Veneer (dentistry)
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In dentistry, a veneer is a thin layer of restorative material placed over a tooth surface, either to improve the aesthetics of a tooth, or to protect a damaged tooth surface. There are two types of material used in a veneer, composite and porcelain. A composite veneer may be directly placed (built-up in the mouth), or indirectly fabricated by a dental technician in a dental laboratory, and later bonded to the tooth, typically using a resin cement such as Panavia. In contrast, a porcelain veneer may only be indirectly fabricated.
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[edit] History
Veneers were invented in the 1930s by a California dentist named Charles Pincus (1). At the time, they fell off in a very short time as they were held on by denture adhesive. They were, however,useful for temporarily changing the appearance of movie actors'/ actresses teeth.
Research started in 1982 by Simonsen and Calamia (2) 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 (3) in an article describing a technique for fabrication, and placement of Etched Bonded Porcelain Veneers using a refractory model technique and Horn (4)describing a platinum foil technique for veneer fabrication. Additional articles have proven the long term reliability of this technique. (5,6,7,8,9,10,11,12,13)
Today, with improved cements and bonding agents, they typically last 10-15 years. But patients who receive veneers should understand that they may only last 10-15 years and then may have to be replaced. This can be very expensive since porcelain veneers cost around $1,000 each in 2006 prices. They are said to be somewhat more durable and less likely to stain than veneers made of composite.
[edit] Usage
The advantages of using a veneer to restore a tooth are many. Very good aesthetics can be obtained, with minimal tooth preparation (i.e. drilling). Normally a reduction of around 0.5 mm is required for a porcelain veneer on a labial tooth surface. Composite veneers are becoming more popular as they are easy to repair, and porcelain veneers have a tendency to fracture. It can be very difficult to match the shade of an individual veneer to the remaining teeth, hence the tendency to place several veneers.
Veneers may be used cosmetically to resurface teeth such as to make them appear more straight and possess a more aesthetically pleasing alignment. This may be a quick way to improve the appearance of malposed teeth without need to use orthodontics. However, the amount of malposition of teeth may be such that veneers alone may not be enough to correct the esthetic imbalance. Instead, orthodontics would need to be used, or orthodontics combined with veneers. The dentist who places veneers must be careful since veneers could increase the thickness of the front face of the teeth. If the teeth are too thick on the face they may appear to stand out and push out the lips. The effect may be enough to give the patient a full or chipmunk appearance when the lips are closed. Veneers must also be created such that the patient bites into them with minimal force. Otherwise, they may chip off. So, patients whose lower jaw protrudes out farther than their upper jaw, otherwise known as a class III bite, may not be good candidates for veneers because the teeth of the lower jaw may bite into the teeth of the upper jaw such as to dislodge the veneers.
[edit] References
1. Pincus CL."Building mouth personality" A paper presented at: California State Dental Association;1937:San Jose, California
2. Simonsen R.J. and Calamia John R. "Tensile Bond Strengths of Etched Porcelain", Journal of Dental Research, Vol. 62, March 1983, Abstract #1099.
3. Calamia John R. "Etched Porcelain Facial Veneers: A New Treatment Modality Based on Scientific and Clinical Evidence", New York Journal of Dentistry, Vol. 53, #6, Sept./Oct. 1983, pp.255-259.
4. Horn HR. "A new lamination, porcelain bonded to enamel" NY St Dent J 1983;49(6):401-403
5. Calamia John R. and Simonsen R.J. "Effect of Coupling Agents on Bond Strength of Etched Porcelain", Journal of Dental Research, Vol. 63, March 1984, Abstract #79.
6. Calamia John R. "Etched Porcelain Veneers: The Current State of the Art", Quintessence International, Vol. 16 #1, January 1985.
7. Quinn F Mc Connell RJ "Porcelain Laminates: A review", Br Dental J 1986:161(2):61-65
8. Calamia John R. "Clinical evaluation of etched porcelain veneers" Am J Dent 1989:2:9-15
9. Nathanson D, Strassler HE. Clinical evaluation of etched porcelain veneers over a period of 18 to 42 months J Esthet Dent 1989:1(1):21-28
10. Strassler HE, Weiner S "Long-term clinical evaluation of etched porcelain veneers" J Dental Res 77 (Special Issue A):233 Abstract 1017,1998
11. Friedman, MJ "A 15-year review of porcelain veneer failure- a clinicians’ observations. Compend Contin Educ Dent. 1998:19(6):625-636.
12. Calamia John R. "Etched Porcelain Laminate Restorations: A 20-year Retrospective- Part 1" AACD Monograph Vol II 2005:137-145 Montage Media Publishing
13. Barghi, N , Overton JD "Preserving Principles of Successful Porcelain Veneers" Contempory Esthetics 2007:11(1)48-51
