CEREC is an acronym which stands for Chairside Economical Restoration of Esthetic Ceramics. It is a system which consists of a chairside computer and a milling unit. This revolutionary piece of technology enables our San Jose dentists to make porcelain crowns, inlays and onlays quickly and bond them into a tooth in a single appointment. Prior to the CEREC system, these type of restorations took two weeks to complete. An impression of your teeth would go to a dental laboratory where the crown would be made, while a temporary crown would be placed in your tooth until the permanent one was ready. With the CEREC system, we take a digital impression of the prepared tooth using a special infrared camera. This digital impression goes into the computer where it appears as a three dimensional model. We design the crowns on this digital model, and send the information to the milling unit when we are satisfied with what we have created. The milling unit uses two precision drill bits to carve a porcelain block to the exact dimensions of the crown we just created on the computer. The milling unit takes ten to twenty minutes to make the restoration, which is then bonded into the tooth.
Aside from convenience, there are several advantages to having these procedures done in a single visit. Single visit restorations eliminate the need for additional appointments and injections, and your tooth is much better off not having a temporary restoration for two weeks. Temporary restorations can fall out and leak, which can lead to subsequent complications. Dental procedures are traumatic to teeth, and eliminating a second appointment reduces the amount of stress put on a tooth.
The CEREC machine can make all three of these porcelain restorations. The difference between inlays, onlays and crowns is the amount of tooth structure they replace. If you look at a tooth from the chewing surface, the raised bumps you see are called cusps. When you chew your food, it is the cusps of opposing teeth which grind and mash your food. Restorations which fit within cusps are called inlays, and those which incorporate a cusp are called onlays. Restorations which cover the entire tooth are called crowns (commonly known as caps). Whenever possible, it is better to place an inlay or an onlay on a tooth because it requires less tooth reduction that needed for a crown. Placing a crown on a tooth requires removing more tooth structure than an inlay or onlay, which increases the chances of the tooth requiring a root canal in the future.
Cavities, fractures and dental procedures are all traumatic and irritating to the pulpal tissues (nerves and blood vessels) of our teeth. The pulpal tissues become swollen and sensitive in response to trauma, and can swell up to the point where their blood supply is cut off since the pulp is confined within the inside of the tooth. Once the pulpal tissue has died, a root canal is required to keep the tooth. This is why a tooth should always be restored as soon as possible with the smallest restoration possible, and is the the backbone of the Minimally Invasive Dentistry philosophy. If a tooth has already had a root canal, is severely broken down, or has an existing crown which is failing, then a crown needs to be placed on it. The CEREC machine is a valuable piece of equipment when it comes to Minimally Invasive Dentistry and reducing pulpal trauma.
A single tooth CEREC usually takes about 90 minutes. A good portion of that time is spent designing and milling the restoration. If multiple restorations are being made, then more time is required. We first numb the tooth, then place a rubber dam to keep the area dry and to keep water, amalgam and anything else from going down your throat. After the restoration comes out of the mill, it is adjusted, bonded into the tooth, and polished. A CEREC inlay, onlay or crown is a very durable and long lasting restoration which will provide you with many years of trouble free service. If you have any questions about the CEREC machine, Dr. Sawyer or Dr. Diercks would be happy to discuss it with you. Call us today at 408-215-1006 for an appointment.