The technique of placing porcelain veneers has been around since the early 1980's and since that time several studies have attempted to evaluate the average porcelain veneer's life span. Each study we reviewed seemed to have chosen a slightly different definition of what constitutes a "failure" of a porcelain veneer, so in some ways these studies aren't directly comparable but they do seem to point toward a general consensus. (As an example, if a veneer has chipped should it be considered a failure even if this defect can be buffed and polished out without significantly detracting from the overall appearance of the tooth? We wouldn't necessarily think so.)
We chose to report on the findings from the studies listed below because they were some of the more recent evaluations that have been published.
Based on this information it seems likely that a porcelain veneer could certainly be expected to last in excess of 10 years. While there is no definitive reason why a porcelain veneer has to fail at all (structurally or cosmetically) it would seem unrealistic not to expect that at some point in time replacement will be needed. Our impression would be that a 20-year life span for a porcelain veneer would be considered the extreme, although this is just an opinion and not based on research.
By exercising a little caution and providing a little care a person can contribute to the longevity of their porcelain veneers.
Just as with natural teeth, brushing and flossing are an integral part of the daily care a tooth with a porcelain veneer on it needs so to remain healthy and trouble free. There are no special rules or techniques for cleaning veneered teeth. One simply needs to be diligent and thorough.
While tooth decay cannot form on or through a veneer's porcelain surface decay certainly can develop on any other natural (untreated) aspect of the tooth (including that tooth structure that surrounds the edges of a porcelain veneer). Keeping a veneered tooth as plaque free as possible will help to insure that tooth decay will not form.
Incomplete plaque removal can also cause gum recession. If that edge of a porcelain veneer that ends at a tooth's gum line is not kept plaque free you can anticipate that gum recession will likely take place. This recession can detract from the overall cosmetic appearance of a tooth and can be a reason why a decision is made to replace a veneer with a new one.
Porcelain veneers can provide a good hard durable surface for teeth but a weakness of porcelain as a material is that it isn't good at withstanding twisting or bending forces. This means that biting into and through objects (biting into food) would offer less potential for damaging porcelain veneers than using veneered teeth in a ripping or tearing motion (like ripping open a snack food bag). These latter types of motion might cause the tooth supporting a veneer to flex. As a result the veneer might crack, break, or come off.
Porcelain veneers can be expected to provide good service for normal oral functions. There can however be some activities that might place a porcelain veneer at risk because the pressures associated with that act are so extreme. Activities like biting one's fingernails, biting on hair pins held between one's teeth, or chewing on ice can put enough force directly on a porcelain veneer that it might come off or break. If you participate in sports activities it would be prudent to wear a mouth protector for fear that you might experience a blow to the mouth or else a collision event might bring your teeth together forcefully.
Tooth clenching and grinding (dentists term this activity "bruxism") can also create extreme forces that can break or dislodge porcelain veneers. In fact people who are known to brux are typically not good candidates for porcelain veneers unless their bruxism can be controlled. A person can in theory exercise some control over this type of activity during their waking hours. The effects of nighttime bruxism are typically controlled by way of wearing a nightguard appliance.
The glass-like nature of a porcelain veneer's surface does possess superior stain resistance but in general it would still seem prudent to minimize any staining influences that your veneered teeth might be exposed to. Exposure to coffee, tea, wine, tobacco products, and other chromogenic products can with time darken teeth and dental restorations. In the case of porcelain veneers a discoloration of the veneer itself is not a concern but
the staining of the cement used to bond the veneer in place is. If this layer becomes noticeably discolored it will spoil the cosmetic appearance of the veneer and the only solution will be to replace it.