, which often depends on perfect matches in deeper layers of the teeth.

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