| 词条 | Veneer (dentistry) |
| 释义 |
|Name = Veneer |Image = Dental veneer.jpg |Caption = A veneer |ICD10 = |ICD9 = |MeshID = D003801 |OPS301 = |OtherCodes = |HCPCSlevel2 = }} In dentistry, a veneer is a layer of material placed over a tooth, veneers improve the aesthetics of a smile and/or protect the tooth's surface from damage. There are two main types of material used to fabricate a veneer: 1) composite and dental porcelain. A composite veneer may be directly placed (built-up in the mouth), 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. Lifespan of composite veneer is approx. 4 years.[1] 2) 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 (Mesial, Distal, Facial, Lingual and Occlusal)"{{citation needed|date=June 2018}}. 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 normally have better performance, aesthetics and are less plaque retentive.[1] Medical usesVeneers are a prosthetic device, by prescription only, used by the cosmetic dentist. A dentist may use one veneer to restore a single tooth 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.[2] Dentists also recommend using thin porcelain veneers to strengthen worn teeth{{citation needed|date=April 2013}}. 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. [1] IndicationsDiscoloured teeth, malformed teeth, enamel hypoplasia (not enough enamel), enamel hypocalcification (enamel not fully mineralised), fluorosis, tetracycline staining, non-vital tooth discolouration, malposition, enamel fractures, enamel loss by erosion, modify shape of tooth.[3] ContraindicationsIn 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[4] 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% [1]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.[5] 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. Also, poor oral hygiene, uncontrolled gingival disease, high caries rate, parafunction, no enamel, unreasonable patient expectations, large existing restorations. [1] Classification{{unreferenced section|date=October 2015}}There are different types of classification for veneers. One of the recently suggested veneer classification (2012) is called Nankali Veneer Classification and divides the veneers as follows:
a) No incisal involvement b) Feathered incisal edge c) Incisal overlap
a) No contact point involvement b) Contact point level c) Passed contact point
a) Indirect veneers b) Direct veneers
a) Ceramic b) Lithium disilicate (very thin and relatively very strong porcelain) c) Da Vinci (Very thin porcelain) d) Mac (High resistance to stains and relatively strong) e) Acrylic (No longer in use for quality work) f) Composite g) Nano Ceramic Types of veneer preparationsThere are four basic preparation designs for porcelain laminate veneers;[6] a) Window b) Feather c) Bevel d) Incisal Overlap Current Veneer Technologiesa) Lumineers b) Smile Infinity® AlternativesIn 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.{{citation needed|date=October 2015}} HistoryVeneers were invented by California dentist Charles Pincus in 1928 to be used for a film shoot for temporarily changing the appearance of actors' teeth.[7] 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[8] 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[9] in an article describing a technique for fabrication, and placement of Etched Bonded Porcelain Veneers using a refractory model technique and Horn[10] describing a platinum foil technique for veneer fabrication. Additional articles have proven the long-term reliability of this technique.[11][12][13][14][15][16][17][18][19] 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.[20] See also
References{{Commons category|Dental veneers}}1. ^1 2 3 4 {{Cite book|title=Oxford Handbook of Clinical Dentistry|last=Mitchell|first=David and Laura|publisher=OXFORD|year=2016|isbn=978-0-19-879581-0|location=|pages=}} {{Dentistry}}{{Prosthodontology}}2. ^ELHAMID A., AAZZAB B. Les facettes en céramique : de l'indication à l'utilisation Le courrier du dentiste 3. ^{{Cite web|url=https://online.manchester.ac.uk/bbcswebdav/pid-6617694-dt-content-rid-27047903_1/orgs/I3115-COMMUNITY-DENT-1/BDS%20Year%203/Clinical%20Skills%20Seminars/Year%203%20CSC%20Session%2001%20-%20Porcelain%20Veneers.pdf|title=Veneers|last=University of Manchester|first=|date=4 March 2019|website=|archive-url=|archive-date=|dead-url=|access-date=4 March 2019}} 4. ^{{Cite web|url=https://columbiariverdentistry.com/fix-your-teeth/veneers/|title=Veneers|website=Columbia River Dentistry|language=en-US|access-date=2019-01-06}} 5. ^Leading dentists{{who|date=July 2018}} question widespread use of porcelain crowns and veneers Very few experienced cosmetic dentists question widespread use of porcelain crowns and veneers 6. ^{{Cite journal|last=Walls|first=A. W. G.|last2=Steele|first2=J. G.|last3=Wassell|first3=R. W.|date=2002-07-27|title=Crowns and other extra-coronal restorations: porcelain laminate veneers|url=https://www.ncbi.nlm.nih.gov/pubmed/12199127|journal=British Dental Journal|volume=193|issue=2|pages=73–76, 79–82|doi=10.1038/sj.bdj.4801489a|issn=0007-0610|pmid=12199127}} 7. ^Pincus CL."Building mouth personality" A paper presented at: California State Dental Association;1937:San Jose, California 8. ^Simonsen R.J. and Calamia John R. "Tensile Bond Strengths of Etched Porcelain", Journal of Dental Research, Vol. 62, March 1983, Abstract #1099. 9. ^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. 10. ^Horn HR. "A new lamination, porcelain bonded to enamel". NY St Dent J 1983;49(6):401-403 11. ^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. 12. ^Calamia John R. "Etched Porcelain Veneers: The Current State of the Art", Quintessence International,Vol. 16 #1, January 1985. 13. ^Quinn F Mc Connell RJ "Porcelain Laminates: A review", Br Dental J. 1986:161(2):61-65 14. ^Calamia John R. "Clinical evaluation of etched porcelain veneers" Am J Dent 1989:2:9-15 15. ^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 16. ^Strassler HE, Weiner S "Long-term clinical evaluation of etched porcelain veneers" J Dental Res 77 (Special Issue A):233 Abstract 1017,1998 17. ^Friedman, MJ "A 15-year review of porcelain veneer failure- a clinicians' observations. Compend Contin Educ Dent. 1998:19 (6):625-636. 18. ^Calamia John R. "Etched Porcelain Laminate Restorations: A 20-year Retrospective- Part 1" AACD Monograph Vol II 2005:137-145 Montage Media Publishing 19. ^Barghi, N , Overton JD "Preserving Principles of Successful Porcelain Veneers" Contemporary Esthetics 2007:11(1)48-51 20. ^Calamia John R.,Calamia Christine S. Porcelain Laminate Veneers: Reasons for 25 Years of Success, Successful Esthetic and Cosmetic Dentistry for the Modern Dental Practice, Dental Clinics of North America. April 2007 Vol 51 No. 2 Calamia, Wolff, Simonsen Saunders/Elsevier, Inc., Veneers by Calamia, Enamelique.com 1 : Restorative dentistry |
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