NTI-Kahla GmbH

Z-Cut Diamond Grinding Instruments for Dentistry and Dental Technology

Zirconia, the second most common natural compound of the element zirconium, was introduced to the dental market over 25 years ago and, in retrospect, has proven to be a revolution. From green zirconia to trendy materials to the white zirconia commonly used today—the continuous improvement of the material is a testament to its immense potential. Development continues: From the first generation of yttrium-stabilized zirconia to the current fourth generation of 4Y-TZP, all zirconia restorations share common characteristics: exceptional hardness, high aesthetic performance, good processability, and excellent biocompatibility. In particular, sintering time has been drastically reduced in recent years and is now approximately 30 minutes for the latest generation. However, the extreme hardness of the material remains a problem. From an economic standpoint in particular, the time-consuming machining of zirconia workpieces poses a challenge. At the same time, instrument wear increases due to the higher stress placed on these instruments. We, the diamond experts from Kahla, have been involved in the machining of all forms of zirconia from the very beginning and are constantly adapting our instruments to the developments in this material. This led us to develop the Z-Cut diamond instruments, which are already valued by many practitioners worldwide for their unique properties. Thanks to a special electroplating process and a unique “Z-Cut diamond coating,” our product has been proven to have the longest service life on the market. Its smooth, quiet operation and high material removal rate ensure efficient processing. To meet the individual needs of users, we have included the most popular shapes in our Z-Cut lineup. This lineup is constantly adapted to the needs of our customers and the requirements of the material’s properties. As with any success story, however, it is also important to address the negative aspects of this development. Zirconia is prone to severe cracking during grinding and milling; while this has been reduced with each new generation of products, it has never been completely eliminated. This initial cracking can lead to friction effects and stress corrosion when used in a moist environment—a phenomenon commonly known as “crack growth.” For this reason, it is essential to polish zirconium dioxide properly; however, grinding also requires a careful selection of instruments. To meet all requirements, we have defined four grit sizes in our Z-Cut line: medium, fine, superfine, and ultrafine. This prevents overly coarse machining, which could lead to problems later on. Minimizing crack formation during the machining of zirconia prevents the need for even more labor-intensive polishing later on and reduces the risk of deeper individual cracks that cannot be completely removed even by polishing. The consequences are well known: crack propagation, material fatigue, and workpiece failure. But it doesn’t have to be that way. Choose Z-Cut—a safe, proven, and cost-effective system.