CEREC Restorations

CEREC (Chairside Economical Restoration of Esthetic Ceramics, or CEramic REConstruction) is a dental restoration product that allows a dental practitioner to produce an indirect ceramic dental restoration using a variety of computer assisted technologies, including 3D photography and CAD/CAM.

With CEREC, teeth can be restored in a single sitting with the patient, rather than the multiple sittings required with earlier techniques. Additionally, with the latest software and hardware updates, crowns, veneers, onlays and inlays can be prepared, using different types of ceramic material.

Single Appointment Dental Care

Most dental restorative methods require more than one visit to the dentist. This means that on the first visit, you get an injection of anesthesia, your tooth prepared, an impression taken, and a temporary restoration put on your tooth. You make a second appointment for a couple of weeks later, get another injection, have the temporary pried off and have a permanent restoration put on. With CEREC, the procedure is done in a single appointment, start to finish.

With CEREC, the Dentist can use strong, tooth colored ceramic materials to restore your teeth to their natural strength, beauty, and function.

Finest Dental Materials

These materials match the composition of natural tooth structure. This means when hot food or cold drinks are consumed the restoration and tooth expand and contract at almost equal rates. Also, the materials are chemically bonded to your tooth, so the dentist can save as much healthy tooth tissue as possible while providing you with a dental restoration that strengthens your tooth.

The cavity preparation is first photographed and stored as a three dimensional digital model and proprietary software is then used to approximate the restoration shape using biogeneric comparisons to surrounding teeth.

The practitioner then refines that model using 3D CAD software. When the design phase is complete, the information is sent wirelessly to the milling unit which mills the actual restoration from a solid block of material using diamond burs. The restoration is bonded to the tooth using a resin cement which bonds to both the restoration as well as the tooth itself.

Technique

The treating dentist prepares the tooth being restored either as a crown, inlay, onlay or veneer. The tooth is then powder sprayed with a thin layer of blue anti-reflective contrast medium, imaged by a 3D imaging camera and uploaded to the CEREC computer.

Using the proprietary CEREC software in various modes, a restoration can be designed to restore the tooth to its appropriate form and function. This data on this restoration is stored in a file and is sent via wireless serial transmission or direct wiring to a milling machine. The restoration can then be milled out of a solid ceramic or composite block.

Milling time varies from as little as four minutes to as long as twenty depending on the complexity of the restoration and the version of the milling unit.

Design Methods

The design software for the CEREC system has undergone significant changes in the years since the technique was first introduced by Professor Mormann. Currently, a dentist can choose from four major design approaches.

Database

This design mode uses a library of tooth shapes that is stored on the computer to suggest the shape of the proposed restoration. Most commonly a recording of the bite registration (the imprint of the opposing or antagonist tooth in a wax like or rubbery material) is also added to the data the software can use when deciding the proposal.

This data together with a 3D optical impression of the prepared tooth establishes the approximate zone with which the new restoration can exist. The proposed restoration can then be morphed to fit into this zone in an anatomically and functionally correct position.

The dentist can then make correction to this proposal as he sees fit and then send it to the milling unit for completion.

Materials

The ceramic material has some properties that make it very suitable for use in dental restorations. It expands and contracts in response to temperature changes at a rate approximately half-way between those of enamel and dentin. It also wears away at approximately the same rate as enamel. There is also a composite material available which has some advantages in restoring smaller inlay type restorations.

Advantages of CEREC Restorations

  1. Time savings. Patients usually only have to go one time, as opposed to two trips for a traditional crown; this also reduces the number of local anesthetic injections (shots) needed.
  2. More conservation of tooth structure. Oftentimes a partial coverage restoration can be completed vs a full conventional crown.
  3. Stronger porcelain. Milled ceramic is stronger than hand layered and pressed.
  4. Aesthetics. Homogeneous porcelain blends in better than other porcelains.
  5. Natural. Ability to copy what was there previously can yield restorations that are duplicates of the pre-prepared tooth.

Disadvantages of CEREC Restorations

Requires investment of time and money for dentist to obtain and learn, however there are no disadvantages for the patient who receives the filling.