MANUFACTURING PROCESSES FOR DENTAL DIAMONDS

First some background on how diamonds are manufactured and a brief look at brazing versus electroplating.

BRAZING VS ELECTROPLATING: Until the early 1970s, all dental diamond instruments were made by electroplating, which simply entraps diamond crystals in a layer of nickel-based plating material. In this manufacturing process, the instrument blank is typically inserted into a bed of loose diamond crystals in a plating tank, an electrical circuit is established within the fluid in the tank, and plating material is electrically deposited on the blank. Since the diamond crystals being trapped on the instrument vary in their orientation to the blank (some are touching the blank while others may be slightly above it), and the plating material attaches to certain sections of the blank at different rates, the instrument will vary in the amount of crystals that are ultimately exposed. Some crystals stick up high while others are partially submerged, while still others are completely buried (Figure 2) in the plating layer. These high and low crystals can adversely affect cutting speed since the high crystals prevent the surrounding low crystals from ever taking part in the cutting process. Additionally, if only a small portion of the diamond crystal is protruding out of the electroplating, this means most of its abrasive strength is buried under the surface. Nearly all diamonds manufactured today use this process for creating their diamond instruments.


ENTER THE BRAZED DIAMOND: In 1971 a process was patented for the high-temperature brazing of diamond crystals to an instrument head. While the electroplating process only traps crystals in a layer of plating material, the brazing process physically bonds the diamond crystals to the instrument. It is analogous to the difference between the physical retention of amalgam fillings and the adhesive bonding retention of composite fillings. Whereas amalgam is mechanically retained by the preparation and composite is chemically bonded to tooth, so too are electroplated diamonds trapped by plating material and brazed diamond crystals physically bonded to the instrument blanks.

We mentioned above how electroplating surrounds the diamond crystals, trapping them at various levels above the plating material. With brazing, a layer of special brazing metal is adhered to both the instrument blank and the diamond crystals with intense heat, permanently bonding the crystals to the instrument blank.

The benefit of the brazing technique is that more diamonds can be bonded to the cutting head, without having so many crystals buried by plating material. A look under magnification quickly identifies a brazed diamond versus an electroplated diamond (Figures 3a & 3b) by the increased concentration of diamond crystals.

Figure 3a: Premium brazed coarse-grit instrument	Figure 3b: Premium electroplated coarse-grit instrument
The brazed diamond instrument on the left shows a higher concentration of crystals than the electroplated instrument on the right.

Further magnification shows how brazed diamonds are more consistent in the amount of diamond crystals exposed as compared to electroplated diamonds (Figures 4a & 4b).

Figure 4a: Premium brazed coarse-grit instrument	Figure 4b: Premium electroplated coarse-grit instrument
The brazed diamond on the left is fairly uniform in the amount of the crystal that is exposed while the electroplated diamond shows a wider range of exposed and buried diamond crystals, especially on the end of the instrument.

The brazed diamond, with its premium diamond attachment technology, soon became a market leader in North America due to its increased performance and aggressive marketing. The original patent on the brazing process has since expired, yet all other diamonds on the market still continue to use electroplating technology until now.