In recent years, the field of cosmetic dentistry has made great strides forward in techniques and materials, and we can choose from many more procedures now than in years past.
Many of us had metal crowns done at one time or another, and these might have been made of:
· Gold or gold alloy
· Nickel alloy
· Chromium alloy
· Palladium
On back teeth, which do the chewing, a metal crown is sometimes a good choice, as the metal materials are very strong and durable.
Disadvantages of old metal crowns
· Their color -- which contrasts strongly with the white teeth surrounding them
· Problems with decay – if bacteria get up underneath the crown, gum disease can set in, requiring the removal of the crown, gum treatment, and a new crown
· Wear and tear – older crowns can become worn or ill-fitting
Alternatives to metal
Porcelain
Dental porcelain is a substance with similar properties to tooth enamel. It absorbs and reflects light the way our natural teeth do. Light travels through the porcelain to the bonding material which attaches the crown to the tooth, and then bounces back. This gives the porcelain crown a translucent look very like that of our natural teeth. With tooth enamel, the light travels through to the tooth dentin underlying the enamel, and bounces back. This is what gives our teeth that shiny, pearly look.
An all-porcelain crown blends in excellently with the surrounding teeth. Porcelain is highly resistant to discoloration, and when bonded to our teeth, it’s strong and durable.
Porcelain fused to metal
Porcelain alone is not as strong as porcelain fused to metal. For some people, this is the best choice, because of the extra strength. But the metal backing on the porcelain stops the light from traveling through the porcelain. It reduces the translucence of porcelain and creates an opaque look. This distinguishes these crowns from the neighboring natural teeth.
Over time, the metal lining of the crown can start to show, and creates a thin black line at the edge of the crown, near the gumline.
The Procedure
There are only two visits with the placement of crowns.
· In the first visit, your dentist removes a thin layer of the tooth to make room for the crown, and prepares the exposed surface to bond well to the new crown. You will have a temporary crown until the next visit.
· In the second visit, the new crown is temporarily attached for fine-tuning, and when both you and your dentist are satisfied with the fit, it’s permanently bonded to the tooth.
