DE102005016728A1 - Optimized silicone materials for digital optical data acquisition and processing in medical technology, especially in the dental field - Google Patents

Abstract

In order to be able to accurately and faithfully reproduce an object and then make it photographically detectable and / or optically palpable without additional work steps and reproducible by CAD / CAM / CIM systems without loss of information, the invention proposes a two-component, addition-crosslinking silicone material for the Bite registration consisting of: DOLLAR A (a) organopolysiloxanes having two or more vinyl groups in the molecule (terminal and / or pendent) and viscosities in the range of 100-350000 mPaÈs DOLLAR A (b) low molecular weight vinyl and ethoxy group-containing QM resins and / or mixtures of QM resins in organopolysiloxanes according to (1) with viscosities of 150-65,000 mPaÈs DOLLAR A (c) organopolyhydrogensiloxanes having at least two SiH groups in the molecule and an SiH content of 0.1-15 mmol / g, preferably from 2-10 mmol / g. DOLLAR A (d) Precious metal catalyst (s) DOLLAR A (e) Mixtures of reinforcing fillers with organopolysiloxanes having a resulting viscosity of 100-2000 PaÈs DOLLAR A (f) non-reinforcing fillers with loaded or unloaded surface DOLLAR A (g) of other additives and customary auxiliaries, auxiliaries and colorants DOLLAR A (h) inhibitors, which is characterized in that the catalyst component DOLLAR A (i) contains a metal oxide powder.

Description

The This invention relates to impression materials and bite registration materials, which are optimized in terms of their composition and therefore are particularly suitable with the help of photographic (camera) and / or optical scanning (laser scanner) a basic set to generate three-dimensional data. Enable this digital data in a more precise way Way further processing in many areas of medical technology in additive and subtractive manufacturing processes. Especially but are they suitable to the dentist and dental technician an optical Working model available to put that the classical physical working model - as a rule made of gypsum in terms of handiness and accuracy. This three-dimensional working model is thanks to powerful computer viewed in magnification and workable. The free rotation and displacement is a Control of the preparation and the constructed restoration easily possible.

Around the increasing desire of patients for aesthetic restorations More and more dentists and dental technicians are using the CAD / CAM / CIM technology (Computer Aided Design / Computer Aided Manufacturing / Computer Integrated Manuacturing) for the production of ceramic restorations, Inlays / onlays, veneers, partial and Full crowns up to multi-unit girder bridges.

The optical detection of three-dimensional bodies and the subsequent reproduction the three-dimensional body by CAD / CAM / CIM systems is known in the art. This data collection or digitizing one or more stumps or the entire jaw situation can be done for example intraoral. This is how the sampling happens a dental surface for obtaining digital data in the Cerec 3 system (Sirona, Germany) with the help of a special camera, which works according to the principle the active triangulation works. The camera sends and receives approximately infrared Light. So that the information thus obtained meets the requirements of a exact reproduction of all morphological details, especially the Edges and unfavorable Angular positions, must the surface be low-reflection. essential In this method, therefore, the coating of the surface of the Scanning area with an antireflection layer.

In The classic way becomes the preparation powdered with titanium dioxide (Cerec powder, Fa. Vita), previously the surface be coated with an adhesive. Because of the sources of error This method can be the quality later Restoration significantly affected be. The powder can easily clump, the picture of the surface becomes clearly falsified. Alternatively, brushable liquid materials offered (ScanFluid, Fa. Dentaco, Germany).

Problematic in this case is the uniform plot and the poor removability of the material. Also a spray variant for the application of the antireflective agent (ScanSpray, Dentaco, Germany) is now available and significantly improves the accuracy of the method when adequate Drying of the surface is respected (A. Kurbad, International Journal of Computerized Dentistry 3 (2000) 269-279). However, all the above methods falsify by the additional application of material as well as uneven layer thicknesses the restoration. Another disadvantage is the additional time required by the additional preparation step.

alternative the dental technician creates from an impression of the situation Gypsum model, which is then captured and converted into digital data got to. These Digitization is done in a non-contact optical method with a laser. The method is based on a projection unit (laser) and a detection unit (one or more cameras) incorporated in are arranged at a known angle to each other. On the to be detected Object laser points or laser lines are projected. By the high resolution (n) Camera s) are the object and the projection (the "track" of the laser) of several Pages captured. This will be knowledge from digital photography used. The composition of all images creates a three-dimensional image Record of the surface as a so-called point cloud.

such Laser scanners are used e.g. by 3Shape APS, Copenhagen, Denmark expelled and their use in medical technology is known to those skilled in the art. In WO 01/05207, for example, the production of earmolds and hearing aid cups in an additive fabrication process, e.g. by laser-sintering, Stereolithography or Thermojet method described. A silicone impression is digitized using a scanner as described above and edited virtually. Controlled with the resulting three-dimensional record is the earmold or the hearing aid shell created in an additive construction process.

It is state of the art that the surface of a model provided for digitization by means of a laser scanner should be as matt as possible. WO 02/16865 describes the calibration of a 3D scanner from 3Shape APS. In this document it is emphasized that the Oberflä surface of the object to be digitized should be as perfect as possible Lambertian surface. The physical basis for this is Lambert's cosine law. The visual impression of such a surface (and thus the recording by the cameras) is independent of the viewing angle.

The modification of different materials to improve readability for the mentioned methods has been described many times. In the DE 195 48 655 For example, it is described how an improvement of the reflection behavior of the plaster plaster commonly used in dentistry should be achieved by the addition of color pigments. However, a sufficient improvement can not be proven.

In the DE 100 38 564 For example, a material is modified by adding metal powders, metal alloy powders, or metallic pigment powders. The improvement of the surface's optical detectability is described as very good, but it is questionable whether the scannability with a laser is similarly good.

In summary can be said that the quality of the optical impression and thus the precision the dental / dental work from the conditioning of the preparation (intraoral data acquisition) or the quality of the surface of the to be scanned object material (laser scan) depends.

aim It is therefore an object of this invention to provide materials which make an object or situation accurate and detailed can and then without additional Work steps through customary optical Systems photographically detectable and / or optically scanned and reproducible by CAD / CAM / CIM systems without loss of information should be.

With Help of the thus produced exact three-dimensional data set should High quality in additive and / or subtractive manufacturing processes dental / dental Work can be made.

Surprisingly this is achieved by the use of suitable metal oxide powder of certain particle size distribution as additives to silicone materials.

since Many years are dental impression materials and also bite registration materials based on organopolysiloxanes (see, e.g. R.G. Craig, J.M. Powers: Restorative Dental Materials, Mosby 2002). For the Exact-accurate impression-forming silicones are known.

condensation Although silicones are just as suitable, but they show in comparison to the addition-curing silicones a larger reaction due to the reaction They will therefore not be discussed in detail in this document. In principle, the optimizations of the silicones according to the invention are but also in condensation-curing silicones feasible.

• (1) Organopolysiloxane mit zwei oder mehr Vinyl-Gruppen im Molekül (endständig und/oder seitenständig) und Viskositäten im Bereich von 100-350.000 mPa s
• (2) Niedermolekulare vinyl- und ethoxygruppenhaltige QM-Harze und/oder Mischungen von QM-Harzen in Organopolysiloxanen gemäß (1) mit Viskositäten von 150-65.000 mPa s
• (3) Organopolyhydrogensiloxane mit mindestens zwei SiH-Gruppen im Molekül
• (4) Edelmetall-Katalysator(en)
• (5) Organopolysiloxane mit mindestens einer Vinyl-Gruppen im Molekül
• (6) Organopolysiloxane ohne reaktive Gruppen
• (7) Öle oder andere Weichmacher
• (8) Verstärkende Füllstoffe, mit beladener oder unbeladener Oberfläche
• (9) Nichtverstärkende Füllstoffe, mit beladener oder unbeladener Oberfläche
• (10) Weitere Additive und übliche Zusatz-, Hilfs- und Farbmittel
• (11) Inhibitoren

The composition of addition-crosslinking silicones according to the prior art consists essentially of the following raw materials (all or only some of them):

• (1) Organopolysiloxanes having two or more vinyl groups in the molecule (terminal and / or pendant) and viscosities in the range of 100-350,000 mPa s
• (2) Low molecular weight vinyl and ethoxy group-containing QM resins and / or mixtures of QM resins in organopolysiloxanes according to (1) with viscosities of 150-65,000 mPa s
• (3) Organopolyhydrogensiloxanes having at least two SiH groups in the molecule
• (4) noble metal catalyst (s)
• (5) organopolysiloxanes having at least one vinyl group in the molecule
• (6) Organopolysiloxanes without reactive groups
• (7) oils or other plasticizers
• (8) Reinforcing fillers, with loaded or unloaded surface
• (9) Non-reinforcing fillers, with loaded or unloaded surface
• (10) Other additives and common additives, auxiliaries and colorants
• (11) inhibitors

The compounds according to (1) are organopolysiloxanes having terminal and / or pendant vinyl reactive groups and a viscosity in the range of 100-350,000 mPa s. The QM resins according to (2) are described in W. Noll, Chemie und Technik der Silicones, Verlag Chemie, Weinheim, 2nd edition 1968 and contain the tetrafunctional SiO _4/2 as Q units and the monofunctional R as M units ₃ SiO _1/2 , where R can be vinyl, methyl, ethyl, phenyl. Furthermore, trifunctional RSiO _3/2 can also be present as T units and the difunctional R ₂ SiO _2/2 as D units. The QM resins used have viscosities of 150-65,000 mPa s and vinyl contents of 0.2-8 mmol / g.

The compounds according to (3) contain reactive SiH groups which build up the polymer network in an addition reaction under noble metal catalysis with the compounds (1) and (2). The compounds used are generally polymethylhydrogensiloxanes having a SiH content from 0.1-15 mmol / g.

The noble metal catalyst (4) is preferably a platinum complex, particularly suitable are platinum-siloxane complexes, such as those already in US 3,715,334 . US 3,775,352 and US 3,814,730 are described.

The Compounds (5) are monofunctional siloxanes end-capped on one side are.

To belong to the compounds according to (6) the silicone oils, which are like the compounds (1) organopolysiloxanes, but for the noble metal-catalyzed addition cross-linking reaction contain unreactive groups. Such compounds are e.g. in W. Noll, chemistry and technology of silicones, Verlag Chemie, Weinheim, 2nd edition 1968 described.

When Compounds according to (7) include, for example, hydrocarbons Question, paraffin oils are particularly preferred.

Reinforcing fillers according to (8) usually have a BET surface area of more than 50 m ² / g. These include, for example, pyrogenic or precipitated silicas and silicon-aluminum mixed oxides. The fillers mentioned can be rendered hydrophobic by surface treatment with, for example, hexamethylsilazane or organosiloxanes or organosilanes. The said reinforcing fillers may also be present in mixtures with organopolysiloxanes according to (1).

The non-reinforcing fillers according to (9) have a BET surface area of up to 50 m ² / g, which includes the quartzes, cristobalites, diatomaceous earths, kieselguhr, calcium carbonates, talc, zeolites, sodium aluminum silicates and glass powder. These fillers, like the reinforcing fillers, may also be rendered hydrophobic by surface treatment. Furthermore, it is customary to use as additives according to (10) moisture binders, hydrophilizing agents, thixotropic agents, emulsifiers, fragrances, stabilizers and hydrogen absorbers. The colorants, which may optionally be used to distinguish between base and catalyst component and to control the homogeneity of the mixture, are generally inorganic and / or organic color pigments which can also be used dissolved in organopolysiloxanes or other solvents ,

To control the reactivity inhibitors (11) are used. Such inhibitors are known and eg in US 3,933,880 described. As a rule, these are acetylenically unsaturated alcohols or vinyl group-containing, aliphatic or cyclic poly-, oligo- and disiloxanes.

To the prior art consist of addition-curing silicones two components (A and B component or catalyst and base component called), which must be stored separately Storage stability too guarantee. The total content of noble metal catalyst (4) is in the catalyst component, the whole Content of SiH compound (3) is in the second, spatially of the first component separate component, the base component, accommodate. After the homogeneous mixing, the two network Components in a noble metal-catalyzed hydrosilylation reaction. The homogeneous mixture of the two components either by manual mixing or over a double cartridge system with static mixer. Such Double cartridge system is available for example from the company Mixpack and contains two separate chambers of 25 ml each. Differently dimensioned mixing tips are for the different viscosities and consistencies of the silicone materials available. The volume ratios of the two components 10: 1 to 1:10. Particularly preferred are volume mixing ratios of 1: 1, 4: 1 and 5: 1 (base to catalyst component).

The aim of this invention is to provide materials that can accurately and faithfully reproduce an object or situation and then be photographically detectable and / or optically scanned without additional operations by commercially available optical systems and reproducible by CAD / CAM / CIM systems without loss of information, is surprisingly achieved by the homogeneous mixing of metal oxide powders in the catalyst component of silicone materials. Metal oxide powders such as alumina and zirconia are suitable, but titanium dioxide is particularly suitable. The particle sizes of these metal oxide powders are less than 50 μm, preferably less than 20 μm and particularly preferably less than 2 μm. Such titanium dioxide powders are sold, for example, by the companies Kronos and Degussa. Also suitable is titanium dioxide powder with a particle size in the nanometer range, which is available under the trade name Aeroxide (Degussa). The titanium dioxide is known as the white pigment due to the high refractive indices of its anatase (2.55) and rutile (2.75) modifications. But of greater importance for this invention is its matting effect. The silicone materials produced with these additives are outstanding both photographically with eg the Cerec 3 system detectable as well as optically scannable with commercially available laser scanners. The outstanding optical properties of the novel silicone materials according to the invention result in the three-dimensional data sets thus obtained being available to the previously available data sets with conventional materials are far superior in terms of precision.

The The following examples are intended to explain the invention in more detail, they are intended to the scope not limit the invention. All parts are to be understood as parts by weight.

Example 1 (Bite registration material)

Catalyst component

In a mixing container 75 parts vinylendgestopptes polydimethylsiloxane with a viscosity of 200 mPa s, 64 parts of a vinyl and ethoxy group-containing QM resin with one viscosity of 2,000 mPa s and a vinyl content of 1.4 mmol / g, 214 parts a surface-treated cristobalite, 44 parts of calcium carbonate, 5 parts of a platinum catalyst, 1 part a zeolite and 1 part of a polyether siloxane as thixotropic agent and mixed homogeneously for 30 minutes. The mixture will subsequently Degassed for 15 minutes in a vacuum.

Base Component

In a mixing container 26 parts vinylendgestopptes polydimethylsiloxane with a viscosity of 200 mPa s, 51 parts of a vinyl- and ethoxy-containing groups QM resin with one viscosity of 2,000 mPa s and a vinyl content of 1.4 mmol / g, 198 parts a surface-treated cristobalite, 70 parts of calcium carbonate, 59 parts of a SiH crosslinker mixture with an average SiH content of 7.8 mmol / g, 7 parts of a dye, 1 Part of a zeolite, 1 part of a polyether siloxane as thixotropic agent and 0.1 part of an inhibitor mixture and 30 minutes homogeneously mixed for a long time. The mixture is then 15 minutes degassed for a long time in a vacuum.

Mixture of Catalyst and base component

50 Parts of the catalyst component and 50 parts of the base component are conveyed from a double cartridge and via a static mixer homogeneously mixed and on an exercise model brought. The Cerec 3 system takes an optical impression. The visualization of the impression with the help of the Cerec software shows clearly an inhomogeneity the lines and irregularities and gaps in the dataset (recognizable by the black areas). For another Editing is not suitable for the data set obtained in this way.

Example 2 (bite registration material according to the invention)

Catalyst component

In a mixing container 133 parts vinylendgestopptes polydimethylsiloxane with a viscosity of 200 mPa s, 101 parts of a vinyl and ethoxy group-containing QM resin with a viscosity of 2,000 mPa s and a vinyl content of 1.4 mmol / g, 93 parts of a mixture of surface-treated silica in vinyl endstopped polydimethylsiloxane having a viscosity of 1,300 Pa s, 15 parts of a side and terminal vinyl-containing Polydimethylsiloxane with a viscosity of 5,000 mPa s and a Vinyl content of 0.8 mmol / g, 310 parts of a surface-treated cristobalite, 66 parts of calcium carbonate, 10 parts of a platinum catalyst, 1 Part of a zeolite, 14 parts of titanium dioxide with a grain size smaller 20 μm and 2 parts of a polyether siloxane presented as thixotropic agent and mixed homogeneously for 30 minutes. The mixture then becomes 15 Degassed for a few minutes in a vacuum.

Base Component

In a mixing container 57 parts vinylendgestopptes polydimethylsiloxane with a viscosity of 200 mPa s, 40 parts of a vinyl- and ethoxy-containing groups QM resin with one viscosity of 2,000 mPa s and a vinyl content of 1.4 mmol / g, 110 parts a mixture of surface treated silica in vinyl endstopped polydimethylsiloxane having a viscosity of 1,300 Pa s, 15 parts of a side and terminal vinyl-containing Polydimethylsiloxane with a viscosity of 5,000 mPa s and a Vinyl content of 0.8 mmol / g, 298 parts of a surface-treated cristobalite, 103 parts of calcium carbonate, 86 parts of a SiH crosslinker mixture with an average SiH content of 7.8 mmol / g, 3 parts of a dye, 1 Part of a zeolite, 2 parts of a polyether siloxane as thixotropic agent and 0.1 part of an inhibitor mixture and 30 minutes homogeneously mixed for a long time. The mixture is then 15 minutes degassed for a long time in a vacuum.

Mixture of Catalyst and base component

50 parts of the catalyst component according to the invention and 50 parts of the base component according to the invention are conveyed from a double cartridge and mixed homogeneously via a static mixer and brought to an exercise model. The Cerec 3 system takes an optical impression. The visualization of the impression with the help of the Cerec software clearly shows an excellent quality. The lines are homogeneous and irregularities and gaps in the record are not recognizable. For further processing, the data set thus obtained is outstandingly suitable.

Example 3 (impression material)

Catalyst component

In a mixing container 68 parts vinylendgestopptes polydimethylsiloxane with a viscosity of 200 mPa s, 68 parts vinylendgestopptes polydimethylsiloxane with a viscosity of 1000 mPa s, 56 parts of a polydimethylsiloxane oil having a viscosity of 50 mPa s, 73 parts of a monofunctional polydimethylsiloxane oil, 204 Parts of a mixture of surface-treated silica in vinyl endstopped polydimethylsiloxane having a viscosity of 1,300 Pa s, 303 parts of a surface-treated Cristobalites, 14 parts of a surface-treated silica, 6 parts a platinum catalyst, 1 part of a zeolite and 8 parts of a polyether siloxane as thixotropic agent and mixed homogeneously for 30 minutes. The mixture will subsequently Degassed for 15 minutes in a vacuum.

Base Component

In a mixing container 71 parts vinylendgestopptes polydimethylsiloxane with a viscosity of 200 mPa s, 69 parts vinylendgestopptes polydimethylsiloxane with a viscosity of 1000 mPa s, 70 parts of a monofunctional polydimethylsiloxane oil, 210 Parts of a mixture of surface-treated silica in vinyl endstopped polydimethylsiloxane having a viscosity of 1,300 Pa s, 304 parts of a surface-treated Cristobalite, 7 parts of a surface-treated silica, 44 parts a SiH crosslinker with a SiH content of 4.3 mmol / g, 1 part of a zeolite, 13 parts of a dye, 10 parts of a polyethersiloxane as thixotropic agent and 0.1 part of an inhibitor and homogeneous for 30 minutes mixed. The mixture is then vacuumed for 15 minutes degassed.

Mixture of Catalyst and base component

50 Parts of the catalyst component and 50 parts of the base component are conveyed from a double cartridge and via a static mixer homogeneously mixed. With a laser scanner from 3Shape APS, Copenhagen the silicone impression is optically scanned. The visual representation The laser line with the help of 3Shape software clearly shows inhomogeneous intensity noise, that is so much too high. For Further processing is not suitable for the data set obtained in this way.

Example 4 (impression material according to the invention)

Catalyst component

In a mixing container 69 parts vinylendgestopptes polydimethylsiloxane with a viscosity of 200 mPa s, 69 parts vinylendgestopptes polydimethylsiloxane with a viscosity of 1000 mPa s, 56 parts of a polydimethylsiloxane oil having a viscosity of 50 mPa s, 87 parts of a monofunctional polydimethylsiloxane oil, 204 Parts of a mixture of surface-treated silica in vinyl endstopped polydimethylsiloxane having a viscosity of 1,300 Pa s, 303 parts of a surface-treated Cristobalite, 12 parts of a surface-treated silica, 8 parts a platinum catalyst, 16 parts of titanium dioxide with a particle size less than 20 microns, 10 parts a zeolite, 17 parts of a hydrophilizing agent, 1 part of a Perfume and 7 parts of a polyether siloxane as thixotropic agent and mixed homogeneously for 30 minutes. The mixture will subsequently Degassed for 15 minutes in a vacuum.

Base Component

In a mixing container 70 parts vinylendgestopptes polydimethylsiloxane with a viscosity of 200 mPa s, 68 parts vinylendgestopptes polydimethylsiloxane with a viscosity of 1,000 mPa s, 55 parts of a monofunctional polydimethylsiloxane oil, 210 Parts of a mixture of surface-treated silica in vinyl endstopped polydimethylsiloxane having a viscosity of 1,300 Pa s, 304 parts of a surface-treated Cristobalite, 11 parts of a surface-treated silica, 44 Parts of a SiH crosslinker with an SiH content of 4.3 mmol / g, 10 parts of a zeolite, 32 Parts of a dyestuff, 8 parts of a polyether siloxane as thixotropic agent, 16 parts of a hydrophilizing agent, 1 part of a fragrance and 0.1 part of an inhibitor and homogeneous for 30 minutes mixed. The mixture is then vacuumed for 15 minutes degassed.

Mixture of Catalyst and base component

50 Parts of the catalyst component according to the invention and 50 parts of the base component of the invention are conveyed from a double cartridge and homogeneous via a static mixer mixed. With a laser scanner from 3Shape APS, Copenhagen the silicone impression is optically scanned. The visual representation The laser line with the help of 3Shape software clearly shows one homogeneous intensity distribution. For another Processing, the data set obtained is excellent.

The inventive examples prove clearly that both silicone materials for impression as well as for bite registration can be produced, which are excellently detectable with photographic systems and at the same time are excellent optically palpable (scannable) with lasers.

Claims (4)

A two-component, addition-curing silicone material for bite registration, consisting of: (a) organopolysiloxanes having two or more vinyl groups in the molecule (terminal and / or pendent) and viscosities in the range of 100-350,000 mPa s (b) low molecular weight vinyl- and ethoxy-containing QM resins and / or mixtures of QM resins in organopolysiloxanes according to (1) with viscosities of 150-65,000 mPa s (c) organopolyhydrogen siloxanes having at least two SiH groups in the molecule and an SiH content of 0.1-15 mmol / g, preferably from 2-10 mmol / g (d) noble metal catalyst (s) (e) mixtures of reinforcing fillers with organopolysiloxanes having a resulting viscosity of 100-2000 Pa s (f) non-reinforcing fillers, with loaded or unloaded surface ( g) Further additives and conventional additives, auxiliaries and colorants (h) inhibitors, characterized in that the catalyst component (i) contains a metal oxide powder. Material according to claim 1, characterized that the metal oxide powder titanium dioxide with a particle size smaller 50 μm, preferred less than 20 μm and more preferably less than 2 microns. A two-component, addition-curing silicone material for the Impression, consisting of: (a) organopolysiloxanes having two or more vinyl groups in the molecule (terminal and / or side-by-side) and viscosities in the range of 100-350,000 mPa s (b) low molecular weight vinyl and ethoxy group-containing QM resins and / or mixtures of QM resins in organopolysiloxanes according to (1) with viscosities from 150-65,000 mPa s (C) organopolyhydrogensiloxanes having at least two SiH groups in the molecule and one SiH content of 0.1-15 mmol / g, preferably 2-10 mmol / g (D) Noble metal catalyst (s) (e) organopolysiloxanes having at least a vinyl groups in the molecule (F) Organopolysiloxanes without reactive groups with a viscosity of 10mPa s to 100,000 mPa s, preferably 50 mPa s to 1,000 mPa s (g) oils or other plasticizers (h) reinforcing fillers, with or without loading unloaded surface (I) Mixtures of reinforcing fillers with organopolysiloxanes having a resulting viscosity of 100-2000 Pa s (j) non-reinforcing fillers, with loaded or unloaded surface (k) other additives and usual Additives, auxiliaries and colorants (I) inhibitors thereby characterized in that the catalyst component (m) a metal oxide powder contains. Material according to claim 3, characterized that the metal oxide powder titanium dioxide with a particle size smaller 50 μm, preferred less than 20 μm and more preferably less than 2 microns.