Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:The reciprocating single file systems such as Reciproc (VDW, Munich, Germany) and WaveOne (Maillefer, Ballaigues, Switzerland) provides more flexibility of the M‐wire Ni‐Ti alloy, greater resistance to cyclic fatigue and better handling of narrow and curved canals than the traditional Ni‐Ti instruments and they are widely used in endodontic treatment.[17,18] These file systems use reciprocating movements in the preparation of root canals.
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