Abstract: The invention provides a method of treating hydrogels formed from the polymerization of monomers having reactive olefinic double bonds by contacting them with reactive thiol compounds. In a preferred embodiment where the hydrogel structure includes a cis-glycol containing unit, a suitable thiol is used in conjunction with a borate buffer. The present invention also provides materials that are treated with the above thiol compounds.

Abstract: This invention relates to a motion mechanism for moving an X-ray film in a panoramic X-ray machine in a predetermined pattern and rate of travel relative to a source of radiation. The mechanism includes a cassette holder on which is carried a rotatable rod or roller driven by a traction wheel, a lever assembly for changing the drive angle between the traction wheel and the rod and a moving or rotatable supporting column or structure on which the motion mechanism is mounted. The panoramic X-ray machine also has a radiation source suspended from one end of the supporting structure at a position opposite the cassette holder. The object or patient to be radiographed is placed between the radiation source and the cassette holder and the supporting structure is rotated at a selected rotational speed about the object.

Abstract: N-Vinyl carbazoles are prepared by reacting an N-unsubstituted carbazole with a dihaloethane in the presence of a phase transfer catalyst followed by reaction with an aqueous solution containing a highly basic agent. These N-vinyl carbazoles are useful, singly or in combination with other materials, as electrical capacitors and insulators, in thermal foam insulators, as components in copolymers and in image-recording systems, and as photoconductive materials in electrophotography.

Abstract: A dental scaler is disclosed wherein an air-driven rotor is driven about a shaft to impart vibrations thereto and drive a work tool or other object attached to the shaft. The vibratory device includes means on the shaft for correcting displacement of the rotor from its drive position. That means comprises a portion of the shaft beneath the rotor means having an enlarged diameter such that movement of the rotor caused by shaft wear is corrected. Additional means may be associated with the rotor, e.g., chamfered end edges of the rotor, which minimize pressure differentials at the end of the rotor edges and consequently assist in centralization of the rotor about the outlet means on the shaft. The fluid outlet means comprises outlet ports in the shaft wall beneath the area of rotation of the rotor, the outlet ports having chamfered outside end edges to minimize power losses from turbulence. Additionally, means are provided along the shaft for selecting the vibrational mode in which the vibratory device operates.

Abstract: The invention at hand concerns a device for supporting the patient in panoramic X-ray radiography. The device has a certain head supporting equipment to support the patient's head in order to keep it in a fixed position during the X-ray radiography. The device also has equipment for placing the patient's head in the right position for radiography. These make it possible to move the X-ray machine in relation to the head supporting equipment, so that the patient's head can be placed in the appropriate position in relation to the X-ray machine.

Abstract: An air-driven dental scaler is disclosed having water transport means associated with the tool assembly for delivering water to a scaling type work tool. The water transport means comprises a tube disposed within a hollow connector body and extending between a water plenum at one end of the connector body to the other end of the connector body, whereat the scaling type work tool is attached. The water transport tube has an internal diameter of greater than 0.010 inch and a surface roughness smoother than 25 micro-inches to minimize clogging of the tube by mineral deposits or sediment. The independent fluid path permits the use of hard, martensitic stainless steels for the work tool and softer, corrosion-resisting austenitic stainless steels for the water transport tube. The water transport means delivers a controlled quantity of water to the work tool and the water is atomized by the vibratory movement of the tool.

Abstract: The method of making plastic lenses ready for fitting to the contour of the wearer's eye comprising supporting a blank of plastic at one end for rotation about a predetermined axis, turning the blank down to a predetermined diameter, making an annular face cut at the distal end of the blank of predetermined radial width, making a spherically concave base cut at said distal end of predetermined depth relative to said annular face cut, reversing the blank end-for-end, making a first spherically convex cut at said end of the blank of a predetermined radius such that the distance between the inner and outer surfaces is of a predetermined thickness and making a flange cut at the marginal edge of the outer convex surface of lesser radius of curvature; and apparatus for carrying out the method.

Abstract: An articulating headrest for a dental chair having a unidirectional locking means is described. The locking means comprises a locking plate engageable with a pivotable shaft connected to a headrest support means. The locking means is adapted to one-handed operation by an operator and permits unhindered forward rotational movement of the headrest about the support means in order to prevent accidental jamming of the headrest against an object during downward movement of the dental chair.

Abstract: A dental wrench is described having a structure which permits application of differing torques to the bur securing collet of a dental handpiece and the end cap of the turbine housing in a single wrench assembly. The wrench combines a shaft, for engaging the bur securing collet, supported rotatively in a frame member and secured to a support member which has means for engaging the end cap of the turbine housing. Interlocking means are provided between the support member and the frame member so that the wrench can be rotated as a unitary assembly to secure or remove the end cap of a turbine housing. The interlocking means are releaseable so that the shaft can be rotated independently within the frame member to secure or remove a dental bur in or from the collet of the handpiece housing.

Abstract: This process relates to the synthesis of unsaturated aliphatic esters useful as insect sex attractants, including gossyplure, the insect sex pheromone of the pink bollworm moth, Pectinophora gossypiella, and intermediates therefor. The process utilizes a cyclic phosphonium (Wittig) reagent.

Abstract: A powered dental scaler is disclosed of a type which drives a vibrating scaling tip in a circular or ellipsoidal pattern of motion. A scaling tip having working surfaces provided by the edges of an elongated, curved element which has a cross-sectional configuration in the shape of a multi-sided figure, e.g., a triangle or a diamond, is particularly useful with a scaler having this type of vibrational pattern. The scaler tip also has a curved free end portion terminating in a point. These configurations enable a dental operator to conduct important dental cleaning operations with a single hand-held instrument.

Abstract: A powered dental scaler is disclosed of a type which drives a vibrating scaling tip in a circular or ellipsoidal pattern of motion. A scaling tip having working surfaces provided by the edges of an elongated, curved element which has a cross-sectional configuration in the shape of a multi-sided figure, e.g., a triangle or a diamond, is particularly useful with a scaler having this type of vibrational pattern. Each of the longitudinal edges has a radius of curvature in the range of about 0.001 inch to about 0.005 inch. The free end of the scaler work tool preferably terminates in rounded or ball-shaped configurations, and the working surfaces can be joined along inactive edges by a convex surface to provide "safe" surfaces. The absence of sharp edges or points on the scaler tool work surfaces substantially reduces the likelihood of damage to tooth dentin, cementum or gums.

Abstract: A dental tool for generating a relatively smooth surface on tooth enamel comprises an elongated shank with an operative end and an end adapted to engage a chuck of a dental handpiece. Any cross-section of the operative end perpendicular to the shank's longitudinal axis is circular with a diameter of less than 0.140 inch. Adjacent, continuous annular grooves extend around the operative end, each groove being defined by a pair of inwardly sloping side surfaces intersecting with each other at least about 0.010 inch from the shank's longitudinal axis and forming an included angle of 60.degree. to 150.degree. between the side surfaces. An abrasive material, such as diamond grit, having a particle size of less than 0.006 inch covers at least a portion of each surface.

Abstract: The invention provides new hydrogel forming materials comprising synthetic, hydrophilic, aqueous-insoluble polymer networks formed by copolymerization of a hydrophilic dihydroxyalkyl acrylate or methacrylate, a substantially water insoluble alkyl acrylate or methacrylate, one or more additional hydrophilic comonomers selected from the group of vinylic monomers, acrylates, and methacrylates, and a cross-linking agent. The hydrogels are preferably used for the formation of contact lenses, but may also be used for drug and pesticides delivery devices; dialysis, ultrafiltration and reverse osmosis membranes; implants in surgery and dentistry; and the like.

Abstract: A single-unit turbine cartridge assembly for a gas-driven dental handpiece includes a pair of bearing assemblies mounted on a turbine rotor shaft and a ring of resilient material around each bearing assembly. The resilient ring provides radial support for the turbine cartridge assembly within the housing of the handpiece and substantially dampens the transfer of vibration from the cartridge assembly to the handpiece during use of the handpiece. The turbine cartridge assembly may optionally include bearing axial pre-load means in association with one or more of the bearing assemblies. The turbine cartridge assembly also includes means for retaining the resilient radial support means and the bearing axial preload means, when used, in association with the bearing assemblies, so as to permit removal, and reinstallation, of the cartridge assembly as an entire unit from, and to, the housing in the dental handpiece.

Abstract: The subject of the invention is a process for resolving mixtures of (+)- and (-)-6-methoxy-.alpha.-methyl-2-naphthaleneacetic acid into the enantiomers thereof, characterized in that N-methyl-D-glucamine [=1-deoxy-1-(methylamino)-D-glucitol] is used as the resolving agent, so that the 6-methoxy-.alpha.-methyl-2-naphthaleneacetic acid is converted into the corresponding diastereoisomeric N-methyl-D-glucamine salt pair which, because of very different solubilities, can be separated easily and completely with high yield.

Abstract: Mixtures of d 2-(6-methoxy-2-naphthyl)propionic acid and 1 2-(6-methoxy-2-naphthyl)propionic acid or soluble salts thereof are resolved with N-R-D-glucamine or salts thereof, where R is alkyl having 2 to 36 carbon atoms or cycloalkyl having 3 to 8 carbon atoms, to yield a product substantially enriched in d 2-(6-methoxy-2-naphthyl)-propionic acid.