CAD/CAM-titanium-ceramic single crowns with non-anatomic coping-design. A six-year follow-up study

Objectives Due to the increasing price of gold CAD/CAM titanium-ceramic restorations were developed to give alternative to the established metal-ceramic restorations with a high gold content. Despite the advantages of excellent biocompatibility, high corrosion resistance and appropriate strength titanium has made the casting process difficult caused by the high affinity of molten titanium to investment materials [1]. It was found that the adhesive bond between titanium and porcelain was compromised due to the existence of reactive layers. Furthermore the titanium’s coefficient of thermal expansion is significantly lower than that of conventional noble metal alloys, therefore titanium required special low-fusing porcelain with a low coefficient of thermal expansion to be veneered. Nowadays titanium coping were fabricated using CAD/CAM technology. Earlier versions of CAD software were limited to design non-anatomic metal copings in even thicknesses. As a result, crowns were fabricated with excess of unsupported veneering porcelain in certain areas. However, there is a lack of data about the clinical performance of CAD/CAM titanium-ceramic crowns with non-anatomic coping design and low-fusing veneering porcelain. The present study reports the clinical results of CAD/CAM titanium-ceramic single crowns with non-anatomic coping design. Fractures of the veneering porcelain were examined after a follow-up of six years.