Method and Arrangement for a Dental Installation
A substrate has or is provided on a surface with a first porosity. A dispersion with low-viscosity liquid is applied to the surface in order to form a ceramic layer with a second porosity having preferably larger and/or more pores than in the first porosity. The liquid has the ability to be sucked by capillary force into the first pore formation and, in a first stage, to retain on the surface material and/or liquid particles which do not penetrate into this first pore formation, and which contribute to the continued construction of the layer. In a second stage, the substrate is subjected to sintering in which the particles finally forming the layer are held together with intermediate spaces which consist of or are included in the second porosity, the spaces being formed either by the fact that material and liquid particles separate from the particles finally forming the layer are driven off during the sintering and/or by the fact that the particles forming the layer are chosen with a particle size which means that the last-mentioned particles are held together after the sintering despite the intermediate spaces. The invention also relates to an arrangement. By means of the invention, a dental product can be provided with excellent porosity which is advantageous in connection with dental installations.
1 . A method for providing a porous surface layer on a ceramic substrate which forms a part of a a dental installation, comprising:
providing the ceramic substrate with, a surface with a first porosity;
forming a ceramic layer with a second porosity having larger and/or more pores than in the first porosity; the step of forming the ceramic layer, comprising:
applying a dispersion with a viscous liquid the surface, said viscous liquid having the ability to be sucked by capillary force into a first pore formation in the ceramic substrate to retain on the surface material and/or liquid particles of the dispersion which do not penetrate into the first pore formation and which contribute to the construction of the ceramic layer, and
sintering the dispersion to form the ceramic layer in which the particles finally forming the ceramic layer are held together with intermediate spaces which are included in the second porosity, the intermediate spaces being formed either by material and/or liquid particles separate from the particles finally forming the layer that are driven off during the sintering and/or by particles forming the layer that are chosen with a particle size that is sufficiently large such that the particles are held together after the sintering despite the intermediate spaces.
2 . The method as in claim 1 , further comprising allocating a size and/or shape of the particles that determines the pore formation, in that the particles are insoluble in the liquid included in the dispersion and are dispersible in the liquid with or without dispersant and can be driven off by a removal function comprising burning in a furnace, etching, leaching, smelting, sublimation and/or dissolving, and arranging the particles to show a low residual degree of impurity after the removal function has been performed.
3 . The method as in patent claim 1 , further comprising pre-sintering the ceramic substrate to form the first porosity, and mixing ceramic particles in the form of zirconia, alumina and/or hydroxyapatite into the dispersion, and assigning the ceramic particles sizes in the range of 0.1-1.0 μm.
4 . The method as in claim 1 , wherein the particles for pore formation can comprise graphite particles or starch particles and are assigned sizes in the range of 0.1-100 μm.
5 . The method as in claim 1 comprising pre-sintering the substrate to form the first porosity, and forming the ceramic particles and the pore formers with an emulsion which comprises an acrylic polymer emulsion with liquid particles which can be driven off.
6 . The method as in claim 1 , comprising pre-sintering the substrate to form the first porosity, and mixing particles of zirconia, alumina or hydroxyapatite into the dispersion that have such a size that the porosity remains after sintering.
7 . The method as in claim 1 , wherein the thickness and/or extent of the layer on the surface is varied by one or more immersions in the dispersion and/or by variation of the dry substance content.
8 . The method as in claim 1 , wherein different pore formers are used to achieve the variation or variations in the pore structure of the layer.
9 . The method as in claim 1 , wherein the substrate is provided with a thread and the layer changes along the extent of the thread between the internal and external diameters.
10 . The method as in claim 1 , wherein the dispersion is applied to the surface by dripping, spraying and/or immersion.
11 . The method as in claim 1 , wherein water and/or alcohol is added to the viscous liquid.
12 . A method for providing a porous ceramic layer on a ceramic substrate of a which forms a part of a a dental installation, comprising:
providing a a non porous surface,
applying a dispersion of a viscous liquid to the surface, said liquid having the ability to dry and to be retained surface material and/or liquid particles which do not penetrate into the non porous surface,
sintering such that the particles finally forming the layer are held together with intermediate spaces which are included in the porosity, the spaces being formed either by separating material and liquid particles separate from the particles finally forming the layer during the sintering and/or by forming the layer with particles that are chosen with a particle size are held together after the sintering despite the intermediate spaces.
13 . A dental assembly comprising a ceramic substrate, wherein ceramic substrate, a first porosity and a ceramic layer applied to the ceramic substrate by sintering and with a second porosity having larger and/or more pores than in the first porosity, wherein first porosity is configured such that before sintering of the ceramic layer, to have the ability to receive, by capillary force, a low-viscosity liquid and at the surface retain particles dispersed in the liquid which contribute to the formation of the ceramic layer, and in that the increased porosity is formed by sintering of particles forming intermediate spaces, or in that the particles which form the layer have a particle size permitting the formation of intermediate spaces despite the sintering.