CEREC® : Craig - Dental Crown

CEREC® : Craig - Dental Crown

Broken teeth can be easily and beautifully replaced in just one visit. The crown’s colors are customized individually to give a natural, unique look that blends in with the surrounding teeth. Cerec One-Visit Dental Crown process Patient presents with problem; ex broken tooth, fracture, deep decay etc Dr. Tang evaluates tooth and diagnoses problem. Example diagnoses: Old defective amalgam filling with fractures and loss of cuspal integrity. Treatment would be diagnosed: Full coverage crown required to restore integrity to the tooth. Tooth is X-rayed and photographed for precision and documentation. Pt is numbed up completely so they are comfortable during the procedure. Dr Tang removes all decayed and compromised tooth structure. 1-1.5 mm of tooth structure removed circumferentially allowing room for the crown. Tooth is scanned with Cerec machine. This replaces the “goopy impression material” The tooth being worked on is scanned as the digital impression, the tooth opposing it is scanned so the machine knows how tall to make it, and lastly the bite is scanned to show how those images come together. The machine organizes the pictures and creates a digital model of the tooth and creates a proposal of what the restoration should look like. Dr. Tang individually adjusts each proposal customizing it for the best, most natural look. This information is sent wirelessly via blue tooth to a milling chamber where the crown is milled out of a solid porcelain block. The tooth comes out purple. The individual colors are hand painted in and a glaze layer is applied. The tooth is then fired in a kiln at around 850°C for approximately 20 minutes. This process is called crystallization. After the crown cools it is ready to be tried in. We check the shape, size, color and fit of the crown; making sure it looks and feels good. We then take a film to check all the areas we can’t see like in-between the teeth and under tissue. The crown and the teeth are then prepared to be cemented. The crown is abraded, etched and bonded; the tooth structure is abraded, cleaned and bonded. The crown is then cemented with the “Multi link” system. All excess cement is removed and a final film is taken to verify perfect margins and cleanliness. Final photo is taken for documentation Post operative instructions given. -Interesting Cerec dental crown facts- -Material used for crowns is EMAX, which is “lithium disilicate” -This material can withstand 360-400 (Mpa) -Material is radiolucent. Porcelain fused to metal crowns are radio opaque making it very difficult to spot new decay on films. The radiolucent nature of the all porcelain crowns allows decay to be easily detected when it is small and simple thus allowing a much easier, cost effective restoration in the future. -The crowns are milled from a solid block. Other types of crowns are porcelain stacked onto a metal or zirconia (ZrO2); while the substructure is hard and solid (ZrO2 withstanding1000 Mpa) the overlaying porcelain can only withstand 90Mpa thus making the singular, non stacked nature of the lithium disilicate crown much less prone to fracture. -Emax crowns are shown to be a very biocompatible material. Agar diffusion tests show the material to be non cytotoxic -Although the material is very durable, studies have shown that it causes less wear on the opposing tooth’s enamel than other materials used. -Emax crowns are dually retained. They are physically retained with resin cement, and chemically retained with a bonding process, thus making it much less likely to come out.