Overcoming challenges in processing zirconia and advanced ceramic materials

Ceramic materials such as zirconia are being used more and more frequently in modern restorative dentistry. However, removing zirconia restorations with conventional contra-angle handpieces is a challenging and lengthy procedure. Added to this is the high wear on the burs, especially with monolithic material. In some cases, the bur has to be changed at one-minute intervals. To address this problem, W&H has developed a new product line specifically tailored for these applications.

The W&H Synea Power Edition has been specially developed for processing zirconia.

The removal of zirconia restorations with standard contra-angle handpieces is a demanding and time-consuming procedure. Conventional contra-angles are struggling to keep up cutting performance. Applying even more load to improve removal rate wears out the bur much faster^1,2 , and may risk thermal damage to vital teeth³. What must be taken into account is therefore on the one hand the effect of speed and torque on the cutting performance and, on the other hand, the generated heat during cutting.

Effects of speed and torque on the cutting efficiency

Cutting efficiency is maximised due to the optimum ratio of torque and speed transmitted to the bur from the electric motor. The clinical indication determines whether higher torque or speed is more efficient. Heavy-duty applications require additional torque, and not the maximum, but the recommended bur speed. Since most manufacturer recommend a rotating speed of 160,000 rpm for their high-performance rotary instruments, a contra-angle handpiece with a transmission rate of 1:4 is an especially convenient solution. It allows working at the optimal bur speed without having to change the standard setting of 40,000 rpm on the electric motor. Studies show that “[…] a higher force for cutting of Zir […] increases the damage to the diamond burs, resulting in a decrease of the total cutting depth.”⁴

Power for the hardest restoration materials

W&H has developed a new Synea series, specifically for processing high-strength ceramic materials such as zirconia. The new Synea Power Edition impresses with an extra robust design and more power. Picture it, like a Jeep effortlessly navigating any terrain. Problems that may occur during the removal of zirconia restorations, such as overheating of the contra-angle handpiece, high wear on burs, and generally the high load on the transfer instrument, can be reduced with the new contra-angels. Thanks to the modified transmission ratio, the Synea Power Edition contra-angle handpieces ensure optimum bur speed and provide the extra torque required for processing hard materials efficiently. The capacity to remove tooth structure more successfully at the same surface pressure reduces both severe wear of the bur and the risk of thermal damage to the teeth.

What makes the difference?

The Synea Power Edition comes with a triple water spray feature, enhancing bur cleaning efficiency.

The Synea Power Edition comes with a triple water spray feature, enhancing bur cleaning efficiency. Despite using the same amount of water as the traditional W&H 5× spray, this development increases the flow rate per nozzle, ensuring thorough cleaning of the bur during treatment while also enhancing cutting performance. One factor that contributes to the durability of the handpieces is the extra-stable chucking system from W&H. With a 20% increase in clamping force, the system is made for applications involving high-strength materials. And although the clamping force has been increased, exchanging burs remains easy and smooth. For this purpose, W&H has designed a new push-button, where the loads are distributed more evenly. Additionally, the new push-button is black, providing a visual indicator of handpieces optimised for demanding applications.

Reliable and easy to handle

The service life of the new Synea series is extended by at least 20% compared to standard transmission instruments, as they are less susceptible to mechanical failures. The high-speed contra-angle handpieces are perfect for crown cutting and lengthy preparations, minimising the need for frequent bur changes and reducing bur consumption. However, it's crucial to match the burs to the material because one thing does not replace the other. Overall, the new high-speed contra-angle handpieces from W&H are very robust and durable. They therefore protect other existing contra-angle handpieces in the dental practice.

The big wave of zirconia separations is yet to come

W&H contra-angle handpieces are generally recognised for their high quality. They are less likely to require repairs and ensure user-friendliness. With the Synea Power Edition, W&H has launched new high-speed contra-angle handpieces to the market, which will also be of great importance in the future. As Zirconia has become more popular in the past, it is obvious that the demand for the removal of Zirconia will increase. It can be assumed that the big wave of zirconia removals is yet to come. The new Synea Power Edition is therefore a must-have for all those who want to remove Zirconia restorations safely and comfortably and at the same time protect their existing high-speed transmission instruments.

With the Synea 900 series, W&H is now offering three particular high-speed contra-angle handpieces.

Reference

1. Cutting efficiency of diamond burs operated with electric high‐speed dental handpiece on zirconia - Nakamura - 2015 - European Journal of Oral Sciences - Wiley Online Library
2. Diamond Bur Cutting Efficiency of Dental Zirconia (wvu.edu)
3. High-speed cavity preparation techniques with different water flows - Journal of Prosthetic Dentistry (thejpd.org)
4. Cutting efficiency of diamond burs operated with electric high‐speed dental handpiece on zirconia - Nakamura - 2015 - European Journal of Oral Sciences - Wiley Online Library