the dental office, making a gold onlay is similar to
making a crown. A a gold onlay covers and protects the
biting surface of a tooth that is severely damaged and is not possible to restore with a dental filling.
It will take two or more visits
to repair a tooth with an overlay. In the first appointment the damaged teeth with be prepared. The dentist then takes the impression after the preparation is completed. He will write a dental prescription for the gold tooth. The prescription includes instruction about the type of the gold and the fitting of the teeth. Sometimes, the dentist also takes many dental photographs and sends them to the lab so that the dental technician can better visualize the patient's dental problem. Normally, the lab needs several weeks to cast the gold tooth. After the gold crown is made from the lab, it is sent to the dental for cementation.
In the preparation appointment, in order to reduce your discomfort, the tooth and its surrounding area are anesthetized. The medication often uses today is 4% septocaine 1:100,000 epinephrine. If the patient has a heart condition, the dentist may use 3% carbocaine instead.
Like any surgical procedure, the first step is "isolation" of the surgical field. In the dental office, a rubber dam is usually used for isolating the tooth to be worked on. It works as a protective raincoat and keeps all the debris away from your mouth. Then, the handpiece is used to carefully remove decay and to shave-off the tooth. On the average, about 2 millimeters of tooth structure are reduced in order to "make-room" for the gold onlay or crown. Comparing to the veneer preparation, the onlay or crown preparation is less conservative.
The key to have a perfectly fitted gold crown is to take an accurate impression of the prepared tooth. Sometimes, the dentist has to take multiple impressions so that he can pick out the best one. To get a better
impression, the dentist may put a dental impression chord in the gap between
the tooth and the gum.
The cord absorbs the moisture and pushes the gum out so that the impression can "read" the edges of the preparation. Alternatively, the dentist may use a soft-tissue laser instead of the string to push the gum away. The laser typically gives the best impression.
Making the temporary crown is the last step in the preparation appointment. If you do not have the temporaty crown, your tooth will become very sensitive to cold. If the tooth is already treated with root canal therapy, the temporary crown will protect it from fracture. For the period that the onlay is being made at the dental lab, a temporary onlay is placed
to cover the prepared tooth. The temporary onlay is taken out and replaced with a permanent one in the next visit.
In the cementation visit your dentist first check the fit of the permanent gold crown. Your bite will also be tested with a marking paper. This paper helps the dentist to determine
whether or not your teeth are meeting properly by marking the "high spots" with red or blue color. A dental floss is used to check that the tooth is contacting its neighboring teeth adequately. Finally, the crown is cemented with a special dental cement such as Vitramere or bonded to the tooth with Variolink. After a few minutes, the cement is initially set and the dentist will clean out the excess cementing materials. He will check the bite with the mraking paper and the floss one more time. When everything looks good, you will be ok to go home and enjoy your new restoration.