摘要:
A mold for embedding histological specimens made of transparent plastic of the kind that is hardenable by irradiation, usually with light, consists of at least one flat-bottomed oval basin depressed with respect to a surrounding surface which, in turn, is externally bounded by a peripheral channel. The containing walls of the basin are outwardly inclined from the vertical. A separating layer covers the entire upper surfaces of the mold, including those of the peripheral channel, and consists of a synthetic resin, such as polyethylene, which does not bond with the resin of the embedding material and can be applied to the sheet of acrylic resin or polyvinyl chloride before the latter is pressed into the shape of the mold. The specimen embedded in the hardened embedding resin can be easily expelled from the mold even if the mold is made from another resin to which the separation layer might bond.
摘要:
A method for producing orthodontic devices and appliances having a highly accurate fit by building up a plurality of resin layers on a plaster cast comprising applying a first thin layer of a composition comprising a diurethanedimethacrylate prepared from 2,2,4-trimethylhexamethylenediisocyanate and 2-hydroxyethylmethacrylate, and a photopolymerization catalyst to the plaster cast and briefly exposing said thin layer to light whereby said thin layer is partially polymerized, successively applying at least one additional thin layer on said first thin layer and partially polymerizing each successive thin layer by brief exposure until the layer thickness and shape desired for the device or appliance are attained, and the shaped partially polymerized material is subsequently polymerized completely by exposure to light.
摘要:
The present invention provides prosthetic dental appliances which contain at least one outer surface portion which includes an outer surface of the appliance which is adapted to be polished and which is highly abrasion resistant. Said shaped body portion is a hardened matrix material containing amorphous silicic acid filler particles of a maximum particle size of about 0.07 micrometer. Preferably, at least 30% of the body portion comprises the filler particles. The polymeric matrix is preferably a hardened organic resin. The invention also includes the hardenable material comprising a hardenable matrix having filler paticles dispersed therein which is used to produce the hardened prosthetic dental appliances.
摘要:
TRIALKYL BORANES ARE PREVENTED FROM SPONTANEOUSLY IGNITING BY ADDING THERETO A STABILIZING AGENT COMPRISING AN ORGANIC COMPOUND OF DIVALENT SULFUR. THESE STABILIZED COMPOUNDS FIND UTILITY AS CATALYSTS.
摘要:
To improve coating of articles such as dental prostheses by flame hydrolysis, a zone of turbulence is generated at the tip portion of an elongated flame cone by a deflection surface (5, 5') located--with respect to flame projection--beyond holders for the articles and positioned to be impinged by the tip of the flame to be deflected and reflected thereby from the conical form, to cause the flame to swirl about the articles.
摘要:
Disclosed is a process for the photopolymerization of vinyl compounds and of photopolymerizable materials containing vinyl compounds and products produced thereby which are especially useful for dental materials. The process utilizes at least one photosensitizer of the formula ##STR1## wherein X is selected from the group consisting of CO, C(R.sup.1)(R.sup.2) and C(R.sup.3)(OR.sup.4); wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 are each selected from the group consisting of hydrogen and a hydrocarbon radical;n is 0 or 1; andA is selected from hydrocarbon radicals which may be substituted and which may be bonded together with the proviso that when n is 1 and X is C(R.sup.1)(R.sup.2), and when n is 0, A is an aromatic radical; andat least one reducing agent of formula (I) or (II) ##STR2## wherein Y is selected from oxygen, sulfur or the group NR.sup.1 where R.sup.1 is a hydrogen atom or an alkyl group having 1-10 carbon atoms, preferably 1-5 carbon atoms;Z is an alkylene group having 2 or 3 carbon atoms where one carbon atom can be substituted with one of the heteroatoms O and S or 2 carbon atoms with the heteroatoms O, S and/or N; andR is a substituted or unsubstituted alkyl group having 1-10 carbon atoms, preferably 1-5 carbon atoms or a substituted or unsubstituted aryl group, preferably a phenyl group, ##STR3## wherein R.sup.5 is selected from the group consisting of alkyl, substituted alkyl, aryl, substituted aryl, aralkyl and substituted aralkyl.
摘要:
A dental opaquing composition comprising (a) at least one polymerizable ester selected from esters of acrylic acid and methacrylic acid; (b) a photopolymerization catalyst; and (c) 30 to 90 percent by weight, based on the weight of said composition, of a pigment mixture consisting essentially of 50 to 66.6% by weight zirconium dioxide and 33.33 to 50% by weight of titanium dioxide. The present composition is useful in the making of metal-based crowns and bridges and to coat natural and false teeth.
摘要:
A dental composition which when used together with a photopolymerizable dental sealing composition promotes adhesion of resin-based dental restorative materials to the tooth consisting of a solution of tetramethacryloyloxyethyl pyrophosphate and a photopolymerization catalyst comprising camphor quinone and an amine in acetone.
摘要:
To apply a silicon oxide adhesion-promoting layer to a metal prosthesis part or frame, for subsequent application of a dental plastic thereon, the prosthesis is subjected to flame hydrolysis derived from a flame hydrolysis burner (11) which has a silicon compound in vapor or gas form applied thereto in addition to a carbon-containing combustion gas, such as propane and air, the prosthesis part or frame being passed through the flame from the burner in the forward third thereof, the burner flame cone having, in operation, a length (L) of between 15 to 20 cm, a gas stream speed of about 1 m/sec., and wherein the length (L) of the cone exceeds the spacing distance (D) of the farthest part of the prosthesis from the mouth of the burner by only up to about 25%. For fine adjustment of the cone, a tinting substance can be added to the flame.
摘要:
A color scale palette has color sample rods tinted all along their lengths from a stem in a frame to the other end projecting from the frame. The frame has a window for exposing a portion of the color sample rods and, for example, a color key, and studs cooperative with a bore through the stem end of each color sample rod for snapping it into the frame. The bore is preferably a funnel-shaped for shadow-free as well as juxtaposed color comparisons.