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    • 专利摘要:
    System of micro-deposition of material on a substrate, in particular for the manufacture of a dental prosthesis or a bone scaffold, comprising a deposition chamber with a controlled, closable and depressurizable atmosphere, a first support arm (ST) configured to support a target and a second component support arm (SS) configured to support a micro-deposition substrate, at least one emitter adapted to irradiate a target associated with the target support according to one of the aforementioned PLD and / or PED techniques, in which said first and second arm are equipped with piezoelectric actuators (10, 12, 13, 9) arranged to be controlled with nanometric precision.
    公开号:CH713652A2
    申请号:CH00411/18
    申请日:2018-03-28
    公开日:2018-09-28
    发明作者:Straziuso Nicola
    申请人:Straziuso Nicola；
    IPC主号:
    专利说明:

    Description
    Claiming priority [0001] This application claims the priority of the Italian Patent Application nr. 10 2017 000 034 142 filed on March 28, 2017, the content of which is incorporated herein by reference.
    Field of the invention [0002] The present invention relates to a method and system for depositing material, in particular for manufacturing a dental prosthesis.
    State of the art [0003] Pulsed Laser Déposition (PLD) and Pulsed Electron Déposition (PED) are known microdeposition techniques.
    [0004] These technologies are able to operate on two levels: - physical-chemical transformation of the surfaces by inserting specific atoms or molecules on the base material; - deposition of thin films of materials such as: metals, oxides, polymers, and others.
    [0005] Surface treatments allow to obtain coatings with particular properties.
    [0006] The field of application of these technologies is generally that of semiconductor products and in particular to devices related to the production and transformation of electrical energy.
    [0007] With the pulsed laser deposition (PLD) method, thin films are obtained by ablation of one or more targets illuminated by a pulsed and focused laser beam.
    [0008] The material that is detached from the target is used to perform a coating.
    [0009] The pulsed nature of the PLD process allows the preparation of polymer-metal and multilayer compounds. Since with this method the energy source is located outside the chamber, it is possible to use both ultra-high vacuum (UHV) and environment in gas pressure. In UHV, the effects of engraftment and mixing generated by the deposition of energetic particles, the atoms and the ablase ions, lead to the formation of metastable phases, for example nanocrystalline solid solution, oversize and amorphous alloys. The preparation of inert gas in the atmosphere by varying the kinetic energy of the deposited particles also makes it possible to modify the properties of the film (stress, texture, reactivity, magnetic properties). All this makes PLD an alternative deposition technique for the growth of high quality thin films. It is important to highlight that with this technique there is no uniformity of the surface of the deposited film.
    [0010] PED is a relatively new technology with great potential, in the literature it is also known as Pseudo-Spark Discharge (PSD), Channel Spark Discharge (CSD) or Pulsed Plasma Déposition (PPD), with installation and operating costs very minor, with greater deposition capacity per unit of time and also on areas of considerable surface as an alternative to a deposition system that covers the same needs that lead to the use of the PLD. Similar to Pulsed Laser Déposition (PLD) technology, the main characteristic of the PED pulsed electron beam is the ability to generate a high power density (~ 108 W / cm2) on the Target surface, but unlike the PLD it does not interfere with the "cloud" of the plasma particles of the ablated material, and therefore a better uniformity of the surface of the obtained layer is obtained. In addition, the thermodynamic properties of the material such as the melting point and the specific heat are irrelevant for the evaporation process, as the dissociation of the material does not generate heat and this aspect is extremely important in the case of complex materials, composed of several elements i which are not so dissociated thus preserving the stoichiometric composition in the plasma and consequently also in the deposited material.
    [0011] The ablation takes place randomly on a rotating target, the movement of which is transmitted by electromagnetic motors allocated outside the vacuum chamber, by means of a closed magnetic loop joint and confined on the chamber wall so as not to influence the direction of the electron beam or cloud that otherwise would make the location of the deposition unpredictable.
    [0012] The results are relatively satisfactory, but at the same time some problems have been highlighted, such as the burden of having to spend time and energy each time to restore the state of pressure and / or vacuum in the deposition chamber when it is necessary to deposit a different material and the possible improvements to be made to automate and speed up the process, innovating the handling system as well as the strategies for mutual positioning of the Target and Substrate on which to deposit the material removed from the target.
    [0013] This becomes even more relevant when it is necessary to use different substrates in the coating of particular objects.
    Summary of the invention [0014] The object of the present invention is to provide a material deposition system, particularly suitable for the manufacture of components that require the use of different materials and more particularly suitable for the manufacture of dental prostheses.
    [0015] A further object of the present invention is to achieve a particularly high level of precision to the point of being able to use such PLD and / or PED techniques in areas in which a high degree of finishing is required to meet predetermined aesthetic requirements.
    [0016] The aforementioned objects are achieved by means of a numerically controlled machine based on piezoelectric actuators, enclosed in a deposition chamber with a controlled, closable and depressurizable atmosphere. Said machine comprises a target support arm comprising a slide or a turntable, capable of replacing the target during processing and a component support arm, preferably of the type having at least six degrees of freedom. The system also comprises an emitter adapted to irradiate a target associated with the target support according to one of the aforementioned PLD and / or PED techniques.
    [0017] Advantageously, the slide or the turntable allows to exchange the target in use without any intervention from the outside of the depressurizable chamber.
    [0018] According to a first preferred variant of the invention, said PED type emitter is housed inside the deposition chamber, preferably in a fixed position, so that the support arm of the target moves with respect to it.
    [0019] According to a second preferred variant of the invention, said emitter of the PLD type is housed externally to the deposition chamber and this comprises an optical window which allows to appropriately direct the laser beam inside the chamber itself in a fixed direction.
    [0020] According to another preferred variant of the invention, a PLD emitter and a PED emitter arranged externally and internally of the deposition chamber in which the aforementioned target support arm and arm are housed are implemented simultaneously. component support.
    [0021] Preferably, said emitters have a fixed position with respect to the deposition chamber, while the target support arm can move in three mutually perpendicular directions to each other besides being able to replace the target in relation to the stage of a coating / manufacturing procedure .
    [0022] More preferably, the target support arm is controlled so as to move the target so as to obtain a uniform consumption of the target surface. Moreover, the arm is controlled so as to maintain a constant reciprocal position between the target and the emitter although the surface of the target is consumed during the ablation of material.
    [0023] This allows to obtain a fixed position of the plasma cloud generated in the irradiation of the target and therefore a reference point for controlling the movement of the component support arm.
    [0024] The support arm of the component being processed / deposited is adapted to move said component as it is covered.
    [0025] Therefore it is evident that two independent controls can be implemented, one aimed at uniform consumption of the target and keeping the position and characteristics of the plasma cloud fixed and invariable, while the other is controlled according to the thickness and of the areas of covering the substrate being processed, obtaining a great simplification of the control.
    [0026] In the following "substrate", "component being processed", "component subject to micro / nano-deposition", are linguistic equivalents.
    [0027] Preferably, the irradiation of the target and the displacement of the component are synchronized. More preferably, the distance between the target and the component, the resolution of the movement and the irradiation power of the target are interrelated so as to obtain a selective coating of the component without resorting to the masking of the areas which it is not desired to cover.
    [0028] Therefore, a hierarchical control can be arranged to control the two arms in a coordinated manner.
    [0029] Preferably, the piezoelectric actuators have nanometric precision and therefore, the aforementioned synchronization and interrelation allows to operate selective coatings with resolutions of the order of nanometers.
    [0030] Since the machine is of the numerically controlled type, the deposition can be carried out point by point and layer by layer, distributed spatially according to a geometry, a structure and / or a predetermined architecture, a micrometric or nanometric definition, with functional properties determined by a predetermined mathematical model for example according to the STL technique (STereoLithography).
    [0031] Historically, the production of high quality and latest generation dental prostheses is carried out by means of a subtractive technique. In other words, portions are removed from a pre-sintered block by hand to get a prosthesis. Beyond the fact that the achievable precision is low, the process itself is not eco-sustainable, as the stolen material cannot be reused with a waste of energy and resources.
    [0032] Furthermore, the pre-sintered block has physico-chemical properties oriented to robustness, neglecting important factors such as the weight of the prosthesis obtained, its high rigidity, and a photo-correlation, i.e. an unsatisfactory aesthetic appearance.
    [0033] Thanks to the present invention, it is allowed not only to coat a prosthetic component, but to build it completely starting from a core, that is starting from deep layers up to the most superficial layers.
    [0034] In addition to fulfilling the function of support, the deeper layer provides the basic color (Value and Tint) and the intermediate layers, through the texture, reflect and diffuse the light, determine the degree of saturation or Croma, while the surface layer , translucent it is crossed by light and resists the unfavorable environment of the oral cavity (acidity).
    [0035] A dental prosthesis is generally internally hollow in order to fit on a so-called prosthetic implant or dental stump. Therefore, surface layers are those that are visible externally but also those intended to fit on a prosthetic system. Conversely, the deeper layers are those underlying the surface layers.
    [0036] The deeper layers can advantageously be made by the PLD technique which allows to increase the mass of the prosthesis quickly even if with a lower precision, while the PED is used at least for the deposition of the more superficial layers.
    [0037] According to a preferred variant of a method of manufacturing a dental prosthesis realized by means of the aforesaid system, it is possible to obtain that all the portions of the prosthesis guarantee biocompatibility, geometric precision, adequate aesthetics and a mechanical and chemical resistance suitable for the purposes.
    [0038] Furthermore, whenever it is appropriate to carry out the deposition without altering the chemical characteristics of the target material, it is preferable to use the PED, while, conversely, when it is necessary to raise the temperature of the target material to obtain, for example, polymerization in the layer of material deposed it is preferable to use the PLD.
    [0039] Furthermore, it could be desired to obtain the formation of a specific alloy on the substrate, therefore the two techniques can be implemented in a reciprocally reciprocal way by exploiting their peculiarities.
    [0040] The present invention allows the materials to be deposited without the need to perform masking of the adjacent areas not involved in the deposition made necessary instead in the known deposition processes, thus avoiding the contamination derived from that production process, improving the quality of the device made and getting the production cycle streamlined, saving time and reducing costs.
    [0041] A further opportunity offered by the technology is the possibility of mixing and / or interchanging the various species of ceramics or other types of materials during the deposition process, even on the same layer to obtain various degrees of hardness, elasticity, translucency, resistance to corrosive agents, precisely in areas where these qualities are essential, without having to undergo subsequent sintering and tempering (Annealing) processes as necessary until now. [0042] The subject of the present invention is a material deposition system in particular for manufacturing a dental prosthesis, according to claim 1.
    [0043] Further objects will be clear to the person skilled in the art, by means of the following detailed description.
    [0044] The claims describe preferred embodiments of the invention, forming an integral part of the present description.
    Brief description of the figures [0045] Further features and advantages of the invention will become more evident in the light of the detailed description of preferred but not exclusive embodiments of a system for depositing material, in particular for manufacturing a dental prosthesis, illustrated in by way of non-limiting example, with the aid of the accompanying drawings in which:
    fig. 1 schematizes, according to the prior art, a deposition process operated by a PLD or PED technique; fig. 2 shows two preferred examples of support arms of the system of the present invention; fig. 3 and 4 respectively show an exploded view of each of said arms of fig. 2; fig. 5 shows a logic-functional diagram of the actuators and of the relative control systems relating to the support arms of fig. 2; fig. 6 shows the modeling of an elementary portion of a deposited surface, from the figure itself, it is understood that the modeling can be three-dimensional; fig. 7 shows operationally an interaction of a deposited component, on whose surface a plasma cloud impacts, modeled by means of interconnected elementary surfaces; fig. 8 Shows the deposition system inside the high-vacuum chamber with parts removed; fig. 9 shows the deposit of a finishing layer, through the system object of the present invention and shown in the preceding figures 1-7, on a previously constructed prosthetic element; fig. 10a and 10b respectively show a longitudinal section view of a prosthetic element, constructed by means of the system of the present invention and shown in the preceding figures 1-7, and a sectional view of the same prosthetic element mounted on a stump; fig. 11 a and 11 b respectively show a longitudinal section view of a prosthetic element, constructed by means of the system of the present invention and shown in the preceding figures 1-7, and a cross section of the same prosthetic element.
    [0046] The same numbers and the same reference letters in the figures identify the same elements or components.
    Detailed description of a preferred embodiment of the invention [0047] Fig. 1 of the prior art shows a TG target irradiated by an emitter EM with an RD radiation. From the target, a cloud of PA plasma comes off and impacts on an SB substrate subject to deposition.
    [0048] The plasma cloud of the ablated material has an ogival shape, with origin in the point of impact of the electronic or laser radiation on the surface of the target and is oriented perpendicularly to the surface of the target itself.
    [0049] In the figure it can be seen that the substrate SB has a surface to be covered substantially tangent to the plasma cloud, therefore, virtually, only an elementary point of the substrate is hit by the plasma cloud.
    [0050] If the distance D between target and substrate SB is reduced, the intersection between the substrate and the cloud PA widens increasing the deposition surface, but obviously the resolution of the deposition is reduced.
    [0051] The target can be any material with which it has been decided to coat a substrate.
    [0052] With reference to fig. 2, an embodiment of a deposition or manufacturing system according to the present invention is shown.
    [0053] To the left of the sheet, with the letter ST a target support arm is indicated.
    [0054] In fig. 2 the target is schematized with a right prism 15 associated with a turntable 8.
    [0055] From the same figure it can be understood that the revolving plate 8 comprises a plurality of support cavities, angularly spaced, which allow to house as many targets on the same plate 8.
    [0056] Advantageously it is possible to replace the target during processing simply by inducing a rotation in the support plate 8.
    [0057] The number of supporting cavities may vary appropriately depending on the circumstances.
    [0058] Alternatively, it is possible to use a slide which translates by replacing the target.
    [0059] Advantageously, the emitter can remain stationary, while the target is moved with respect to the emitter thanks to the relative support arm ST.
    [0060] The support arm comprises three movable slides 10, 12 and 13 mutually associated so as to allow a perpendicular displacement along three coordinated axes X, Y and Z.
    [0061] More particularly, the slides are able to determine a displacement of the order of the nanometer.
    [0062] While the slides 12 and 13 can be interconnected directly with each other, the slides 10 and 12 are interconnected by means of an interconnection element 11 able to maintain the slide 10 offset by 90 ° with respect to the XY plane to which the slides 12 are parallel and 13.
    [0063] According to the variant shown in figs 2 and 3, a rotating plate is implemented around a fulcrum 7 supported axially by a rotary actuator 9 fixed directly or indirectly to the slide 10.
    [0064] Also said rotary actuator is able to impart a rotation to the rotary plate 8 with resolution of the order of the nanometer.
    [0065] The rotary plate comprises, for example, eight target support slots arranged circumferentially to a face, opposite to the face facing the rotary actuator 9. Furthermore, the target support slots are angularly spaced apart.
    [0066] Preferably, the fulcrum 7 defines a quick-coupling system comprising blind eyelets which extend axially, on a cylindrical surface, while the rotary plate 8 comprises a central hole complementary to the fulcrum and of the corresponding openings in the cylindrical surface of the central hole , from which partially facing spring-loaded spheres which allow a rapid association between the turntable and the fulcrum 7. So that in operative condition of assembly the spheres adhere in the blind slots preventing the dissociation of the rotary plate from the fulcrum 7.
    [0067] This fact is particularly useful when the system is intended for several different processes which require a much higher number of coating materials than the eight target support slots available in the example of the figures. [0068] This does not mean that the plate can be fixed differently and that the number of support slots is different. [0069] To the right of the sheet, the component support SS is shown, where by component is meant an object that must be simply coated or a core on which it is intended to construct a complete object. The difference between the two situations is that in the first case the thickness of the material applied is a few orders of magnitude lower than any of the dimensions of the object to be coated, while, in the second case, a massive supply of material is made to obtain a considerable growth of the initial nucleus and subsequent coatings. An example of a dental prosthesis is described below.
    [0070] With reference to fig. 3 shows an exploded view of a support arm of a component being processed.
    [0071] It comprises a support device 6, preferably of the three-point type to support a component being processed, shown for example in Figs. 9-12. It can be seen that this supporting device comprises a cross-shaped element, but only three of the ends support as many longitudinal elements fixed to the same by means of a spherical joint to obtain a three-point support, which gives a higher precision in the support itself.
    [0072] The support device 6 is axially associated directly or indirectly with a rotary actuator 5, for example similar to the aforementioned device 9.
    [0073] Optionally, a tripod 4 may be present, which will be discussed below.
    [0074] The rotary actuator, similarly to what described for the target support arm ST, is connected to a set of slides 19, 1 and 3 which allow displacements according to coordinated axes X, Y, Z.
    [0075] Also in this case, a pair of slides 19 and 1 is interconnected directly defining the displacement plane X, Y, while the slide 3 is connected to the slides 19 and 1 by means of an interconnection element 2 which keeps the slide 3 a 90 ° with respect to the XY plane to which the slides 1 and 19 are parallel.
    [0076] The slides 19, 1,3 are able to determine a displacement of the order of the nanometer.
    [0077] The component supporting support arm SS can thus be directly associated with a support base 20, common to both arms SS and ST.
    [0078] In this case, it is preferred that the rotation axis of the rotary actuator 5 is directed in an approximately perpendicular direction with the rotation axis of the rotary actuator 9. Said axes may not be coplanar, but lie on planes mutually parallel.
    [0079] The reciprocal position of the rotation axes is not essential to the operation of the system, although the arrangements just described allow to simplify the management methods of the support arms SS and ST; in fact, with reference to the figures, the ST arm is oriented along the X axis, while the SS arm is oriented according to the Y axis. Evidently, different angles can be chosen, possibly depending on the shape of the component being processed. [0080] According to a preferred variant of the invention, the support component arm SS is associated with the common base 20, by means of a balanced fifth wheel.
    [0081] This fifth wheel is associated with the common base 20 by means of a rotary actuator 18 having an axis of rotation perpendicular to the common base, i.e. oriented along the axis Z. The arm SS is associated with the thrust ring in an eccentric position, therefore, the fifth wheel is shaped to balance the weight of the same arm.
    [0082] This fifth wheel allows to vary the angle formed between the rotation axis of the rotary actuator 5 with the rotation axis of the rotary actuator 9.
    [0083] According to a further preferred variant of the invention which can be combined with the previous ones, the support component arm SS is equipped with a so-called tripod 4, that is to say a further actuator having six degrees of freedom as indicated in fig. 4, through the system of coordinated axes enclosed in the circle connected to the same tripod.
    [0084] The implementation of the tripod is not essential. It introduces in the kinematics of the ST arm the rotation around the Z axis and the Y axis. This allows to obtain small inclinations of the component being processed, useful above all to follow any concavity and convexity of the component being processed.
    [0085] It is evident that there is an overlap between some degrees of freedom of the tripod with the degrees of freedom of the slides 19, 1.3. This allows on the one hand to extend the motility of the arm along the same grades of freedom, to speed up the same motility, considering that the actuators are of piezoelectric nature at nanometric resolution, in addition, the fact of having the tripod arranged at an inclusive point between the rotary actuator 5 and the "vertical" slide 3, it makes it easier to follow the rounded shapes of a component, in particular a dental prosthesis.
    [0086] It is worth noting that the emitter power can also be controlled and thus also the mutual distance between the emitter and the target to obtain a variation of the shape of the plasma cloud. It is evident that the angle between the direction of irradiation RD with respect to the surface is fixed and about 45 °.
    [0087] The deposition chamber C is only schematized, since it can have any shape and size. Likewise, the means for controlling the atmosphere within the chamber itself, or of other devices for controlling deposition operations are not shown, since this is an art in itself known that does not require a specific description.
    The rooms are associated [0088] - Means for handling and measuring the atmosphere inside the chamber, including one or more vacuum pumps and pressure / vacuum meters; - Means for monitoring the deposition process, including a measurement laser, a camera and possibly a mass spectrometer.
    [0089] The controlled atmosphere deposition chamber is compatible with the so-called "Ultra High Vacuum", that is with pressures of the order of 10Λ-9 hPa. It has compatible dimensions for housing the aforementioned target support A and component support B.
    [0090] In fact, the high-energy PED electron source, where present, is housed inside the chamber, while the PLD laser source, where present, is housed externally to the chamber and interacts with the target from which to ablate the material from micro and or by means of a suitable optical window made in the casing of the chamber C in a vacuum-tight manner.
    [0091] Preferably, at least one laser device (not shown in the attached drawings) for measuring a distance to measure a position of the component being processed, with respect to a predefined reference point, is housed in the confinement chamber. In fact, since the external surface moves towards the target due to the deposition process; this measurement allows to correctly check a reciprocal position between the target and the position in which this surface to be covered is expected to be hit by the plasma cloud.
    [0092] Preferably, a second laser (shown in Fig. 8 and indicated as a laser measure) for measuring a distance is associated with the chamber C, inside it, to measure a position of the target to control the movement of the support arm of the target for the same purposes described above.
    [0093] Preferably, at least one of the aforementioned laser measurement devices is of the differential interferometric type implementing a homodyne method, known per se, with a subnanometric resolution.
    [0094] The aforementioned measurements allow to recalculate and dynamically adjust the spatial coordinates of the vertices of the triangles that describe the surface of the Substrate that have been modified by the deposited material, of the quantities inherent in the thickness deposited, in order to automatically repeat the process of deposition on the same area until the required thickness is reached.
    [0095] According to a preferred variant of the invention, a quantity of material removed from the target is calculated by means of an energy balance both in the case of the PLD technology and in the case of the PED.
    [0096] Preferably, inside the chamber there is housed a television camera (not shown in the illustrative drawings) for monitoring and recording events related to a deposition process.
    [0097] Preferably, the chamber comprises - several sealed openings to allow the loading of one or more targets and of the component being processed - an optical window, evidently vacuum-sealed, for the visual observation of the carrying out of the deposition processes; - a flange with an optical window, evidently a vacuum seal, equipped with lenses and mirrors to direct and align the high-energy laser beam generated by the PLD emitter (Pulsed Laser Beam) on the target material; - an opening for the introduction of activating or inert gases inside the deposition chamber, equipped with shut-off valves and gas flow regulation devices; - one or more openings equipped with fixing elements of at least one shut-off valve for interfacing with the internal volume of the deposition chamber any pressure measuring devices and / or other quantities, including the vacuum measurement; - a flange to connect a mass spectrometer in order to monitor and analyze in real time the stoichiometry of the plasma flow ablated by the target; - a flange to connect a vacuum pump to the deposition chamber. Preferably, two pumps are implemented, one of which is of the "Turbo" type for rapid emptying of the deposition chamber and a high vacuum pump for maintaining the vacuum during the operation of the deposition system; - a flange for the passage of electrical cables for the supply and control of the actuators associated with the target and component supports.
    [0098] As described above, the area involved in the deposit depends on the distance of the surface to be covered (Substrate) with respect to the Target surface and the irradiation power of the target. This area is minimal when it tears the (virtual) apex of the plasma cloud and increases by reducing the distance from the Target because it increases the area of intersection with the plasma cloud. Therefore, the parameters necessary to control the deposition area are the irradiation power and the distance between the target and the surface.
    [0099] To meet the needs of speed of response and precision of movements, the actuators are piezoelectric with a resolution of a few nanometers and the total weight of a few hundred grams suitable for use in a high vacuum environment (10-7 hPa). They advantageously do not generate electromagnetic fields that can interfere with the supersonic flow of the plasma cloud of the material removed from the target to be deposited on the substrate being processed.
    [0100] The movement of the support arms SS and ST and the intensity of the RD radiation is automatically controlled by one or more computers interconnected with each other, which synchronously govern the piezoelectric actuator system which sub-micrometrically moves the support of the target and the substrate deposition object.
    [0101] From the above description, the system can reach fifteen degrees of freedom, allowing to select the material to be deposited from one to several types and / or different nature without having to open the deposition chamber.
    [0102] Fig. 5 shows a logic control scheme of the actuators and emitters.
    [0103] From top to bottom - «Atmosphère Control» indicates an atmosphere control system in the high vacuum chamber. - HVG «High Vacuum Gauge» indicates the empty control system; - VC «Vacuum Chamber» indicates the vacuum chamber; - «Measure Laser» indicates the measurement laser and MLCS «Measure Laser Control System» indicates the »Measure laser» control system and that converts the electrical signals of the Measure Laser into digital signals for the interface with the central control system ; - HPS indicates the high power source (High Power Source) of the «HP Laser» laser emitter, - PHVS indicates the high voltage source (Power High Voltage Source) of the «Eb» electron emitter, - CTMC indicates the device of control of the target support arm ST, - CSMC indicates the control device of the support arm component SS; - CMMC indicates the supervisory control device that sends signals and reference values to the CTMC and CSMC devices, which independently proceed to guarantee the achievement of predetermined spatial positions of the plasma cloud on one side and of the substrate subject to deposition from the other.
    [0104] According to a preferred variant of the invention, the coating surface is modeled by means of elementary triangular surfaces, as defined in the STL "STereoLithography" standard, by the spatial coordinates of the relative vertices, as shown in fig. 6.
    [0105] In fig. 7 shows the same elementary triangle shown in figure 6 as part of a surface of a substrate SB being coated.
    [0106] It is seen that the intersection, substantially circular - but may have different shapes in relation to the convexity of the substrate surface - between the plasma plasma PA and the surface of the substrate is focused exactly on the elementary triangle having the most pronounced edges.
    [0107] Once the target support arm ensures the correct spatial position of the plasma cloud, also in relation to the power radiated by the emitter, the positioning of the substrate and in particular the focusing of each modeled elementary triangle and consequently the same amplitude of the aforementioned area of intersection is the task of the substrate support arm.
    [0108] According to a preferred variant of the invention, the width of the intersection area is controlled by varying the emission power of the emitter.
    [0109] According to a further preferred variant of the invention, the width of the intersection is varied by moving the reciprocal position between the emitter and the target.
    [0110] With reference to fig. 7, compared with Figs. 2 and 6, it is understood that the actuators are controlled so as to guarantee the alignment of the X axis of the reference system of the target support arm ST with the unitor normal to the surface of the elementary triangle. The center of the triangle that determines the area to be covered is identified by the spatial coordinates of its vertices V1 (x, y, z), V2 (x, y, z), V3 (x, y, z), as contained in a .stl file that models a three-dimensional representation of the substrate surface.
    [0111] In relation to the angle formed between the axis of rotation of the actuator 5 with the axis of rotation of the actuator 9, the width of the intersection area is controlled by acting on the slides 1 and / or 19 of the arm of support SS and / or the slides 12 and / or 13 of the support arm ST. When the support arm SS is equipped with eccentric fifth wheel 17/18 and / or tripod 4, these can also be suitably checked for this purpose.
    [0112] The electron beam is preferably guided by a cannula, also called "capillary" 16, shown both in fig. 2 which in fig. 7. It, by driving the electron beam can be conceptually confused with the beam itself.
    [0113] The piezoelectric actuators are advantageously compatible with a high vacuum environment (10-7 hPa) such as that realized in the deposition chamber C.
    [0114] The rotary actuators 5 and 9, preferably provide a rotation range> 360 ° with angular resolution 0.75 prad; with minimum incremental motion of 3 prads.
    [0115] As far as slide actuators are concerned, they comprise piezoelectric motors with inertial movement, preferably designed to achieve a stroke 26 mm with a resolution of 1 nm with minimum incremental motion of 6 nm.
    [0116] The motorized tripod 4, with six axes is also equipped with piezoelectric motors with inertial movement, preferably with 1 nm resolution able to make the rotary actuator perform 5 short movements and even contemporaneously between the aforementioned six degrees of freedom .
    [0117] As far as the manufacture of dental prostheses is concerned, this allows depositing colored pigments, in such a precise way as to obtain an extremely close to a human tooth.
    [0118] At the same time, the fact of implementing a multiple support of target materials, such as for example the rotary plate 8, allows to mix the pigmentations allowing to determine the concentrations and the mixing of the same point by point to reproduce color tones and gradients most likely equal to those of a reference sample, affecting the trans-gloss of the deposited material.
    [0119] In the same way, it is possible to vary, point by point, and not only layer by layer, the nature and physical and chemical properties of the building as a function of both aesthetic and structural characteristics of the prosthesis being manufactured.
    [0120] It is evident that in the case of stratified deposits of material, the geometry of the object that received the deposited material is modified; it is therefore necessary to update the spatial coordinates of the vertices of the triangles that describe the surface of the object, of the quantities derived from the thickness of the material deposited on them, so that at the next passage on the same center of the area to be covered, the conditions are respected of reciprocity pertaining to the regulation of distances and movements that influence the deposition. This update can be made dynamically, automatically modifying the parametric data of the spatial coordinates of the vertices of the triangles that describe the surface of the object to be covered, affected by the deposition, when the plasma flow generated by the pulsation of the electron beam on the material to be deposited it has just been deposited in the quantity envisaged to obtain the required thickness, so as to compensate for the modification of the intervened geometry.
    [0121] It is preferred that the updating be carried out automatically knowing in advance the quantity of matter transferred, at the level of individual atoms, and possibly controlling this estimate in feedback by means of the aforementioned laser measurement devices.
    [0122] Therefore, the CMMC supervision device is programmed to vary the coordinates of the elementary superficial triangles as the micro and / or nano deposition proceeds.
    [0123] Alternatively, the CMMC supervision device receives and processes successive complete processing phases based on expected coordinates of the substrate surface.
    [0124] The first solution is certainly more accurate and allows the deposition process to be checked in feedback even if it requires a calculation power certainly more relevant than in the second case.
    [0125] The following is an example of a list of dental prosthetic artifacts, which can be manufactured both in series and on measure with the aforementioned technology: - repair of dental elements, bridges and dental prostheses - realization of part of tooth, between which inlay, facet (aesthetic reconstruction of the vestibular surface of the incisors and canines) - realization of stump pins - realization of single dental element - realization of crowns on dental stumps - realization of crowns on implants - realization of bridges - realization of partial prostheses, fixed and removable - realization of total, fixed and removable prostheses - realization of standard standard dental implants - realization of customized dental implants also on CAD processing - layering of biocompatible materials on implants - orthodontic staples - stabilizer bars - restraint systems - standard scaffold (or scaffolds of predefined dimensions, produced in serious and are adaptable in the grafting phase by the sector operator, surgeon and dentist) - bioactive scaffolds also customized on CAD processing - autologous, homologous, heterologous and alloplastic bone scaffolds.
    [0126] The so-called bone scaffolds are grafts destined to be inserted in suitable bone cavities, for example, the jaw and / or jaw of a man and favor osseointegration - ability to bind biocompatibly with the receiving bone -, l 'osteoconduction - ability to act as a three-dimensional physical support to the processes of bone formation -, osteoinduction - ability to provide a biological stimulus to induce the differentiation of undifferentiated pluripotent cells, local or originating from adjacent tissues - and the osteogenesis ability to form new bone from vital osteoblastic cells -.
    [0127] With the aforementioned technology innovative bone scaffolds can be built, combining the mineral structures of natural bones, coming for example from human or bovine corpse with biopolymers, customized on the patient's dimensional needs.
    [0128] Inorganic and organic technical materials can be used alternatively, point-to-point on the same layer and differently on an underlying and / or overlying layer according to a predetermined design and / or architecture, favoring the PLD for the "spots" of larger dimensions and the PED in the areas of interconnection between two different materials - see for example in fig. 11a and 11b the layers 35 and 37 interposed respectively between the layers 34-36 and 36-38 -, in the inner and outer coating layers and in the points where the preservation requirements of the stoichiometry, and in general of the physicochemical properties, of the target material to be transferred must be preserved during the deposition process.
    [0129] In the manufacture of a dental prosthesis, the relative hardness and flexibility can be controlled by varying the inorganic fraction such as, for example, zirconium protoxide, or by modifying the degree of cross-linking of the organic fraction using functional groups that prevent crosslinking, the alkyls or phenyls, or groups that favor cross-linking forming a very dense network. Furthermore, organic-inorganic hybrid coatings can be loaded with ceramic-type particles for applications in orthopedics and dental implants.
    [0130] Another very interesting application of the hybrid coatings obtainable thanks to the system object of the present invention consists in the creation of surfaces with self-cleaning properties (self-cleaning). This is achieved by stratifying with PED materials, such as titanium dioxide, which have the following characteristics: photocatalytic, which allow in the presence of light radiation to decompose organic substances and pollutants; super hydrophilicity, which enhance the ability to self cleanse. The greater the irradiation with UV light of the treated surface, the less the contact angle with water decreases, which even tends to zero after a reasonable time interval. The water spreads and dilates easily. In practice, thanks to photocatalysis, the hydrophilicity is added to the action of the titanium dioxide which breaks down the organic deposits present on the treated surface; antibacterial, obtained thanks to the effect of UV rays contained in sunlight. The irradiation triggers a reaction on the treated surface, able to produce active oxygen and decompose the bacteria.
    [0131] Some examples of production processes are described below.
    [0132] The device described above offers opportunities unimaginable until now in the dental field; by way of example the following is a description of the lining of one or more prosthetic elements, the fully automated construction of high quality dental prostheses and the construction of an innovative prosthetic element consisting of a customized bone scaffold, a periodontal-like structure, a structure similar to - dentin, enamel-like structure.
    Coating of a prosthetic element [0133] The prosthetic coating with the aforementioned system replaces the manual phases of brushing and firing of the ceramic material completing the so-called digital flow (intra-oral scanners, scanners for casts, CAD software, CAM milling machines), standstill from years on subtractive production processes, incomplete in the finalization of the product, blocked to the realization of a Metal-Free prosthetic substructure, of excellent quality, but suspended pending the manual brushing and sequential firing of the different types of ceramic coating masses prosthetic. Limited in photocoloring properties, with excessive weight and resistance in the realization of precolored monolithic prostheses. Limited by poor resistance to load and fatigue tests with regard to the fabrication of crowns, bridges and superstructures of integral ceramics or coupled structures (zirconium infrastructure and ceramic superstructure).
    [0134] It starts from the colorimetric reproduction of the tooth in 2D or Dentine, Enamel, Plaque and Texture, choosing one of the systems or standards (RGB, Lch, Cie-Lab, Scala Vita Lumin, Classical Life, Cromascop) each of them is applied in the corresponding layer generated starting from the CAM modeling of the same tooth. The resulting file containing geometric, spatial information with associated color assignments is processed in near real-time and / or subsequently by the computerized main machining controller (CMMC) to schedule the deposition.
    [0135] The covering 25 of fig. 9 is deposited, via PED, on a pre-constructed prosthetic element, seen according to a longitudinal section, with a subtractive technique known in itself. The coating layer can be made in dental ceramic or in the patient's natural enamel, obtained, for example, from a supernumerary tooth previously removed and preserved after being properly treated.
    [0136] An opportunely treated means for example that it is subject to one or more of the following operations: 1) Cutting 2) Segmentation 3) Morcellation 4) Lyophilization 5) Demineralization (partial or total) 6) Production of a paste of bone.
    [0137] Generally, these operations are performed as part of a wider procedure for preparing the scaf-fold, which comprises the following steps: A Detection of the dental and bony shape and Texture, previously necessary for the implant by one of the following techniques: Radiography endoral, endoral biteswit radiography, dental orthopantomography, Tac type Dentalscan, 3D scanner; B Integration and digital reconstruction of acquired data C Fabrication of the scaffold in any way, including the additive method described here; C Positioning on the support device 6 of the scaffold obtained in the previous step and coating of the same by means of a target material associated with the turntable 8.
    [0138] The thickness of this layer, consisting of several layers, ranges from 10 to 50 μm and has an aesthetic, anti-scratch, anti-acid, reflecting and resembling with the natural tooth function, also has a respectful hardness to the adjacent tissues.
    [0139] As will be seen later, as a target material a bone fragment or tooth from the same patient on which the scaffold is to be implanted can be used.
    Automated realization of dental prosthesis or a hollow prosthetic device to be anchored on implant or dental stump.
    [0140] In figs 10a and 10b shows the longitudinal section view of a prosthetic element mounted on a titanium abutment 27 which is part of a dental implant or on a dental stump. As it is possible to see in the figure, the prosthetic element is formed by a supporting part 30 made of zirconium dioxide, a titanium shell (which has a lattice structure) 31, a hollow part 28 and a finishing layer 29 which is particularly finished. and can, as in the previous case, be made in dental ceramic or in the patient's natural dental enamel starting from the aforementioned supernumerary tooth, for example.
    [0141] A part of the prosthesis obtained in an additive way is the crown 32. As in the previous case, the crown is built by successive layers (layer).
    [0142] The part in zirconium dioxide 30 associated with the titanium part 31 which confines the internal cavity forming a shell with an overall thickness ranging from 0.3 to 0.5 mm, this being the part destined to withstand the chewing loads, is sized according to the structural analysis techniques customary for example with a finite element calculation.
    [0143] The stratification of the part 30 is performed with the PLD and / or PED technology. The external part 29, made of dental ceramic or treated natural enamel, has a thickness of 10 to 50 μm and is layered with PED technology.
    [0144] By external surface part 29 is meant not only the surface of the prosthesis that faces the oral cavity including the adjacent tooth (s) and opposite (i), but also optionally the surface of the prosthesis in contact with the connecting connecting element 27 described below.
    Construction of a prosthetic element [0145] In figs 11a and 11b a prosthetic element is represented, an incisive tooth in this case, which reproducing a natural tooth in the form will allow to obtain aesthetic and functional results never obtained with traditional methods.
    [0146] The manufactured article is constructed through an additive deposition of successive layers of material obtained through PLD or PED depending on the chemical-physical characteristics that the areas to be covered must have.
    [0147] The steps for the construction of the prosthetic element shown in fig. 11a and 11 b.
    [0148] The detail 33 is the initial substrate, built in Teflon or other material, on which the different layers are deposited up to the top indicated by the portion 39. A layer, which cuts perpendicularly the longitudinal development of the prosthesis is indicated with «layer» in fig. 11a and represents a deposition layer.
    [0149] The detail 33 is mounted on a support of the arm SS shown for example in fig. 1, while the different target materials are positioned on the rotating plate 8, for example of fig. 1. The detail 15 of fig. 3 is an example of positioned target material. Everything is subjected to high vacuum thanks to the chamber described above.
    [0150] The construction of the manufactured article takes place by depositing spots so as to form successive layers of deposition according to an axial growth, that is to say by layers transverse to the longitudinal development of the complete product.
    [0151] Therefore, by axial or parallel growth to the development of the prosthesis, it is meant that layers transversal to the same development are deposited.
    [0152] Each spot of deposited material can have a variable thickness from 6 nm to 100 μm or more, in each layer different materials can be deposited both with PLD technology and with PED technology.
    [0153] In detail, for the prosthetic element of fig. 11, the PLD technology is used for the construction of the numbered parts: 34, 36, 38, 41; PED technology, on the other hand, for parts 35, 37, 39, 40, 42.
    [0154] To better clarify the principle and referring to the sectional view (SECTION A-A) of fig. 11 b, the construction starts with the deposit of the first layer, in which the portion of layer 42 - hydroxyapatite of preferred thickness 100 μm- with PED technology will be deposited, then the portion of layer 34 - hydroxyapatite with PLD technology, hereinafter the portion of layer 35 - hydroxylapatite- of 50 μm thickness with PED technology, subsequently the portion of layer of zirconium dioxide 36, and possibly the portion of teflon layer 41, which can be optionally left hollow, with PLD technology. At each change of material the rotating plate 8 of fig. 1 will rotate making the material (target) to be transferred to the PLD or PED ray available, depending on the technology to be used.
    Order described above of the realization of the portions [0155] Observing the fig. 11 a we can recognize three-dimensional contiguous layers of the same material obtained by the transverse layer deposition described above. A geometric scaffold is thus obtained that can be adapted to the morphostructural conditions of the receiving site 34. The bone scaffold has a porous form appropriately hollow with a pore diameter of 200-300 μm or even less and consists of hydroxyapatite.
    [0156] In the case in which the patient has severe bone atrophy or does not have sufficient bone to allow the installation of a dental implant or prefers a prosthetic device as likely as possible to the bone-paradonto-dental anatomy it is possible to prepare and / or add a synthetic or autologous bone scaffold taken from the same patient, for example from the pelvic bone or from bone derived from human or bovine corpse or a mixed scaffold.
    [0157] The states shown in fig. 11a and 11b by performing radial depositions with respect to the development of the prosthesis, rather than axially, as described above.
    [0158] By mixed scaffold it is meant that the innermost portion 34 is obtained by synthesis either of homologous bone or derived from human or bovine cadaver and is coated by depositing a small amount or thin layer of autologous bone indicated with 42 in fig. 11a and 11b which forms an interface that integrates with the patient's bone (receiving site) so as to start from a consistent base volume that allows rapid osseointegration of the implant-prosthetic treatment.
    [0159] In other words, a small fragment of the patient's bone is used to coat a scaffold of any material from the heterologous bone from a human or bovine corpse to synthetic bone.
    [0160] Advantageously, since the interface of this scaffold is made with bone from the same patient, osseointegration is practically guaranteed.
    [0161] This means that the aforesaid portion of bone coming from the patient on which the bone implant is to be made (scaffold) represents the target material to be housed on the aforementioned turntable 8.
    [0162] Therefore, the same coated scaffold represents a semi-finished product available for implantation.
    [0163] Usually the interconnection between the tooth and the scaffold is made after the scaffold has been attached by means of a metal interconnection element indicated above as «titanium abutment (abutment) 27». According to a preferred variant of the invention, this interconnection element is not used, since the manufacture of the dental prosthesis is carried out by growth directly on the bone scaffold being implanted.
    [0164] In this way the entire element would integrate into the patient's bone simulating in all respects a natural tooth.
    [0165] The load-bearing part of the prosthetic element, detail 36, is constructed of zirconium dioxide, sintered and pre-colored, or alternatively of titanium for medical use, and has the appropriate shape and size, similar to those of dentin in a natural tooth. The adhesion between the part 36 and the bone scaffold 34 is guaranteed by the interconnecting layer 37 in hydroxyapatite with a thickness of 50 μm obtained by PLD. The internal part 41 can be in Teflon or empty according to the lightness requirements of the prosthetic product. Part 38 is made of dental ceramic and has the appropriate shape and size similarly to the enamel of a natural tooth. The interface layer 37 between the part 36 and the part 38 is a transition layer consisting of hydroxyapatite, 50-100 μm thick, which having a tubular prismatic texture of 5 μm in diameter sets the foundation for the growth of the ceramic layer 38 which also has a structure replicating the tubules up to the outermost part. The texture combinations of layers 37 and 38, allow the prosthetic artifact to obtain an appearance with a base color (HUE) comparable to a natural tooth. The outer layer 39 is particularly refined and can be made, as described above, in dental ceramic or in enamel of the patient's natural tooth. The detail 40 is an orthodontic clip, used to keep the element in position during the bone rooting and repopulation phase, which can be constructed simultaneously with the prosthetic element and then subsequently eliminated once healing has taken place. The clip can be made of zirconium dioxide, or titanium.
    [0166] According to a preferred variant of the invention, a dental prosthesis is covered by at least one meta-material layer.
    [0167] Metamaterials are artificial structures whose properties are determined by form rather than chemical nature. Thanks to metamaterials it is possible to obtain structures having mechanical properties depending on the shape of the cells they are made of.
    [0168] The cells are repeated according to a predetermined pattern designed to allow the material to change, for example, the response to an external stimulus, reducing its own hardness without altering or damaging the same material.
    [0169] Thanks to the present invention it is possible to obtain specific structural properties of the manufactured articles described above by structuring the nanometric coating capacity offered by the present device. In particular, the last phase of the coating of a prosthesis is controlled so as to obtain a metamaterial, thus being able to control its surface hardness under load. By making the contact surfaces between the teeth softer, thanks to this structural behavior the teeth will be protected from possible traumas caused by repeated rubbing (eg bruxism).
    [0170] The metamaterials in the dental field, thanks to the technology described in this description, can also be used for the construction of retention elements used to favor the primary stability of the implant-prosthetic graft. By covering these elements with metamaterials engineered to increase their stiffness under load, the stability of the prosthetic element will be considerably increased by reducing the time of osteo-genesis, osteo-induction and osteo-conduction.
    [0171] The elements and characteristics illustrated in the various preferred embodiments can be combined with one another without, however, departing from the scope of protection of the present application.
    权利要求:
    Claims (13)
    [1]
    1. System for depositing material on a substrate, in particular for manufacturing a dental prosthesis or a bone scaffold, comprising - a deposition chamber (C) with a controlled, closable and depressurizable atmosphere, - a first arm (ST) of support configured to support a target and - a second support-component arm (SS) configured to support a substrate subject to deposition, - at least one emitter (EM) adapted to irradiate a target associated with the target support according to a PLD technique and / or PED, wherein said first and second arms are equipped with piezoelectric actuators (10, 12, 13, 9; [1, 19, 3, 5; 1, 19, 3, 5, 4]) arranged to be controlled with nanometric precision .
    [2]
    2. System according to claim 1, wherein said support arm (ST) supports a rotary plate (8) or a sliding plate comprising two or more supports of a target from which to ablate the material being deposited.
    [3]
    3. System according to claim 2, wherein said first support arm (ST) comprises three movable slides (10, 12 and 13) associated with each other so as to allow a perpendicular displacement along three coordinated axes X, Y and Z between them and in which said rotary plate is fixed on a fulcrum (7) supported axially by a rotary actuator (9) associated with one of said movable slides (10).
    [4]
    4. System according to Claim 3, in which the said fulcrum (7) is formed by means of a quick-coupling system comprising blind slots and wherein the rotary element 8 comprises corresponding openings from which spring-loaded spheres partially allow a quick association between turntable and fulcrum (7).
    [5]
    5. System according to any one of the preceding claims, wherein said target support arm (ST) is controlled by a processing unit (CTMC) so as to move the target during a process to obtain a uniform surface ablation of the same target.
    [6]
    6. System according to any of the previous claims, wherein said target support arm (ST) is controlled by a first processing unit (CTMC) so as to move the target during a processing so as to keep a reciprocal position constant between the target and said emitter.
    [7]
    7. System according to any of the previous claims, wherein said second arm (SS) is controlled by a second processing unit (CSMC) so as to define a predetermined intersection area with a plasma cloud generated by an irradiation of said target by said at least one emitter.
    [8]
    8. System according to claim 7, further comprising a supervision unit (CMMC) of the movement control of said first and second arm and of an emission intensity of said at least one emitter (EM), configured to model a surface of a substrate , such as said dental prosthesis or said bone scaffold, by means of an interconnection of elementary triangles and to control said second processing unit to carry out said deposition relative to each elementary triangle.
    [9]
    9. System according to any one of the preceding claims, in which the said chamber (C) comprises at least one of: -Means for handling and measuring an atmosphere inside the chamber, including one or more vacuum pumps and pressure meters / vacuum of said atmosphere; - Means for monitoring the deposition process, including at least one of a measurement laser for detecting a position of said target and / or said substrate, • a video camera, • a mass spectrometer.
    [10]
    10. Manufacturing method and / or coating of a dental prosthesis and / or a bone scaffold comprising the use of a deposition system according to any of the previous claims from 1 to 9.
    [11]
    11. Method according to claim 10 comprising at least one of the following steps: - activation of said emitter implementing said PLD technology to realize larger-sized layers and possibly to obtain a cross-linking of organic material, - activation of said emitter implementing said PED technology to preserve a stoichiometry of the target material transferred into a layer to be made, in particular to realize an interconnection layer and to realize an inner or outer layer exposed to external agents.
    [12]
    12. Method according to one of the preceding claims 10 or 11, further comprising a step of making an outer layer of a dental prosthesis based on titanium dioxide.
    [13]
    13. Method according to one of the claims 10 or 11 comprising a step of coating a scaffold of heterologous or synthetic bone material with homologous bone, defining said target, taken from a patient on which said scaffold is intended to be implanted.
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    同族专利:
    公开号 | 公开日
    IT201700034142A1|2018-09-28|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US20050067389A1|2003-09-25|2005-03-31|Greer James A.|Target manipulation for pulsed laser deposition|
    GB201500541D0|2015-01-14|2015-02-25|Uhv Design Ltd|Support stage for vacuum apparatus|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    IT102017000034142A|IT201700034142A1|2017-03-28|2017-03-28|MATERIAL DEPOSITION SYSTEM, IN PARTICULAR FOR THE MANUFACTURE OF A DENTAL PROSTHESIS|
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