Search

EP-4400075-B1 - INSTRUMENT KIT, METHOD OF ADOPTING A MILLING BLOCK TO BE USED FOR FORMING A CROWN BY COMPUTER-AIDED DESIGN AND A METHOD FOR DETERMINING A SHAPE OF AN OPEN CAVITY OF A CROWN

EP4400075B1EP 4400075 B1EP4400075 B1EP 4400075B1EP-4400075-B1

Inventors

  • NAGASAWA, YUKO
  • MIMAKI, Hidenori

Dates

Publication Date
20260506
Application Date
20220822

Claims (10)

  1. An instrument kit (1), comprising: at least one abutment tooth sample (20) that is configured as an exemplar of an abutment tooth of a patient and includes an abutment tooth portion (21) formed into a standard shape of the abutment tooth; and at least one crown sample (10) that is configured as an exemplar of a crown, the crown being a tooth crown prosthesis including an open cavity (11) into which the abutment tooth is to be inserted, the at least one crown sample (10) being formed into a standard shape of the crown and including an open cavity (11) corresponding to the abutment tooth portion (21) of the abutment tooth sample (20), wherein the instrument kit (1) includes at least one of a plurality of abutment tooth samples (20) or a plurality of crown samples (10), the plurality of abutment tooth samples (20) constitutes at least one of a first abutment tooth sample group (31b) or a second abutment tooth sample group, the first abutment tooth sample group (31b) including the abutment tooth portions (21) having shapes substantially identical to each other and having surface color patterns different from each other, the second abutment tooth sample group including the abutment tooth portions (21) having surface color patterns substantially identical to each other and having shapes different from each other, and the plurality of crown samples (10) constitutes at least one of a first crown sample group (31a) or a second crown sample group, the first crown sample group (31a) including the crown samples (10) having shapes substantially identical to each other and having surface color patterns different from each other, the second crown sample group including the crown samples (10) having surface color patterns substantially identical to each other and having shapes different from each other.
  2. The instrument kit (1) according to claim 1, wherein the surface color patterns of the at least one abutment tooth sample (20) and the at least one crown sample (10) are configured using a plurality of colors including a color corresponding to one selected from 18 shades representing a color of a tooth.
  3. The instrument kit (1) according to claim 1, wherein the at least one crown sample (10) is formed by the CAD/CAM using a milling block that is made of a hybrid resin or ceramics.
  4. The instrument kit (1) according to claim 1, wherein the at least one abutment tooth sample (20) further includes a pinch portion that extends from the abutment tooth portion (21) to an opposite side in a direction of insertion into the open cavity (11).
  5. The instrument kit (1) according to claim 1, wherein the instrument kit (1) includes the first abutment tooth sample group (31b) and the first crown sample group (31a), and the shapes of the abutment tooth portions (21) of the plurality of abutment tooth samples (20) constituting the first abutment tooth sample group (31b) coincide with the shapes of the open cavities (11) of the plurality of crown samples (10) constituting the first crown sample group (31a) on a one-to-one basis.
  6. The instrument kit (1) according to claim 1, wherein the instrument kit (1) includes the second abutment tooth sample group and the second crown sample group, and the plurality of crown samples (10) constituting the second crown sample group includes crown samples (10) including the open cavities having shapes corresponding to all the shapes of the abutment tooth portions (21) of the plurality of abutment tooth samples (20) constituting the second abutment tooth sample group.
  7. A method of adopting a milling block to be used for forming a crown by computer-aided design, CAD, / computer-aided manufacturing, CAM, the crown being a tooth crown prosthesis including an open cavity (11), the method comprising: preparing the instrument kit (1) according to claim 5; selecting, from the first abutment tooth sample group (31b), an abutment tooth sample (20) including an abutment tooth portion (21) having a shape and a surface color pattern that are similar to a shape and a surface color pattern of an abutment tooth of a patient; inserting the abutment tooth portion (21) of the abutment tooth sample (20) selected in the selecting step into the open cavity (11) of each of the plurality of crown samples (10) and, thereby, confirming an appearance color after the abutment tooth portion (21) of the abutment tooth sample (20) selected in the selecting step is inserted into the open cavity (11), for each of the plurality of crown samples (10) constituting the first crown sample group (31a); and determining, from the plurality of crown samples (10) constituting the first crown sample group (31a), a crown sample (10) having the appearance color confirmed in the confirmation step that best matches an appearance color of the tooth of the patient, and adopting a milling block that is substantially identical to a milling block used for forming the determined crown sample (10).
  8. The method of adopting a milling block according to claim 7, wherein in the confirming step, an image or image data obtained by imaging appearances of the plurality of crown samples (10) is used, the image or image data being obtained before and after the abutment tooth portion (21) of the abutment tooth sample (20) is inserted into the open cavity (11) of each of the plurality of crown samples (10).
  9. A method for determining a shape of an open cavity of a crown, the crown being a tooth crown prosthesis including an open cavity (11) and being formed by computer-aided design, CAD, / computer-aided manufacturing, CAM, using a milling block, the method comprising: preparing the instrument kit (1) according to claim 6, in which the surface color patterns of the abutment tooth portions (21) of the plurality of abutment tooth samples (20) constituting the second abutment tooth sample group are substantially identical to or similar to a surface color pattern of the abutment tooth, and the plurality of crown samples (10) constituting the second crown sample group are each formed using a milling block substantially identical to the candidate milling block; and inserting the abutment tooth portion (21) of the abutment tooth sample (20) selected in the selecting step into the open cavity (11) of each of the plurality of crown samples (10) and, thereby, confirming the appearance color after the abutment tooth portion (21) of the abutment tooth sample (20) is inserted into the open cavity (11), for each of combinations of the crown sample (10) and the abutment tooth sample (20), respectively, including the open cavity (11) and the abutment tooth portion (21) having shapes corresponding to each other and respectively selected from the second crown sample group and the second abutment tooth sample group; and determining, from among combinations of the crown sample (10) and the abutment tooth sample (20) for which the appearance color has been confirmed, a combination in which the appearance color most closely matches an appearance color of a tooth of a patient, and determining a shape of the open cavity of a crown to be formed by CAD/CAM using a milling block based on a shape of the open cavity of the crown sample in the determined combination.
  10. The method for determining according to claim 9, wherein in the confirming step, an image or image data obtained by imaging an appearance of the crown sample (10) is used, the image or image data being obtained before and after the abutment tooth portion (21) of the abutment tooth sample (20) is inserted into the open cavity (11) of the crown sample (10).

Description

Technical Field The present invention relates to a crown appearance color confirming method of confirming a color tone of a tooth crown (crown) having a predetermined appearance color, the crown being a kind of a dental prosthesis made of a non-metal material such as a hybrid resin, when the crown is actually mounted onto an abutment tooth of a patient, an instrument kit that can be suitably used for the method, a demonstration instrument including the instrument kit, and the like. Background Art Dental prostheses used for dental treatment are generally formed by casting a metal material such as gold, silver, titanium, or a palladium alloy, formed by processing a non-metal material such as ceramics or a hybrid resin, or formed by making a core portion from a metal material and making a superficial layer portion such as a facing portion from a non-metal material. Note that a hybrid resin (hereinafter, abbreviated as "HR" in some cases) means a composite material in which inorganic infill (hereinafter, also referred to as "inorganic filler") is dispersed in a resin matrix at a high density. Usually, the hybrid resin is obtained by polymerizing and curing a paste-like polymerizable curable composition containing a polymerizable monomer, an inorganic filler, and a polymerization initiator by pressurizing, heating, and the like. Dental prostheses entirely formed of a non-metal material have advantages of eliminating a concern about metal allergy and being excellent in aesthetics, and additionally, have been easily processed due to the recent development of digital image technologies or computer processing technologies. Thus, the demand for the dental prostheses has been rapidly increasing. For example, as disclosed in JP 6004769 B2, a computer-aided design (CAD)/computer-aided manufacturing (CAM) system has been widely used, in which a CAD/CAM apparatus based on the CAD and CAM technologies is used to perform cutting processing on a "CAD/CAM milling block" (also referred to as a dental processing blank in some cases) made of a non-metal material and to form a dental prosthesis on the basis of a captured image of an oral cavity. Here, the CAD/CAM milling block means a cut body (also referred to as a milling blank) that is attachable to a cutting machine in the CAD/CAM system, and usually includes a cut portion and a holding portion for enabling the cut portion to be attached to a cutting machine. As the cut portion, a (solid) block formed into a rectangular parallelepiped shape or columnar shape, a (solid) disk formed into a plate-like or disc-like shape, and the like are generally known. A milling blank including a cut portion made of a hybrid resin (hereinafter, a CAD/CAM milling block made of HR will also be simply referred to as "HR milling block") is also known. Incidentally, in order to achieve highly aesthetic restoration, it is necessary to determine the color (specified by hue, brightness, and saturation, that is, hue and color tone) of a tooth to be restored (restored tooth) or the color of surrounding teeth (such color determination is referred to as "shade taking" in some cases), select an HR milling block including a cut portion having a color that matches the determined color, and perform the restoration. Note that the shade taking is generally performed using a color tone sample for teeth, which is called a shade guide. There are various shade guides in which the number of color samples, the configuration of a holding instrument that holds the color samples, and the like are designed to facilitate color determination. Among them, "VITA Classical" (trade name) manufactured by VITA, which includes samples of total of 16 colors (a color specified by an index including a combination of hue and a mixed index of brightness and saturation or by an index considering hue, brightness, and saturation will also be referred to as "shade") and is capable of determining the color of a site to be restored by comparing the shade guide with the colors of the site to be restored and surrounding teeth, is the most prevalent (see JP 6004769 B2). Further, in addition to the above, a plurality of types of white tones, which are called bleach shades and simulate a state after whitening, are also used in some cases. Note that, in the VITA shade guide, the colors of A to D systems are classified according to brightness and are represented by marks. In other words, the colors are classified into the A system (red brown), the B system (red yellow), the C system (ash), and the D system (red ash), and when 16 shades are arranged in the order of brightness (high to low in brightness), the following order is obtained: "B1→A1→B2→D2→A2→C1→C2→D4→A3→D3→B3→A3.5→B4→C3→A4→C4". HR blanks include a single-color blank including a cut portion made of a single HR layer (hereinafter, also referred to as "single-layer HR milling block"), and a blank including a plurality of HR layers having different colors (hereinafter, also referred to as "l