Abstract: Dental cements and adhesives are provided which are polymerizable with visible light. Such adhesives may be applied in thinner films than heretofore possible and demonstrate superior physical properties. Processes employing such materials are disclosed wherein the polymerization of the adhesive is accomplished by transmitting visible light through tooth or other structures to effect the adhesion.

Abstract: Novel compositions, especially light curable compositions, are provided which are coherent, but frangible when cured. Preferred compositions comprising a major proportion of inert, preferably inorganic filler material, polymerizable resin and frangibility enhancing material are provided which are light curable. The materials are particularly useful for "temporary" dental fillings and removable endodontic fillings. The cured materials are easily dissected, comminuted and removed as desired after curing without trauma to the filled teeth.

Abstract: Methods for the manufacture and repair of dental appliance prostheses are provided comprising providing a shaped metallic underlayment, and plating onto at least a portion of the underlayment a layer of a second metallic species. An amount sufficient substantially to obscure the layer, of a polymerizable opaqueing agent is then applied to the layer. Following polymerization of the opaqueing agent through application of heat or radiant energy, especially visible light, the layer is ideally suited for the application of dental aesthetic veneers or other surfacing materials. In accordance with the preferred embodiment, an adhesion promotion species is employed either in a separate treating step for the second metallic layer or through inclusion thereof in the opaqueing agent.

Abstract: Methods for accurately joining objects, especially optical objects, are disclosed comprising contacting the objects with light curable composition, causing light to transit at least one of the objects, evaluating the light, positioning the objects in response to the evaluation and irradiating the composition to harden it, thus to fixedly maintain a preselected spatial orientation among the objects.

Abstract: Endodontic filling systems are provided having improved properties over those known to the prior art. Endodontic points are provided comprising hydrophilic, polymeric compositions. Such points are swellable when placed into a prepared root canal space and provide substantially complete filling of lateral cavity spaces without invasion of the subapicial space. According to a preferred embodiment, such points are used in conjunction with pastes or fluids comprising hydrophilic, polymeric compositions.

Abstract: Processes are provided for the adhering together of articles employing vitrifiable adhesives. According to a preferred embodiment, two or more articles are contacted with a polymerizable adhesive comprising a particulate, inorganic filler and a polymerizable resin comprising at least 0.25% by weight of the adhesive of a polymerizable silane. The adhesive is then polymerized and the polymerized adhesive heated to afford a vitrified bond.

Abstract: Compositions hardenable by exposure to heat or electromagnetic radiation are provided by blending from about 0% to about 50% by weight of an uncrosslinked polymer, from about 20% to about 66% of a polymerizable monomer capable of dissolving said polymer, from about 10% to about 70% of a crosslinked polymer in the form of discrete particles having average diameters of from 0.001 micron to about 500 microns and being swellable by said monomer, and from about 0.25% to about 27% of a crosslinking agent for said monomer. Such compositions exhibit superior chemical and physical characteristics when hardened and are suitable in a wide variety of applications as construction media. In accordance with a preferred form of the invention, a precursor blend is formed from a mixture comprising (A) from 13 to 52 weight percent of a crosslinked polymer of an ester of a C.sub.1 -C.sub.6 alkyl acrylic acid and a C.sub.1 -C.sub.

Abstract: Compositions hardenable by exposure to heat or electromagnetic radiation are provided by blending from about 0% to about 50% by weight of an uncrosslinked polymer, from about 20% to about 66% of a polymerizable monomer capable of dissolving said polymer, from about 10% to about 70% of a crosslinked polymer in the form of discrete particles having average diameters of from 0.001 micron to about 500 microns and being swellable by said monomer, and from about 0.25% to about 27% of a crosslinking agent for said monomer. Such compositions exhibit superior chemical and physical characteristics when hardened and are suitable in a wide variety of applications as construction media. In accordance with a preferred form of the invention, a precursor blend is formed from a mixture comprising (A) from 13 to 52 weight percent of a crosslinked polymer of an ester of a C.sub.1 -C.sub.6 alkyl acrylic acid and a C.sub.1 -C.sub.

Abstract: A control circuit for an electrical device which includes a switch that is electrically isolated from other components. The switch is connected in series with a photovoltaic cell and relay means. The photovoltaic cell is illuminated so that closing of contacts of the switch causes actuation of the relay means. The relay means is connected to actuate the electrical device. Voltage at the switch is limited by the voltage produced by the photovoltaic cell.

Abstract: A monitor for a patient return circuit of a radiofrequency electrosurgical device in which an interrogation or measurement circuit is powered by a photovoltaic cell. Characteristics of the photovoltaic cell can limit the interrogation or measurement current to a value considered to be safe to a patient.

Abstract: A radiofrequency electrosurgical device which includes an active electrode and a passive electrode coupled to a chassis ground of a radiofrequency generator of the device. If the passive electrode is disconnected from the chassis ground, a potential develops between the chassis ground and a system ground. This potential is used to actuate a relay to disable the radiofrequency generator if the passive electrode becomes disconnected.

Abstract: An operatory stool having an arcuate rest member supported above the seat by a pair of parallel upstanding support members pivotally connected to and between said rest and seat to permit lateral adjustment of said rest relative to said seat, and manually operable clutch mechanism on said rest member operable relative to the upper ends of said upstanding support members to maintain said rest member in a desired adjusted position relative to said seat.

Abstract: A new orthodontic bracket assembly is disclosed together with a method of attachment to a tooth wherein a metal orthodontic bracket with a perforated base is attached to the tooth by means of a photopolymerizable adhesive applied to the area to which the bracket is to be affixed. Subsequent exposure of the adhesive, including particularly portions of adhesive extending through the perforations in the bracket base, to electromagnetic energy of predetermined wave lengths and intensity sufficient to polymerize the adhesive thereby affixes the bracket to the tooth.

Abstract: A shield for a radiation piping rod is formed by shrinking a length of plastic resin tubing on a rod or on a mandrel having a portion conforming to a portion of the rod to be shielded. The shrunken tubing is provided with a lengthened slit to permit stripping from the rod or mandrel to form the shield. The shield is mounted on the rod after stripping, and an air interface is formed between the rod and the shield to minimize loss of radiation caused by the shield.

Abstract: A bur grinding machine especially adapted to grind dental burs and including a turntable supporting a plurality of similar workheads having collets to support bur blanks; a plurality of grinding units mounted on a stationary base in circumferentially spaced locations around the periphery of said table and repsectively operable to perform different grinding operations in sequence upon the heads of bur blanks; means to index, rotate, and advance the collets of the workheads automatically at each grinding unit to form a plurality of teeth upon the bur blanks; means to index said table to advance the burs in the workheads to the next grinding unit; means to feed and accurately position bur blanks within the collets of the workheads; and means to control the cycle of the machine throughout.

Abstract: A foot control for a dental unit having a control unit for the delivery of power to operate dental equipment, and including a plunger to effect a range of speeds for the equipment, said control unit being operated by an actuating member which engages said plunger to depress it, and said actuating member being universally actuated by a pedal selected from a series thereof arranged in spaced relationship upon a base and extending radially from the base and capable of being moved either pivotally in a horizontal plane or depressed vertically downward to actuate said actuating member in one direction to depress the plunger of said control unit to a degree corresponding to the speed desired for the dental equipment.

Abstract: An angularly adjustable headrest for an operatory chair having means to quickly and effectively latch and unlatch the headrest pad relative to the supporting member incident to positioning the headrest member at a desired angle relative to the back of the chair.

Abstract: A radiofrequency electrosurgical device which includes an active electrode and a passive electrode coupled to a chassis ground of a radiofrequency generator of the device. If the passive electrode is disconnected from the chassis ground, a potential develops between the chassis ground and a system ground. This potential is used to actuate a relay to disable the radiofrequency generator if the passive electrode becomes disconnected. The relay is reset when a main power off-on switch is turned to off position.

Abstract: An operatory chair, such as a dental chair, having an upper supporting member to which the seat and back unit of an operatory chair may be attached, particularly pertaining to the mechanism by which said supporting member for the seat and back is raised and lowered. The preferred construction comprises a pair of sets of pivotally connected links arranged in lazy tong manner, said links being operated by linkage mechanism actuated by a rotatable screw and follower in such manner that the movement of the supporting member for the seat and back is smooth and relatively slow, particularly at the commencement of elevating movement so as not to include sudden and rapid upward movement as is conventional with typical lazy tong structures used in jacks and the like.

Abstract: A helical dental bur having a shank provided on one end with a cutting head having a series of similar teeth extending longitudinally and spaced evenly around the circumference thereof; said teeth each having a flat cutting face extending from the cutting edge radially toward the axis of the head to form one side of said tooth and provide a positive cutting rake therefor, a relative deep chip gash adjacent said face, and a convex relief surface extending from the cutting edge toward said gash adjacent the next succeeding tooth to form the opposite side of each tooth, said convex relief surface permitting said chip gashes to be substantially deeper than such gashes in conventional burs without sacrificing strength of said teeth to resist chipping and breakage of said cutting edges, as well as including the benefit of said flat cutting face which extends radially to provide said positive cutting rake.