Yes they do and they are "caps" (crowns are for the molars.) I just spent $12,000 on my teeth and had the front ones capped as well as the bottom front and the rest bonded. You can't tell they aren't your real teeth. Remember, even though the teeth are capped you have to go in for dental check-ups because you can still get cavities.
Porcelain crowns should be cleaned just like your natural teeth: with toothbrush and toothpaste, floss, and mouthwash.
Porcelain-fused-to-metal crowns are not ideal for front teeth because they do not have the same esthetics as natural teeth (the metal on the inside, which is added for strength, does not allow light to pass through the crown like it would on a natural tooth, so these crowns look more opaque). Also, as the gums recede, you may see the edge of where the crown meets the tooth, and a black metal line may appear. All ceramic (porcelain) crowns are great for front teeth, because you can get really good esthetics. However, they are not as strong as natural teeth. So if you tend to grind your teeth, you may break the porcelain. A new kind of metal, Zicronia, is white, so you don't get the same problems as with the metal in typical PFM crowns. Emax and Lava are two types of zirconia crowns that are very nice looking.
They aren't porous like natural teeth which have 'rods' that the tooth breathes with.
how can i clean my porclien teeth or n crowns
All-ceramic or all-porcelain dental crowns provide the best natural color match than any other crown type and may be more suitable for people with metal allergies. However, they are not as strong as porcelain-fused-to-metal crowns and they wear down opposing teeth a little more than metal or resin crowns. All-ceramic crowns are a good choice for front teeth.
crown marking ? any type of dental crowns would have to be shaped like our natural teeth. There are 2 types of porcelain crowns. the first being porcelain fused metal crowns and secondly an all porcelain crown. The only difference between the two is that for a porcelain fuse metal crown, the metal can usually be seen as a line at the neck of the crown. Try this article on porcelain crown, there is a detail explanation there. http://www.intelligentdental.com/2010/03/28/interested-in-the-different-types-of-porcelain-dental-crowns/
yes, eventually 'All porcelain' crowns do not generally stain or fade. 'Porcelain fused to metal' crowns might show a dark line near the gum after time. In rare cases the porcelain can pick up staining from poor oral hygiene or from heavy use of red wine tobacco cola etc. but is easily polished off with the correct dental tools. Porcelain does not stain as it is not porous like natural teeth.
Porcelain and gold crowns do not fuse to the teeth. They are attached by either mechanical contact or some glue. As far as i know special cements like the glass ionomer can fuse with the dentin layer.
Sorry, you can;t whiten a crown. Unfortunately some crowns are made of gold or part gold part other precious metal, which obviously can't be whitened. White crowns, or porcelain crowns are baked porcelain, which is a set color that goes down the entire depth of the crown. Your natural teeth whiten because bleaching removes stain on your teeth, the crowns can't whiten, because their color is intrinsic to the material that they are made of. In order to whiten a crown you need to replace it.
Dental gold crowns can last for decades. I've personally seen some last over forty years. In general, porcelain-fused-to-metal or all-porcelain crowns do not last as long a gold crowns. A goal for dental providers is to be able to place a crown that will last at least ten years. This is considered a adequate lifespan of a crown. Most crowns will last longer than this but gold has the best track-record for longevity. One reason gold lasts longer is because it is more forgiving to the chewing forces created in the mouth. Porcelain is more brittle and can fracture, whereas gold is malleable and can change shape to accommodate the force rather than fracture. Gold crowns are often recommended for back teeth which actually bear higher chewing stresses when compared to front teeth. Porcelain is opted for when aesthetics is a concern. This is why porcelain is generally recommended for teeth closer to the front. They look more like real teeth and they can last a long time when they aren't under a lot of chewing stress.
Porcelain veneers remove less enamel from the teeth and are preferrable when you are covering discolorations and small imperfections in the teeth. They are not designed for teeth that are not healthy. On the other hand, caps (or crowns) are stronger and more durable and will work on teeth that are not as healthy.
Dental braces with a porcelain jacket in the front teeth is perfectly acceptable and very common. The only disadvantage is how easily the porcelain can be broken.