The state of the art and future trends of root canal files from the perspective of patent analysis: a study design

Table 1 Overview of improved material methods of root canal files

Material-based	Material objects	Substrate internal materials/ Surface treatment materials	Processes/methods	Performance	Characteristics	Code
Matrix material	NiTi	MA and AU	CDA	Gradient flexible	GF	CN105852991 [32]
	NiTi	MA M phase MA R phase AU A phase	CDA	Adapt to canal	FR	CN107242911 [33]
	NiTi	MA and AU	HT, Ultrafine crystal process	HCE	WR	CN102743233 [34]
	NiTi	AU	Mechanical process	Different material application	GS	CN206518610 [35]
	Polymer	Stainless steel, NT	3D printing/mold making	Can be made smaller	GF, IS	WO2020243281 [36]
	Magnesium alloy	Magnesium and fluorine	Fluorine coating	Safety for the human body	Degradable, IS	CN203677273 [37]
Surface material	NiTi	Electrolytic materials	HT, CP	Improve surface performance	WR	US20110159458 [42]
	NiTi	High vacuum atmosphere compounding	Electrochemical polishing	Good glossy finish	FR	CN111685897 [43]
	NiTi	Polisher	Mechanical polishing	Save manufacturing time	Easy production	CN108788644 [44]
	NiTi	Chemistry	CP	Stabilize passivated oxide layer	FR, GF	US20160024311 [45]
	NiTi	TiZrON	Chemical composite membranes	Inhibits the diffusion of nickel ions	IS	CN105908136 [52]
	N/A	Metal	CDA, Reduced material process	Metal coating	GF	CN112453828 [53]
	NiTi	Fullerenes, NiTi, inorganic	Selective coating	Reduce the friction	IS	CN103096830 [54]
	NiTi	Metal	Magnetron Sputtering	High hardness	HCE	CN104630730 [55]

Materials/Processes: NiTi Nickel-titanium, MA Martensite, AU Austenite, CDA Cold drawn Annealed, HT Heat treatment, CP Chemical polishing
Performance/Characteristics: GF Good flexibility, FR Fatigue resistance, WR Wear resistance, IS Improve safety, HCE High cutting efficiency, GS Good stability

ISSN: 1475-925X