CEREC inlays and crowns
The CEREC restoration is the result of a cutting-edge technology developed 30 years ago and continuously improved since then. The name CEREC comes from an English acronym (Chairside-Economical-Restauration-Esthetic-Ceramic), which means “Restoration in Economic Ceramics and Aesthetics made at the Chair”. This technology allows a high quality ceramic restoration to be produced in a single visit. Indirect crowns and inlays are the most commonly used restorations.
It is also possible to manufacture crowns on implants, temporary acrylic bridges, or ceramic veneers. Thanks to recent advances, this technology now allows the creation of surgical guides in implantology incorporating 3D scanning technology.
The CEREC device also allows users to transmit their digital models to their dental laboratory. This saves patients from having to take conventional fingerprints that are often more uncomfortable.
Indications for treatment
A CEREC restoration is mainly indicated for:
- Reinforce a tooth after root canal treatment;
- Protect a tooth weakened by cavities;
- Reinforce a broken, cracked, cracked or fractured tooth;
- Reinforce a tooth that already has a large amalgam or composite restoration;
- Cover a deformed, discoloured, devitalized tooth;
- Improve the appearance of the smile;
- Restore height to heavily worn teeth.
The advantages of the CEREC restoration
- CEREC ceramic restorations offer many technical advantages. Since the crown is made and placed in a single appointment, it is possible to keep a larger healthy portion of the tooth. Indeed, the bonding bond between the tooth and the ceramic is known to be stronger at the level of healthy enamel and it allows to keep some walls that should be removed if the restoration was done in two visits. According to scientific studies, CEREC ceramic restorations restore 98% of the strength of a natural virgin tooth. It therefore offers better durability than white composite fillings;
- As this technology allows the patient to receive the restoration in a single visit, only one anaesthesia is required. In addition, no temporary restorations are required, which is a definite advantage, as they tend to be fragile, peel off and can cause temporary pain in contact with the cold. In addition, in the case of temporary inlays, since the temporary restoration is only maintained with temporary cement, the remaining tooth is not yet as strong and is more likely to break;
- CEREC technology also uses a digital or video camera, depending on the generation used by the dentist. This camera allows you to create a 3D model from which the ceramic piece is designed. This eliminates the need to take impressions with standard materials, which may be difficult to tolerate or may give some people a hard time;
- Finally, this restoration is usually less expensive for the patient than laboratory-made restorations. These require transportation, fingerprinting and the use of various other more expensive technologies and materials, in addition to two visits.
The advantages of ceramics
- Dental ceramics is the material that most closely resembles dental enamel because of its rigidity, texture and how it reacts to temperature variations when eating;
- In addition to being biocompatible, dental ceramics gives strength to a damaged tooth;
- Ceramic provides great chewing comfort, and its wear is comparable to that of natural teeth.
- Ceramic CEREC restorations are more expensive than amalgam (grey filling) or composite (white filling) restorations;
- A minimum thickness and width of the natural dental substance is required to achieve good strength;
- Finally, it is necessary to take into account the manufacturing times of the restorations (drawing, machining and firing). In most cases of more than 4 units, it is preferable to place the restorations in the mouth during a second visit. In this case, an impression is taken (either with a viscoelastic material or with the CEREC device and sent to the laboratory electronically). In case 2 visits are necessary, the dentist prepares temporary restorations. Permanent restorations will be fabricated either by an external dental laboratory or by a team member using CEREC technology. When restorations are fabricated in the clinic, this often reduces the manufacturing time compared to cases that are sent to the external laboratory.
Risks and consequences of not treating
- Dental fracture;
- A root canal treatment may be required if the fracture is progressing to the vital part of the tooth;
- Loss of the tooth if the fracture is too deep.
Processing steps and times
- The first step in the design of a CEREC ceramic restoration is to capture images of the preparation made by the dentist using a digital or video camera depending on the generation of the device used;
- Then, the restoration is created virtually using a specialized computer program. The dentist can then analyze the preparation, define the contours and draw the restoration in 3D using several virtual tools. This is similar to technical drawing used in several technological fields. We often talk about CAD-CAM (Computer Assisted Design-Computer Assisted Manufacturing) technologies. The drawing is then sent to a machining chamber;
- The dentist chooses the color and size of the ceramic block to be cut. There is a wide selection of very aesthetic shades and blocks with a gradient of colors that allow the patient to have a restoration that perfectly matches the natural shade of his teeth. Some ceramics are also more resistant to fracture (E-MAXTM), and are indicated to strengthen a short tooth that has lost height over the years due to wear (attrition) or a brittle tooth in a patient who clenches or grinds teeth (bruxism). There is also a category of block of pressed composite materials (family of polymers such as white fillings) that can be used in the same cases as those mentioned above. The size of the block is established by the software according to the size of the restoration to be performed;
- The next step is to insert the selected ceramic block into the milling chamber. This device is equipped with two 5-axis rotating instruments, which cut the block and reproduce the 3D drawing created by computer. A jet of water and oil controls the temperature and reduces friction to obtain a very precise cut of the ceramic block. The machining time is between 5 and 20 minutes depending on the type of restoration, block and machining device used;
- Some blocks require cooking to reach their full strength. This is the case for E-Max ceramics and zircon. Other ceramics can be glazed and baked to improve their strength or to colour them for superior aesthetics. This step requires more time and that is why this type of restoration is slightly more expensive.
- The part is then glued with resin or glass ionomer cement into or onto the patient’s tooth. The restoration is polished and no time is required before eating.
The cost of CEREC crowns is similar or lower than that of laboratory crowns and varies depending on the type of block or material used. However, since only one appointment is required, you save both time and money.
- Dental crowns require the same maintenance as natural teeth, including regular brushing (2 to 3 times a day), flossing and routine visits to your dentist (1 to 2 times a year).
- Inadequate oral hygiene;
- Painful tooth, irritated vital part;
- Failure of a root canal treatment present with or without abscess;
- Bruxism or clenching of teeth not treated by a protective device;
- Insufficient space;
- Tooth too damaged or broken too deep under the gum;
- Tooth too decayed;
- Tooth with too much loss of support bone.
- Composite or porcelain veneer;
- Inlay or laboratory crown;
- Composite restoration;
- Amalgam restoration.
Please note that the clinical indications for each restoration are different.
Your dentist will make the right diagnosis and propose possible treatment solutions based on your particular situation. No general rule applies in a treatment choice.