CEREC

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 Restorations:

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 removed 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 beauty and function.

Dental Materials:

CEREC materials match the physical properties of natural tooth more closely than metal crowns. Specifically, when hot food or cold drinks are consumed the restoration and tooth expand and contract at closer rates so that they don't interfere with each other. Also, the materials are chemically bonded to your tooth, so the dentist can save as much healthy tooth structure as possible while providing you with a dental restoration that strengthens your tooth.

Technology

CEREC 1 2 and 3 from Sirona

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.

History

The system is manufactured by "Sirona Dental" in Bensheim, Germany .

• 1980 - Development of the CEREC method at the University of Zurich W. Mörmann, M. Brandestini).
• 1985 - Treatment of the first patient with CEREC (University of Zurich, material: VITABLOCS Mark I).
• 1986 - Siemens acquires the license to market and further develop the CEREC equipment.
• 1987 - CEREC 1 is introduced (chief indication: single and dual-surface inlays; material: VITABLOCS Mark II).
• 1990 - International CEREC Symposium at the University of Zurich.
• 1991 - Hydraulic machining drive replaced by an electronically controlled motor.
• 1994 - CEREC 2 is introduced (range of indications: inlays, onlays, veneers).
• 1996 - CAD/CAM Symposium to mark a decade of CEREC (University of Zurich).
• 1997 - Sirona was formed as the result of the sale of the Dental Division of Siemens AG.
• 1997 - CROWN 1.0 program for producing full-ceramic posterior crowns.
• 1998 - Second material manufacturer partnership is formed (lvoclar, ProCAD).
• 1998 - CROWN 1.11 program for producing posterior and anterior restorations.
• 2000 - CEREC 3 is introduced (compact Windows-based CAD/CAM system).
• 2000 - Third material manufacturer partnership is formed (3M Paradigm MZ100).
• 2002 - More than 2,500 CEREC users in the United States and over 5,000,000 CEREC restorations placed worldwide.
• 2003 - 3D software version is released, allowing users to see 3D views of teeth and models.
• 2005 - IPS e.max CAD by Ivoclar Vivadent launches for CEREC, 360MPa flexural strength all ceramic restorations
• 2006 - CEREC Celebrates 20 Years.
• 2006 - Sirona releases BIOGENERIC version of software. This software allows for the machine to accurately reconstruct the missing tooth shape and surface.
• 2007 - More than 23,000 CEREC users world wide.
• 2008 - Sirona release the MCXL milling unit, this milling unit can produce a crown in 4 mins.
• 2009 - Sirona release CEREC Acquisition Center (AC) powered by Bluecam
• 2010 - CEREC Celebrates 25 Years.
• 2011 - CEREC v4.0

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 / Disadvantages

Advantages

1. Xrays can see through the material and detect decay or problems, whereas Xrays cannot see through metal crowns.
2. 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.
3. More conservation of tooth structure. Oftentimes a partial coverage restoration can be completed vs a full conventional crown.
4. Stronger porcelain. Milled ceramic is stronger than hand layered and pressed.
5. Aesthetics. Homogeneous porcelain blends in better than other porcelains.
6. Natural. Ability to copy what was there previously can, but not necessarily, yield restorations that are duplicates of the pre-prepared tooth.

Disadvantages

    1. Requires investment of time and money for dentist to obtain and learn.
 
    2. Success of CEREC restorations is dependent on the abilities of the treating dentist. A poorly designed restoration   
       may not match the color/shade of adjacent teeth and/or it can break, leading to additional problems. 
    3. Restorations can be more costly to the patient.

See also

• Brontes Technologies

External links

• CEREC pages of the manufacturer
• The largest CEREC community on the WWW with hundreds of clinical videos and a discussion forum for questions
• CEREC in Greece
• Sirotech - The UK's No. 1 Cerec Service & Support Centre