Abstract: A process for reacting titanium tetrachloride vapors with oxygen to produce titanium dioxide wherein the oxygen is introduced into the reactor in at least two points. The process has the ability to control properties, such as particle size, of the raw pigment produced. The temperature of the oxygen introduced to the reactor at the further inlet point is above, below, or at the same temperature of the oxygen introduced at the first inlet point. The further inlet point can be located before or after the all the titanium tetrachloride has been introduced into the reactor. The titanium tetrachloride is introduced at a relatively low temperature, below about 427° C., and the reaction temperature in the reactor is at least about 700° C. The process includes the use of an auxilary fuel such as carbon monoxide, methane, propane, butane, pentane, hexane, benzene, xylene, toluene, or combinations thereof for increasing the temperature in the reactor.

Abstract: The present invention provides hydrophilically modified curable silicone dental impression materials comprising an addition curable silicone prepolymer composition and a polymerizable hydrophilic modifier. The addition curable silicone prepolymer in the composition of the present invention comprises blended vinyl terminated organopolysiloxane fluids, an organohydrogen polysiloxane crosslinker, a platinum catalyst, a retarder, filler and optional additives. The cured compositions have a stable hydrophilic nature, excellent mechanical properties, and maximum long-term dimensional stability.

Abstract: A hand held dental instrument for curing light-curable compounds comprises a housing and an array of solid state, light emitting junctions or dies for generating light having wavelengths within a narrow band of wavelengths (e.g. 400-500 nm). Preferably, a peak wavelength of 470 nm is generated. The device further comprises an optical fiber light pipe for capturing the light and transmitting a beam of the light to a work surface containing a light-curable compound. An optical lens or lenses may be used for focusing the light into the light pipe.

Abstract: A superelastic endodontic instrument, such as a file, is formed by grinding a superelastic wire to form a file preform or blank, and rotating a first end of the blank while preventing rotation of a second end of the blank. The file blank is maintained in the austenite phase at least until twisted to form a stress induced martensite which is plastically deformed by the twisting. A heat treatment step may be performed prior to twisting, during twisting or after twisting of the preform. The file blank may be heated by electrical heating methods or by submerging the blank in a heated liquid.

Abstract: There are provided titanium dioxide pigments characterized by improved gloss developing and dispersibility properties in surface coating vehicles and reduced dispersant requirements. Said titanium dioxide pigments comprise pigmentary titanium dioxide particles having deposited thereon a treating agent comprising at least one amine salt of a monoprotic.

Abstract: The invention describes a transparent, elastomeric dental cement composition suitable for temporary or provisional restorations that comprises: (a) at least one multifunctional oligomer or prepolymer as a binder; (b) at least one finely divided filler; and (c) at least one initiation system for polymerization. The cement has a high translucency which does not alter the color shade of a temporary prosthesis or appliance and great flexibility which allows the dentist to remove the temporary appliance easily and clean both the temporary appliance and the dental tissues easily. The invention also describes a method of using the transparent, elastomeric dental cement.

Abstract: Dental restorative compositions of the composite resin/glass ionomer hybrid type and resins used in the compositions. The compositions contain an aromatic-moiety-containing polymerizable resin, a finely divided ion-leachable fluoroaluminosilicate glass filler, a polymerization initiator system, and may contain other components. The aromatic-moiety-containing polymerizable resin has at least one carboxylic acid group and at least one ethylenically unsaturated group such as a (meth)acrylate group. The compositions have improved mechanical strength, improved wear resistance, and sustained long-term fluoride release.

Abstract: The present invention provides a resin-based dental restorative that exhibits high condensability, low volumetric shrinkage and low shrinkage stress. To this end, one or more of a rheological modifier, dispersant and fluorocopolymer are mixed with a methacrylate resin and a fine mineral filler in amounts effective to improve the condensability of the resulting composite to achieve amalgam-like condensation, to reduce the volumetric shrinkage to less than about 2% during polymerization, to improve wear resistance, and to provide a composite with generally improved physical properties.

Abstract: The present invention provides a dental composite which has the high strength required for load bearing restorations, yet maintains a glossy appearance, even after substantial wear. Through the use of particles having a mean particle size between about 0.05 .mu.m and about 0.50 .mu.m, the composite is useful in stress bearing restorations and in cosmetic restorations. The structural filler used is typically ground to a mean particle size of less than 0.5 .mu.m and also includes a microfill having a mean particle size less than 0.05 .mu.m to improve handling and mechanical characteristics. The preferred dental composites maintain their surface finish even after substantial use and also have the strength properties of hybrid composite resins. The structural filler is ground, typically by agitator milling, to the preferred particle size.

Abstract: A process for treating radioactive contaminated soils to remove radioactive contaminants therefrom includes creating a suspension of particles of the soil in water, and directing the slurry to a particle size separator. The small particles including radioactive contaminants are collected and handled for radioactive waste material storage. The aqueous slurry of large soil particles is directed to separators for removing substantial amounts of water after which the particles are directed to a conveyor and spread out to a substantially uniform thickness and detected for any radioactivity. Portions of material in which radioactive particles are detected are diverted and the uncontaminated soil material is recovered.

Abstract: The present invention provides a vibratory mill for grinding dental filler having a grinding chamber, preferably coated with an abrasion resistant polymer, the grinding chamber being charged with glass beads having a diameter in the range of about 0.1 mm to about 10.00 mm, and a refractive index substantially matching that of the dental filler to be ground. There is further provided a method of using this mill and media to provide substantially pure ground particles having an average particle size less than the average wavelength of visible light that, when incorporated into a dental restorative composite, impart good optical properties to the cured material.

Abstract: A closure according to the present invention includes an annular inner member defining an opening, the inner member having a camming recess. The closure also includes an outer member engageable with the inner member, the outer member including a lid base, a lid hingably connected to the lid base, and an annular guard ring surrounding the lid and lid base. The annular guard ring is frangibly connected to at least one of the lid and lid base, preferably along a frangible line formed by a plurality of bridges. The outer member can be formed integrally as one piece. When the inner member and outer member are joined, the guard ring preferably separates from the lid and lid base, and the lid base is at least partially retained within the camming recess. Once separated from the lid and lid base, the guard ring is movable between a guarding position in which it obstructs access to the lid, and a revealing position in which the lid can be rotated upward, away from the opening.

Abstract: A child resistant adult friendly container and closure device is provided with a pivot arm on the container which engages a detent on the closure. The pivot arm carries on one end a press tab and on an opposite end a locking lug. The locking lug engages with the detent to prevent the closure from being rotated in an opening direction. To open the closure, the press tab is manually depressed, causing the pivot arm to pivot about a point on the container such that the locking lug disengages from the detent on the closure. The closure can thus be unscrewed in a opening direction to obtain the contents of the container.

Abstract: A child-resistant, tamper indicating closure according to the present invention includes a closure top having an outer edge. An annular skirt depends from the outer edge of the closure top, the skirt having a plurality of internal splines located on an inner surface. A tamper indicating band is connected to the skirt, for example, along a frangible line, the tamper indicating band having a plurality of external splines located on an outer surface. The internal and external splines may cooperate with a locking mechanism disposed on the container so that when a tab of the locking mechanism is not depressed, an inner locking member contacts an internal spline to lock the closure in place. When the tab is depressed, the inner locking members are free to rotate, but outer locking member contacts an external spline, so that if the closure is rotated, for example, in the counter-clockwise direction, the tamper indicating band separates from the skirt along a frangible line.

Abstract: A homogeneous microfilled dental composite material comprised of a mixture of polymerizable monomers and an inorganic filler, wherein said filler is comprised of silane treated fused silica aggregates having a size ranging from submicron to about 160 .mu.m. The aggregates are comprised of agglomerates of fumed silica having an average agglomerate size in the range of approximately 0.5 to 50 .mu.m, and the agglomerates are comprised of primary particles of fumed silica having an average particle size in the range of approximately 1 to 100 nm. The primary particles are interconnected by siloxane bridges formed by burning an organosilane coating on the fumed silica.

Abstract: The present invention relates to a method and apparatus for molding a tamper-evident closure with tabs that extend radially inward and upward. In order to produce tabs with such a configuration, the present invention employs a tab forming element having a mold surface with an inclination corresponding to the degree to which the tabs are desired to extend radially inward and upward. After the tabs have been molded in their inclined position, they are withdrawn from the mold, temporarily altering their angle of inclination. After removal of the closure from the a first portion of the mold, the tabs are returned to the original angle of inclination through contact with a second portion of the mold.

Abstract: The present invention provides a mill having an agitator and grinding chamber which is coated with a non-pigmented, abrasion resistant polymer and a method of using this mill to provide substantially pure ground particles. The polymer coating is typically a thermosetting polymer such as polyurethane or an elastomer such as a fluoroelastomer. The polymer coating provides an abrasion resistant layer between the milling media and the agitator as well as between the grinding chamber and the milling media to prevent spalling, thus increasing the purity of the resultant ground material. The agitator mill may optionally include a ceramic gap separator which is typically formed of stacked plates separated a predetermined distance by shims to separate the ground particles from the milling media in the grinder chamber, thus allowing only the ground particles to pass out of the grinding chamber.

Abstract: The recovery of aluminum chloride from deactivated alkylation catalyst complexes by hydrogenation using hydrogen gas and an aluminum catalyst is disclosed. Using aluminum to catalyze the hydrogenation allows the reaction to proceed at a lower temperature and pressure while reducing the amount of hydrogen chloride present in the reactor thus reducing the corrosiveness and cost of the aluminum chloride recovery. Methods for batch, batchwise continuous, and continuous aluminum chloride recovery are disclosed.

Abstract: The present invention provides a vibratory mill having a grinding chamber, preferably coated with an abrasion resistant polymer, the grinding chamber being charged with glass beads having a diameter in the range of about 0.1 mm to about 10.00 mm. There is further provided a method of using this mill to provide substantially pure ground dental filler particles having an average particle size less than the average wavelength of visible light.