A couple of months ago I was biting into some peanuts and somehow a part of my tooth chipped off. I immediately scheduled a dentist appointment and went to see him couple of days later. The technician in the dental office quickly took bunch of X-rays and the dentist evaluated what needed to be done. He gave me two options to consider. One was to patch the tooth with a filling and the other was to place a crown with a promise the crown will stay with me even after I am gone! He also gave me an educational background as to how crowns are made these days.
Earlier, patients have to make at least 2 or 3 visits to the dentist office to make a crown as on the first day they will take X-Rays and an examination along the roots of the tooth receiving the crown and the bone etc. Then they will determine whether you need a root canal treatment if there is extensive decay of the tooth. If there is no treatment required they will make an impression of the tooth to make the crown. The second visit requires to place the crown. But these days with advanced technology, I was told, they can design, build and place the crown within 2 hours during the same visit. I had crowns before but with this advanced technology and living along with a new crown throughout my life, I said to myself.. what the heck, let’s go with the crown option! The Dentist was thrilled with my option and he promised me to get me involved with the process as an observer. He even let me video record the design and the fabrication process. I had the chance to observe the advanced technology in real time!
The first part of the process of building a crown is to build a 3D image of the tooth. The Dentist used a digital probe going around the tooth scanning many times to build a 3D model of the tooth in the computer as to how it should looks when the crown is installed. This is called CAD/CAM dentistry which involves taking digital impressions. As you see the name of the machine in the picture, CRER EC, which is developed by Prof Werner H. Mormann and Dr. Marco Bradestini at the University of Zurich. Read the Wiki, you can find very interesting information on this. This technology is extremely precise as it can take every last detail of the tooth without having to worry about taking inaccurate dental impressions. It is basically a computer aided digital scanner and crown milling system that enables the dentist to fabricate a crown in only one visit. The computer uses the 3D model to formulate a crown that can be further customized with the help of the dentist.
Once 3D image was completed, the design was sent via a wireless signal to a milling machine that carves a crown out of a ceramic block. The Ceramic block was (about 0.5x0.5x0.5 in) placed between two long arms of the machine. Once the machine started to work, after about 20 minutes or so the tooth was fabricated based on the design. The newly fabricated ceramic tooth was then placed in an oven with a temperature about 1300C for the crystallization process where the tooth got extremely hardened. The final crown was custom stained and glazed to get an excellent color match. Then the crown was cemented to the base of the exiting tooth and the bite was adjusted. Woo–hoo! My crown was done within 2 hours and I came home thinking this tooth is going to last long throughout my lifespan!! J
Watch this video all the way to the end. You will see the final product...