Despite the rise in popularity of air abrasion, lasers and chemo-mechanical preparation techniques, dental burs remain the most commonly used tool in dentistry for cutting hard tissue. Specifically, they are used for cavity preparations, tooth pre-forming and caries excavation as well as coronoplasty and removal of old restorative material.
When it comes to cutting zirconia however, it is often challenging to achieve good results with conventional tungsten carbide or diamond burs. In a recent study, researchers set out to find an effective diamond bur for zirconia, using an air turbine handpiece in a custom-built test rig. The researchers tested three different burs, including a standard blue diamond, a zirconia-cutting diamond and a conventional tungsten carbide rotary bur. The performance of each bur was measured over a series of five-minute cuts. The findings of the study showed that while all three burs cut zirconia, only the zirconia-cutting diamond had a consistently high level of efficiency over time.
The research was conducted by a team of PhD candidates from the University of Melbourne and the Centre for Oral Health Sciences, with Dr. Mark Schilder as the head researcher. A customised rig was developed to measure the position and speed of the rotary bur at each point of its cutting cycle on a series of zirconia and metal alloy specimens. Wireless data acquisition was used to monitor machinability and the burs were examined after each use with light microscopy and scanning electron microscopy. The results of the study showed that the zirconia-cutting diamond consistently outperformed the other two burs, with the tungsten carbide bur showing significantly less efficiency over time.
Sintered diamond burs, also known as sintered diamond points or bonded diamond bits, contain precisely graded diamonds embedded in a metal matrix throughout the entire bur head to carve consistently over an extended lifetime. The combination of a durable, hardwearing diamond with a robust metallic binder makes them ideal for high-speed rotary tool applications such as cutting zirconia and other dental ceramics and metals.
The benefits of a sintered diamond bur include a longer life than traditional stones, as well as less wear on the rotor shaft and handpiece. In addition, a sintered diamond bur requires less pressure during operation than a traditional stone, reducing vibration and prolonging the lifespan of the tool.
These rounded bullet shape diamond rotary burs from Neosint feature a diamond head with a 3/32″ long steel mandrel shank that fits a Foredom, Dremel with 3/32″ collet or any other flex shaft hand piece that accepts 3/32″ diameter shanks. They are suitable for gem carving, pre-forming glass, stone and ceramics, as well as some hard woods. Simply lubricate the tip with clean water before and during use.