Second Shadow Day with Dr. Shelley

Yesterday I was able to observe a fitting for an oral sleep appliance and more CEREC crown fittings. The crowns that I had seen previously were for decayed molars, however one patient on Wednesday needed a crown for the lateral incisor. Incisors are in the front which makes appearance even more important and have a very different shape than molars. The restoration also needed to fit onto a dental implant and abutment, which I will go into more detail about in my post tomorrow. This means that in order to create a crown with the CEREC, Dr. Shelley had to go through a few more steps.

During the acquisition phase of the CEREC when the omnicam is mapping out the patients mouth for a crown over remaining natural tooth it would only need lower jaw, upper jaw and buccal views. Implants need a gingiva mask view as well in order for the computer to map it out correctly. 

CEREC acquiring gingiva mask view of implant

After the three-dimensional model of the mouth is made, the doctor places a screw and a plastic cap on the implant so the computer software will recognize the cap and design a crown to go over it. The doctor can then change the contact and anatomy of the abutment and crown before milling it out. I thought it would be interesting to post a short video of the crown being milled out of the lithium disilicate block in the chamber. In the video below the milling machine has just begun to mill out the crown from the block. 

Another interesting step Dr. Shelley had to take with this patient has to do with the color of the surrounding teeth. Since the incisor is in the front, appearance is very important. The patient had a very unique blue and gray coloring which was difficult to match with the standard palette that the lithium disilicate blocks that the office has. So, Dr. Shelley is sending the restorations to a lab that has an artist who will match the color of the crown much closer to that of the patient's surrounding teeth.