If you’ve ever had your teeth whitened, you’ve noticed that after only a few days the initial glow or brightness fades a bit. This is because of some re-hydration of the tooth enamel. “Laser” bleaching is even worse as the dehydration is much greater than other light bleaching; which is why the teeth look so white at first. (not to mention the proven cell damage to the nerve tissues). This should not be the case with porcelain veneers; what you see the first day is what you get. More importantly, with bleaching, the entire whitening lasts only from a few months to a couple of years. This is dependent on the type of staining that was there in the first place; intrinsic or extrinsic staining. Also, it is dependent on the “softness” or density of your individual tooth enamel. Less dense enamel may whiten well but it will also get stained much faster. Also, there are issues with what you eat. Unfortunately, many times the healthier the food, the more it stains. Take for example blueberries, beets, ketchup, cranberries, in fact, most berries. Also consider the staining by somewhat less healthful beverages like coffee and red wine, irrespective of their health claims as of late. I won’t even mention smoking. I’m not talking about just superficial surface stains; these are stains that again go into the tooth structure and can’t be cleaned off by brushing or even a simple dental cleaning.
Porcelain veneers, on the other hand, may stain only on the very outside surface. These stains do not penetrate to the inside and can be easily cleaned off by your own home care like brushing or by a simple dental cleaning. The reason is that porcelain veneers have an impenetrable glaze on the outside; similar to but even tougher than a glaze on pottery or fine china. My longest lasting porcelain veneers have been in place for 30 years as of 2011, the last time the patient was in for a check-up and photo. You can see a picture of the 2011 photo on my website. This patient of mine has had some of the veneers fade a bit because the background tooth color got darker. The only thing that can happen, because porcelain veneers should have a certain amount of translucency for life-like naturalness, is that if the tooth structure in the background stains and darkens there will be a certain show-through of that interior staining. But this may take 1- to 20 years to develop and even this can be helped by bleaching the teeth from the back, lingual in the dental parlance. Many of my patients’ porcelain veneers that have been in for 20 plus years still look great.
Back in the late 70’s and early 80’s I was searching for new ways to treat my patients’ cosmetic problems, especially on the front (anterior) teeth. The earliest bleaching procedures were starting to gain popularity and of course, there was always the tried-and-true crowning/capping procedure. By the way, crowns and caps are basically the same things; in dentistry today we usually call them “crowns”. In case you didn’t know, with crowns, you have to remove tooth structure or filling material all around the tooth; at least 2 mm 360 degrees all around the tooth circumferentially and the same amount on the biting surface. I always felt and still always feel a little sad that you had to remove so much natural tooth; for years I kept saying to myself, “there has to be a better way”. Finally, in 1981, my lab person and I came up with a way to be much more conservative and minimally invasive. The Porcelain Laminate Veneer was born. A thin piece of porcelain, like a contact lens or a fingernail, which was glazed on the outside and micro-roughened (etched) on the inside. I took a while to develop the bonding cement but when things were perfected it was a miraculous restoration. To find out more about this, see the history of PV’s on my website.
Going back to the Veneers’ advantages over crowns, the obvious one is that they are far more conservative, necessitating the removal of only about ¼ the tooth structure as crowns. This can be a little more or less depending on the dentist’s particular preparation technique and the esthetic situation that needs to be fixed. In a 2002 German Study it was found that approximately 63% to 72% of the coronal (above the gum line) tooth structure was removed when the teeth were prepared for either ceramic (zirconium, these days) or metal/ceramic crowns. Ceramic/Porcelain Veneers were found to be far less invasive, taking away 3% to 30% of the tooth structure by weight. In another page, I will explain why the 3-30% range in the amount of tooth structure removed; as I mentioned it has to do the dentist’s prep technique and also the cosmetic problem. For example, the darker the tooth or the more “sticking out” the tooth is, the more may have to be removed.
The conservation of good, sound tooth structure also helps to preserve the vitality of the tooth (far less chance of needing a root canal afterward) and reduces sensitivity after the preparation. Obviously, the less depth of the tooth removed, the farther away from the sensitive nerve/pulp you are and the least pain postoperative.
“Bonding” is typically thought of as the white material that is attached to your front teeth for esthetics or sometimes as part of a “cavity filling”. Bonding, which once was a verb has taken on a new meaning as the filling or layering material itself. Actually, the white, porcelain-like putty materials that are shaped and hardened (with a bonding light) for back or front teeth are pretty much the same. They all have a “glue” or matrix into which is put filler particles of various sizes, shapes, and chemistry. Since, unlike Porcelain Veneers that are made in a laboratory, they must be placed directly on the teeth under body temperature of 98.6 F and with a totally safe curing process. These limitations cause the “bonding” material to be far less durable and esthetic than porcelain veneers, although steady improvement in the last 20 years has closed this gap.
This “bonding” material, known as “resin composite” to dentists and insurance companies, is known to be less strong and durable than porcelain or other even stronger porcelain-like materials that have been invented recently; like lithium disilicate, zirconia and zirconium. What these newer materials gain in strength they lose in naturalness, but this is a topic for another blog.
Thus the bonding or composite resin materials are limited as far as what they can do esthetically before breaking too soon. For example, for most patients with fairly normal bites, composites should not be used for lengthening the teeth because the lower front teeth will always hit them in the chewing or grinding motion. They will chip or break or just plain come off way before they should. I actually do like doing composite veneers on my patients that require a quick one-appointment placement or less financial burden (they cost less). They allow me to be much more “artistic” because I am creating the new smile from start to finish with no lab person involved, but I always tell my patients that their composite veneers will need slight touch-ups and repairs because of the lower durability.
This problem is even worse when doing composites for the lower front teeth because their top edges (incisals) are always hitting the backs of the upper front teeth. Even when closing spaces between teeth, if you try to close a gap too wide it means that the biting forces will hit beyond the support of the tooth into a “cantilever” situation. Many times there is breakage in the unsupported area. Porcelain veneers are much stronger and you can do much more esthetically in situations that would be dangerous with composites. Of course, even porcelain veneers have limitations and the dentist must be very careful with the final bite, in all sliding directions. If the patient is a bruxer/grinder many times a Night Guard is prescribed.
Composites also tend to stain faster than porcelain and stains can penetrate the top layer, unlike porcelain, and cause permanent staining. The reason for this is even though we can place a surface finish on the composite, it always wears off. Then the “glue” part of the composite or the rough filler particles get exposed microscopically and surface and inner stains happen. On porcelain the stains should roll off like on glass, in fact, many of the materials are a glass.
Lastly, the light diffraction, both on the surface and internally, is mimicked by porcelain a lot better than composite. Therefore porcelain laminate veneers, ones without too much opacity by the lab or dentist, will always look much more natural than “bonding” in a variety of lighting conditions. This is especially true of daylight and the lights for TV and movie cameras.
