Abstract: For composite materials having a total filler content of 80 to 95% by weight, containing A) 0.5 to 10% by weight of non-agglomerated nanofillers having particle sizes of 1 to 50 nm in the filler component, B) at least 60% by weight of a filler mixture of 50 to 90% coarse-particle and 10 to 50% fine-particle dental glass in the filler component, having a size ratio, relative to the average particle size (d50 value), of coarse to fine particles of >1:4 to 1:30, C) as monomer component, a monomer mixture of i. 60 to 80% bis-GMA or TCD-di-HEMA or TCD-di-HEA, ii. 10 to 18% UDMA, iii. Residual TEDMA and/or multifunctional crosslinkers, D) up to 1% photoinitiator(s); and E) optionally, at least one additional dental glass in the filler component having a different particle size than the coarse- and fine-particle dental glass, the polymerization shrinkage may be reduced to <1.

Abstract: Dental composite materials based on (meth)acrylate, exhibiting a proportion of TCD monomers in the total composition of 1-15% by weight and the quotient of flexural strength/shrinkage tension is at least 35.

Abstract: Compositions for dental composites comprising monomers, crosslinking agents, fillers, initiators, A the proportion of crosslinking agent being formed in an amount of more than 50% by acrylate monomers with a TCD urethane structure having the general formula in which A, X, Z, R1 R2 R3 and r have the meaning indicated in claim 1, provide polymerized composite materials with a particularly low cytotoxicity according to the standard requirements according to ISO 10993-5 and DIN EN ISO 7405.

Abstract: The invention relates to a method for producing a silica glass tube which is characterized by depositing SiO2 particles on an elongate support that rotates about its longitudinal axis, thereby producing a porous with a cylindrical inner bore. Said blank is vertically aligned, suspended in a furnace using a suspension that engages with a constriction in the upper zone of the inner bore of the blank, and vitrified. The aim of the invention is to provided a method with which also heavy blanks can be secured safely and substantially without any danger of contaminations of the inner bore without using complicated securing devices. To this end, the constriction (6b) is generated by shaping the inner bore (7) when the SiO2 particles are deposited. For vitrification a suspension (8; 9; 10) is used that supports itself on the constriction (6b) and that otherwise projects into the cylindrical inner bore (7) without having any contact therewith.

Abstract: The present invention relates to a method for manufacturing dental prostheses according to a digitized virtual model which reflects the maximally situation, comprising the steps providing a data record that reflects the maxillary situation and relationship, digital modeling of the tooth, creating a divided negative mold (rapid manufacturing) from the data from the digital tooth modeling, insertion of the fabricated teeth into the opened negative mold, closing the negative mold, filling the remaining cavity with plastic for the prosthesis.

Abstract: A dental kit made up of: A at least one pre-shaped dental crown made from a plastically deformable dental composite material curable by light, B a container impermeable to light, in which the pre-shaped dental crown is kept before it is applied to a tooth stump, C optionally a film which covers the outer surface of the pre-shaped dental crown.

Abstract: Disclosed are polymerizable dental materials containing silver particles having a primary particles diameter <40 nm as an antimicrobidal additive. The inventive dental materials are suitable as filling composites, basic prosthetic materials, adhesives, coating composites for crowns and bridges, and materials for artificial teeth, for example.

Abstract: For composite materials having a total filler content of 80 to 95% by weight, containing A) 0.5 to 10% by weight of non-agglomerated nanofillers having particle sizes of 1 to 50 nm in the filler component, B) at least 60% by weight of a filler mixture of 50 to 90% coarse-particle and 10 to 50% fine-particle dental glass in the filler component, having a size ratio, relative to the average particle size (d50 value), of coarse to fine particles of >1:4 to 1:30, C) as monomer component, a monomer mixture of i. 60 to 80% bis-GMA or TCD-di-HEMA or TCD-di-HEA, ii. 10 to 18% UDMA, iii. Residual TEDMA and/or multifunctional crosslinkers, D) up to 1% photoinitiator(s); and E) optionally, at least one additional dental glass in the filler component having a different particle size than the coarse- and fine-particle dental glass, the polymerization shrinkage may be reduced to <1.

Abstract: Dental materials containing at least one dendritic compound composed of a core and two shells, the core and first and second shells of which are joined to one another by means of polyurethane groups, and the second shell of which is modified by reaction with a (meth)acrylate, exhibit improved mechanical properties, in particular elasticity, flexural strength, and improved rheological properties before curing.

Abstract: Agglomerated inorganic glass fillers for dental materials comprising 0.5 to 50 ?m large agglomerates of inorganic glass particles having a particle size of 200 to 7,000 nm that are fused at their boundary surfaces with at least one adjacent particle, are particularly suitable for dental materials with good polishability, lasting shine and good abrasion-resistance.

Abstract: Dental materials containing an aqueous and/or organic solvent or dispersion with nanoparticles dispersed in it that have an average particle size of 1 to <10 nm and are not agglomerated are particularly suitable for use as filling composites, fastening cement, prostheses base materials, crown veneer composites and bridge veneer composites or adhesives. Preferably the dental materials in accordance with the invention contain SiO2 and/or ZrO2 and/or Al2O3 and/or TiO2 nanoparticles.

Abstract: The invention relates to a method for producing a silica glass tube which is characterized by depositing SiO2 particles on an elongate support that rotates about its longitudinal axis, thereby producing a porous with a cylindrical inner bore. Said blank is vertically aligned, suspended in a furnace using a suspension that engages with a constriction in the upper zone of the inner bore of the blank, and vitrified. The aim of the invention is to provided a method with which also heavy blanks can be secured safely and substantially without any danger of contaminations of the inner bore without using complicated securing devices. To this end, the constriction (6b) is generated by shaping the inner bore (7) when the SiO2 particles are deposited. For vitrification a suspension (8; 9; 10) is used that supports itself on the constriction (6b) and that otherwise projects into the cylindrical inner bore (7) without having any contact therewith.

Abstract: In a known procedure for manufacture of a quartz glass body, a glass starting material and fuel gas are fed to a rotationally symmetrical deposition burner (1) having several annular gap nozzles (7-9) and being formed by coaxial arrangement of a number of quartz glass tubes (2-5), such glass starting material in a burner flame forming SiO2 particles which, under back and forth motion of the deposition burner (1) along the longitudinal axis of a rotating mandrel (12), are deposited on such rotating mandrel under formation of an essentially cylindrical porous blank. To enable replacement of such deposition burner without major efforts in terms of work and costs, the procedure of the inventioin proposes to use a deposition burner (1) the annular gap nozzles (7- 9) of which have gap widths with a maximum dimensional deviation of 0.

Abstract: In a known procedure for manufacture of a quartz glass body, a glass starting material and fuel gas are fed to a rotationally symmetrical deposition burner (1) having several annular gap nozzles (7-9) and being formed by coaxial arrangement of a number of quartz glass tubes (2-5), such glass starting material in a burner flame forming SiO2 particles which, under back and forth motion of the deposition burner (1) along the longitudinal axis of a rotating mandrel (12), are deposited on such rotating mandrel under formation of an essentially cylindrical porous blank. To enable replacement of such deposition burner without major efforts in terms of work and costs, the procedure of the invention proposes to use a deposition burner (1) the annular gap nozzles (7-9) of which have gap widths with a maximum dimensional deviation of 0.

Abstract: An equalization chamber has a first plurality of gas inlet openings for a gas stream and a second plurality of gas outlet openings for partial gas streams, each outlet being connected by way of a gas line to a gas consumer, the maximum flow resistance for each partial gas stream being located in the area under the gas outlet openings, seen in the flow direction of the partial gas streams. To guarantee the highest possible degree of uniformity and reproducibility of the gas supply to the consumers, the maximum flow resistance for each partial gas stream is provided in the gas line between the gas outlet opening and the gas consumer.

Abstract: In a known method, a quartz glass preform is produced by supplying a glass-forming base material in liquid form to an injection nozzle of a multi-nozzle flame deposition burner, vaporizing or gasifying the liquid glass-forming base material in the deposition burner, mixing the vaporized or gasified glass-forming base material with a gas containing oxygen under creation of SiO.sub.2 particles in a chemical reaction, deposition of the SiO.sub.2 particles on a substrate under creation of a porous preform and sintering of the preform. In this method, expensive devices such as pumps and ultrasonic vaporizers are needed for the vaporization of the liquid glass-forming base material; in addition, these devices are subject to mechanical wear and chemical attack and furthermore, they require extensive maintenance and due to their size result in a great height of construction.

Abstract: In a known process for the production of quartz glass bodies, SiO.sub.2 particles are deposited of the mantle surface of a cylindrical carrier rotating about its longitudinal axis, forming an elongated, porous preform, where the SiO.sub.2 particles are formed in a plurality of flame hydrolysis burners which are arranged in at least one burner row parallel to the longitudinal axis of the carrier and are moved at a preset translational speed forward and back between turnaround points at which points their direction of movement is reversed, and in which process the preform is sintered. In order to make available on this basis an easily accomplished process that makes it possible to manufacture a preform which is largely free of localized density variations, the invention proposes on the one hand that the base value of the surface temperature of the preform being formed be kept in a range between 1,050.degree. C. and 1,350.degree. C.

Abstract: A silicon-containing glass starting material is fed through a central area of a multi-nozzle burner head while the fuel gases are fed through an outer area surrounding the center. In a reaction zone near the burner head, fine SiO.sub.2 soot particles are formed, which are deposited on a carrier to build up a porous soot body, which is then sintered. During the process of building up the soot body, the fuel gas stream is varied to achieve a desired radial or axial density profile in the soot body. To separate the glass starting material from the fuel gas in the area extending from the burner head to the reaction zone, a barrier gas stream is provided between the burner gas stream and the stream of glass starting material. The burner head has a central, tubular nozzle and several ring nozzles arranged coaxially around it. Between the central nozzle and the ring nozzles, a ring-shaped barrier gas nozzle is provided, which has inner and outer boundary walls which are circular in radial cross section.

Abstract: A hollow cylinder is held in a vertical orientation and sent continuously through a heating zone for sintering. In a first phase of the sintering operation, the hollow cylinder stands on a support while the upper end (12) of the cylinder is being sintered. In a second phase the cylinder hangs from a hanging element while its lower end (10) is sintered. A vertical rod is fixed to the base on which the lower end is supported, and extends through the hollow cylinder. A retaining ring is fixed inside the upper end of the hollow cylinder. During the first phase, the upper end vitrifies and contracts so that the retaining ring engages the vertical rod. Longitudinal contraction causes the lower end to lift off the base so that the cylinder is suspended during the second phase.

Abstract: A hollow cylinder is held in a vertical orientation and sent continuously through a heating zone for sintering. In a first phase of the sintering operation, the hollow cylinder stands on a support while the upper end (12) of the cylinder is being sintered. In a second phase the cylinder hangs from a hanging element while its lower end (10) is sintered. A vertical rod is fixed to the base on which the lower end is supported, and extends through the hollow cylinder. A retaining ring is fixed inside the upper end of the hollow cylinder. During the first phase, the upper end vitrifies and contracts so that the retaining ring engages the vertical rod. Longitudinal contraction causes the lower end to lift off the base so that the cylinder is suspended during the second phase.