CAD/CAM Technology

CAD/CAM stands for computer-aided design/ computer-aided manufacturing. This technology is revolutionizing dental restrains because the overall process is more efficient for the dentist and the patient. On the down side, this technology is expensive, costing upwards of $100,000. Not to mention the expense to purchase blocks of crown material in a variety of different shades. However, its chair-side convenience makes it worth the price for dentists and patients. 

The specific machine that Arrowhead Lakes Dentistry owns is called the CEREC (Chairside Economical Restoration of Esthetic Ceramics). When a patient comes in needing a crown the dentist will first clean up the tooth, which is basically cleaning up the decayed or broken parts of the tooth. Next the dentist will use the CEREC omnicam to scan the patient's mouth around the problem tooth. 

CEREC Omnicam

The scan takes continuous photos and strings them together based on the background so it can create an accurate three-dimensional image on the computer pictured below. The dentist will continue scanning the area until the computer has gathered enough pictures to complete the three-demential replica of the patient's mouth. The dentist needs to complete this process three times for each of the sides of the tooth; the lingual, occlusal and facial surfaces. 

Lingual is the inside surface
Occlusal is the top surface
Facial is the outside surface

Once the model of the patient's mouth is complete the computer software creates a crown and fits it onto the problem tooth. The dentist can then manually adjust how the crown will contact neighboring teeth on all three surfaces. As pictured below, the image will have highlighted areas of the crown with corresponding colors for how much contact there will be. 

CEREC computer unit

Once the dentist is satisfied, the computer sends the image of the crown to the milling unit where the crown will physically be made. In the picture below, the milling chamber is the center panel. 

CEREC milling unit

A block of zirconia or lithium disilicate is placed inside and then milled into the shape of the crown using diamond infused drills and a lubricant substance. 

Unmilled blocks of lithium disilicate

Zoomed in photo of a crown being milled

It takes about 12-15 minutes for the crown to be shaped, depending on the complexity of the tooth shape. After the crown is milled, the dentist will do a preliminary fitting with the patient to ensure that it is the correct size. Then the crown goes into an oven so it can achieve its maximum strength. During this process lithium disilicate looses its purple color and becomes a shade that mimics a natural tooth. The crown is in the oven for about 12 minutes at more 575 degrees celsius. 

CEREC oven

Once the crown has cooled the dentist can permanently cement the crown into the patient's mouth and the procedure is completed.