Mani, Inc.

Norio Maeda

Shinsaku Kuroyanagi

Koichi Nabana

Provided is a dental file exhibiting high performance and having high flexibility and excellent root canal followability. A dental file () of the present invention includes a working portion () in a spiral shape. An outer edge of the sectional shape of the working portion () at any position includes a single arc () and three or more lines (). One end of the arc () forms a first cutting blade. The three or more lines () are positioned inside a virtual circle () partially including the arc (). The length of the arc () may be equal to or greater than 1/12 and equal to or less than ⅓ of the circumferential length of the virtual circle (), or a second cutting blade () may be further provided inside the virtual circle ().

Dental file

Provided is a dental file with excellent flexibility, cutting performance, and fracture resistance. The dental file () of the present invention has a spiral working portion () of which cross sections become smaller toward a tip end. At least one of shapes of the cross sections of the working portion () is a substantially rectangular shape formed of a single arc () and three lines (), Two points of four points at four corners of the substantially rectangular shape are arranged on a virtual circle (), which includes the arc () as part thereof. The other two points are arranged inside the virtual circle (). The center position of the virtual circle () is inside the substantially rectangular shape. A shortest one of lengths of perpendicular lines each extending from the center position of the virtual circle () including the arc () as part thereof to the three lines () is equal to or greater than 45% and equal to or less than 65% of the radius of the virtual circle ().

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Utsunomiya, Japan

Norio Maeda