Rough milling for a dental product

Abstract

A rough milling blank for a dental product, comprising a fixing portion (1) and a portion (2) intended to be milled, a recess for fixing the portion to be milled being provided in the fixing portion. Fig. 1

Description

Title of the invention: Milling blank for a dental product Field of invention

[0001] The invention relates to a milling blank for a dental product. The milling blank comprises a fixing portion and a portion intended to be milled. Background and objects of the invention

[0002] Milling blanks are used in various technological fields and in dentistry, among others for the manufacture of root canal posts and crowns. Milling blanks are used in particular in computer-aided design (CAD) and computer-aided manufacturing (CAM).

[0003] Milling blanks generally comprise a metal attachment portion that can be attached to a milling device. The attachment portion has a portion to be milled disposed thereon, which may, for example, be made of plastic, a composite comprising plastic and fibers, or a ceramic material.

[0004] Typically, the part to be milled has the shape of a cube or a cuboid, and its surface that faces the fastening part is essentially the same size as the surface of the fastening part that faces the part to be milled. This ensures a reliable connection between the fastening part and the part to be milled, since the part to be milled remains securely in place during milling. Once milling is complete, the product is removed from the fastening part, for example by cutting. The fastening part can then either be reused or its material can be recycled.

[0005] The fixing parts are generally standardized so that they are easily adapted to different milling devices. Their dimensions are therefore generally the same for all manufacturers.

[0006] The milling blanks of the prior art are well suited for products having a volume close to the volume of the part intended to be milled. When it is desired to manufacture a product having a volume significantly smaller than the volume of the part intended to be milled, however, a significant proportion of the part intended to be milled is wasted, and, moreover, the milling takes a significant amount of time. On the other hand, milling is easier and the finished product is reliable and accurate as desired, when the surfaces of the parts intended to be milled and the fixing part facing each other are as large as possible.

[0007] It is therefore an objective of the invention to provide a milling blank, which is suitable for milling small or thin parts, while at the same time maintaining easy milling and the final product being reliable as desired. Brief description of the drawings

[0008] [Fig.l] schematically illustrates in side view a milling blank according to an embodiment of the invention.

[0009] [Fig.2] schematically illustrates in end view a milling blank according to a embodiment of the invention. Description of the invention

[0010] The invention relates to a milling blank for a dental product, comprising a fixing portion and a portion intended to be milled. The fixing portion comprises a recess for fixing the portion intended to be milled.

[0011] In the milling blank according to the invention, the fixing portion has a recess which has essentially the size and shape of the fixing end of the portion intended to be milled and in which the portion intended to be milled can be arranged and fixed. The portion intended to be milled therefore has one fixing end intended to be arranged in the recess of the fixing portion, and another opposite end. Typically, the portion intended to be milled is longitudinal in shape, i.e. its length is significantly greater than its largest diameter. The cross-section of the portion intended to be milled may, for example, have the shape of a circle, an oval, a square or a rectangle. The cross-section may for example be circular, i.e. the portion intended to be milled has the shape of a right cylinder with a circular base.The cross-section can also be elliptical or rectangular, in which case the recess has essentially the same shape. Such non-circular shapes can be advantageous, because the part to be milled cannot then twist in the recess.

[0012] By using the milling blank of the invention, it is therefore possible to manufacture, for example, root canal posts, without significant loss of material and more quickly than with conventional methods. The part to be milled, when fixed in the recess of the fixing part, remains reliably in place during milling. This also allows the problem-free use of standardized fixing parts.

[0013] According to one embodiment, the part intended to be milled is a composite rod comprising fibers arranged longitudinally along the rod and a polymer. The length of the composite rod may be for example 10 to 25 mm, typically 15 to 20 mm, and its diameter may be for example 2 to 10 mm, typically 4 to 6 mm. In the case of non-circular cross-sections, the diameter refers to the largest dimension of the cross-section.

[0014] The composite rod may comprise, for example, 2 to 65% by volume of fibers. The amount of fibers in the composite may be, for example, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60% by volume up to 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60 or 65% by volume of the composite. A preferred range for the amount of fibers is 2 to 35% by volume.

[0015] The fibers may be selected from a group consisting of inert glass fibers, bioactive glass fibers, sol-gel treated silica fibers, any other silicon oxide based fibers, alumina fibers, zirconia fibers, apatite fibers and quartz fibers. Mixtures of different fibers may also be used. Preferably, the fibers are therefore inorganic fibers.

[0016] The fibers may be surface treated to better adhere to the surrounding polymer matrix. Such surface treatments are known in the prior art.

[0017] The diameter of the fibers can vary between 0.1 qm and 100 qm. The diameter can thus be for example 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 or 95 qm up to an upper limit of 0.2, 0.3, 0.4, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100 qm. Some preferred ranges are for example from 1 to 30 qm and from 10 to 25 qm. More than one fiber diameter can also be used in the composite.

[0018] According to a preferred embodiment, the fibers of the composite are long, continuous and essentially parallel to the longest dimension of the portion to be milled, i.e. they are longitudinal to the rod. However, the fibers may also be arranged in the composite in the form of twisted bundles, or the portion to be milled may comprise discontinuous fibers, i.e. short fibers, so that the inner layer consists of continuous fibers and the outer layer of discontinuous fibers, or so that the continuous fibers and the discontinuous fibers form a layered structure in the longitudinal direction of the rod.

[0019] The polymer forms the matrix of the composite, and the amount of matrix in the composite may be, for example, 20 to 98% by volume of the composite. The amount of matrix in the composite may be, for example, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 or 95% by volume up to an upper limit of 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 98% by volume of the composite.

[0020] The matrix may be a polymer whose monomer is selected from the group consisting of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, morpholinoethyl methacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate (TEGDMA), diurethane dimethacrylate, 2,2-bis(4-(2-hydroxy-3-methacryloxy)phenyl)propane (BisGMA), methacrylate-functionalized dendrimers, other methacrylated hyperbranched oligomers, and mixtures thereof. The matrix may also consist of epoxy or crosslinkable monomers or polymers, such as e-caprolactone, polycaprolactone, polylactides, polyhydroxyproline, and other biopolymers, as well as polyamides, polyurethane, polyethylene, polypropylene, and other polyolefins.

[0021] The composite may further comprise fillers, typically in the form of particles. By particles is meant herein shapes in which no dimension is significantly larger than any other dimension. The filler particles may be bioactive or inert, and both may be used. The filler may be, for example, bioactive glass, silicon (Si), calcium (Ca), phosphorus (P), barium (Ba), magnesium (Mg), potassium (K), sodium (Na) or titanium (Ti) oxides, or fluorine (F) or other compounds thereof, colored pigments, inert ceramics, hydroxyapatite or other calcium phosphates, xerogels, growth factors, antigens, antibiotics, disinfectants, radiopaque materials, interferons, corticosteroids, biphosphates, hormones, vitamins, anti-inflammatory agents, antimicrobial agents or combinations thereof.

[0022] The filler may constitute from 0 to 80% by volume of the composite. The amount of filler in the composite may be, for example, from 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70 or 75% by volume up to an upper limit of 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 or 80% by volume of the composite.

[0023] The largest diameter of the filler particles (or the diameter if they are spherical) may vary for example in the range from 10 nm to 50 pm. The diameter may be for example 10 nm, 50 nm, 100 nm, 500 nm, 1 pm, 5 pm, 10 pm, 25 pm or 40 pm up to 50 nm, 100 nm, 500 nm, 1 pm, 5 pm, 10 pm, 25 pm, 40 pm or 50 pm.

[0024] The part to be milled is fixed to the fixing part. According to one embodiment, the part to be milled is fixed to the recess of the fixing part with glue. The recess may then be slightly larger than the part to be milled, for example its diameter may be 0.5 to 1 mm larger than the diameter of the part to be milled. The glue may be, for example, a one- or two-component glue, generally based on acrylate. The glue may be a dual-cure or light-cure glue.

[0025] According to another embodiment of the invention, the part intended to be milled is fixed to the recess of the fixing part by friction. In this embodiment, the fixing end of the part intended to be milled is therefore essentially of the same size as the recess, so that the part intended to be milled fits closely to the fixing part, with friction. If the material of the part intended to to be milled is slightly elastic, the end of the fastener can also be slightly larger than the recess, in which case the fastener is even more robust. For example, if the part to be milled is a rod with a circular cross-section with a diameter of 5 mm, the diameter of the recess of the fastening part can be 4.8 to 4.9 mm, for example.

[0026] The depth of the recess may be between 2 and 15 mm, for example between 3 and 6 mm. The depth may typically be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 mm up to a depth of 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 mm. In some cases, the recess may extend across the entire fixing portion.

[0027] If desired, it is possible to provide threads on the side walls of the recess, and corresponding threads can in this case be arranged at the fixing end of the part intended to be milled, which allows the part intended to be milled to be screwed into the recess of the fixing part.

[0028] According to one embodiment of the invention, the dental product is a root canal post and / or a post-forming abutment. The invention therefore makes it easy to manufacture individual products that are exactly suited to the patient.

[0029] The milling blank according to the invention can also be used for the manufacture of products other than dental products, for example for the manufacture of nails and similar products used in medicine. Description of the drawings

[0030] [Fig. 1] schematically illustrates in side view a milling blank according to an embodiment of the invention. The figure shows a fixing part 1 and a part intended to be milled 2. The fixing part 1 has an enlargement 3, in which a recess is formed to which the part intended to be milled is fixed.

[0031] [Fig. 2] schematically illustrates in end view a milling blank according to an embodiment of the invention. It can thus be seen in [Fig. 2] that the part intended to be milled 2 is arranged essentially in the center of the widening 3, for easy milling.

Claims

Claims

1. Milling blank for a dental product, comprising a fixing part (1) and a part (2) intended to be milled, characterized in that a recess for fixing the part intended to be milled is provided in the fixing part.

2. Milling blank according to claim 1, characterized in that the part (2) intended to be milled is a composite rod comprising fibers arranged along the longitudinal dimension of the rod and a polymer.

3. Milling blank according to claim 2, characterized in that the cross-section of the composite rod is circular, elliptical or rectangular.

4. Milling blank according to any one of the preceding claims, characterized in that the part (2) intended to be milled is fixed to the recess of the fixing part (1) with glue.

5. Milling blank according to any one of claims 1 to 3, characterized in that the part (2) intended to be milled is fixed to the recess of the fixing part (1) by friction.

6. A milling blank according to any preceding claim, characterized in that the dental product is a root canal post or a post-forming abutment.

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