Fig. 5From: The state of the art and future trends of root canal files from the perspective of patent analysis: a study designA surface modification method. Reproduced with permission. Source: CNIPA, www.cnipa.gov.cn. a The schematic diagram of the magnetron sputtering principle. b Schematic diagram of the cross-section of a nickel-titanium alloy root canal file. c Comparison of the hardness of nickel-titanium alloy root canal files after treatment and before treatmentBack to article page