Onlays
Onlays are frequently used to restore teeth that are severely damaged by decay, cracks, or wear. Onlays are similar to crowns. The difference is that an onlay covers the chewing sufaces of a back tooth. A crown covers the entire surface and sides of a tooth.
Procedure
First, damaged tooth structure is removed and shaped to receive the onlay. An impression is taken of the tooth, the opposing teeth and a bite relationship is taken between the top and bottom teeth. The impressions and bite are sent to a dental laboratory where the onlay is made. At a second visit to the dentist the onlay is checked for fit and bonded or cemented to the tooth.
Materials
Until about 10 - 15 years ago onlays were made from a mixture of metals, most of which had a high gold content and gold color. Today, cosmetic onlays are made from very strong ceramic materials, which very closely match the color of the surrounding teeth.
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