Veneers can be compared to false fingernails, they look great cosmetically but are very limited functionally as they are quite fragile.  Veneers should only be used in certain situations.

A veneer is usually a thin layer of material placed over a tooth which will improve the look of a smile and protect the tooth surface from damage.  Veneers are made from white tooth filling material or porcelain and are usually bonded to the tooth after preparing the tooth surface.

Some dental claims are started because the dentist does not tell the patient that tooth preparation is needed and that this can cause extreme sensitively if the tooth is over prepared by the dentist.

Whilst veneers can give an instant dental result, there is some controversy over using them.  

In a controversial opinion, Dr. Michael Zuk, DDS from small town in Canada 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, that have little experience 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.[2]

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.