Abstract: Silica with the following physico-chemical properties:______________________________________ Specific surface m.sup.2 /g 80-400 Primary particle size nm 7-40 Tapped density g/l 50-300 pH value 3-10 Carbon content % 0.1-15 DBP number % <200 ______________________________________is produced by spraying a silica under intensive mixing, optionally with water or dilute acid at first and then with a surface-modifying reagent or a mixture of several surface-modifying reagents, then mixing, tempering, and subsequently destructuring/compressing and grinding.

Abstract: The invention provides dental cement compositions and methods of using them for binding hard tooth material, metal and ceramic. The cement compositions include shelf stable complexes of ethylenically unsaturated monomers reacted with cations. The cements have superior adhesion to tooth without separately acid etching dentin or enamel.

Abstract: A dental material based on an organic polymerisable binding agent has a content ofA) one or more mixed apatites of the typeA1) A.sub.10 (XO.sub.4).sub.6 Z.sub.2 +/B*.sub.10-u C*.sub.u (Y*).sub.6 Z'.sub.2 and/orA2) A'.sub.10-r (X'O.sub.4).sub.6-s Z".sub.2-t +/B'.sub.r (Y').sub.s Q.sub.t -B".sub.10-u' C'.sub.u' (Y").sub.6 Z'".sub.2 and/orA3) A".sub.10-r' (X"O.sub.4).sub.6-s' Z"".sub.2-t' +/A'".sub.r' (X'"O.sub.4).sub.s' +/B'".sub.10-u" C".sub.u" (Y'").sub.6 Z'"".sub.2in which the formulae assume the significance specified in the description, in a quantity that is effective for the absorption of ions from the biological application environment of the dental material. The polymerisable dental material has variably adjustable transparency, good polishability, high strength and the capacity to release and absorb ions into and from a biological environment. Also described is a process for using the mixed apatites A1), A2) and/or A3) in polymerisable dental materials.

Abstract: Novel contrast media for use in ultrasonic imaging are described. Such contrast media may be comprised of an aqueous solution of one or more biocompatible polymers, wherein said biocompatible polymers are coated with and/or in admixture with at least one silicon containing compound. Alternatively, the contrast media may be comprised of an aqueous solution of one or more biocompatible synthetic polymers, or an aqueous solution of cellulose. The contrast media may be employed, if desired, with anti-gas agents and/or suspending agents.

Abstract: A composition for removing a substance from a surface is prepared by: forming a gelatinous base material comprising water and a rheology agent; forming a solvent; forming a neutralizing agent; combining the gelatinous base material and the solvent with microscopic crystalline particles and an agent which reduces the effective rubbing coefficient of the microscopic crystalline particles to form a non-neutralized composition; and combining the non-neutralized composition with the neutralizing agent to form the composition. Foreign substances can be removed from a finished surface and the visibility of superficial scratches in the finished surface can be reduced by gently rubbing the composition on the finished surface and then removing the composition. The composition includes microscopic (approximately 1 micron) crystalline particles which contact, dislodge and remove the foreign substance or minute portions of the finish.

Abstract: A method for preparing a lens having UV-absorbing properties involves charging to a mold a monomer mixture comprising lens-forming monomers and an essentially non-UV-absorbing compound; exposing the monomer mixture in the mold to a light source including ultraviolet light to cure the monomer mixture and form the lens, whereby the non-UV-absorbing compound converts to a UV-absorbing agent.

Abstract: A storage solution for a hydrogel contact lens comprising a material having polar groups at one end and non-polar groups at the other end. The storage solution desirably further contains an oil. The material comprising polar and non-polar groups modifies the surface properties of the lens and facilitating the formation of a lipid layer over the lens.

Abstract: A block copolymer containing one or more polyoxyethylene blocks and one or more polyoxy(higher alkylene) blocks, wherein at least some of the blocks are linked together by an oxymethylene group, can be prepared by reacting one or more dihydroxy terminated polymers selected from poly(ethylene glycol), poly(higher alkylene glycol), and block copolymers thereof in solution with a dihalomethane in the presence of a base. Such copolymers can be used as surfactants and surface modifiers. The reaction can be conducted at ambient temperature, and does not require the addition of heat.

Abstract: The present invention is directed to remoistenable and non-remoistenable adhesives which contain at least about 50 wt % of a maltodextrin syrup having a reducing sugar content of about 5-19 dextrose equivalent and solids content of about 60-80 % water, and an effective amount of other conventional adhesive additives. When the adhesive is a remoistenable adhesive, a chemically derivatized starch having an amylose content of 40 % or less and a D.S. of about 0.01 to less than about 0.50 is used. A preferred remoistenable adhesive also contains polyvinyl acetate and/or ethylene vinyl acetate in an amount from about 15-90 wt. % The maltodextrin syrup is prepared from a converted or a non-converted, chemically derivatized or underivatized granular starch, by a high solids, single phase enzyme conversion process. When derivatized, the maltodextrin has (i) substituents in an amount sufficient to provide a degree of substitution between greater than about 0.01 and less than about 0.50.

Abstract: The invention provides a fluoride releasing dental primer composition which includes a polymerizable acrylic compound, a light activated catalyst, and an organic amino hydrofluoride. This fluoride releasing dental primer composition is used by applying it to dentin and illuminating it with visible light to polymerize the polymerizable acrylic compound. The invention provides a method of priming dentin by applying a fluoride releasing dental primer composition. The fluoride releasing dental primer composition has a polymerizable acrylic compound, a light activated catalyst, and an organic amino hydrofluoride having from about 2 to about 30 carbon atoms. The polymerizable acrylic compound is adapted to polymerize to form polymeric material. The organic amino hydrofluoride is adapted to leach from the polymeric material, chelate to dentin and release fluoride.

Abstract: A method of making polymer-coated pigment particles, involving the steps of providing a plurality of pigment particles, each of which has an outer surface coated with a layer of material that operates as a nucleus for initiating polymerization on the outer surface of each of the pigment particles. The pigment particles are mixed with a reaction mixture containing a solvent and a monomer material, wherein the layer of material coating each of the pigment particles causes the monomer material to polymerize on the outer surface of substantially each of the pigment particles to form a polymer coating thereon.

Abstract: A biocidal material comprises an organic biocide immobilised on a polymeric support characterised in that the support is water-insoluble and the biocide is covalently bound to the support by a hydrolytically stable covalent linkage. The material can be used for inhibiting bacterial growth in an aqueous medium e.g. the wash water of a photoprocessing system. The material can be housed in a flow-through container.

Abstract: A library of diverse molecular configurations containing many combinations and permutations of polymerizable cyclodextrin derivatives (PCDs) is disclosed for use in dental bonding formulations and other applications. Each PCD molecule in the library contains numerous (at least one or more) covalently attached polymerizable groups, and may also contain covalently attached ligand groups, such as free carboxyl groups, tertiary amino groups, or both, which substituents are attached in statistically predetermined proportions by ether or ester linkages. The PCDs may also contain molecularly encapsulated comonomers, polymerization inhibitors (stabilizers), polymerization initiators, and other desirable molecules. The molecular members of the PCD libraries may have quasi-random molecular configurations in the numbers and locations of their various substituents.

Abstract: A method for the recovery of microfine suspended particles from a suspension medium, characterized by subjecting a polymeric monomer suspended in a suspension medium to suspension polymerization thereby forming microfine globular particles in the suspension solution, adding microfine water-insoluble particles to said suspension solution of microfine globular particles thereby inducing cohesion of said microfine globular particles, and separating said microfine globular particles in the form of an aggregate from said suspension solution filtration.

Abstract: The latex is treated by passage through a heat exchanger consisting of a closed chamber 1 divided into two distinct superposed parts, the unobstructed upper part 3 being placed under reduced pressure and communicating with a plant for recovery of the residual monomer or monomers, and the lower part 4 being equipped with a partitioning 9 bounding two separate extended and adjoining circuits 10 and 11, one of the circuits 10 being traversed by the latex to be treated and being maintained in communication, via its top and over its entire path, with the upper part 3 of the chamber, and the other circuit 11, isolated from the upper part 3 of the chamber, being traversed by a heat-transfer fluid maintained at a temperature of 40 to 100.degree. C.Preferably, the two circuits 10 and 11 are bounded by a partitioning 9 arranged in the form of a double spiral.

Abstract: A dental composition which comprises (A) a phosphoric acid group-containing monomer, (B) a carboxylic acid groups-containing monomer and (C) water as main components in amounts of 0.5 to 50% by weight, 1 to 50% by weight and 5 to 90% by weight, based on the composition, respectively; and a dental adhesive kit comprising a dental primer composition containing the monomer (A) and water and an adhesive containing a carboxylic acid-containing polyfunctional monomer and a polymerizable initiator.

Abstract: Use of a transparent grip tab for a strip of adhesive film for a temporary bond based on thermoplastic rubber and tackifier resins, where the adhesive film is of high elasticity and low plasticity and where the adhesion is lower than the cohesion, the adhesion largely disappears when the film is extended, the ratio of peel force to tear load is at least 1:1.5, and where an adhesive bond produced therewith can be detached by pulling on the adhesive film in the direction of the bond plane.

Abstract: A multiple-part dental adhesive primer composition is provided in at least two parts, A and B. Part A comprises an acidic polymerizable compound and a polymerizable diluent. This part is selected such that if water is present the pH of Part A is greater than about 2. Part B comprises an acidic material such that the pH of Part B is below about 2. Methods of bonding substrates are also described.

Abstract: A fiber-reinforced phthalonitrile composite is made by impregnating or coating a fibrous material with a phthalonitrile prepolymer mixture containing a phthalonitrile monomer and an aromatic amine curing agent that is thermally stable and nonvolatile at a temperature up to about 375.degree. C., and that contains at least one electron withdrawing substituent effective to reduce the reactivity of the aromatic amine curing agent with the phthalonitrile monomer.

Abstract: Dental resins and dental compositions utilizing such resins are described. The dental compositions are particularly useful as cavity liners and root canal sealants which contain calcium hydroxide (or calcium oxide) and which are utilized to deliver calcium to exposed dental pulp. The resins, and resin-containing compounds, include eutectic mixtures of polyfunctional salicylates. In particular, the transesterification of a blend of trimethylolpropane and neopentylglycol with methyl salicylate yields a blend of trimethylolpropanetrisalicylate and neopentylglycoldisalicylate, which is contemplated by the present invention.