Abstract: Acetabular implant and method for its manufacture, wherein the implant has a bone side with a contact surface to be fixed against the bone of the hip socket. A plastically deformable zone with an open porous structure connects to the contact surface, the zone being formed by a three-dimensional structure composed of strut elements with opposite ends, wherein these strut elements are connected at their ends in nodes. The zone is made of a material having an elongation at break of at least 15%.

Abstract: The present invention relates to a composition of an intracanal medication agent for medicating root canals for a predetermined period of time. According to one aspect of the invention, there is provided an intracanal medication composition based on a calcium hydroxide component, comprising: calcium hydroxide or a calcium hydroxide producing component as a powder component; and at least one of diethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP) and diethylene glycol monoethyl ether (DEGEE) as a liquid component.

Abstract: The present invention relates to the controllable degradation, filling-type complex bone implant of multivariant amino acid polymer-organic calcium/phosphorus salts, as well as to the preparative method thereof. The complex bone implant is consisted of multivariant amino acid polymers and medically acceptable organic calcium/phosphorus salts, while the content of organic calcium/phosphorus salts is 20-90% based on the total mass of composite material; the multivariant amino acid polymer is polymerized by ?-aminocaproic acid and at least two other amino acids, in which the molar content of ?-aminocaproic acid is at least 50% of the total molar quantity of amino acid polymers, while the amounts of other amino acids are at least 0.5% of the total molar quantity of amino acid polymers.

Abstract: The invention relates to hardenable ceramic bone substitute compositions having improved setting, powders for such compositions and methods for their manufacture and use in medical treatment. More specifically the invention relates to hardenable bone substitute powder and hardenable bone substitute paste with improved setting properties, comprising calcium sulfate and heat-treated hydroxyapatite (passivated HA), which bone substitute is suitable for treatment of disorders of supportive tissue such as bone loss, bone fracture, bone trauma and osteomyelitis.

Abstract: Methods and compositions for producing flowable compositions, e.g. pastes, that set into calcium phosphate products are provided. In the subject methods, dry reactants that include a calcium source and a phosphate source are combined with a setting fluid to produce the flowable composition. A feature of the subject methods is that the dry reactants include a particulate calcium and/or phosphate reactant having a mean particle size of less than about 8 ?m and narrow size distribution. Also provided are the compositions themselves as well as kits for use in practicing the subject methods. The subject methods and compositions produced thereby find use in a variety of applications, including the repair of hard tissue defects, e.g., bone defects.

Abstract: The invention relates to dimensionally stable molded bone replacement elements made of mineral bone cement with residual hydraulic activity that contain at least one share of hardened mineral bone cement and at least one share of unconverted or unhardened reactive mineral bone cement, wherein the share of hardened mineral bone cement is 5% to 90% by weight. The dimensionally stable molded bone replacement elements have at least 5% of the maximum value of the strength of a completely hardened bone cement comprised of the same mineral components and with the same structural characteristics and reach compressive strengths in the range of 2 to 200 MPa. They are substantially free of water and can be converted under biological conditions.

Abstract: The invention relates to implants which are based on a biodegradable thixotropic compound having pseudoplastic properties and which can be injected subcutaneously or intradermally into the fibrous tissue. The inventive implant comprises microparticles of at least one biocompatible ceramic compound which are suspended in a vector fluid containing at least one hyaluronic acid-based compound and at least one biodegradable thixotropic compound having pseudoplastic properties. The invention also relates to a kit for the extemporaneous use of such implants, the production of said implants and the use thereof in order to fill wrinkles and/or fine lines and/or cutaneous depressions and/or scars.

Abstract: This invention includes a subchondral bone repair system, comprising a structural component and a fluid settable component and an optional non-core component. The fluid settable component may penetrate into any pores of the structural component, and set to a solid, thereby fixing the structural component in place. The fluid settable component will penetrate interporously into the pores of the subchondral bone tissue surrounding the device, beneficially displacing any fluid to reduce edema in the affected bone region. Furthermore, the settable component, once solid is osteoconductive to promote repair and regrowth of bone in the affected region, and will also transmit mechanical force stimuli (such as compressive forces) directed through the structural component, into the adjacent bone tissue, thereby providing appropriate force stimuli necessary for appropriate tissue growth.

Abstract: The present invention relates to a method of implanting a prosthesis device in a subject. In one embodiment, this method involves: (i) providing a prosthesis device to be attached to an exposed surface of a bone; (ii) applying bone cement in liquid form to a bone-implant interface region, the bone-implant interface region including a region between the exposed surface of the bone and an outer surface of the prosthesis device; and (iii) contacting the bone cement to the exposed surface of the bone and the outer surface of the prosthesis device under conditions effective to allow the bone cement to cure, thereby resulting in attachment of the prosthesis device to the bone of the subject. The present invention also relates to a kit for implanting a prosthesis device in a subject, a method of performing a joint arthroplasty surgical procedure, and other methods of using bone cement in liquid form.

Abstract: Compositions of, methods of making, and methods of using alkaline earth phosphate bone cements are disclosed. A bone cement composition includes a powder comprising a basic source of calcium, magnesium, or strontium, a setting solution comprising H3PO4 and a buffer, and a biocompatible polymer that is incorporated into the setting solution. The powder is mixed with the setting solution to form a bone cement paste that either (a) sets into a hardened mass, or (b) is irradiated with electromagnetic radiation to form dry powders, the dry powders then being mixed with a second setting solution to form a radiation-assisted bone cement paste that sets into a hardened mass.

Abstract: Disclosed is an artificial bone material having controlled calcium ion elution, which does not induce cytotoxicity or any inflammatory response. It is found that the elution of a calcium ion from an artificial bone material for transplantation which contains a calcium-containing substance can be prevented effectively by subjecting the carrier to a surface treatment or adding a surface-treating agent to the carrier. It is also found that the induction of cytotoxicity can be prevented and the induction of an inflammatory response can also be prevented by using the above-mentioned carrier having controlled calcium ion elution.

Abstract: Bone cements and methods provided include a bone cement composition having collective attributes and properties desirable for initial fixation as well as interventional applications. Compositions include an amount of Portland cement and an amount of calcium sulfate.

Abstract: Bone cement compositions and methods of making two-part bone cements. The methods comprise transferring premixed powder and a liquid component into a receptacle, and mixing the powder component and the liquid component to form a cement composition. The premixed powder component comprises an acrylic polymer and a radical initiator. The bone cement is loaded with from about 5% to about 6% gentamicin by weight of the powder component, and from about 4% to about 5% vancomycin by weight of the powder component. The methods include filling a mold cavity with the bone cement composition to form a temporary spacer implant. The bone cement compositions provide a viscosity profile sufficient for the bone cement composition to flow within the mold cavity for an elapsed working time period of greater than about 6 minutes from the start of mixing at approximately 23° C.

Abstract: A bioactive PMMA (polymethylmethacrylate) bone cement contains a powder component and a reactive monomer liquid, wherein the powder component and the reactive monomer liquid when mixed with one another react with one another and form a polymer-based solid material. The powder component contains particulate polymer powder of polymethylmethacrylates; a radical starter; and anionic copolymer nanoparticles. The anionic copolymer nanoparticles are distributed in nano-particulate form within the particulate powder component or coated as a film on particles of the particulate polymer powder.

Abstract: A bone cement is provided that includes a solid component and a liquid component. The solid component and liquid component are mixed together to form the bone cement. After completion of the solid and liquid component mixing, the bone cement has an initial viscosity effective for manual application or manual injection onto or into a targeted anatomical location, e.g., bone, and the cement has stable viscosity range that over both time and temperature is effective for uniformly filling the targeted anatomical location, for example an osteoporotic bone or a fractured vertebral body, with minimal to no leakage of the cement from the targeted anatomical location. Additionally, both the initial viscosity and the stable viscosity of the bone cement are within a range that renders the bone cement effective for injection with a manually operated syringe or multiple syringes.

Abstract: Disclosed are cement products, methods of forming cement using the cement product, and methods of using the cement product in orthopedic and dental applications. Generally, the disclosed cement product includes a first component and a second component. The first component comprises a polymerizable resin comprising ethylenic unsaturated double bond, a suitable glycidyl group and/or a suitable isocyanate group. The second component includes a compound comprising more than one type of amine selected from the group consisting of primary amine, secondary amines, tertiary amines and quaternary amines. Alternatively, the second component includes a compound comprising a suitable mercapto (SH—) group, a hindered amine or a dimethylthiotoluenediamine (DMTDA). Optionally, the cement product includes a filler and/or a bioactive component to promote bone formation.

Abstract: Disclosed are cement products, methods of forming cement using the cement product, and methods of using the cement product in orthopedic and dental applications. Generally, the disclosed cement product includes a first component comprising a polymerizable resin comprising ethylenic unsaturated double bond, a second component comprising a compound comprising more than one type of amine selected from the group consisting of primary amines, secondary amines, tertiary amines and quaternary amines, and, optionally, the cement product includes a bioactive component to promote bone formation.

Abstract: A paste is provided from which bone cement can be formed, which is to the largest extent possible bubble-free and has a high impact strength. The paste includes (i) 15-50 weight percent of at least one mono-functional, hydrophobic methacrylic acid ester, (ii) 40-85 weight percent of at least one filler, (iii) 0.01-4 weight percent of at least one radical initiator soluble in the methacrylic acid ester (i) and having at least one peroxide group, (iv) 0.01-4 weight percent of at least one radical initiator soluble in the methacrylic acid ester (i) and having no peroxide groups, (v) 0.000001-3 weight percent of at least one accelerator soluble in the methacrylic acid ester (i) and capable of forming radicals from the radical initiators according to (iii) and (iv), (vi) 0.001-5 weight percent of at least one halide salt, and (vii) 0.2-3 weight percent of at least one cross-linking agent.

Abstract: The present invention relates to mosaic implant (15) comprising a plurality of mosaic plates (17) connected by a wire or mesh anchoring arrangement (9). Methods for forming such implants and methods for using said implants for correction of bone and soft tissue defects are described.

Abstract: Methods are provided for producing compositions, e.g. pastes or clays, which rapidly set into high-strength calcium phosphate products. In the subject methods, dry reactants that include calcium and phosphate sources, as well as a monovalent cation dihydrogen phosphate salt, are combined with a setting fluid and the combined reactants are mixed to produce the settable composition. A feature of the invention is that cements rapidly set into high strength product compositions. Also provided are the compositions themselves as well as kits for preparing the same. The subject methods and compositions produced thereby find use in a variety of applications, including hard tissue repair applications.

Abstract: Implantable components configured to be secured to a recipient with a bonding agent are presented herein. The implantable components are configured to be implanted adjacent to a recipient's bone and/or tissue and have a surface for attachment to the bonding agent.

Abstract: A bioactive and osteoconductive bone cement is produced from polyacrylates or polymethylacrylates by addition of small amounts of polymerizable monomers containing anionic groups which cause the cement surface to mineralize after being incubated in simulated body fluid. The obtained mineralized layers contain calcium phosphate phases such that the formation of fibrous intermediate layers is prevented once the bone cement has been implanted in bones. Optionally, other additives, e.g. biocompatible calcium salts, biocompatible buffering substances, or x-ray contrast agents, antibiotics, antimicrobial agents, and/or anti-inflammatory agents can be added in order to improve the properties of the cement for individual purposes. The bone cement can be used for anchoring prosthesis components in the bone, stiffening bones, filling and reconstructing all types of bone defects, as dowels for bone screws, or as an implant material for anchoring screws and other implants used for osteosynthesis.

Abstract: A synthetic, flexible tissue matrix and methods for repairing hyaline cartilage defects in a joint using the flexible tissue matrix are described. The flexible tissue matrix includes a high molecular weight polycaprolactone polymer entangled with a polysaccharide such as hyaluronic acid. In the methods, autologous bone mesenchymal stem cells are introduced to a joint by a microfracturing technique, and a membrane made of the flexible matrix is applied to the joint. Cartilage which forms in the joint is hyaline cartilage rather than fibrocartilage.

Abstract: The present invention relates to a bone cement precursor system that is presented in the form of two shelf-stable pastes which have been terminally sterilized and are held in separate containers during product transport and storage. When the product is used during surgery, these pastes inject to a site of application through a static mixing device by the action of applied injection force. When the two pastes are mixed, they start to react to each other while injecting out. The resulting composition is highly biocompatible, osteoconductive, injectable, rapid setting and bioresorbable, and is useful in connection with bone repair procedures, for example, in the craniomaxillofacial, trauma and orthopedic areas.

Abstract: Calcium-strontium-hydroxyphosphate (strontium-apatite-) cement preparations are described, comprising a powder mixture, which contains molar quantities of the components calcium (Ca), strontium (Sr) and phosphate (P) in the mixture in the ranges 1.00<Ca/P?1.50 and 0<Sr/P<1.5, together with an alkali salt or an ammonium salt of phosphoric acid, and with water and/or an aqueous solution. The powder mixture particularly contains, as the Ca-component, Ca3(PO4)2 (TCP), and as the Sr-component SrHPO4 and/or Sr3(PO4)2 and optionally additional SrCO3. As the aqueous mixing solution for the formation of the strontium-apatite cement, an aqueous solution of an alkali salt or an ammonium salt of the phosphoric acid is suitable.

Abstract: The invention relates to an operation system comprising at least one implant and means for the fastening of the implant to a bone, wherein the fastening means include at least one solid spacer, which can be formed of hardened bone cement and is arranged between the implant and the bone in the implanted state, and hardenable liquid bone cement which can be introduced into hollow spaces or intermediate spaces present between the spacer and the implant and/or between the spacer and the bone and wherein the spacer, on the one hand, and the liquid bone cement, on the other hand, are provided with contrast agents chosen in dependence on an imaging observation process or inspection process, in particular an X-ray process, to be used in or after the operation such that the spacer and the liquid cement can be distinguished from the surroundings and from one another on the observation or inspection of their position, in particular in an X-ray.

Abstract: A curable material delivery cannula device and method are disclosed. The device includes a cannula and a hub. The cannula includes an open proximal end, a deflectable segment forming a plurality of pre-set curves, each of which corresponds to a pre-determined temperature of the cannula, a lumen, and side orifice(s) adjacent, and proximally spaced from, the distal end and fluidly connected to the lumen. When distally extended from the guide cannula, and upon being heated to a predetermined temperature (before, during, or after extension), the deflectable segment assumes a curved shape, which may be used to create a void in the bone for receiving curable material. The distal cannula end includes a blunt tip for non-traumatic interface with bodily material. During use, curable material, such as bone cement, is delivered from the side orifice(s) in a radial direction relative to the lumen.

Abstract: A method of cranial repair and the cranial implant molding device used therein, the device having a frame or base that receives a bottom or convex molding plate and a top or concave molding plate in a manner whereby the two plates are separated a distance to receive a settable or curable implant forming material therebetween. The plates are separated by a compressible member such that by the use of threaded mechanical fasteners or similar members the distance between the two plates can be adjusted by tightening or loosening the mechanical members. The thickness of the implant is varied by varying the separation distance on different sides of the frame.

Abstract: An injectable biocompatible material delivery system is disclosed and can include an injector and a material delivery cannula that can be in fluid communication with the injector. Further, the injectable biocompatible material delivery system can include a light source that can be configured to emit light to at least a portion of the injector, at least a portion of the material delivery cannula, or a combination thereof. Further, the light source can be configured to activate an injectable biocompatible material as it moves through the system.

Abstract: The invention refers to an artificial bone mineral substitute material which comprises at least one ceramic and at least one water soluble non-ionic X-ray contrast agent. The invention refers to a composition for producing the same, which further comprises an aqueous liquid, as well as the use of the composition as a X-ray contrast medium.

Abstract: The invention relates to a phase and sedimentation-stable, plastically deformable preparation with intrinsic pore formation that can be used for instance for filling bone defects and for augmentation, and also relates to a method for producing same.

Abstract: A method for filling a bone defect in a subject in need thereof is disclosed. The method includes heating a bone cement composition at a first temperature where the bone cement composition is fluidic, and delivering an effective amount of the fluidic bone cement composition at a second temperature to the bone defect thereby filling the bone defect and allowing the fluidic bone cement composition to solidify, the second temperature being sufficiently high for maintaining the bone cement composition fluidic without causing thermal necrosis. Also disclosed are systems for carrying out the method.

Abstract: An injectable bone mineral substitute material composition with the capability of being hardened in a body fluid in vivo, which comprises at least one calcium phosphate component and at least one calcium sulfate component as a dry mixture mixed with an aqueous liquid, and at least one accelerator, the at least one calcium sulfate component being particulate hardened calcium sulfate, which has a specified particle size that is in order to confer injectablity to the composition. The invention also concerns the bone mineral substitute material produced from the composition as well as methods and uses thereof.

Abstract: A bone cement is provided that includes a solid component and a liquid component. The solid component and liquid component are mixed together to form the bone cement. After completion of the solid and liquid component mixing, the bone cement has an initial viscosity effective for manual application or manual injection onto or into a targeted anatomical location, e.g., bone, and the cement has stable viscosity range that over both time and temperature is effective for uniformly filling the targeted anatomical location, for example an osteoporotic bone or a fractured vertebral body, with minimal to no leakage of the cement from the targeted anatomical location. Additionally, both the initial viscosity and the stable viscosity of the bone cement are within a range that renders the bone cement effective for injection with a manually operated syringe or multiple syringes.

Abstract: Compositions for use in treating and repairing orthopedic defects are provided. The compositions are especially useful for performing percutaneous vertebroplasty, percutaneous kyphoplasty and other procedures. When cured, the compositions are relatively solid but compressible, and prior to curing are viscous liquids with a low enough viscosity to fill voids in cavities such as voids within fractured vertebrae. Optionally, the properties of a composition according to the invention can be adjusted taking into account the hardness and density of the orthopedic structure to be repaired. Also disclosed are devices and methods for using the compositions, and a kit containing components for forming and utilizing the composition.

Abstract: Described herein is the synthesis of adhesive complex coacervates and their use thereof. The adhesive complex coacervates are composed of a mixture of one or more polycations and one or more polyanions. The polycations and polyanions in the adhesive complex coacervate are crosslinked with one another by covalent bonds upon curing. The adhesive complex coacervates have several desirable features when compared to conventional bioadhesives, which are effective in water-based applications. The adhesive complex coacervates described herein exhibit good interfacial tension in water when applied to a substrate (i.e., they spread over the interface rather than being beaded up). Additionally, the ability of the complex coacervate to crosslink intermolecularly increases the cohesive strength of the adhesive complex coacervate.

Abstract: The present invention relates to a bone cement precursor system that is presented in the form of two shelf-stable pastes which have been terminally sterilized and are held in separate containers during product transport and storage. When the product is used during surgery, these pastes inject to a site of application through a static mixing device by the action of applied injection force. When the two pastes are mixed, they start to react to each other while injecting out. The resulting composition is highly biocompatible, osteoconductive, injectable, rapid setting and bioresorbable, and is useful in connection with bone repair procedures, for example, in the craniomaxillofacial, trauma and orthopedic areas.

Abstract: Bone cement compositions and methods of making two-part bone cements. The methods comprise transferring premixed powder and a liquid component into a receptacle, and mixing the powder component and the liquid component to form a cement composition. The premixed powder component comprises an acrylic polymer and a radical initiator. The bone cement is loaded with from about 5% to about 6% gentamicin by weight of the powder component, and from about 4% to about 5% vancomycin by weight of the powder component. The methods include filling a mold cavity with the bone cement composition to form a temporary spacer implant. The bone cement compositions provide a viscosity profile sufficient for the bone cement composition to flow within the mold cavity for an elapsed working time period of greater than about 6 minutes from the start of mixing at approximately 23° C.

Abstract: A ready-for-use polymer cement spacer device for the replacement of a permanent joint prosthesis during a two-stage replacement, includes a shank includes for attachment for placing to the supporting bone and a head in the joint region. The spacer device includes two complementary members incorporating rigid members for assembly between them, the first member being loaded with a first active substance and the second member being loaded with a second active substance. The first and second active substances are preferably antibiotics, selected from gentamycin, trobamycin, vancomycin, erythromycin, fucidin, tetracycline or other suitable antibiotics. The temporary joint implant maintains a suitable space for the time necessary for the operation of replacing a permanent prosthesis to prevent tissues from occupying the space released by removal of the permanent prosthesis and ensures effective treatment of resistant infections by local treatment of the joint area through at least two different active substances.

Abstract: An adhesive precursor and method of delivering an adhesive precursor for fixing bone fragments together.

Abstract: Methods and compositions for producing flowable compositions, e.g. pastes, that set into calcium phosphate products are provided. In the subject methods, dry reactants that include a calcium source and a phosphate source are combined with a setting fluid to produce the flowable composition. A feature of the subject methods is that the dry reactants include a particulate calcium and/or phosphate reactant having a mean particle size of less than about 8 ?m and narrow size distribution. Also provided are the compositions themselves as well as kits for use in practicing the subject methods. The subject methods and compositions produced thereby find use in a variety of applications, including the repair of hard tissue defects, e.g., bone defects.

Abstract: A bone cement has a liquid acrylic monomer component, a powdered acrylic polymer component and yellowish beta-carotene (Pro-vitamin A) mixed into one of the liquid or powdered component and FDC blue No. 2 Lake powder mixed into the powdered component. The beta-carotene and FDC blue adds a greenish (yellow plus blue) color to the combined liquid and powdered component. The yellowish color disappears on setting of the bone cement leaving the cement blue.

Abstract: A biocompatible, self-supporting, curved, collagen membrane adapted to be secured by bone tacks or bone screws over exposed bone at a desired bone graft site in the alveolar ridge of a patient such that the membrane defines a space having a predetermined height and width over the exposed bone, in which the membrane maintains its structural integrity for at least 4 months after implantation at the bone graft site and then naturally breaks down and is resorbed by the patient's body, a method of making such a membrane, and a method of using such a membrane for vertical augmentation of the alveolar ridge of the patient.

Abstract: A hydraulic cement comprising a calcium silicate and at least one phosphate compound. The phosphate compound is included in an amount sufficient to react a major portion of the calcium hydroxide that is produced during hydration of the cement to hydroxyapatite or other calcium phosphates. The phosphate compound is preferably a mono-calcium phosphate. The cement is useful in both bio-medical/dental and engineering applications. The calcium hydroxide is reacted by the phosphate to form hydroxiapatite or other calcium phosphate that is co-precipitated with the calcium silicate hydrate to form a composite-like structure on a nano-scale level. The reduced calcium hydroxide content in the set cement increases its strength and reduces its pH. The hydroxiapatite content and the reduced pH render the cement bio-active and suitable for use in medical and dental implants, for example, for replacement bone and tooth material. Due to its high strength, the cement may also be used for structural/engineering applications.

Abstract: The present invention relates to mosaic implant (15) comprising a plurality of mosaic plates (17) connected by a wire or mesh anchoring arrangement (9). Methods for forming such implants and methods for using said implants for correction of bone and soft tissue defects are described.

Abstract: Compositions and methods of their use to adhere a variety of materials together are disclosed herein. The compositions include at least multivalent metal compound, an effective amount of a compound that is structurally similar to phosphoserine, and can be mixed with an aqueous solution. The compositions provide adhesive and cohesive strength in both wet and dry environments which exhibit bond strength upon curing with the possible usage as bone cement for bone filler applications.

Abstract: A curable material delivery cannula device and method are disclosed. The device includes a cannula and a hub. The cannula includes an open proximal end, a deflectable segment forming a plurality of pre-set curves, each of which corresponds to a pre-determined temperature of the cannula, a lumen, and side orifice(s) adjacent, and proximally spaced from, the distal end and fluidly connected to the lumen. When distally extended from the guide cannula, and upon being heated to a predetermined temperature (before, during, or after extension), the deflectable segment assumes a curved shape, which may be used to create a void in the bone for receiving curable material. The distal cannula end includes a blunt tip for non-traumatic interface with bodily material. During use, curable material, such as bone cement, is delivered from the side orifice(s) in a radial direction relative to the lumen.

Abstract: Methods for preparing a tricalcium phosphate coarse particle composition are provided. Aspects of the methods include converting an initial tricalcium phosphate particulate composition to hydroxyapatite, sintering the resultant hydroxyapatite to produce a second tricalcium phosphate composition and then mechanically manipulating the second tricalcium phosphate composition to produce a tricalcium phosphate coarse particle composition. The subject methods and compositions produced thereby find use in a variety of applications.

Abstract: The invention relates to implant materials that are based on hydraulic cements in the form of one or more pastes, suspensions or dispersions that contain mineral and/or organic and/or organomineral solids and that react, when combined or when reacted with an aqueous liquid, to a solid in a cement-type initiation reaction. The invention also relates to the use of these materials as technical, medical-technical and/or pharmaceutical products, especially as bone cements, bone replacement materials, bone glues, dental filling materials and implantable active ingredient carriers.

Abstract: The present invention provides a technique for prolonging the working time and setting time of a calcium sulfate hemihydrate paste by mixing calcium sulfate hemihydrate powder with an aqueous solution containing phosphate ions, so that the paste is suitable for operation and the resultant hardened calcium sulfate dihydrate block from the paste has an improved mechanical strength.