Veneer (dentistry)


In dentistry, a veneer is a layer of material placed over a tooth. Veneers can improve the aesthetics of a smile and protect the tooth's surface from damage.
There are two main types of material used to fabricate a veneer: composite and dental porcelain. A composite veneer may be directly placed, or indirectly fabricated by a dental technician in a dental lab, and later bonded to the tooth, typically using a resin cement. Usually used for treatment of adolescent patients who will require a more permanent design once they are fully grown. The lifespan of a composite veneer is approximately 4 years. In contrast, a porcelain veneer may only be indirectly fabricated. A full veneer crown is described as "a restoration that covers all the coronal tooth surfaces ". Laminate veneer, on the other hand, is a thin layer that covers only the surface of the tooth and generally used for aesthetic purposes. These typically have better performance and aesthetics and are less plaque retentive.

Medical uses

Veneers are a prosthetic device, by prescription only, used by the cosmetic dentist. A dentist may use one veneer to restore a single tooth or veneer with high quality that may have been fractured or discolored, or in most cases multiple teeth on the upper arch to create a big bright "Hollywood" type of smile makeover. Many people have small teeth resulting in spaces that may not be easily closed by orthodontics. Some people have worn away the edges of their teeth resulting in a prematurely aged appearance, while others may have malpositioned tooth/teeth that appear crooked. Multiple veneers can close these spaces, lengthen teeth that have been shortened by wear, fill the black triangles between teeth caused by gum recession, provide a uniform color, shape, and symmetry, and make the teeth appear straight. Dentists also recommend using thin porcelain veneers to strengthen worn teeth. It is also applied to yellow teeth that won't whiten. Thin veneers are an effective option for aging patients with worn dentition. In many cases, minimal to no tooth preparation is needed when using porcelain veneers.
When preparing, in between prep and fit appointments of the veneer, you can make temporaries, usually out of composite. These are not normally indicated but can be used if the patient is complaining of sensitivity or aesthetics. According to a leading Beverly Hills Cosmetic Dentist, temporaries are really important to design and finalize the aesthetics of the final veneers. Temporaries help patients and the dentist decide on the right color, length and shape of the veneers.

Indications

Discoloured teeth, malformed teeth, enamel hypoplasia, enamel hypocalcification, fluorosis, tetracycline staining, non-vital tooth discolouration, malposition, enamel fractures, enamel loss by erosion, modify shape of tooth.

Contraindications

In a controversial opinion, Dr. Michael Zuk, a Canadian DDS, profiles in his opinion and problems of overuse of porcelain veneers by certain cosmetic dentists in 'Confessions of a Former Cosmetic Dentist'. He suggests that the use of veneers for 'instant orthodontics' or simulated straightening of the teeth can be harmful, especially for younger people with healthy teeth. Leading dentists caution that minor superficial damage or normal wear to the teeth is not justification for porcelain or ceramic veneers. This is because the preparation needed to apply a veneer may in some cases destroy 3–30% of the tooth's surface if performed by an inexperienced dentist. It has been found that after 10 years, 50% of veneers are either displaced, need re-treatment, or are no longer in satisfactory condition.
Some cosmetic dentists may push unnecessarily for prosthodontic treatment in adolescents or young to middle-aged adults who have otherwise healthy teeth that only necessitate whitening or more routine cleaning. As preparation for veneers requires shaving down the tooth in some cases, sensitivity and decay may become a problem if this procedure is not properly performed. In addition, a veneer's maintenance cost can also be prohibitive for many individuals. Veneer placement should be limited to individuals with significant aesthetic problems, such as badly cracked or broken teeth, that do not meet the requirements for a crown or full replacement.
Additional contraindications include but are not limited to the following: poor oral hygiene, uncontrolled gingival disease, high caries rate, parafunction, no enamel, unreasonable patient expectations, large existing restorations.

Classification

There are different types of classification for veneers. One of the recently suggested veneer classification is called Nankali Veneer Classification and divides the veneers as follows:
There are four basic preparation designs for porcelain laminate veneers;
a) Window
b) Feather
c) Bevel
d) Incisal Overlap
Recent technological advances have been made, which allow the construction of ultra-thin porcelain laminate veneers. These veneers require only very modest, or in some instances, no reduction of the tooth structure. There are often referred to as "non-prep" veneers.

Current Veneer Technologies

a) Lumineers
b) Smile Infinity®

Alternatives

In the past, the only way to correct dental imperfections was to cover the tooth with a crown. Today, in most cases, there are several possibilities from which to pick: crown, composite resin bonding, cosmetic contouring or orthodontics.
Non-permanent dental veneers, which are molded to existing teeth, are a feasible option as well. These dental veneers are removable and reusable, and are made from a flexible resin material. Do-it-yourself kits are available for the impression-taking process, and then the actual veneers are made in a lab and sent to the wearer through the mail.

History

Veneers were invented by California dentist Charles Pincus in 1928 to be used for a film shoot for temporarily changing the appearance of actors' teeth. Later, in 1937 he fabricated acrylic veneers to be retained by denture adhesive, which were only cemented temporarily because there was very little adhesion.
The introduction of etching in 1959 by Dr. Michael Buonocore aimed to follow a line of investigation of bonding porcelain veneers to etched enamel.
Research in 1982 by Simonsen and Calamia revealed that porcelain could be etched with hydrofluoric acid, and bond strengths could be achieved between composite resins and porcelain that were predicted to be able to hold porcelain veneers on to the surface of a tooth permanently. This was confirmed by Calamia in an article describing a technique for fabrication, and placement of Etched Bonded Porcelain Veneers using a refractory model technique and Horn describing a platinum foil technique for veneer fabrication. Additional articles have proven the long-term reliability of this technique.
Today, with improved cements and bonding agents, they typically last 10–30 years. They may have to be replaced in this time due to cracking, leaking, chipping, discoloration, decay, shrinkage of the gum line and damage from injury or tooth grinding. The cost of veneers can vary depending on the experience and location of the dentist. In the US, costs range anywhere from $1000 a tooth upwards to $3000 a tooth as of 2011. Porcelain veneers are more durable and less likely to stain than veneers made of composite.