Diamond instruments are usually rotary and rotationally symmetrical, sometimes oscillating, dental instruments almost always used in drive units (handpieces, contra-angles, turbines) in all areas of dental medicine and technology for widely varying purposes ranging from preparation and trimming conservative or prosthetic restorations to reducing proximal enamel during orthodontic treatment or surgical applications. Certain diamond instruments are for manual use only such as for roughening sites prepared for posts prior to adhering.
Diamond instruments are manufactured by embedding single or multiple layers of multi-surface natural or industrial diamond particles into a layer of bonder (often galvanically bonded or sintered to the metal blank). The edges of the particles abrade tissue and many types of material (mostly hard tooth structure such as enamel and dentine). Worn edges and particles breaking out of the bonder cause the instruments to become blunt. Sintered diamonds and silicone (“rubber”) polishers are not only “coated” on the surface, the entire instrument is impregnated with diamond particles making them self-sharpening (but their original size and shape wear down). Colour-coded rings are used for classifying diamond instruments according to their abrasivity (depending on the particle size) ranging from extra-coarse (approx. 150 µm for reducing structure rapidly) to ultra-fine (approx. 15 µm for final finishing).
When manufactured carefully (precise dimensioning of the instrument geometry, quality, sharpness/homogeneity of the particles, steel quality) diamond instruments run smoothly, perform efficiently and are long lasting.
The different shapes and sizes of diamond instruments can be designated numerically and uniformly acc. to DIN EN ISO 6360-1 (e.g. shank length/material, grit size, diameter of the working section).
Different degrees of frictional force are generated depending on the pressure exerted, speed, diameter, grit size and traction of the drive unit. To prevent the undesirable effects of frictional heat in tissue (e.g. coagulation of proteins) or materials (e.g. cracked zirconia or melted acrylic), diamond instruments are often (a “must” when used intraorally) cooled continually with water. This ensures that dust particles can be flushed away simultaneously thus preventing the instrument clogging. Non-coated grooves, axial or spiralling around the instrument, have the same effect.
The integration of tungsten carbide blades, guide lugs, non-coated areas etc. allows certain structures to be protected against reduction or reduced even more.
Most diamond instruments are autoclavable and for multiple usage. Sterile, disposable diamond instruments are increasingly in use for clinical purposes.