| Abstract | | The first engine-driven root canal instrument was developed by Rollins already in 1899, but a major step forward in this area was made only in the seventies with the appearance of the Giromatic system. Another important landmark in this field was the introduction of Ni-Ti alloys into dentistry. At present, a wide range of endodontic instrumentation systems are available on the market, and knowledge of the properties of different products and materials is essential when purchasing this equipment. The advantages of Ni-Ti instrumentation systems include: excellent "shape memory" and elasticity, computer-designed non-cutting instrument tips, efficient elimination of infected material, easy handling and rapid work, and the possibility of a built-in irrigation system or automatic reverse torque clutch. The main disadvantages are: a high cost and short life-span, a high risk of instrument fracture and difficult fragment removal from the root canal, very demanding apical work, fast corrosin and loss of sharpness, and the possibility of propagation of infection to the periapical region.
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