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. In this user report, Dr Romana Krapf, MSC, reviews the new W&H Synea Power Edition contra-angle handpiece product line specifically tailored for these applications.

Synea Power Edition

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 teeth.3

What must be considered 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.

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 manufacturers recommend a rotating speed of 160,000rpm 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 40,000rpm on the electric motor.

Studies show that a higher force for cutting of zirconia increases the damage to the diamond burs, resulting in a decrease of the total cutting depth.4

POWER AND RELIABILITY MAKES THE DIFFERENCE

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 a robust design and more power.

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 transmission instrument, can be reduced with the new contra-angles.

Synea Power Edition
The power and durability of the new Synea Power Edition makes it a lasting tool for applications on high-strength materials

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.

The Synea Power Edition also comes with a triple water spray feature, enhancing bur cleaning efficiency. Despite using the same amount of water as the traditional W&H 5x spray, this development increases the flow rate per nozzle, ensuring thorough cleaning of the bur during treatment while also enhancing cutting performance.

Another 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. 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.

To read the full article, click here or ref­­­­er to Dental Asia May/June 2024 issue.

ABOUT THE AUTHOR

Dr Romana Krapf

Dr Romana Krapf, MSC is an experienced dentist with a focus on prophylaxis, implantology, periodontology, and dental preservation. From 2006-2007, she served as a dental hygienist at Dr med dent Hans-Dieter John’s dental practice in Düsseldorf, Germany where she managed the prophylaxis department before pursuing her dental studies and completing her PhD at the Ernst-Moritz-Arndt-University in Greifswald, Germany from 2007-2012.

Since 2018, Dr Romana Krapf has been operating as an independent dentist in her own practice, and recently completed a Master of Science degree in Implantology and Periodontology at DTMD in Luxembourg in 2021.

REFERENCES

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