Porcelain Veneers
Porcelain veneers are a rapid, aesthetic, and safe way to correct
unattractive front teeth. Porcelain veneers correct heavy
permanent stains, teeth that are crooked, disproportionate,
small (with spaces), and structurally damaged. Porcelain veneers
are shells of ceramic material that can be chemically
bonded to tooth structure. Porcelain veneers are the primary treatment modality for the popular extreme makeovers.
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."
The 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.
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This patient had considered porcelain veneers for a long time.
He had received many consultations with different dentists, until he decided
to ask Dr. Rabanus to design his new smile.
He didn't like the spaces, his small teeth, the shade, and the irregular gumline and tooth size.
The new porcelain veneers addressed all his concerns.
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The clinical images below show different
views of the same porcelain veneers:
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Note the differences in tooth size in the pre-operative situation on the left side.
Also note the tilt of the central incisors towards the left, and the irregular gumline.
All of these aspects were corrected by the new porcelain veneers (picture on the right side).
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Note the short lateral incisor in the pre-operative picture on the left side.
After placement of the porcelain veneers, the relative proportions of the neighboring teeth were more
harmonic. The smile line became more aligned with the inside border of the lower lip.
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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.
More porcelain veneers.
Even more veneers, and info about lumineers.
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:
- translucency
- 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.
Dr. Rabanus emphasizes the development of incisal characterizations and 3-dimensional effects. Youthful teeth have a high degree of incisal
translucency and display dentinal developmental lobes. They often coincide with incisal irregularities, such as notches, which are especially
cute in female patients. Lateral incisors that have these incisal notches look sexy, playful, and youthful. It is a desirable effect for female
patients, but some male patients have opted for this choice in porcelain veneers as well. Hence, Dr. Rabanus and his dental laboratory have
developed well-defined communications regarding the desired outcomes of anatomic layerings for each individual patient.
It is understood that the above design details of porcelain veneers are easier understood with illustrations. Since this website is always a work in progress,
Dr. Rabanus will eventually add those illustration, some of which can already be found on other pages about smile design within this website.
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