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DE-102024133100-A1 - Dental instrument for processing ceramic crowns

DE102024133100A1DE 102024133100 A1DE102024133100 A1DE 102024133100A1DE-102024133100-A1

Abstract

The invention relates to a dental instrument for processing ceramic crowns, comprising a shaft area, comprising a shaft (2) for clamping the dental instrument into a drive, and a working area (3) studded with diamonds for processing the ceramic crown, wherein a bonding agent (6) is applied to the working area (3), wherein the diamonds are partially arranged and fixed in the bonding agent (6) and partially protrude over an outer surface of the bonding agent (6), and wherein the diamonds are fractured diamonds (5).

Inventors

  • Michael Küllmer
  • Frank Hagemann

Assignees

  • GEBR. BRASSELER GMBH & CO. KG

Dates

Publication Date
20260513
Application Date
20241112

Claims (10)

  1. Dental instrument for processing ceramic crowns, comprising: - a shaft (2) for clamping the dental instrument into a drive, and - a diamond-coated working area (3) for processing the ceramic crown, - wherein a bonding agent (6) is applied to the working area (3), - wherein the diamonds are partially arranged and fixed in the bonding agent (6) and partially protrude over an outer surface of the bonding agent (6), and - wherein the diamonds are fractured diamonds (5).
  2. Dental instrument according to Claim 1 , wherein the fractured diamonds of the working area (3) are synthetic fractured diamonds which are produced from synthetic diamonds by fracturing processes.
  3. Dental instrument according to one of the preceding claims, wherein the fractured diamonds have a maximum length L and a maximum width B perpendicular to the maximum length L, and wherein a ratio V of the maximum length L to the maximum width B is in a range of V = L/B = 1.00 to 2.10, in particular in a range of 1.20 to 1.80, and further in particular in a range of 1.40 to 1.60.
  4. Dental instrument according to one of the preceding claims, - wherein a maximum length L of the fracture diamonds (5) is in a range of 85 µm to 190 µm, in particular in a range of 100 µm to 170 µm, and further in particular in a range of 140 µm to 150 µm, and/or - wherein a maximum width B of the fracture diamonds is in a range between 70 µm and 125 µm, in particular in a range of 80 µm to 120 µm, and further in particular in a range of 100 µm to 110 µm.
  5. Dental instrument according to one of the preceding claims, wherein the embedding depth of the fractured diamonds (5) in the binder (6) is such that 60% to 70% of a volume of the fractured diamonds are embedded in the binder (6).
  6. Dental instrument according to one of the preceding claims, wherein the fractured diamonds (5) have a protrusion above a surface of the binder (6) in a range of 44 µm to 86 µm, in particular 55 µm to 75 µm, and further in particular 60 µm to 70 µm.
  7. Dental instrument according to one of the preceding claims, wherein the coverage density of the fractured diamonds (5) on the binder (6) is in a range of 45% to 61% and in particular in a range of 50% to 55%.
  8. Dental instrument according to one of the preceding claims, wherein the fractured diamonds (5) are unprocessed after fracture and are introduced unprocessed into the binder (6).
  9. Dental instrument according to one of the preceding claims, wherein the binder (6) comprises nickel.
  10. Dental instrument according to one of the preceding claims, wherein the working area (5) has a cylindrical shape or a conical shape.

Description

The present invention relates to a dental instrument for processing ceramic crowns, in particular crowns made of zirconium oxide ( ZrO2 ), and in particular for separating such ceramic crowns. For approximately 15 years, all-ceramic crowns, bridges, and similar restorations have been increasingly used as dental prostheses. Unlike ceramic-veneered metal crowns, all-ceramic crowns are made entirely of ceramic, particularly zirconium oxide. A problem with all-ceramic crowns arises when they need to be removed. Because the ceramic used ( ZrO₂ ) is very hard, the dental instruments used for this purpose wear down very quickly. This is especially true when entire all-ceramic bridges need to be removed. DE 199 08 507 A1 It is known, for example, to arrange diamond grains on the surface of a grinding head in dental instruments for grinding operations. However, the dental instrument disclosed there is only suitable for processing tooth enamel, which has a significantly lower hardness than all-ceramic crowns. It is therefore an object of the present invention to provide a dental instrument for processing all-ceramic crowns with excellent wear resistance, while being easy and cost-effective to manufacture. This problem is solved by a dental instrument having the features of claim 1. The dependent claims describe preferred embodiments of the invention. In contrast, the dental instrument according to the invention with the features of claim 1 has the advantage that it exhibits a very low wear rate and is therefore ideally suited for processing ceramic full crowns, particularly those made of zirconium oxide. The dental instrument of the invention also exhibits significantly better cutting performance than comparable dental instruments. Furthermore, the thermal stress on the dental instrument during the processing of ceramic full crowns can be significantly reduced, which also contributes to an extended service life of the dental instrument. This is achieved according to the invention by the fact that the dental instrument for processing ceramic full crowns has a shank for clamping into a drive and a working area studded with diamonds for processing the ceramic crown. The working area has, in particular, a core that is formed integrally with the shank, with a bonding agent applied to the core. The diamonds are partially arranged and thus fixed within the bonding agent and partially protrude beyond an outer surface of the bonding agent. These diamonds are fractured diamonds. Fractured diamonds are produced from larger diamonds by means of a fracturing process. The fractured diamonds used according to the invention are thus specifically produced by fracturing larger diamonds. The fractured diamonds have a multitude of sharp edges and corners, yet they are still lumpy diamonds. Due to the multitude of sharp edges and corners that protrude beyond the bonding agent of the dental instrument, exceptionally hard materials such as ceramics can be processed and, in particular, separated to remove a dental ceramic or a bridge from a patient as quickly and effectively as possible. Preferably, the fractured diamonds in the working area are synthetic fractured diamonds. Synthetic fractured diamonds are produced by fracturing synthetically manufactured diamonds. Theoretically, natural diamonds could also be fractured for the invention; however, this is too expensive for dental instruments, so synthetic diamonds are preferably used to produce the fractured diamonds. Preferably, the fractured diamonds have a maximum length L and a maximum width B perpendicular to the maximum length L, wherein the ratio V of maximum length L to maximum width B, V=L/B, is in a range of 1.00 to 2.10, particularly in a range of 1.20 to 1.80 and further particularly in a range of 1.40 to 1.60. The maximum length L of the fractured diamonds is particularly preferably in the range of 85 µm to 190 µm, particularly in the range of 100 µm to 170 µm, and further particularly in the range of 140 µm to 150 µm. Preferably, the maximum width B of the fractured diamonds is between 70 µm and 125 µm, particularly between 80 µm and 120 µm, and further particularly between 100 and 110 µm. A particularly long service life when working with hard ceramic materials can be achieved if the dental instrument has an embedding depth of the fracture diamonds in the bonding agent such that 60% to 70% of the fracture diamonds' volume is embedded in the bonding agent. This means that between 30% and 40% of the fracture diamonds' volume protrudes from the surface of the bonding agent on the dental instrument and can be used for further processing. can be used for processing ceramic crowns. The fracture diamonds particularly preferably have a protrusion above the surface of the binder in a range of 44 µm to 86 µm, and especially in a range of 55 µm to 75 µm, and further particularly in a range of 60 µm to 70 µm. This height of the fracture diamonds protruding above the binder ensures that