DE4209191A1 - Bone and dental surgery tissue removing tool - is of oscillating type for shaping,using both longitudinal and transverse oscillations - Google Patents

Abstract

At least one oscillating tool (9) is used for shaping hard tissue material. The tool is subject to both longitudinal and transverse oscillations. The different oscillating movements are generated by rotary movements. The induced tool oscillations are within an MF spectrum of up to 15 kHz, or a HF spectrum up to 30 kHz, esp. 18-22 kHz. The longitudinal and lateral oscillations can be of different frequency spectrums,i.e. similar and/or matching and/or directly or indirectly apart. The oscillating system (11), coupled to the tool (9), can be mechanical, pneumatic, electromagnetic, or piezoelectric (ultrasonic) with a resonance body to amplify the amplitude. USE/ADVANTAGE - For dental or orthopaedic surgery,without any damage to organic structures.

Description

State of the art

The subtractive processing and preparation of natural hard tissue, such as B. Zahnhart Substances and bone tissue are the basis of almost every tooth-preserving, restaurati ven and / or surgical intervention. So far, the processing of the above Fabric with rotating diamond tools or carbide instruments.

Disadvantages of conventional processing methods:

• - Some pronounced vibrations
• - rough surface topography
• - Machining-induced edge zone damage, flaking and breakouts
• - induction of pain
• - unpleasant sensation of noise for the patient
• - Risk of overheating of the processed tissue, with the consequence of a possible Denaturation of organic components; possibly irreversible damage to the tooth pulp or the vital bone tissue
• - limited possibility of selective material removal
• - Problems with the controlled preparation of fine cavities and runners
• - Problems with the preparation of thin and / or elongated cavities  
• - Defined minimum layer thickness of the instruments used
• - The concentricity of the instruments only with a certain minimum diameter and limited length guaranteed
• - complex process
• - short service life of the instruments used
• - Risk of injury to the soft parts

The processing of vital hard tissue with laser energy also shows other essentials disadvantages that limit clinical use so far:

• - induced temperature gradients with the result of a causal crack induction and edge zone damage
• - Partly pronounced heating of the processing structures with the consequence of an irreversi blen damage (denaturation and / or carbonization) of the organic tissue parts of the immediate and / or indirect environment
• - thermal damage
• - low removal rates
• - no controlled depth removal
• - Risk of injury to surrounding soft tissues
• - eye damage

Advantages of the invention

The invention enables the subtractive processing of vital and / or devital natural hard rifles. Due to the different elastic properties between the inorganic and organic hard tissue components are removed tends to the inorganic surfaces instead of without damaging the organic structures.

• - extremely gentle, controlled processing
• - simple, safe handling
• - no vibrations
• - no thermal damage to the processed tissue
• - Possibility of selective processing of different hard tissues due to the under different elasticity properties - potential possibility for preferred Treatment of diseased tissue
• - Possibility to use simple, ready-made tools or (for the first time) too custom-made tools (molds) that shape the shape to be prepared Code the cavity in the negative.
• - high stock removal rate
• - Simultaneous processing of artificial filling materials is possible
• - If necessary, painless processing, since the work impulses are smaller than the required Receptor impulses for inducing pain

Description of the preferred embodiment using the example of the preparation of a tooth cavity (see FIG. 1)

The described embodiment describes the preparation of a tooth cavity and is therefore representative of any subtractive processing of natural hard tissue (tooth hard tissue and bone tissue), especially for shaping as well as for processing hard tissues with adherent artificial materials.

1 = tooth pulp
2 = tooth retention apparatus
3 = dentine
4 = cavity
5 = enamel cap
6 = fluid
7 = fluid supply
8 = handpiece (holding device)
9 = oscillating tool
10 = clamping device
11 = vibration-giving and / or vibration-guiding system

The vibration-generating system ( 11 ) can either be integrated in the handpiece ( 8 ) or localized in a peripheral device. The tool ( 9 ) is coupled in a vibration-locking manner to the vibration-giving or guiding system. It is advisable to tune the vibrating system in resonance, although in principle the basic idea according to the invention can also be implemented with non-coordinated systems. The clamping device ( 10 ) ensures a secure connection of the tool ( 9 ) with the vibration generating or guiding system ( 11 ) without influencing the vibrations themselves. The tensioning device can be designed technically application-related to who, for. B. by friction fit, clamp fit, pliers clamping etc. It can be clamped under different tools or work with a firmly anchored tool.

The tool ( 9 ) oscillates in at least one spatial direction, ie it carries out either pure longitudinal vibrations or pure transverse vibrations or defined longitudinal vibrations with superimposed transverse vibrations. The frequency of the superimposed longitudinal and transversal vibrations can be coordinated or arbitrarily superimposed. In addition to the various degrees of freedom of oscillatory movements mentioned above, the tool can also perform rotating movements. Through the superposition of the rotational movement and the oscillating movements, the material removal can be increased significantly and the surface quality can be significantly improved.

The tool ( 9 ) can either consist of metallic and / or organic and / or inorganic materials and / or a combination of these materials. Multi-part tools are conceivable, moreover the tool surface can be individually coated and, for example, have a hard, wear-resistant layer.

The surface can be smooth, have a defined surface relief or geometrically defined cutting edges arranged on the surface. The tool surface ( 9 ) can additionally have a layer of geometrically undefined cutting edges, such as, for. B. adherent diamond grains or other geometrically indefinite cutting edges that have a higher microhardness than the hard tissue to be machined (e.g. ceramic cutting, quartz cutting, feldspar cutting etc.). In addition, the tool can be continuously flushed with a fluid during machining (cooling, rinsing effect). The fluid can consist of water or saline and additionally contain chemical agents and / or suspended particles. The chemical agents can support the removal and the rinsing effect. By adding particles, e.g. B. in the form of geometrically indefinite cutting with higher microhardness than that of the materials to be machined there are induced erosive effects on the hard tissue surfaces to be machined; The abrasive particles are accelerated by the oscillation of the tool and lead to micro-erosion processes and thus to material removal when they hit the brittle inorganic hard tissue structures. The elastic tool surface itself is subject to relatively little wear. Through spatial and temporal summation of these effects, the tool is "mapped" into the surfaces to be machined. The preparation of a defined cavity ( 4 ) can be supported by translational movements of the tool ( 9 ) relative to the hard surface to be machined ( 5 ).

To optimize the fluid supply in the working gap, a hollow tool ( 9 ) with an integrated fluid supply and at least one, or better, several openings is proposed. Another possibility is the use of hollow tools ( 9 ) with at least one opening in a vacuum suction of the fluid through the tool . This also ensures adequate wetting of the working gap between the tool surface ( 9 ) and the prepared hard tissues.

For machining, the oscillating tool is possibly with a superimposed rotation movement the surface of the hard tissue surfaces to be processed and under continuous or soaked in fluid. The fluid is continuously coming from the Opera suction field.

The prepared shape is created by vertically sinking an individually made one Tool. In the event that the geometry of the "mold" from the rotation symme no additional rotational movement is superimposed.

In most cases, however, the use of rotationally symmetrical is recommended Tools, the shape of the prepared cavity - analogous to previous preparations tion techniques - through controlled three-dimensional relative movements between the work tool and hard tissue surface is created. The material removal is a summation effect indirect micro-erosive grain interventions (coupling through dispersed abrasive grain in the fluid), and from directly oscillatory grain interventions or with oscillation support grinding from rotary grain interventions (geome trically defined and / or indefinite cutting edges).

Claims (36)

1. Device for subtractive processing of natural hard tissue, such as. B. Zahnhartge weave or bone tissue using at least one oscillating tool Ges ( 9 ). 2. Device for shaping natural hard tissue, such as. B. tooth hard tissue or bone tissue using at least one oscillating tool ( 9 ). 3. Device according to claim 1 or 2, characterized in that the tool ( 9 ) executes longitudinal vibrations. 4. Apparatus according to claim 1 or 2, characterized in that the tool ( 9 ) executes transverse vibrations. 5. Apparatus according to claim 1 or 2, characterized in that the tool ( 9 ) executes both longitudinal vibrations and transverse vibrations. 6. The device according to claim 5, characterized in that the superimposed longitudinal nal and transverse vibrations through at least 2 different vibrations systems are stimulated.   7. The device according to claim 5, characterized in that the superimposed Transver salschwingen additionally by targeted design of the shape and the mass distribution of the tool ( 9 ) arise from an excited longitudinal vibration or vice versa that the longitudinal vibrations additionally arise from excited Transversalschwin conditions. 8. The vibrating tool can be in addition to the various oscillation movements Carry out rotational movements (in the sense of rotating processing instruments). 9. The induced vibrations of the tool ( 9 ) lie within a medium frequency spectrum (15 kHz). 10. The induced vibrations of the tool ( 9 ) lie within a high frequency spectrum (30 kHz). 11. The induced vibrations of the tool ( 9 ) are within a frequency spectrum of 15 to 30 kHz, in particular in a range between 18 and 22 kHz. 12. The longitudinal and transverse vibrations of the tool ( 9 ) can have different frequency ranges. 13. The longitudinal and transverse vibrations of the tool ( 9 ) can have similar frequency ranges and / or be coordinated with one another and / or emerge from one another directly or indirectly. 14. The vibrations of the tool ( 9 ) are excited by at least one vibration generating system ( 11 ) which is directly and / or indirectly coupled to the tool ( 9 ) via a vibration guide of the system. The vibrations can by any vibrator, for. B. mechanically, pneumatically, electromagnetically or pie zoelectrically (ultrasound). The amplitude can be amplified by means of resonance bodies interposed. 15. The geometric shape, size, mass and mass distribution of the tool ( 9 ) results from the shapes to be prepared and is a function of the vibration-giving and guiding system components ( 11 ). All elements of the vibrating system are coordinated in terms of shape and mass distribution - the energy is focused on the tool crown. 16. The vibrating elements ( 11 and 9 ) are tuned in resonance frequency. 17. Multi-part tools ( 9 ) can be used. 18. Multi-part tools ( 9 ) can consist of a standardized tool holder with an individually attached, shape-coding tool crown. The connection between the tool holder and the tool crown results from the vibration-guiding (vibration-locking) requirements (e.g. casting, soldering, lasering, welding, gluing, etc.). 19. Basically, geometrically coded and / or simple standardized (e.g. rotationally symmetrical, elipsoid etc.) tools can be used. In the case of geometrically defined "molds", a cavity is preferably created by direct or indirect imaging of the mold surface in the hard tissue to be processed, while with standardized tools (assembly tools) the shape preferably by a relative movement of the tool relative to the one to be machined Hard tissue is created. Transitional forms are conceivable. The shape of the ready-made tools is based on the purpose previously common forms of conventional preparation instruments, while defined Molds can be manufactured based on DE 39 28 684 C2. 20. The tools ( 9 ) used can be made from metallic and / or organic and / or inorganic materials and / or from a combination of at least two different materials. 21. The tools ( 9 ) can have a defined, hard and wear-resistant surface layer made of metallic, organic or inorganic materials. The tool surface can be made of the same material or the same combination of materials as the tool ( 9 ) itself. 22. The tool surface ( 9 ) can be smooth and / or have a defined surface relief and / or superficially arranged geometrically defined cutting edges. The arrangement of the surface features can be homogeneously uniform over the entire tool surface or can have heterogeneously different surfaces at different sections. The geometrically defined cutting edges can be manufactured from the tool ( 9 ) or its surface layer itself and / or applied in an additional layer. Recesses in the tool surface, such as. B. Longitudinal grooves can facilitate a directed fluid flow and a defined chip removal. 23. The tool surface can (if necessary additionally) a layer of geometrically un have matching cutting edges, e.g. B. in the form of adherent grains or granules (ceramics cutting, quartz cutting, feldspar cutting etc.) characterized in that the ad hardened cutting edges have a higher microhardness than the hard tissues to be machined be. A coating with diamond grains is particularly suitable. The binding of this layer can in principle be rigid or elastic and / or the grains Release immediately when the beads are engaged. 24. The tool ( 9 ) can be coupled to the vibration generating or guiding system ( 11 ) by means of a dedicated clamping device ( 10 ) or a clamping device or by friction fitting or by a fixed connection. The Spannvorrich device ( 10 ) or equivalent dedicated connectors are integrated into the hand piece ( 8 ). The vibration-generating system ( 11 ) can be directly integrated in the handpiece or installed in a peripheral device, in any case there is a vibration-guiding (vibration-locking) connection between the vibration-generating system ( 11 ) and the tool ( 9 ). 25. At least one fluid supply ( 7 ) is integrated on the handpiece ( 8 ). 26. The fluid ( 6 ) consists of a liquid phase with / or without additives. 27. The liquid phase of the fluid ( 6 ) can consist of water or possibly sterile saline. Chemically defined additives can be included. 28. In addition, solid components, in the sense of abrasive particles, can be added to the fluid ( 6 ). Particularly fine-grained, geometrically indefinite cutting edges with higher microhardness than that of the hard tissue to be processed, such as. B. diamond grains, quartz grains, silicate grains, boron carbide grains, silicate carbide grains, ceramic grains etc. It is important to ensure that the additives used are biocompatible and are sufficiently suspended. 29. The fluid supply can run directly through the tool ( 9 ), characterized in that the tool ( 9 ) has at least one outlet opening for the fluid ( 6 ). In addition, additional fluid feeds ( 7 ) z. B. be used on the handpiece. 30. The tool ( 9 ) can have at least one central bore with at least one outlet opening and can be connected directly to a vacuum system by the handpiece ( 8 ). This ensures a directed fluid flow through the tool ( 9 ). 31. Process for subtractive and / or shaping processing of natural Hard tissues such as B. hard tooth tissue or bone tissue with the help of oscillating Tools. 32. The method according to claim 31, wherein the tool ( 9 ) executes longitudinal vibrations or transverse vibrations or a combination of longitudinal and transverse vibrations. The above-mentioned oscillation movements can additionally be superimposed on a rotational movement of the tool. 33. The method according to claim 31 or 32, wherein the material removal takes place by direct engagement of the adhered to the tool geometrically defined and / or undefined cutting edge and / or by an indirect intervention (erosion) through-read tool accelerated, abrasive components of the fluid ( 6 ) is generated or supported. The erosion process occurs because the abrasive components of the fluid ( 6 ) are accelerated in the working gap between the tool surface ( 9 ) and the hard tissue surface ( 5 ) and induce microerosion processes when they hit the hard tissue surfaces, which cause a spatial and temporal summation to sink and " Imaging "of the tool into the tissue to be machined. The wear of the tool surface is relatively low in comparison. 34. The method according to any one of claims 31 to 33, wherein the material removal by erosive Flows of the filled fluid take place in the working gap or the removal according to claim 33 is supported.   35. The method according to any one of claims 31 to 34, wherein the fluid continuously from the Surgical field is suctioned off. 36. The method according to any one of claims 31 to 33, wherein standardized tools and / or individually made shape-coded "molds" can be used.