# US 9,872,740 B2 · Endodontic system and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,872,740 B2 - Document ID: US9872740B2 - Status: Granted - Kind: B2 - Application number: 14/195,120 - Filed: 2014-03-03 - Published: 2014-10-23 - Granted: 2018-01-23 - Earliest claimed: 2010-10-06 - Assignees: DENTSPLY SIRONA Inc. - Applicants: DENTSPLY International Inc. - Inventors: Markus Borgschulte - Web page: https://patentgrep.com/patent/US9872740B2 ## CPC - A61C 1/0007: {Control devices or systems (fluid temperature control in air and water supply systems of dental machines or apparatus A61C1/0069)} - A61C 1/003: {Control of rotation of instrument} - A61C 5/40: Implements for surgical treatment of the roots or nerves of the teeth; Nerve needles; Methods or instruments for medication of the roots - A61C 5/42: Files for root canals; Handgrips or guiding means therefor - A61C: DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE (non-driven toothbrushes A46B; {tongue scrapers A61B17/24;} preparations for dentistry A61K6/00; preparations for cleaning the teeth or mouth A61K8/00, A61Q11/00) ## Abstract The present invention provides a system for the endodontic treatment of a root canal that includes (i) an endodontic instrument; (ii) an endodontic handpiece having a drive motor for rotating the endodontic instrument releasably attached to the handpiece; (iii) a control unit for controlling the rotation of the endodontic instrument according to one or more predetermined rotational sequences. ## Claims ### Claim 1 A system for the endodontic treatment of a root canal, comprising (i) an endodontic instrument; (ii) an endodontic handpiece having a drive motor for rotating the endodontic instrument releasably attached to the handpiece; (iii) a control unit for controlling the rotation of the endodontic instrument according to one or more predetermined rotational sequences; the rotational sequences comprising reciprocating the endodontic instrument by continuously sequentially rotating the endodontic instrument in a first direction followed by reversing the direction of rotation so that 0.5×ψ≦α<ψ and 3≦α/β≦20, wherein α represents a rotational angle in a direction in which the rotating endodontic instrument removes debris from the root canal, β represents a rotational angle in the opposite direction, and ψ represents the elastic angle of the endodontic instrument at which plastic deformation occurs in the direction of α; and wherein the control unit controls a frequency of reciprocation (Fr) in a range of from 5 to 30 Hz. ### Claim 2 (depends on 1) The system for the endodontic treatment of a root canal according to claim 1, wherein 0.7×ψ≦α<0.9×ψ, and α and ψ are as defined in claim 1. ### Claim 3 (depends on 1, 4) The system for the endodontic treatment of a root canal according to claim 1, 4≦α/β≦10, and α and β are as defined in claim 1. ### Claim 4 (depends on 1) The system for the endodontic treatment of a root canal according to claim 1, wherein the control unit further controls one or more parameters of the rotational sequence, said parameters being selected from the frequency of reciprocation (Fr), the number of reciprocation cycles (Nr) and the torque (Tr) exerted on the file. ### Claim 5 (depends on 1) The system for the endodontic treatment of a root canal according to claim 1, wherein α, β, Fr, Nr, and/or Tr are predetermined based on ψ. ### Claim 6 (depends on 1) The system for the endodontic treatment of a root canal according to claim 1, wherein the endodontic instrument has an elastic angle (ψ) in the range of from 120 to 420°. ### Claim 7 (depends on 1) The system for the endodontic treatment of a root canal according to claim 1, wherein the endodontic instrument comprises a NiTi alloy. ### Claim 8 (depends on 1) The system for the endodontic treatment of a root canal according to claim 1, wherein the endodontic instrument has a non-cutting tip. ### Claim 9 (depends on 1) The system for the endodontic treatment of a root canal according to claim 1, wherein the endodontic instrument has one or more spiral grooves. ### Claim 10 (depends on 1) The system for the endodontic treatment of a root canal according to claim 1, wherein the endodontic instrument has a diameter at the tip in the range of from 0.20 to 0.35 mm and a taper over the first 3 mm from the tip in the range of taper of from 7 to 9% and a diameter D16 in the range of from 1.00 to 1.10 mm; or wherein the endodontic instrument has a diameter at the tip in the range of from 0.35 to 0.55 mm and a taper over the first 3 mm from the tip in the range of taper of from 5 to 7% and a diameter D16 in the range of from 1.05 to 1.15 mm; or wherein the endodontic instrument has a diameter at the tip in the range of from 0.45 to 0.65 mm and a taper over the first 3 mm from the tip in the range of taper of from 4 to 6% and a diameter D16 in the range of from 1.12 to 1.22 mm. ### Claim 11 (depends on 1) The system for the endodontic treatment of a root canal according to claim 1, wherein the drive motor is battery operated. ### Claim 12 A method for operating the system for the endodontic treatment of a root canal, the method comprising the steps of: reciprocating an endodontic instrument in a first rotational direction when a control parameter is less than or equal to a threshold value, wherein the control parameter is a number of reciprocation cycles; and further when the control parameter is greater than the threshold value reciprocating the endodontic instrument by continuously sequentially rotating the endodontic instrument in the first direction followed by a rotational direction opposite of the first rotational direction so that 0.5×ψ≦α≦ψ and 3≦α/β≦20, wherein α represents a rotational angle in a direction in which the rotating endodontic instrument removes debris from the root canal, β represents a rotational angle in the opposite direction, and ψ represents the elastic angle of the endodontic instrument at which plastic deformation occurs in the direction of α. ### Claim 13 (depends on 12) The method for operating the system for the endodontic treatment of a root canal according to claim 12, wherein method further comprises reciprocating the endodontic instrument when the control parameter is greater than or equal to the first threshold value, and rotating the endodontic instrument only in the rotational direction opposite to the first rotational direction in order to free the instrument, when the control parameter is greater than or equal to a second threshold value that is greater than the first threshold value.