Reciprocal and continuous rotation is two sides of the same coin

The birth of modern Endodontic occurred with the appearance of NiTi rotary instruments on market around 1993.The reciprocal and continuous rotational tools are successive evolutions of the rotary motion techniques, which are closely associated with rapid cleaning and shaping of the root canal system. 1 A multitude of studies has been performed in the last years, substantiating their high efficiencies, studying their specific characteristics, proposing unifying theories, and testing possible countermeasures. 2,3To date, however, the role of an instrument's motion in long-term researches has not been explicitly tested.Here the literature review was specifically interested in whether an instrument's motion patterns can affect its characteristics.To that end, we used a simple classification where both movements were categorized on the basis of dynamic properties such as cyclic fatigue, And biological properties (apical extrusion of bacteria).