In simple terms, a crown – also known as a ‘cap’ – is a covering of the tooth. We prepare your tooth for a crown by filing it down slightly. Then we make, fit and cement the crown permanently in place. Dental crowns can be made using various types of metals or ceramic materials, or a combination of both.
Why might I need a crown?
Crowns are usually used to protect heavily damaged or weakened teeth from fracturing. A number of things can weaken the teeth, such as extensive decay, large fillings, root canal treatments or tooth fracture.
You may also need a crown to cover a severely worn-down tooth, to hold a dental bridge in place, to cover a dental implant, or to make your teeth look better if they are misshapen or severely discoloured.
What are the different types of crowns?
Generally speaking, crowns can be made using tooth-coloured ceramic materials and/or metal. Experienced technicians custom-make all crowns by hand.
All-ceramic or metal-ceramic crowns
Tooth-coloured crowns are made from specialised ceramic materials that look and work like natural teeth. An ‘all-ceramic’ crown can be made entirely from ceramic materials, which looks particularly good. Alternatively, for a ‘metal-ceramic’ crown, a metal substructure is covered with a layer of ceramic material.
As some people are allergic to some metals – such as nickel – used in the metal alloy, an all-ceramic crown can be the best option. In addition, with the metal-ceramic crown a thin dark line may show where it meets the gum line.
With no metal substructure in an all-ceramic crown, the colour can be better matched to your natural teeth. Since these crowns tend to look better, they are often used for the teeth that show when you smile.
Metal crowns are often made for back teeth, where looks are less important. Although they may not be an acceptable option for some, if they will sometimes show (in which case a tooth-coloured crown can be considered), they are considerably thinner compared to tooth-coloured crowns. A metal crown is about 0.5mm thick, while a tooth-coloured crown can vary from 0.5mm to 2mm.
Metal crowns can be made using non-precious metals. Alternatively, metal alloys containing various proportions of gold can be used to make full metal crowns. Gold is a very biocompatible, non-toxic, non-corrosive and hypoallergenic material. It expands with temperature changes in a way that is very similar to enamel, so a better natural fit can be achieved. Gold does not chip or break, even at thin points, and its durability and longevity are excellent.